[PATCH 00/25] xen: Xen implementation for paravirt_ops

[PATCH 00/25] xen: Xen implementation for paravirt_ops

[Jeremy Fitzhardinge]

Hi Andi,

This series of patches implements the Xen paravirt-ops interface.
It applies to 2.6.21-rc7 + your patches + the last batch of pv_ops
patches I posted.

This patch generally restricts itself to Xen-specific parts of the tree,
though it does make a few small changes elsewhere.

These patches include:
 - some helper routines for allocating address space and walking pagetables
 - Xen interface header files
 - Core Xen implementation
 - Efficient late-pinning/early-unpinning pagetable handling
 - Virtualized time, including stolen time
 - SMP support
 - Preemption support
 - Batched pagetable updates
 - Xen console, based on hvc console
 - Xenbus
 - Netfront, the paravirtualized network device
 - Blockfront, the paravirtualized block device

Thanks,
	J
-- 

[PATCH 01/25] xen: Add apply_to_page_range() which applies a function to a pte range.

[Jeremy Fitzhardinge]

[-- Attachment #1: apply-to-page-range.patch --]
[-- Type: text/plain, Size: 4252 bytes --]

Add a new mm function apply_to_page_range() which applies a given
function to every pte in a given virtual address range in a given mm
structure. This is a generic alternative to cut-and-pasting the Linux
idiomatic pagetable walking code in every place that a sequence of
PTEs must be accessed.

Although this interface is intended to be useful in a wide range of
situations, it is currently used specifically by several Xen
subsystems, for example: to ensure that pagetables have been allocated
for a virtual address range, and to construct batched special
pagetable update requests to map I/O memory (in ioremap()).

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Matt Mackall <mpm@waste.org>
Acked-by: Ingo Molnar <mingo@elte.hu> 

---
 include/linux/mm.h |    5 ++
 mm/memory.c        |   94 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+)

===================================================================
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1135,6 +1135,11 @@ struct page *follow_page(struct vm_area_
 #define FOLL_GET	0x04	/* do get_page on page */
 #define FOLL_ANON	0x08	/* give ZERO_PAGE if no pgtable */
 
+typedef int (*pte_fn_t)(pte_t *pte, struct page *pmd_page, unsigned long addr,
+			void *data);
+extern int apply_to_page_range(struct mm_struct *mm, unsigned long address,
+			       unsigned long size, pte_fn_t fn, void *data);
+
 #ifdef CONFIG_PROC_FS
 void vm_stat_account(struct mm_struct *, unsigned long, struct file *, long);
 #else
===================================================================
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1448,6 +1448,100 @@ int remap_pfn_range(struct vm_area_struc
 }
 EXPORT_SYMBOL(remap_pfn_range);
 
+static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
+				     unsigned long addr, unsigned long end,
+				     pte_fn_t fn, void *data)
+{
+	pte_t *pte;
+	int err;
+	struct page *pmd_page;
+	spinlock_t *ptl;
+
+	pte = (mm == &init_mm) ?
+		pte_alloc_kernel(pmd, addr) :
+		pte_alloc_map_lock(mm, pmd, addr, &ptl);
+	if (!pte)
+		return -ENOMEM;
+
+	BUG_ON(pmd_huge(*pmd));
+
+	pmd_page = pmd_page(*pmd);
+
+	do {
+		err = fn(pte, pmd_page, addr, data);
+		if (err)
+			break;
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+
+	if (mm != &init_mm)
+		pte_unmap_unlock(pte-1, ptl);
+	return err;
+}
+
+static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
+				     unsigned long addr, unsigned long end,
+				     pte_fn_t fn, void *data)
+{
+	pmd_t *pmd;
+	unsigned long next;
+	int err;
+
+	pmd = pmd_alloc(mm, pud, addr);
+	if (!pmd)
+		return -ENOMEM;
+	do {
+		next = pmd_addr_end(addr, end);
+		err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
+		if (err)
+			break;
+	} while (pmd++, addr = next, addr != end);
+	return err;
+}
+
+static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
+				     unsigned long addr, unsigned long end,
+				     pte_fn_t fn, void *data)
+{
+	pud_t *pud;
+	unsigned long next;
+	int err;
+
+	pud = pud_alloc(mm, pgd, addr);
+	if (!pud)
+		return -ENOMEM;
+	do {
+		next = pud_addr_end(addr, end);
+		err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
+		if (err)
+			break;
+	} while (pud++, addr = next, addr != end);
+	return err;
+}
+
+/*
+ * Scan a region of virtual memory, filling in page tables as necessary
+ * and calling a provided function on each leaf page table.
+ */
+int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
+			unsigned long size, pte_fn_t fn, void *data)
+{
+	pgd_t *pgd;
+	unsigned long next;
+	unsigned long end = addr + size;
+	int err;
+
+	BUG_ON(addr >= end);
+	pgd = pgd_offset(mm, addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
+		if (err)
+			break;
+	} while (pgd++, addr = next, addr != end);
+	return err;
+}
+EXPORT_SYMBOL_GPL(apply_to_page_range);
+
 /*
  * handle_pte_fault chooses page fault handler according to an entry
  * which was read non-atomically.  Before making any commitment, on

-- 

[PATCH 02/25] xen: Allocate and free vmalloc areas

[Jeremy Fitzhardinge]

[-- Attachment #1: alloc-vm-area.patch --]
[-- Type: text/plain, Size: 2664 bytes --]

Allocate/destroy a 'vmalloc' VM area: alloc_vm_area and free_vm_area
The alloc function ensures that page tables are constructed for the
region of kernel virtual address space and mapped into init_mm.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: "Jan Beulich" <JBeulich@novell.com>
Cc: "Andi Kleen" <ak@muc.de>

---
 include/linux/vmalloc.h |    4 +++
 mm/vmalloc.c            |   51 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

===================================================================
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -68,6 +68,10 @@ extern int map_vm_area(struct vm_struct 
 			struct page ***pages);
 extern void unmap_vm_area(struct vm_struct *area);
 
+/* Allocate/destroy a 'vmalloc' VM area. */
+extern struct vm_struct *alloc_vm_area(unsigned long size);
+extern void free_vm_area(struct vm_struct *area);
+
 /*
  *	Internals.  Dont't use..
  */
===================================================================
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -757,3 +757,54 @@ out_einval_locked:
 }
 EXPORT_SYMBOL(remap_vmalloc_range);
 
+static int f(pte_t *pte, struct page *pmd_page, unsigned long addr, void *data)
+{
+	/* apply_to_page_range() does all the hard work. */
+	return 0;
+}
+
+/**
+ *	alloc_vm_area - allocate a range of kernel address space
+ *	@size:		size of the area
+ *	@returns:	NULL on failure, vm_struct on success
+ *
+ *	This function reserves a range of kernel address space, and
+ *	allocates pagetables to map that range.  No actual mappings
+ *	are created.  If the kernel address space is not shared
+ *	between processes, it syncs the pagetable across all
+ *	processes.
+ */
+struct vm_struct *alloc_vm_area(unsigned long size)
+{
+	struct vm_struct *area;
+
+	area = get_vm_area(size, VM_IOREMAP);
+	if (area == NULL)
+		return NULL;
+
+	/*
+	 * This ensures that page tables are constructed for this region
+	 * of kernel virtual address space and mapped into init_mm.
+	 */
+	if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
+				area->size, f, NULL)) {
+		free_vm_area(area);
+		return NULL;
+	}
+
+	/* Make sure the pagetables are constructed in process kernel
+	   mappings */
+	vmalloc_sync_all();
+
+	return area;
+}
+EXPORT_SYMBOL_GPL(alloc_vm_area);
+
+void free_vm_area(struct vm_struct *area)
+{
+	struct vm_struct *ret;
+	ret = remove_vm_area(area->addr);
+	BUG_ON(ret != area);
+	kfree(area);
+}
+EXPORT_SYMBOL_GPL(free_vm_area);

-- 

[PATCH 03/25] xen: Add nosegneg capability to the vsyscall page notes

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-vsyscall-note.patch --]
[-- Type: text/plain, Size: 2250 bytes --]

Add the "nosegneg" fake capabilty to the vsyscall page notes. This is
used by the runtime linker to select a glibc version which then
disables negative-offset accesses to the thread-local segment via
%gs. These accesses require emulation in Xen (because segments are
truncated to protect the hypervisor address space) and avoiding them
provides a measurable performance boost.

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Acked-by: Zachary Amsden <zach@vmware.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ulrich Drepper <drepper@redhat.com>

---
 arch/i386/kernel/vsyscall-note.S |   28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

===================================================================
--- a/arch/i386/kernel/vsyscall-note.S
+++ b/arch/i386/kernel/vsyscall-note.S
@@ -23,3 +24,31 @@ 3:	.balign 4;		/* pad out section */			 
 	ASM_ELF_NOTE_BEGIN(".note.kernel-version", "a", UTS_SYSNAME, 0)
 	.long LINUX_VERSION_CODE
 	ASM_ELF_NOTE_END
+
+#ifdef CONFIG_XEN
+/*
+ * Add a special note telling glibc's dynamic linker a fake hardware
+ * flavor that it will use to choose the search path for libraries in the
+ * same way it uses real hardware capabilities like "mmx".
+ * We supply "nosegneg" as the fake capability, to indicate that we
+ * do not like negative offsets in instructions using segment overrides,
+ * since we implement those inefficiently.  This makes it possible to
+ * install libraries optimized to avoid those access patterns in someplace
+ * like /lib/i686/tls/nosegneg.  Note that an /etc/ld.so.conf.d/file
+ * corresponding to the bits here is needed to make ldconfig work right.
+ * It should contain:
+ *	hwcap 0 nosegneg
+ * to match the mapping of bit to name that we give here.
+ */
+#define NOTE_KERNELCAP_BEGIN(ncaps, mask) \
+	ASM_ELF_NOTE_BEGIN(".note.kernelcap", "a", "GNU", 2) \
+	.long ncaps, mask
+#define NOTE_KERNELCAP(bit, name) \
+	.byte bit; .asciz name
+#define NOTE_KERNELCAP_END ASM_ELF_NOTE_END
+
+NOTE_KERNELCAP_BEGIN(1, 2)
+NOTE_KERNELCAP(1, "nosegneg")
+NOTE_KERNELCAP_END
+#endif
+

-- 

Re: [PATCH 03/25] xen: Add nosegneg capability to the vsyscall page notes

[Roland McGrath]

> + * It should contain:
> + *	hwcap 0 nosegneg
> + * to match the mapping of bit to name that we give here.

This needs to be "hwcap 0 nosegneg" to match:

> +NOTE_KERNELCAP_BEGIN(1, 2)
> +NOTE_KERNELCAP(1, "nosegneg")
> +NOTE_KERNELCAP_END

The actual bits you are using should be fine.  (You're intentionally
skipping bit 0 to work around hold glibc bugs, which you might want to add
to the comments.  Also a comment or perhaps using 1<<1 syntax would make it
more clear that "2" is the bit mask containing bit 1 and that's why it has
to be 2, and not because of some other magical property of 2.)  But if
kernel packagers don't write the matching bit number in their ld.so.conf.d
files, then ld.so.cache lookups won't work right.


Thanks,
Roland

Re: [PATCH 03/25] xen: Add nosegneg capability to the vsyscall page notes

[Jeremy Fitzhardinge]

Roland McGrath wrote:
>> + * It should contain:
>> + *	hwcap 0 nosegneg
>> + * to match the mapping of bit to name that we give here.
>>     
>
> This needs to be "hwcap 0 nosegneg" to match:
>
>   
>> +NOTE_KERNELCAP_BEGIN(1, 2)
>> +NOTE_KERNELCAP(1, "nosegneg")
>> +NOTE_KERNELCAP_END
>>     
>
> The actual bits you are using should be fine.  (You're intentionally
> skipping bit 0 to work around hold glibc bugs, which you might want to add
> to the comments.  Also a comment or perhaps using 1<<1 syntax would make it
> more clear that "2" is the bit mask containing bit 1 and that's why it has
> to be 2, and not because of some other magical property of 2.)  But if
> kernel packagers don't write the matching bit number in their ld.so.conf.d
> files, then ld.so.cache lookups won't work right.

I have to admit I still don't really understand all this.  Is it
documented somewhere?

What does "hwcap 0 nosegneg" actually mean?  What does the "0" mean here?

In the ELF note, what does the "nosegneg" string mean?  How is it used? 
Is it compared to the "nosegneg" in ld.so.conf?  How does this relate to
the bitfields?

Thanks,
    J

Re: [PATCH 03/25] xen: Add nosegneg capability to the vsyscall page notes

[Roland McGrath]

> I have to admit I still don't really understand all this.  Is it
> documented somewhere?

I have explained it in public more than once, but I don't know off hand
anywhere that was helpfully recorded.

> What does "hwcap 0 nosegneg" actually mean?  What does the "0" mean here?

ldconfig is usually run at library install time.  It reads ld.so.conf (and
its include files, usually found in /etc/ld.so.conf.d/*.conf).  ldconfig
finds libraries on the disk and stores their names in ld.so.cache.  For
libraries in "hwcap directories", it records in ld.so.cache a bitmask of
hwcap bits for each library, based on which hwcap names appeared in the
library file name.  The hard-wired hwcap names are things such as "mmx" and
"sse2", a chosen subset of the AT_HWCAP bits the kernel provides.  

When the dynamic linker is finding a library at runtime, it uses a match
from ld.so.cache unless none was found or LD_LIBRARY_PATH was set.  When
there is no cache hit, it searches a directory path for the library's name.
The subset of hwcap names whose AT_HWCAP bits are set yields a list of
subdirectories to try under each directory in the path.  To see the list:

$ LD_LIBRARY_PATH=/lib:/usr/lib LD_DEBUG=libs /bin/true
     21491:     find library=libc.so.6 [0]; searching
     21491:      search path=/lib/tls/i686/sse2:/lib/tls/i686:/lib/tls/sse2:/lib/tls:/lib/i686/sse2:/lib/i686:/lib/sse2:/lib:/usr/lib/tls/i686/sse2:/usr/lib/tls/i686:/usr/lib/tls/sse2:/usr/lib/tls:/usr/lib/i686/sse2:/usr/lib/i686:/usr/lib/sse2:/usr/lib            (system search path)

(Here you can notice that "tls" is used as a pseudo-hwcap; it is in fact
hard-wired into the list if the dynamic linker supports ELF TLS, which all
recent ones do.  Also you'll notice "i686" is not a hwcap bit, but is the
AT_PLATFORM string, which is treated similarly.)

The hwcap bitmasks in ld.so.cache are intended to make the single cache
file equivalent to this varying search path depending on runtime hwcap bits
set.  A cache entry whose bitmask has bits not set at runtime is ignored.
Running "ldconfig -p | grep hwcap" (read-only, need not be root) will show
you any entries in your ld.so.cache that have an hwcap bitmask set.

The "hwcap" directive in ld.so.conf tells ldconfig to understand a new
hwcap name that is not in the hard-wired set.  There is some number of
extra bits available; "hwcap 0" assigns the first extra bit, "hwcap 1" the
second, and so on.  The name is what to use as a subdirectory name,
analogous to "sse2" et al.

On my system with an ld.so.conf.d file installed doing "hwcap 0 nosegneg":

$ ldconfig -p | grep libc.so.6
        libc.so.6 (libc6, hwcap: 0x0018000000000000, OS ABI: Linux 2.6.9) => /lib/i686/nosegneg/libc.so.6
        libc.so.6 (libc6, OS ABI: Linux 2.6.9) => /lib/libc.so.6

(There are two bits set because the "tls" pseudo-bit is also set.)

With this in ld.so.cache, the libc.so.6 lookup will find
/lib/i686/nosegneg/libc.so.6 first, but only if the hwcap bit set.

> In the ELF note, what does the "nosegneg" string mean?  How is it used? 
> Is it compared to the "nosegneg" in ld.so.conf?  How does this relate to
> the bitfields?

Each bit + string element in the note (there's just the one in what we
have) establishes for the dynamic linker at runtime the association between
the "extra" pseudo-hwcap bit number and the name.  If that pseudo-hwcap is
enabled, then that string will figure into the directory search path as
"sse2" does in the example above.  This string is never consulted when
looking in ld.so.cache.

The mask field in NOTE_KERNELCAP_BEGIN says which "extra" bits are enabled.
If the corresponding bit is not set here, then it's just like a hard-wired
hwcap bit like "sse2" when that bit was not set in AT_HWCAP.  That is, a
cache lookup will ignore entries with that hwcap bit in their bitmask, and
that hwcap name will not be used in constructing the directory search path.
I put this bitmask in so that the kernel has the option of using a single
vDSO image for multiple different runtime configurations.  It can simply
modify the bitmask in the image at setup time to disable some entries.

For example, a Xen-enabled kernel can use a single vDSO image (or a single
pair of int80/sysenter images), containing the "nosegneg" hwcap note.  When
there is no need for it (native or hvm or 64-bit hv or whatever), it just
clears the mask word.  If you actually do this, you'll want to modify the
NOTE_KERNELCAP_BEGIN macro to define a global label you can use with VDSO_SYM.



Thanks,
Roland

Re: [PATCH 03/25] xen: Add nosegneg capability to the vsyscall page notes

[Jeremy Fitzhardinge]

Roland McGrath wrote:
>> I have to admit I still don't really understand all this.  Is it
>> documented somewhere?
>>     
>
> I have explained it in public more than once, but I don't know off hand
> anywhere that was helpfully recorded.
>   

Thanks very much.  I'd been poking about, but the closest I came to an
actual description was various patches fixing bugs, so it was a little
incomplete.

> For example, a Xen-enabled kernel can use a single vDSO image (or a single
> pair of int80/sysenter images), containing the "nosegneg" hwcap note.  When
> there is no need for it (native or hvm or 64-bit hv or whatever), it just
> clears the mask word.  If you actually do this, you'll want to modify the
> NOTE_KERNELCAP_BEGIN macro to define a global label you can use with VDSO_SYM.
>   

Thanks for the pointer.  I'd been getting a bit of heat for enabling the
nonegseg flag unconditionally.  If I can make Xen-specific then that
will be one less source of complaints.

    J

[PATCH 04/25] xen: Add XEN config options

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-config.patch --]
[-- Type: text/plain, Size: 1379 bytes --]

The XEN config option enables the Xen paravirt_ops interface, which is
installed when the kernel finds itself running under Xen.

Xen is no longer a sub-architecture, so the X86_XEN subarch config
option has gone.

Xen is currently incompatible with PREEMPT, but this is fixed up later
in the series.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

---
 arch/i386/Kconfig     |    2 ++
 arch/i386/xen/Kconfig |   10 ++++++++++
 2 files changed, 12 insertions(+)

===================================================================
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -216,6 +216,8 @@ config PARAVIRT
 	  under a hypervisor, improving performance significantly.
 	  However, when run without a hypervisor the kernel is
 	  theoretically slower.  If in doubt, say N.
+
+source "arch/i386/xen/Kconfig"
 
 config VMI
 	bool "VMI Paravirt-ops support"
===================================================================
--- /dev/null
+++ b/arch/i386/xen/Kconfig
@@ -0,0 +1,10 @@
+#
+# This Kconfig describes xen options
+#
+
+config XEN
+	bool "Enable support for Xen hypervisor"
+	depends on PARAVIRT && HZ_100 && !PREEMPT && !NO_HZ
+	default y
+	help
+	  This is the Linux Xen port.

-- 

Re: [PATCH 04/25] xen: Add XEN config options

[Andi Kleen]

On Monday 23 April 2007 23:56:42 Jeremy Fitzhardinge wrote:
> The XEN config option enables the Xen paravirt_ops interface, which is
> installed when the kernel finds itself running under Xen.
> 
> Xen is no longer a sub-architecture, so the X86_XEN subarch config
> option has gone.
> 
> Xen is currently incompatible with PREEMPT, but this is fixed up later
> in the series.

Shouldn't this be after the change that adds arch/i386/xen/Kconfig?

Otherwise you break bisects

-Andi

Re: [PATCH 04/25] xen: Add XEN config options

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> On Monday 23 April 2007 23:56:42 Jeremy Fitzhardinge wrote:
>   
>> The XEN config option enables the Xen paravirt_ops interface, which is
>> installed when the kernel finds itself running under Xen.
>>
>> Xen is no longer a sub-architecture, so the X86_XEN subarch config
>> option has gone.
>>
>> Xen is currently incompatible with PREEMPT, but this is fixed up later
>> in the series.
>>     
>
> Shouldn't this be after the change that adds arch/i386/xen/Kconfig?
>
> Otherwise you break bisects
>   

It should be OK.  The series should build and run at each patch (though
I have to admit I haven't tested this).  In general I've been adding
config options for each feature as the feature itself is added.

    J

Re: [PATCH 04/25] xen: Add XEN config options

[Andi Kleen]

> > Shouldn't this be after the change that adds arch/i386/xen/Kconfig?
> >
> > Otherwise you break bisects
> >   
> 
> It should be OK.  The series should build and run at each patch (though
> I have to admit I haven't tested this).  In general I've been adding
> config options for each feature as the feature itself is added.

But i don't see anything that creates arch/i386/xen before this?

-Andi

[PATCH 05/25] xen: Add Xen interface header files

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-interface.patch --]
[-- Type: text/plain, Size: 108568 bytes --]

Add Xen interface header files. These are taken fairly directly from
the Xen tree, but somewhat rearranged to suit the kernel's conventions.

Define macros and inline functions for doing hypercalls into the
hypervisor.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>


---
 include/asm-i386/xen/hypercall.h      |  413 ++++++++++++++++++++++++++++++
 include/asm-i386/xen/hypervisor.h     |   72 +++++
 include/asm-i386/xen/interface.h      |  187 +++++++++++++
 include/xen/interface/elfnote.h       |  133 +++++++++
 include/xen/interface/event_channel.h |  195 ++++++++++++++
 include/xen/interface/features.h      |   43 +++
 include/xen/interface/grant_table.h   |  301 ++++++++++++++++++++++
 include/xen/interface/io/blkif.h      |   96 +++++++
 include/xen/interface/io/console.h    |   23 +
 include/xen/interface/io/netif.h      |  152 +++++++++++
 include/xen/interface/io/ring.h       |  260 +++++++++++++++++++
 include/xen/interface/io/xenbus.h     |   42 +++
 include/xen/interface/io/xs_wire.h    |   87 ++++++
 include/xen/interface/memory.h        |  145 ++++++++++
 include/xen/interface/physdev.h       |   61 ++++
 include/xen/interface/sched.h         |   77 +++++
 include/xen/interface/vcpu.h          |  164 ++++++++++++
 include/xen/interface/version.h       |   60 ++++
 include/xen/interface/xen.h           |  446 +++++++++++++++++++++++++++++++++
 19 files changed, 2957 insertions(+)

===================================================================
--- /dev/null
+++ b/include/asm-i386/xen/hypercall.h
@@ -0,0 +1,413 @@
+/******************************************************************************
+ * hypercall.h
+ *
+ * Linux-specific hypervisor handling.
+ *
+ * Copyright (c) 2002-2004, K A Fraser
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __HYPERCALL_H__
+#define __HYPERCALL_H__
+
+#include <linux/errno.h>
+#include <linux/string.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/sched.h>
+#include <xen/interface/physdev.h>
+
+extern struct { char _entry[32]; } hypercall_page[];
+
+#define _hypercall0(type, name)						\
+({									\
+	long __res;							\
+	asm volatile (							\
+		"call %[call]"						\
+		: "=a" (__res)						\
+		: [call] "m" (hypercall_page[__HYPERVISOR_##name])	\
+		: "memory" );						\
+	(type)__res;							\
+})
+
+#define _hypercall1(type, name, a1)					\
+({									\
+	long __res, __ign1;						\
+	asm volatile (							\
+		"call %[call]"						\
+		: "=a" (__res), "=b" (__ign1)				\
+		: "1" ((long)(a1)),					\
+		  [call] "m" (hypercall_page[__HYPERVISOR_##name])	\
+		: "memory" );						\
+	(type)__res;							\
+})
+
+#define _hypercall2(type, name, a1, a2)					\
+({									\
+	long __res, __ign1, __ign2;					\
+	asm volatile (							\
+		"call %[call]"						\
+		: "=a" (__res), "=b" (__ign1), "=c" (__ign2)		\
+		: "1" ((long)(a1)), "2" ((long)(a2)),			\
+		  [call] "m" (hypercall_page[__HYPERVISOR_##name])	\
+		: "memory" );						\
+	(type)__res;							\
+})
+
+#define _hypercall3(type, name, a1, a2, a3)				\
+({									\
+	long __res, __ign1, __ign2, __ign3;				\
+	asm volatile (							\
+		"call %[call]"						\
+		: "=a" (__res), "=b" (__ign1), "=c" (__ign2),		\
+		"=d" (__ign3)						\
+		: "1" ((long)(a1)), "2" ((long)(a2)),			\
+		  "3" ((long)(a3)),					\
+		  [call] "m" (hypercall_page[__HYPERVISOR_##name])	\
+		: "memory" );						\
+	(type)__res;							\
+})
+
+#define _hypercall4(type, name, a1, a2, a3, a4)				\
+({									\
+	long __res, __ign1, __ign2, __ign3, __ign4;			\
+	asm volatile (							\
+		"call %[call]"						\
+		: "=a" (__res), "=b" (__ign1), "=c" (__ign2),		\
+		"=d" (__ign3), "=S" (__ign4)				\
+		: "1" ((long)(a1)), "2" ((long)(a2)),			\
+		  "3" ((long)(a3)), "4" ((long)(a4)),			\
+		  [call] "m" (hypercall_page[__HYPERVISOR_##name])	\
+		: "memory" );						\
+	(type)__res;							\
+})
+
+#define _hypercall5(type, name, a1, a2, a3, a4, a5)			\
+({									\
+	long __res, __ign1, __ign2, __ign3, __ign4, __ign5;		\
+	asm volatile (							\
+		"call %[call]"						\
+		: "=a" (__res), "=b" (__ign1), "=c" (__ign2),		\
+		"=d" (__ign3), "=S" (__ign4), "=D" (__ign5)		\
+		: "1" ((long)(a1)), "2" ((long)(a2)),			\
+		  "3" ((long)(a3)), "4" ((long)(a4)),			\
+		  "5" ((long)(a5)),					\
+		  [call] "m" (hypercall_page[__HYPERVISOR_##name])	\
+		: "memory" );						\
+	(type)__res;							\
+})
+
+static inline int
+HYPERVISOR_set_trap_table(
+	struct trap_info *table)
+{
+	return _hypercall1(int, set_trap_table, table);
+}
+
+static inline int
+HYPERVISOR_mmu_update(
+	struct mmu_update *req, int count, int *success_count, domid_t domid)
+{
+	return _hypercall4(int, mmu_update, req, count, success_count, domid);
+}
+
+static inline int
+HYPERVISOR_mmuext_op(
+	struct mmuext_op *op, int count, int *success_count, domid_t domid)
+{
+	return _hypercall4(int, mmuext_op, op, count, success_count, domid);
+}
+
+static inline int
+HYPERVISOR_set_gdt(
+	unsigned long *frame_list, int entries)
+{
+	return _hypercall2(int, set_gdt, frame_list, entries);
+}
+
+static inline int
+HYPERVISOR_stack_switch(
+	unsigned long ss, unsigned long esp)
+{
+	return _hypercall2(int, stack_switch, ss, esp);
+}
+
+static inline int
+HYPERVISOR_set_callbacks(
+	unsigned long event_selector, unsigned long event_address,
+	unsigned long failsafe_selector, unsigned long failsafe_address)
+{
+	return _hypercall4(int, set_callbacks,
+			   event_selector, event_address,
+			   failsafe_selector, failsafe_address);
+}
+
+static inline int
+HYPERVISOR_fpu_taskswitch(
+	int set)
+{
+	return _hypercall1(int, fpu_taskswitch, set);
+}
+
+static inline int
+HYPERVISOR_sched_op(
+	int cmd, unsigned long arg)
+{
+	return _hypercall2(int, sched_op, cmd, arg);
+}
+
+static inline long
+HYPERVISOR_set_timer_op(
+	u64 timeout)
+{
+	unsigned long timeout_hi = (unsigned long)(timeout>>32);
+	unsigned long timeout_lo = (unsigned long)timeout;
+	return _hypercall2(long, set_timer_op, timeout_lo, timeout_hi);
+}
+
+static inline int
+HYPERVISOR_set_debugreg(
+	int reg, unsigned long value)
+{
+	return _hypercall2(int, set_debugreg, reg, value);
+}
+
+static inline unsigned long
+HYPERVISOR_get_debugreg(
+	int reg)
+{
+	return _hypercall1(unsigned long, get_debugreg, reg);
+}
+
+static inline int
+HYPERVISOR_update_descriptor(
+	u64 ma, u64 desc)
+{
+	return _hypercall4(int, update_descriptor, ma, ma>>32, desc, desc>>32);
+}
+
+static inline int
+HYPERVISOR_memory_op(
+	unsigned int cmd, void *arg)
+{
+	return _hypercall2(int, memory_op, cmd, arg);
+}
+
+static inline int
+HYPERVISOR_multicall(
+	void *call_list, int nr_calls)
+{
+	return _hypercall2(int, multicall, call_list, nr_calls);
+}
+
+static inline int
+HYPERVISOR_update_va_mapping(
+	unsigned long va, pte_t new_val, unsigned long flags)
+{
+	unsigned long pte_hi = 0;
+#ifdef CONFIG_X86_PAE
+	pte_hi = new_val.pte_high;
+#endif
+	return _hypercall4(int, update_va_mapping, va,
+			   new_val.pte_low, pte_hi, flags);
+}
+
+static inline int
+HYPERVISOR_event_channel_op(
+        int cmd, void *arg)
+{
+        int rc = _hypercall2(int, event_channel_op, cmd, arg);
+        if (unlikely(rc == -ENOSYS)) {
+                struct evtchn_op op;
+                op.cmd = cmd;
+                memcpy(&op.u, arg, sizeof(op.u));
+                rc = _hypercall1(int, event_channel_op_compat, &op);
+                memcpy(arg, &op.u, sizeof(op.u));
+        }
+        return rc;
+}
+
+static inline int
+HYPERVISOR_xen_version(
+	int cmd, void *arg)
+{
+	return _hypercall2(int, xen_version, cmd, arg);
+}
+
+static inline int
+HYPERVISOR_console_io(
+	int cmd, int count, char *str)
+{
+	return _hypercall3(int, console_io, cmd, count, str);
+}
+
+static inline int
+HYPERVISOR_physdev_op(int cmd, void *arg)
+{
+	int rc = _hypercall2(int, physdev_op, cmd, arg);
+	if (unlikely(rc == -ENOSYS)) {
+		struct physdev_op op;
+		op.cmd = cmd;
+		memcpy(&op.u, arg, sizeof(op.u));
+		rc = _hypercall1(int, physdev_op_compat, &op);
+		memcpy(arg, &op.u, sizeof(op.u));
+	}
+	return rc;
+}
+
+static inline int
+HYPERVISOR_grant_table_op(
+	unsigned int cmd, void *uop, unsigned int count)
+{
+	return _hypercall3(int, grant_table_op, cmd, uop, count);
+}
+
+static inline int
+HYPERVISOR_update_va_mapping_otherdomain(
+	unsigned long va, pte_t new_val, unsigned long flags, domid_t domid)
+{
+	unsigned long pte_hi = 0;
+#ifdef CONFIG_X86_PAE
+	pte_hi = new_val.pte_high;
+#endif
+	return _hypercall5(int, update_va_mapping_otherdomain, va,
+			   new_val.pte_low, pte_hi, flags, domid);
+}
+
+static inline int
+HYPERVISOR_vm_assist(
+	unsigned int cmd, unsigned int type)
+{
+	return _hypercall2(int, vm_assist, cmd, type);
+}
+
+static inline int
+HYPERVISOR_vcpu_op(
+	int cmd, int vcpuid, void *extra_args)
+{
+	return _hypercall3(int, vcpu_op, cmd, vcpuid, extra_args);
+}
+
+static inline int
+HYPERVISOR_suspend(
+	unsigned long srec)
+{
+	return _hypercall3(int, sched_op, SCHEDOP_shutdown,
+			   SHUTDOWN_suspend, srec);
+}
+
+static inline int
+HYPERVISOR_nmi_op(
+	unsigned long op,
+	unsigned long arg)
+{
+	return _hypercall2(int, nmi_op, op, arg);
+}
+
+static inline void
+MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,
+			pte_t new_val, unsigned long flags)
+{
+	mcl->op = __HYPERVISOR_update_va_mapping;
+	mcl->args[0] = va;
+#ifdef CONFIG_X86_PAE
+	mcl->args[1] = new_val.pte_low;
+	mcl->args[2] = new_val.pte_high;
+#else
+	mcl->args[1] = new_val.pte_low;
+	mcl->args[2] = 0;
+#endif
+	mcl->args[3] = flags;
+}
+
+static inline void
+MULTI_grant_table_op(struct multicall_entry *mcl, unsigned int cmd,
+		     void *uop, unsigned int count)
+{
+	mcl->op = __HYPERVISOR_grant_table_op;
+	mcl->args[0] = cmd;
+	mcl->args[1] = (unsigned long)uop;
+	mcl->args[2] = count;
+}
+
+static inline void
+MULTI_update_va_mapping_otherdomain(struct multicall_entry *mcl, unsigned long va,
+				    pte_t new_val, unsigned long flags, domid_t domid)
+{
+	mcl->op = __HYPERVISOR_update_va_mapping_otherdomain;
+	mcl->args[0] = va;
+#ifdef CONFIG_X86_PAE
+	mcl->args[1] = new_val.pte_low;
+	mcl->args[2] = new_val.pte_high;
+#else
+	mcl->args[1] = new_val.pte_low;
+	mcl->args[2] = 0;
+#endif
+	mcl->args[3] = flags;
+	mcl->args[4] = domid;
+}
+
+static inline void
+MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
+			struct desc_struct desc)
+{
+	mcl->op = __HYPERVISOR_update_descriptor;
+	mcl->args[0] = maddr;
+	mcl->args[1] = maddr >> 32;
+	mcl->args[2] = desc.a;
+	mcl->args[3] = desc.b;
+}
+
+static inline void
+MULTI_memory_op(struct multicall_entry *mcl, unsigned int cmd, void *arg)
+{
+	mcl->op = __HYPERVISOR_memory_op;
+	mcl->args[0] = cmd;
+	mcl->args[1] = (unsigned long)arg;
+}
+
+static inline void
+MULTI_mmu_update(struct multicall_entry *mcl, struct mmu_update *req,
+		 int count, int *success_count, domid_t domid)
+{
+	mcl->op = __HYPERVISOR_mmu_update;
+	mcl->args[0] = (unsigned long)req;
+	mcl->args[1] = count;
+	mcl->args[2] = (unsigned long)success_count;
+	mcl->args[3] = domid;
+}
+
+static inline void
+MULTI_mmuext_op(struct multicall_entry *mcl, struct mmuext_op *op, int count,
+		int *success_count, domid_t domid)
+{
+	mcl->op = __HYPERVISOR_mmuext_op;
+	mcl->args[0] = (unsigned long)op;
+	mcl->args[1] = count;
+	mcl->args[2] = (unsigned long)success_count;
+	mcl->args[3] = domid;
+}
+#endif /* __HYPERCALL_H__ */
===================================================================
--- /dev/null
+++ b/include/asm-i386/xen/hypervisor.h
@@ -0,0 +1,72 @@
+/******************************************************************************
+ * hypervisor.h
+ *
+ * Linux-specific hypervisor handling.
+ *
+ * Copyright (c) 2002-2004, K A Fraser
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __HYPERVISOR_H__
+#define __HYPERVISOR_H__
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/version.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/version.h>
+
+#include <asm/ptrace.h>
+#include <asm/page.h>
+#if defined(__i386__)
+#  ifdef CONFIG_X86_PAE
+#   include <asm-generic/pgtable-nopud.h>
+#  else
+#   include <asm-generic/pgtable-nopmd.h>
+#  endif
+#endif
+#include <asm/xen/hypercall.h>
+
+/* arch/i386/kernel/setup.c */
+extern struct shared_info *HYPERVISOR_shared_info;
+extern struct start_info *xen_start_info;
+#define is_initial_xendomain() (xen_start_info->flags & SIF_INITDOMAIN)
+
+/* arch/i386/mach-xen/evtchn.c */
+/* Force a proper event-channel callback from Xen. */
+extern void force_evtchn_callback(void);
+
+/* Turn jiffies into Xen system time. */
+u64 jiffies_to_st(unsigned long jiffies);
+
+
+#define MULTI_UVMFLAGS_INDEX 3
+#define MULTI_UVMDOMID_INDEX 4
+
+#define is_running_on_xen()	(xen_start_info ? 1 : 0)
+
+#endif /* __HYPERVISOR_H__ */
===================================================================
--- /dev/null
+++ b/include/asm-i386/xen/interface.h
@@ -0,0 +1,187 @@
+/******************************************************************************
+ * arch-x86_32.h
+ *
+ * Guest OS interface to x86 32-bit Xen.
+ *
+ * Copyright (c) 2004, K A Fraser
+ */
+
+#ifndef __XEN_PUBLIC_ARCH_X86_32_H__
+#define __XEN_PUBLIC_ARCH_X86_32_H__
+
+#ifdef __XEN__
+#define __DEFINE_GUEST_HANDLE(name, type) \
+    typedef struct { type *p; } __guest_handle_ ## name
+#else
+#define __DEFINE_GUEST_HANDLE(name, type) \
+    typedef type * __guest_handle_ ## name
+#endif
+
+#define DEFINE_GUEST_HANDLE_STRUCT(name) \
+	__DEFINE_GUEST_HANDLE(name, struct name)
+#define DEFINE_GUEST_HANDLE(name) __DEFINE_GUEST_HANDLE(name, name)
+#define GUEST_HANDLE(name)        __guest_handle_ ## name
+
+#ifndef __ASSEMBLY__
+/* Guest handles for primitive C types. */
+__DEFINE_GUEST_HANDLE(uchar, unsigned char);
+__DEFINE_GUEST_HANDLE(uint,  unsigned int);
+__DEFINE_GUEST_HANDLE(ulong, unsigned long);
+DEFINE_GUEST_HANDLE(char);
+DEFINE_GUEST_HANDLE(int);
+DEFINE_GUEST_HANDLE(long);
+DEFINE_GUEST_HANDLE(void);
+#endif
+
+/*
+ * SEGMENT DESCRIPTOR TABLES
+ */
+/*
+ * A number of GDT entries are reserved by Xen. These are not situated at the
+ * start of the GDT because some stupid OSes export hard-coded selector values
+ * in their ABI. These hard-coded values are always near the start of the GDT,
+ * so Xen places itself out of the way, at the far end of the GDT.
+ */
+#define FIRST_RESERVED_GDT_PAGE  14
+#define FIRST_RESERVED_GDT_BYTE  (FIRST_RESERVED_GDT_PAGE * 4096)
+#define FIRST_RESERVED_GDT_ENTRY (FIRST_RESERVED_GDT_BYTE / 8)
+
+/*
+ * These flat segments are in the Xen-private section of every GDT. Since these
+ * are also present in the initial GDT, many OSes will be able to avoid
+ * installing their own GDT.
+ */
+#define FLAT_RING1_CS 0xe019    /* GDT index 259 */
+#define FLAT_RING1_DS 0xe021    /* GDT index 260 */
+#define FLAT_RING1_SS 0xe021    /* GDT index 260 */
+#define FLAT_RING3_CS 0xe02b    /* GDT index 261 */
+#define FLAT_RING3_DS 0xe033    /* GDT index 262 */
+#define FLAT_RING3_SS 0xe033    /* GDT index 262 */
+
+#define FLAT_KERNEL_CS FLAT_RING1_CS
+#define FLAT_KERNEL_DS FLAT_RING1_DS
+#define FLAT_KERNEL_SS FLAT_RING1_SS
+#define FLAT_USER_CS    FLAT_RING3_CS
+#define FLAT_USER_DS    FLAT_RING3_DS
+#define FLAT_USER_SS    FLAT_RING3_SS
+
+/* And the trap vector is... */
+#define TRAP_INSTR "int $0x82"
+
+/*
+ * Virtual addresses beyond this are not modifiable by guest OSes. The
+ * machine->physical mapping table starts at this address, read-only.
+ */
+#ifdef CONFIG_X86_PAE
+#define __HYPERVISOR_VIRT_START 0xF5800000
+#else
+#define __HYPERVISOR_VIRT_START 0xFC000000
+#endif
+
+#ifndef HYPERVISOR_VIRT_START
+#define HYPERVISOR_VIRT_START mk_unsigned_long(__HYPERVISOR_VIRT_START)
+#endif
+
+#ifndef machine_to_phys_mapping
+#define machine_to_phys_mapping ((unsigned long *)HYPERVISOR_VIRT_START)
+#endif
+
+/* Maximum number of virtual CPUs in multi-processor guests. */
+#define MAX_VIRT_CPUS 32
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Send an array of these to HYPERVISOR_set_trap_table()
+ */
+#define TI_GET_DPL(_ti)      ((_ti)->flags & 3)
+#define TI_GET_IF(_ti)       ((_ti)->flags & 4)
+#define TI_SET_DPL(_ti,_dpl) ((_ti)->flags |= (_dpl))
+#define TI_SET_IF(_ti,_if)   ((_ti)->flags |= ((!!(_if))<<2))
+struct trap_info {
+    uint8_t       vector;  /* exception vector                              */
+    uint8_t       flags;   /* 0-3: privilege level; 4: clear event enable?  */
+    uint16_t      cs;      /* code selector                                 */
+    unsigned long address; /* code offset                                   */
+};
+DEFINE_GUEST_HANDLE_STRUCT(trap_info);
+
+struct cpu_user_regs {
+    uint32_t ebx;
+    uint32_t ecx;
+    uint32_t edx;
+    uint32_t esi;
+    uint32_t edi;
+    uint32_t ebp;
+    uint32_t eax;
+    uint16_t error_code;    /* private */
+    uint16_t entry_vector;  /* private */
+    uint32_t eip;
+    uint16_t cs;
+    uint8_t  saved_upcall_mask;
+    uint8_t  _pad0;
+    uint32_t eflags;        /* eflags.IF == !saved_upcall_mask */
+    uint32_t esp;
+    uint16_t ss, _pad1;
+    uint16_t es, _pad2;
+    uint16_t ds, _pad3;
+    uint16_t fs, _pad4;
+    uint16_t gs, _pad5;
+};
+DEFINE_GUEST_HANDLE_STRUCT(cpu_user_regs);
+
+typedef uint64_t tsc_timestamp_t; /* RDTSC timestamp */
+
+/*
+ * The following is all CPU context. Note that the fpu_ctxt block is filled
+ * in by FXSAVE if the CPU has feature FXSR; otherwise FSAVE is used.
+ */
+struct vcpu_guest_context {
+    /* FPU registers come first so they can be aligned for FXSAVE/FXRSTOR. */
+    struct { char x[512]; } fpu_ctxt;       /* User-level FPU registers     */
+#define VGCF_I387_VALID (1<<0)
+#define VGCF_HVM_GUEST  (1<<1)
+#define VGCF_IN_KERNEL  (1<<2)
+    unsigned long flags;                    /* VGCF_* flags                 */
+    struct cpu_user_regs user_regs;         /* User-level CPU registers     */
+    struct trap_info trap_ctxt[256];        /* Virtual IDT                  */
+    unsigned long ldt_base, ldt_ents;       /* LDT (linear address, # ents) */
+    unsigned long gdt_frames[16], gdt_ents; /* GDT (machine frames, # ents) */
+    unsigned long kernel_ss, kernel_sp;     /* Virtual TSS (only SS1/SP1)   */
+    unsigned long ctrlreg[8];               /* CR0-CR7 (control registers)  */
+    unsigned long debugreg[8];              /* DB0-DB7 (debug registers)    */
+    unsigned long event_callback_cs;        /* CS:EIP of event callback     */
+    unsigned long event_callback_eip;
+    unsigned long failsafe_callback_cs;     /* CS:EIP of failsafe callback  */
+    unsigned long failsafe_callback_eip;
+    unsigned long vm_assist;                /* VMASST_TYPE_* bitmap */
+};
+DEFINE_GUEST_HANDLE_STRUCT(vcpu_guest_context);
+
+struct arch_shared_info {
+    unsigned long max_pfn;                  /* max pfn that appears in table */
+    /* Frame containing list of mfns containing list of mfns containing p2m. */
+    unsigned long pfn_to_mfn_frame_list_list;
+    unsigned long nmi_reason;
+};
+
+struct arch_vcpu_info {
+    unsigned long cr2;
+    unsigned long pad[5]; /* sizeof(struct vcpu_info) == 64 */
+};
+
+#endif /* !__ASSEMBLY__ */
+
+/*
+ * Prefix forces emulation of some non-trapping instructions.
+ * Currently only CPUID.
+ */
+#ifdef __ASSEMBLY__
+#define XEN_EMULATE_PREFIX .byte 0x0f,0x0b,0x78,0x65,0x6e ;
+#define XEN_CPUID          XEN_EMULATE_PREFIX cpuid
+#else
+#define XEN_EMULATE_PREFIX ".byte 0x0f,0x0b,0x78,0x65,0x6e ; "
+#define XEN_CPUID          XEN_EMULATE_PREFIX "cpuid"
+#endif
+
+#endif
===================================================================
--- /dev/null
+++ b/include/xen/interface/elfnote.h
@@ -0,0 +1,133 @@
+/******************************************************************************
+ * elfnote.h
+ *
+ * Definitions used for the Xen ELF notes.
+ *
+ * Copyright (c) 2006, Ian Campbell, XenSource Ltd.
+ */
+
+#ifndef __XEN_PUBLIC_ELFNOTE_H__
+#define __XEN_PUBLIC_ELFNOTE_H__
+
+/*
+ * The notes should live in a SHT_NOTE segment and have "Xen" in the
+ * name field.
+ *
+ * Numeric types are either 4 or 8 bytes depending on the content of
+ * the desc field.
+ *
+ * LEGACY indicated the fields in the legacy __xen_guest string which
+ * this a note type replaces.
+ */
+
+/*
+ * NAME=VALUE pair (string).
+ *
+ * LEGACY: FEATURES and PAE
+ */
+#define XEN_ELFNOTE_INFO           0
+
+/*
+ * The virtual address of the entry point (numeric).
+ *
+ * LEGACY: VIRT_ENTRY
+ */
+#define XEN_ELFNOTE_ENTRY          1
+
+/* The virtual address of the hypercall transfer page (numeric).
+ *
+ * LEGACY: HYPERCALL_PAGE. (n.b. legacy value is a physical page
+ * number not a virtual address)
+ */
+#define XEN_ELFNOTE_HYPERCALL_PAGE 2
+
+/* The virtual address where the kernel image should be mapped (numeric).
+ *
+ * Defaults to 0.
+ *
+ * LEGACY: VIRT_BASE
+ */
+#define XEN_ELFNOTE_VIRT_BASE      3
+
+/*
+ * The offset of the ELF paddr field from the acutal required
+ * psuedo-physical address (numeric).
+ *
+ * This is used to maintain backwards compatibility with older kernels
+ * which wrote __PAGE_OFFSET into that field. This field defaults to 0
+ * if not present.
+ *
+ * LEGACY: ELF_PADDR_OFFSET. (n.b. legacy default is VIRT_BASE)
+ */
+#define XEN_ELFNOTE_PADDR_OFFSET   4
+
+/*
+ * The version of Xen that we work with (string).
+ *
+ * LEGACY: XEN_VER
+ */
+#define XEN_ELFNOTE_XEN_VERSION    5
+
+/*
+ * The name of the guest operating system (string).
+ *
+ * LEGACY: GUEST_OS
+ */
+#define XEN_ELFNOTE_GUEST_OS       6
+
+/*
+ * The version of the guest operating system (string).
+ *
+ * LEGACY: GUEST_VER
+ */
+#define XEN_ELFNOTE_GUEST_VERSION  7
+
+/*
+ * The loader type (string).
+ *
+ * LEGACY: LOADER
+ */
+#define XEN_ELFNOTE_LOADER         8
+
+/*
+ * The kernel supports PAE (x86/32 only, string = "yes" or "no").
+ *
+ * LEGACY: PAE (n.b. The legacy interface included a provision to
+ * indicate 'extended-cr3' support allowing L3 page tables to be
+ * placed above 4G. It is assumed that any kernel new enough to use
+ * these ELF notes will include this and therefore "yes" here is
+ * equivalent to "yes[entended-cr3]" in the __xen_guest interface.
+ */
+#define XEN_ELFNOTE_PAE_MODE       9
+
+/*
+ * The features supported/required by this kernel (string).
+ *
+ * The string must consist of a list of feature names (as given in
+ * features.h, without the "XENFEAT_" prefix) separated by '|'
+ * characters. If a feature is required for the kernel to function
+ * then the feature name must be preceded by a '!' character.
+ *
+ * LEGACY: FEATURES
+ */
+#define XEN_ELFNOTE_FEATURES      10
+
+/*
+ * The kernel requires the symbol table to be loaded (string = "yes" or "no")
+ * LEGACY: BSD_SYMTAB (n.b. The legacy treated the presence or absence
+ * of this string as a boolean flag rather than requiring "yes" or
+ * "no".
+ */
+#define XEN_ELFNOTE_BSD_SYMTAB    11
+
+#endif /* __XEN_PUBLIC_ELFNOTE_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/event_channel.h
@@ -0,0 +1,195 @@
+/******************************************************************************
+ * event_channel.h
+ *
+ * Event channels between domains.
+ *
+ * Copyright (c) 2003-2004, K A Fraser.
+ */
+
+#ifndef __XEN_PUBLIC_EVENT_CHANNEL_H__
+#define __XEN_PUBLIC_EVENT_CHANNEL_H__
+
+typedef uint32_t evtchn_port_t;
+DEFINE_GUEST_HANDLE(evtchn_port_t);
+
+/*
+ * EVTCHNOP_alloc_unbound: Allocate a port in domain <dom> and mark as
+ * accepting interdomain bindings from domain <remote_dom>. A fresh port
+ * is allocated in <dom> and returned as <port>.
+ * NOTES:
+ *  1. If the caller is unprivileged then <dom> must be DOMID_SELF.
+ *  2. <rdom> may be DOMID_SELF, allowing loopback connections.
+ */
+#define EVTCHNOP_alloc_unbound    6
+struct evtchn_alloc_unbound {
+    /* IN parameters */
+    domid_t dom, remote_dom;
+    /* OUT parameters */
+    evtchn_port_t port;
+};
+
+/*
+ * EVTCHNOP_bind_interdomain: Construct an interdomain event channel between
+ * the calling domain and <remote_dom>. <remote_dom,remote_port> must identify
+ * a port that is unbound and marked as accepting bindings from the calling
+ * domain. A fresh port is allocated in the calling domain and returned as
+ * <local_port>.
+ * NOTES:
+ *  2. <remote_dom> may be DOMID_SELF, allowing loopback connections.
+ */
+#define EVTCHNOP_bind_interdomain 0
+struct evtchn_bind_interdomain {
+    /* IN parameters. */
+    domid_t remote_dom;
+    evtchn_port_t remote_port;
+    /* OUT parameters. */
+    evtchn_port_t local_port;
+};
+
+/*
+ * EVTCHNOP_bind_virq: Bind a local event channel to VIRQ <irq> on specified
+ * vcpu.
+ * NOTES:
+ *  1. A virtual IRQ may be bound to at most one event channel per vcpu.
+ *  2. The allocated event channel is bound to the specified vcpu. The binding
+ *     may not be changed.
+ */
+#define EVTCHNOP_bind_virq        1
+struct evtchn_bind_virq {
+    /* IN parameters. */
+    uint32_t virq;
+    uint32_t vcpu;
+    /* OUT parameters. */
+    evtchn_port_t port;
+};
+
+/*
+ * EVTCHNOP_bind_pirq: Bind a local event channel to PIRQ <irq>.
+ * NOTES:
+ *  1. A physical IRQ may be bound to at most one event channel per domain.
+ *  2. Only a sufficiently-privileged domain may bind to a physical IRQ.
+ */
+#define EVTCHNOP_bind_pirq        2
+struct evtchn_bind_pirq {
+    /* IN parameters. */
+    uint32_t pirq;
+#define BIND_PIRQ__WILL_SHARE 1
+    uint32_t flags; /* BIND_PIRQ__* */
+    /* OUT parameters. */
+    evtchn_port_t port;
+};
+
+/*
+ * EVTCHNOP_bind_ipi: Bind a local event channel to receive events.
+ * NOTES:
+ *  1. The allocated event channel is bound to the specified vcpu. The binding
+ *     may not be changed.
+ */
+#define EVTCHNOP_bind_ipi         7
+struct evtchn_bind_ipi {
+    uint32_t vcpu;
+    /* OUT parameters. */
+    evtchn_port_t port;
+};
+
+/*
+ * EVTCHNOP_close: Close a local event channel <port>. If the channel is
+ * interdomain then the remote end is placed in the unbound state
+ * (EVTCHNSTAT_unbound), awaiting a new connection.
+ */
+#define EVTCHNOP_close            3
+struct evtchn_close {
+    /* IN parameters. */
+    evtchn_port_t port;
+};
+
+/*
+ * EVTCHNOP_send: Send an event to the remote end of the channel whose local
+ * endpoint is <port>.
+ */
+#define EVTCHNOP_send             4
+struct evtchn_send {
+    /* IN parameters. */
+    evtchn_port_t port;
+};
+
+/*
+ * EVTCHNOP_status: Get the current status of the communication channel which
+ * has an endpoint at <dom, port>.
+ * NOTES:
+ *  1. <dom> may be specified as DOMID_SELF.
+ *  2. Only a sufficiently-privileged domain may obtain the status of an event
+ *     channel for which <dom> is not DOMID_SELF.
+ */
+#define EVTCHNOP_status           5
+struct evtchn_status {
+    /* IN parameters */
+    domid_t  dom;
+    evtchn_port_t port;
+    /* OUT parameters */
+#define EVTCHNSTAT_closed       0  /* Channel is not in use.                 */
+#define EVTCHNSTAT_unbound      1  /* Channel is waiting interdom connection.*/
+#define EVTCHNSTAT_interdomain  2  /* Channel is connected to remote domain. */
+#define EVTCHNSTAT_pirq         3  /* Channel is bound to a phys IRQ line.   */
+#define EVTCHNSTAT_virq         4  /* Channel is bound to a virtual IRQ line */
+#define EVTCHNSTAT_ipi          5  /* Channel is bound to a virtual IPI line */
+    uint32_t status;
+    uint32_t vcpu;                 /* VCPU to which this channel is bound.   */
+    union {
+        struct {
+            domid_t dom;
+        } unbound; /* EVTCHNSTAT_unbound */
+        struct {
+            domid_t dom;
+            evtchn_port_t port;
+        } interdomain; /* EVTCHNSTAT_interdomain */
+        uint32_t pirq;      /* EVTCHNSTAT_pirq        */
+        uint32_t virq;      /* EVTCHNSTAT_virq        */
+    } u;
+};
+
+/*
+ * EVTCHNOP_bind_vcpu: Specify which vcpu a channel should notify when an
+ * event is pending.
+ * NOTES:
+ *  1. IPI- and VIRQ-bound channels always notify the vcpu that initialised
+ *     the binding. This binding cannot be changed.
+ *  2. All other channels notify vcpu0 by default. This default is set when
+ *     the channel is allocated (a port that is freed and subsequently reused
+ *     has its binding reset to vcpu0).
+ */
+#define EVTCHNOP_bind_vcpu        8
+struct evtchn_bind_vcpu {
+    /* IN parameters. */
+    evtchn_port_t port;
+    uint32_t vcpu;
+};
+
+/*
+ * EVTCHNOP_unmask: Unmask the specified local event-channel port and deliver
+ * a notification to the appropriate VCPU if an event is pending.
+ */
+#define EVTCHNOP_unmask           9
+struct evtchn_unmask {
+    /* IN parameters. */
+    evtchn_port_t port;
+};
+
+struct evtchn_op {
+    uint32_t cmd; /* EVTCHNOP_* */
+    union {
+        struct evtchn_alloc_unbound    alloc_unbound;
+        struct evtchn_bind_interdomain bind_interdomain;
+        struct evtchn_bind_virq        bind_virq;
+        struct evtchn_bind_pirq        bind_pirq;
+        struct evtchn_bind_ipi         bind_ipi;
+        struct evtchn_close            close;
+        struct evtchn_send             send;
+        struct evtchn_status           status;
+        struct evtchn_bind_vcpu        bind_vcpu;
+        struct evtchn_unmask           unmask;
+    } u;
+};
+DEFINE_GUEST_HANDLE_STRUCT(evtchn_op);
+
+#endif /* __XEN_PUBLIC_EVENT_CHANNEL_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/features.h
@@ -0,0 +1,43 @@
+/******************************************************************************
+ * features.h
+ *
+ * Feature flags, reported by XENVER_get_features.
+ *
+ * Copyright (c) 2006, Keir Fraser <keir@xensource.com>
+ */
+
+#ifndef __XEN_PUBLIC_FEATURES_H__
+#define __XEN_PUBLIC_FEATURES_H__
+
+/*
+ * If set, the guest does not need to write-protect its pagetables, and can
+ * update them via direct writes.
+ */
+#define XENFEAT_writable_page_tables       0
+
+/*
+ * If set, the guest does not need to write-protect its segment descriptor
+ * tables, and can update them via direct writes.
+ */
+#define XENFEAT_writable_descriptor_tables 1
+
+/*
+ * If set, translation between the guest's 'pseudo-physical' address space
+ * and the host's machine address space are handled by the hypervisor. In this
+ * mode the guest does not need to perform phys-to/from-machine translations
+ * when performing page table operations.
+ */
+#define XENFEAT_auto_translated_physmap    2
+
+/* If set, the guest is running in supervisor mode (e.g., x86 ring 0). */
+#define XENFEAT_supervisor_mode_kernel     3
+
+/*
+ * If set, the guest does not need to allocate x86 PAE page directories
+ * below 4GB. This flag is usually implied by auto_translated_physmap.
+ */
+#define XENFEAT_pae_pgdir_above_4gb        4
+
+#define XENFEAT_NR_SUBMAPS 1
+
+#endif /* __XEN_PUBLIC_FEATURES_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/grant_table.h
@@ -0,0 +1,301 @@
+/******************************************************************************
+ * grant_table.h
+ *
+ * Interface for granting foreign access to page frames, and receiving
+ * page-ownership transfers.
+ *
+ * Copyright (c) 2004, K A Fraser
+ */
+
+#ifndef __XEN_PUBLIC_GRANT_TABLE_H__
+#define __XEN_PUBLIC_GRANT_TABLE_H__
+
+
+/***********************************
+ * GRANT TABLE REPRESENTATION
+ */
+
+/* Some rough guidelines on accessing and updating grant-table entries
+ * in a concurrency-safe manner. For more information, Linux contains a
+ * reference implementation for guest OSes (arch/i386/mach-xen/grant_table.c).
+ *
+ * NB. WMB is a no-op on current-generation x86 processors. However, a
+ *     compiler barrier will still be required.
+ *
+ * Introducing a valid entry into the grant table:
+ *  1. Write ent->domid.
+ *  2. Write ent->frame:
+ *      GTF_permit_access:   Frame to which access is permitted.
+ *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
+ *                           frame, or zero if none.
+ *  3. Write memory barrier (WMB).
+ *  4. Write ent->flags, inc. valid type.
+ *
+ * Invalidating an unused GTF_permit_access entry:
+ *  1. flags = ent->flags.
+ *  2. Observe that !(flags & (GTF_reading|GTF_writing)).
+ *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
+ *  NB. No need for WMB as reuse of entry is control-dependent on success of
+ *      step 3, and all architectures guarantee ordering of ctrl-dep writes.
+ *
+ * Invalidating an in-use GTF_permit_access entry:
+ *  This cannot be done directly. Request assistance from the domain controller
+ *  which can set a timeout on the use of a grant entry and take necessary
+ *  action. (NB. This is not yet implemented!).
+ *
+ * Invalidating an unused GTF_accept_transfer entry:
+ *  1. flags = ent->flags.
+ *  2. Observe that !(flags & GTF_transfer_committed). [*]
+ *  3. Check result of SMP-safe CMPXCHG(&ent->flags, flags, 0).
+ *  NB. No need for WMB as reuse of entry is control-dependent on success of
+ *      step 3, and all architectures guarantee ordering of ctrl-dep writes.
+ *  [*] If GTF_transfer_committed is set then the grant entry is 'committed'.
+ *      The guest must /not/ modify the grant entry until the address of the
+ *      transferred frame is written. It is safe for the guest to spin waiting
+ *      for this to occur (detect by observing GTF_transfer_completed in
+ *      ent->flags).
+ *
+ * Invalidating a committed GTF_accept_transfer entry:
+ *  1. Wait for (ent->flags & GTF_transfer_completed).
+ *
+ * Changing a GTF_permit_access from writable to read-only:
+ *  Use SMP-safe CMPXCHG to set GTF_readonly, while checking !GTF_writing.
+ *
+ * Changing a GTF_permit_access from read-only to writable:
+ *  Use SMP-safe bit-setting instruction.
+ */
+
+/*
+ * A grant table comprises a packed array of grant entries in one or more
+ * page frames shared between Xen and a guest.
+ * [XEN]: This field is written by Xen and read by the sharing guest.
+ * [GST]: This field is written by the guest and read by Xen.
+ */
+struct grant_entry {
+    /* GTF_xxx: various type and flag information.  [XEN,GST] */
+    uint16_t flags;
+    /* The domain being granted foreign privileges. [GST] */
+    domid_t  domid;
+    /*
+     * GTF_permit_access: Frame that @domid is allowed to map and access. [GST]
+     * GTF_accept_transfer: Frame whose ownership transferred by @domid. [XEN]
+     */
+    uint32_t frame;
+};
+
+/*
+ * Type of grant entry.
+ *  GTF_invalid: This grant entry grants no privileges.
+ *  GTF_permit_access: Allow @domid to map/access @frame.
+ *  GTF_accept_transfer: Allow @domid to transfer ownership of one page frame
+ *                       to this guest. Xen writes the page number to @frame.
+ */
+#define GTF_invalid         (0U<<0)
+#define GTF_permit_access   (1U<<0)
+#define GTF_accept_transfer (2U<<0)
+#define GTF_type_mask       (3U<<0)
+
+/*
+ * Subflags for GTF_permit_access.
+ *  GTF_readonly: Restrict @domid to read-only mappings and accesses. [GST]
+ *  GTF_reading: Grant entry is currently mapped for reading by @domid. [XEN]
+ *  GTF_writing: Grant entry is currently mapped for writing by @domid. [XEN]
+ */
+#define _GTF_readonly       (2)
+#define GTF_readonly        (1U<<_GTF_readonly)
+#define _GTF_reading        (3)
+#define GTF_reading         (1U<<_GTF_reading)
+#define _GTF_writing        (4)
+#define GTF_writing         (1U<<_GTF_writing)
+
+/*
+ * Subflags for GTF_accept_transfer:
+ *  GTF_transfer_committed: Xen sets this flag to indicate that it is committed
+ *      to transferring ownership of a page frame. When a guest sees this flag
+ *      it must /not/ modify the grant entry until GTF_transfer_completed is
+ *      set by Xen.
+ *  GTF_transfer_completed: It is safe for the guest to spin-wait on this flag
+ *      after reading GTF_transfer_committed. Xen will always write the frame
+ *      address, followed by ORing this flag, in a timely manner.
+ */
+#define _GTF_transfer_committed (2)
+#define GTF_transfer_committed  (1U<<_GTF_transfer_committed)
+#define _GTF_transfer_completed (3)
+#define GTF_transfer_completed  (1U<<_GTF_transfer_completed)
+
+
+/***********************************
+ * GRANT TABLE QUERIES AND USES
+ */
+
+/*
+ * Reference to a grant entry in a specified domain's grant table.
+ */
+typedef uint32_t grant_ref_t;
+
+/*
+ * Handle to track a mapping created via a grant reference.
+ */
+typedef uint32_t grant_handle_t;
+
+/*
+ * GNTTABOP_map_grant_ref: Map the grant entry (<dom>,<ref>) for access
+ * by devices and/or host CPUs. If successful, <handle> is a tracking number
+ * that must be presented later to destroy the mapping(s). On error, <handle>
+ * is a negative status code.
+ * NOTES:
+ *  1. If GNTPIN_map_for_dev is specified then <dev_bus_addr> is the address
+ *     via which I/O devices may access the granted frame.
+ *  2. If GNTPIN_map_for_host is specified then a mapping will be added at
+ *     either a host virtual address in the current address space, or at
+ *     a PTE at the specified machine address.  The type of mapping to
+ *     perform is selected through the GNTMAP_contains_pte flag, and the
+ *     address is specified in <host_addr>.
+ *  3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a
+ *     host mapping is destroyed by other means then it is *NOT* guaranteed
+ *     to be accounted to the correct grant reference!
+ */
+#define GNTTABOP_map_grant_ref        0
+struct gnttab_map_grant_ref {
+    /* IN parameters. */
+    uint64_t host_addr;
+    uint32_t flags;               /* GNTMAP_* */
+    grant_ref_t ref;
+    domid_t  dom;
+    /* OUT parameters. */
+    int16_t  status;              /* GNTST_* */
+    grant_handle_t handle;
+    uint64_t dev_bus_addr;
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_map_grant_ref);
+
+/*
+ * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings
+ * tracked by <handle>. If <host_addr> or <dev_bus_addr> is zero, that
+ * field is ignored. If non-zero, they must refer to a device/host mapping
+ * that is tracked by <handle>
+ * NOTES:
+ *  1. The call may fail in an undefined manner if either mapping is not
+ *     tracked by <handle>.
+ *  3. After executing a batch of unmaps, it is guaranteed that no stale
+ *     mappings will remain in the device or host TLBs.
+ */
+#define GNTTABOP_unmap_grant_ref      1
+struct gnttab_unmap_grant_ref {
+    /* IN parameters. */
+    uint64_t host_addr;
+    uint64_t dev_bus_addr;
+    grant_handle_t handle;
+    /* OUT parameters. */
+    int16_t  status;              /* GNTST_* */
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_unmap_grant_ref);
+
+/*
+ * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least
+ * <nr_frames> pages. The frame addresses are written to the <frame_list>.
+ * Only <nr_frames> addresses are written, even if the table is larger.
+ * NOTES:
+ *  1. <dom> may be specified as DOMID_SELF.
+ *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
+ *  3. Xen may not support more than a single grant-table page per domain.
+ */
+#define GNTTABOP_setup_table          2
+struct gnttab_setup_table {
+    /* IN parameters. */
+    domid_t  dom;
+    uint32_t nr_frames;
+    /* OUT parameters. */
+    int16_t  status;              /* GNTST_* */
+    GUEST_HANDLE(ulong) frame_list;
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_setup_table);
+
+/*
+ * GNTTABOP_dump_table: Dump the contents of the grant table to the
+ * xen console. Debugging use only.
+ */
+#define GNTTABOP_dump_table           3
+struct gnttab_dump_table {
+    /* IN parameters. */
+    domid_t dom;
+    /* OUT parameters. */
+    int16_t status;               /* GNTST_* */
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_dump_table);
+
+/*
+ * GNTTABOP_transfer_grant_ref: Transfer <frame> to a foreign domain. The
+ * foreign domain has previously registered its interest in the transfer via
+ * <domid, ref>.
+ *
+ * Note that, even if the transfer fails, the specified page no longer belongs
+ * to the calling domain *unless* the error is GNTST_bad_page.
+ */
+#define GNTTABOP_transfer                4
+struct gnttab_transfer {
+    /* IN parameters. */
+    unsigned long mfn;
+    domid_t       domid;
+    grant_ref_t   ref;
+    /* OUT parameters. */
+    int16_t       status;
+};
+DEFINE_GUEST_HANDLE_STRUCT(gnttab_transfer);
+
+/*
+ * Bitfield values for update_pin_status.flags.
+ */
+ /* Map the grant entry for access by I/O devices. */
+#define _GNTMAP_device_map      (0)
+#define GNTMAP_device_map       (1<<_GNTMAP_device_map)
+ /* Map the grant entry for access by host CPUs. */
+#define _GNTMAP_host_map        (1)
+#define GNTMAP_host_map         (1<<_GNTMAP_host_map)
+ /* Accesses to the granted frame will be restricted to read-only access. */
+#define _GNTMAP_readonly        (2)
+#define GNTMAP_readonly         (1<<_GNTMAP_readonly)
+ /*
+  * GNTMAP_host_map subflag:
+  *  0 => The host mapping is usable only by the guest OS.
+  *  1 => The host mapping is usable by guest OS + current application.
+  */
+#define _GNTMAP_application_map (3)
+#define GNTMAP_application_map  (1<<_GNTMAP_application_map)
+
+ /*
+  * GNTMAP_contains_pte subflag:
+  *  0 => This map request contains a host virtual address.
+  *  1 => This map request contains the machine addess of the PTE to update.
+  */
+#define _GNTMAP_contains_pte    (4)
+#define GNTMAP_contains_pte     (1<<_GNTMAP_contains_pte)
+
+/*
+ * Values for error status returns. All errors are -ve.
+ */
+#define GNTST_okay             (0)  /* Normal return.                        */
+#define GNTST_general_error    (-1) /* General undefined error.              */
+#define GNTST_bad_domain       (-2) /* Unrecognsed domain id.                */
+#define GNTST_bad_gntref       (-3) /* Unrecognised or inappropriate gntref. */
+#define GNTST_bad_handle       (-4) /* Unrecognised or inappropriate handle. */
+#define GNTST_bad_virt_addr    (-5) /* Inappropriate virtual address to map. */
+#define GNTST_bad_dev_addr     (-6) /* Inappropriate device address to unmap.*/
+#define GNTST_no_device_space  (-7) /* Out of space in I/O MMU.              */
+#define GNTST_permission_denied (-8) /* Not enough privilege for operation.  */
+#define GNTST_bad_page         (-9) /* Specified page was invalid for op.    */
+
+#define GNTTABOP_error_msgs {                   \
+    "okay",                                     \
+    "undefined error",                          \
+    "unrecognised domain id",                   \
+    "invalid grant reference",                  \
+    "invalid mapping handle",                   \
+    "invalid virtual address",                  \
+    "invalid device address",                   \
+    "no spare translation slot in the I/O MMU", \
+    "permission denied",                        \
+    "bad page"                                  \
+}
+
+#endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/io/blkif.h
@@ -0,0 +1,96 @@
+/******************************************************************************
+ * blkif.h
+ *
+ * Unified block-device I/O interface for Xen guest OSes.
+ *
+ * Copyright (c) 2003-2004, Keir Fraser
+ */
+
+#ifndef __XEN_PUBLIC_IO_BLKIF_H__
+#define __XEN_PUBLIC_IO_BLKIF_H__
+
+#include "ring.h"
+#include "../grant_table.h"
+
+/*
+ * Front->back notifications: When enqueuing a new request, sending a
+ * notification can be made conditional on req_event (i.e., the generic
+ * hold-off mechanism provided by the ring macros). Backends must set
+ * req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()).
+ *
+ * Back->front notifications: When enqueuing a new response, sending a
+ * notification can be made conditional on rsp_event (i.e., the generic
+ * hold-off mechanism provided by the ring macros). Frontends must set
+ * rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
+ */
+
+#ifndef blkif_vdev_t
+#define blkif_vdev_t   uint16_t
+#endif
+#define blkif_sector_t uint64_t
+
+/*
+ * REQUEST CODES.
+ */
+#define BLKIF_OP_READ              0
+#define BLKIF_OP_WRITE             1
+/*
+ * Recognised only if "feature-barrier" is present in backend xenbus info.
+ * The "feature_barrier" node contains a boolean indicating whether barrier
+ * requests are likely to succeed or fail. Either way, a barrier request
+ * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
+ * the underlying block-device hardware. The boolean simply indicates whether
+ * or not it is worthwhile for the frontend to attempt barrier requests.
+ * If a backend does not recognise BLKIF_OP_WRITE_BARRIER, it should *not*
+ * create the "feature-barrier" node!
+ */
+#define BLKIF_OP_WRITE_BARRIER     2
+
+/*
+ * Maximum scatter/gather segments per request.
+ * This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE.
+ * NB. This could be 12 if the ring indexes weren't stored in the same page.
+ */
+#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
+
+struct blkif_request {
+    uint8_t        operation;    /* BLKIF_OP_???                         */
+    uint8_t        nr_segments;  /* number of segments                   */
+    blkif_vdev_t   handle;       /* only for read/write requests         */
+    uint64_t       id;           /* private guest value, echoed in resp  */
+    blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
+    struct blkif_request_segment {
+        grant_ref_t gref;        /* reference to I/O buffer frame        */
+        /* @first_sect: first sector in frame to transfer (inclusive).   */
+        /* @last_sect: last sector in frame to transfer (inclusive).     */
+        uint8_t     first_sect, last_sect;
+    } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+};
+
+struct blkif_response {
+    uint64_t        id;              /* copied from request */
+    uint8_t         operation;       /* copied from request */
+    int16_t         status;          /* BLKIF_RSP_???       */
+};
+
+/*
+ * STATUS RETURN CODES.
+ */
+ /* Operation not supported (only happens on barrier writes). */
+#define BLKIF_RSP_EOPNOTSUPP  -2
+ /* Operation failed for some unspecified reason (-EIO). */
+#define BLKIF_RSP_ERROR       -1
+ /* Operation completed successfully. */
+#define BLKIF_RSP_OKAY         0
+
+/*
+ * Generate blkif ring structures and types.
+ */
+
+DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
+
+#define VDISK_CDROM        0x1
+#define VDISK_REMOVABLE    0x2
+#define VDISK_READONLY     0x4
+
+#endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/io/console.h
@@ -0,0 +1,23 @@
+/******************************************************************************
+ * console.h
+ *
+ * Console I/O interface for Xen guest OSes.
+ *
+ * Copyright (c) 2005, Keir Fraser
+ */
+
+#ifndef __XEN_PUBLIC_IO_CONSOLE_H__
+#define __XEN_PUBLIC_IO_CONSOLE_H__
+
+typedef uint32_t XENCONS_RING_IDX;
+
+#define MASK_XENCONS_IDX(idx, ring) ((idx) & (sizeof(ring)-1))
+
+struct xencons_interface {
+    char in[1024];
+    char out[2048];
+    XENCONS_RING_IDX in_cons, in_prod;
+    XENCONS_RING_IDX out_cons, out_prod;
+};
+
+#endif /* __XEN_PUBLIC_IO_CONSOLE_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/io/netif.h
@@ -0,0 +1,152 @@
+/******************************************************************************
+ * netif.h
+ *
+ * Unified network-device I/O interface for Xen guest OSes.
+ *
+ * Copyright (c) 2003-2004, Keir Fraser
+ */
+
+#ifndef __XEN_PUBLIC_IO_NETIF_H__
+#define __XEN_PUBLIC_IO_NETIF_H__
+
+#include "ring.h"
+#include "../grant_table.h"
+
+/*
+ * Notifications after enqueuing any type of message should be conditional on
+ * the appropriate req_event or rsp_event field in the shared ring.
+ * If the client sends notification for rx requests then it should specify
+ * feature 'feature-rx-notify' via xenbus. Otherwise the backend will assume
+ * that it cannot safely queue packets (as it may not be kicked to send them).
+ */
+
+/*
+ * This is the 'wire' format for packets:
+ *  Request 1: netif_tx_request -- NETTXF_* (any flags)
+ * [Request 2: netif_tx_extra]  (only if request 1 has NETTXF_extra_info)
+ * [Request 3: netif_tx_extra]  (only if request 2 has XEN_NETIF_EXTRA_MORE)
+ *  Request 4: netif_tx_request -- NETTXF_more_data
+ *  Request 5: netif_tx_request -- NETTXF_more_data
+ *  ...
+ *  Request N: netif_tx_request -- 0
+ */
+
+/* Protocol checksum field is blank in the packet (hardware offload)? */
+#define _NETTXF_csum_blank     (0)
+#define  NETTXF_csum_blank     (1U<<_NETTXF_csum_blank)
+
+/* Packet data has been validated against protocol checksum. */
+#define _NETTXF_data_validated (1)
+#define  NETTXF_data_validated (1U<<_NETTXF_data_validated)
+
+/* Packet continues in the next request descriptor. */
+#define _NETTXF_more_data      (2)
+#define  NETTXF_more_data      (1U<<_NETTXF_more_data)
+
+/* Packet to be followed by extra descriptor(s). */
+#define _NETTXF_extra_info     (3)
+#define  NETTXF_extra_info     (1U<<_NETTXF_extra_info)
+
+struct netif_tx_request {
+    grant_ref_t gref;      /* Reference to buffer page */
+    uint16_t offset;       /* Offset within buffer page */
+    uint16_t flags;        /* NETTXF_* */
+    uint16_t id;           /* Echoed in response message. */
+    uint16_t size;         /* Packet size in bytes.       */
+};
+
+/* Types of netif_extra_info descriptors. */
+#define XEN_NETIF_EXTRA_TYPE_NONE  (0)  /* Never used - invalid */
+#define XEN_NETIF_EXTRA_TYPE_GSO   (1)  /* u.gso */
+#define XEN_NETIF_EXTRA_TYPE_MAX   (2)
+
+/* netif_extra_info flags. */
+#define _XEN_NETIF_EXTRA_FLAG_MORE (0)
+#define XEN_NETIF_EXTRA_FLAG_MORE  (1U<<_XEN_NETIF_EXTRA_FLAG_MORE)
+
+/* GSO types - only TCPv4 currently supported. */
+#define XEN_NETIF_GSO_TYPE_TCPV4        (1)
+
+/*
+ * This structure needs to fit within both netif_tx_request and
+ * netif_rx_response for compatibility.
+ */
+struct netif_extra_info {
+    uint8_t type;  /* XEN_NETIF_EXTRA_TYPE_* */
+    uint8_t flags; /* XEN_NETIF_EXTRA_FLAG_* */
+
+    union {
+        struct {
+            /*
+             * Maximum payload size of each segment. For example, for TCP this
+             * is just the path MSS.
+             */
+            uint16_t size;
+
+            /*
+             * GSO type. This determines the protocol of the packet and any
+             * extra features required to segment the packet properly.
+             */
+            uint8_t type; /* XEN_NETIF_GSO_TYPE_* */
+
+            /* Future expansion. */
+            uint8_t pad;
+
+            /*
+             * GSO features. This specifies any extra GSO features required
+             * to process this packet, such as ECN support for TCPv4.
+             */
+            uint16_t features; /* XEN_NETIF_GSO_FEAT_* */
+        } gso;
+
+        uint16_t pad[3];
+    } u;
+};
+
+struct netif_tx_response {
+    uint16_t id;
+    int16_t  status;       /* NETIF_RSP_* */
+};
+
+struct netif_rx_request {
+    uint16_t    id;        /* Echoed in response message.        */
+    grant_ref_t gref;      /* Reference to incoming granted frame */
+};
+
+/* Packet data has been validated against protocol checksum. */
+#define _NETRXF_data_validated (0)
+#define  NETRXF_data_validated (1U<<_NETRXF_data_validated)
+
+/* Protocol checksum field is blank in the packet (hardware offload)? */
+#define _NETRXF_csum_blank     (1)
+#define  NETRXF_csum_blank     (1U<<_NETRXF_csum_blank)
+
+/* Packet continues in the next request descriptor. */
+#define _NETRXF_more_data      (2)
+#define  NETRXF_more_data      (1U<<_NETRXF_more_data)
+
+/* Packet to be followed by extra descriptor(s). */
+#define _NETRXF_extra_info     (3)
+#define  NETRXF_extra_info     (1U<<_NETRXF_extra_info)
+
+struct netif_rx_response {
+    uint16_t id;
+    uint16_t offset;       /* Offset in page of start of received packet  */
+    uint16_t flags;        /* NETRXF_* */
+    int16_t  status;       /* -ve: BLKIF_RSP_* ; +ve: Rx'ed pkt size. */
+};
+
+/*
+ * Generate netif ring structures and types.
+ */
+
+DEFINE_RING_TYPES(netif_tx, struct netif_tx_request, struct netif_tx_response);
+DEFINE_RING_TYPES(netif_rx, struct netif_rx_request, struct netif_rx_response);
+
+#define NETIF_RSP_DROPPED         -2
+#define NETIF_RSP_ERROR           -1
+#define NETIF_RSP_OKAY             0
+/* No response: used for auxiliary requests (e.g., netif_tx_extra). */
+#define NETIF_RSP_NULL             1
+
+#endif
===================================================================
--- /dev/null
+++ b/include/xen/interface/io/ring.h
@@ -0,0 +1,260 @@
+/******************************************************************************
+ * ring.h
+ *
+ * Shared producer-consumer ring macros.
+ *
+ * Tim Deegan and Andrew Warfield November 2004.
+ */
+
+#ifndef __XEN_PUBLIC_IO_RING_H__
+#define __XEN_PUBLIC_IO_RING_H__
+
+typedef unsigned int RING_IDX;
+
+/* Round a 32-bit unsigned constant down to the nearest power of two. */
+#define __RD2(_x)  (((_x) & 0x00000002) ? 0x2                  : ((_x) & 0x1))
+#define __RD4(_x)  (((_x) & 0x0000000c) ? __RD2((_x)>>2)<<2    : __RD2(_x))
+#define __RD8(_x)  (((_x) & 0x000000f0) ? __RD4((_x)>>4)<<4    : __RD4(_x))
+#define __RD16(_x) (((_x) & 0x0000ff00) ? __RD8((_x)>>8)<<8    : __RD8(_x))
+#define __RD32(_x) (((_x) & 0xffff0000) ? __RD16((_x)>>16)<<16 : __RD16(_x))
+
+/*
+ * Calculate size of a shared ring, given the total available space for the
+ * ring and indexes (_sz), and the name tag of the request/response structure.
+ * A ring contains as many entries as will fit, rounded down to the nearest
+ * power of two (so we can mask with (size-1) to loop around).
+ */
+#define __RING_SIZE(_s, _sz) \
+    (__RD32(((_sz) - (long)&(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
+
+/*
+ * Macros to make the correct C datatypes for a new kind of ring.
+ *
+ * To make a new ring datatype, you need to have two message structures,
+ * let's say struct request, and struct response already defined.
+ *
+ * In a header where you want the ring datatype declared, you then do:
+ *
+ *     DEFINE_RING_TYPES(mytag, struct request, struct response);
+ *
+ * These expand out to give you a set of types, as you can see below.
+ * The most important of these are:
+ *
+ *     struct mytag_sring      - The shared ring.
+ *     struct mytag_front_ring - The 'front' half of the ring.
+ *     struct mytag_back_ring  - The 'back' half of the ring.
+ *
+ * To initialize a ring in your code you need to know the location and size
+ * of the shared memory area (PAGE_SIZE, for instance). To initialise
+ * the front half:
+ *
+ *     struct mytag_front_ring front_ring;
+ *     SHARED_RING_INIT((struct mytag_sring *)shared_page);
+ *     FRONT_RING_INIT(&front_ring, (struct mytag_sring *)shared_page,
+ *                     PAGE_SIZE);
+ *
+ * Initializing the back follows similarly (note that only the front
+ * initializes the shared ring):
+ *
+ *     struct mytag_back_ring back_ring;
+ *     BACK_RING_INIT(&back_ring, (struct mytag_sring *)shared_page,
+ *                    PAGE_SIZE);
+ */
+
+#define DEFINE_RING_TYPES(__name, __req_t, __rsp_t)                     \
+                                                                        \
+/* Shared ring entry */                                                 \
+union __name##_sring_entry {                                            \
+    __req_t req;                                                        \
+    __rsp_t rsp;                                                        \
+};                                                                      \
+                                                                        \
+/* Shared ring page */                                                  \
+struct __name##_sring {                                                 \
+    RING_IDX req_prod, req_event;                                       \
+    RING_IDX rsp_prod, rsp_event;                                       \
+    uint8_t  pad[48];                                                   \
+    union __name##_sring_entry ring[1]; /* variable-length */           \
+};                                                                      \
+                                                                        \
+/* "Front" end's private variables */                                   \
+struct __name##_front_ring {                                            \
+    RING_IDX req_prod_pvt;                                              \
+    RING_IDX rsp_cons;                                                  \
+    unsigned int nr_ents;                                               \
+    struct __name##_sring *sring;                                       \
+};                                                                      \
+                                                                        \
+/* "Back" end's private variables */                                    \
+struct __name##_back_ring {                                             \
+    RING_IDX rsp_prod_pvt;                                              \
+    RING_IDX req_cons;                                                  \
+    unsigned int nr_ents;                                               \
+    struct __name##_sring *sring;                                       \
+};
+
+/*
+ * Macros for manipulating rings.
+ *
+ * FRONT_RING_whatever works on the "front end" of a ring: here
+ * requests are pushed on to the ring and responses taken off it.
+ *
+ * BACK_RING_whatever works on the "back end" of a ring: here
+ * requests are taken off the ring and responses put on.
+ *
+ * N.B. these macros do NO INTERLOCKS OR FLOW CONTROL.
+ * This is OK in 1-for-1 request-response situations where the
+ * requestor (front end) never has more than RING_SIZE()-1
+ * outstanding requests.
+ */
+
+/* Initialising empty rings */
+#define SHARED_RING_INIT(_s) do {                                       \
+    (_s)->req_prod  = (_s)->rsp_prod  = 0;                              \
+    (_s)->req_event = (_s)->rsp_event = 1;                              \
+    memset((_s)->pad, 0, sizeof((_s)->pad));                            \
+} while(0)
+
+#define FRONT_RING_INIT(_r, _s, __size) do {                            \
+    (_r)->req_prod_pvt = 0;                                             \
+    (_r)->rsp_cons = 0;                                                 \
+    (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
+    (_r)->sring = (_s);                                                 \
+} while (0)
+
+#define BACK_RING_INIT(_r, _s, __size) do {                             \
+    (_r)->rsp_prod_pvt = 0;                                             \
+    (_r)->req_cons = 0;                                                 \
+    (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
+    (_r)->sring = (_s);                                                 \
+} while (0)
+
+/* Initialize to existing shared indexes -- for recovery */
+#define FRONT_RING_ATTACH(_r, _s, __size) do {                          \
+    (_r)->sring = (_s);                                                 \
+    (_r)->req_prod_pvt = (_s)->req_prod;                                \
+    (_r)->rsp_cons = (_s)->rsp_prod;                                    \
+    (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
+} while (0)
+
+#define BACK_RING_ATTACH(_r, _s, __size) do {                           \
+    (_r)->sring = (_s);                                                 \
+    (_r)->rsp_prod_pvt = (_s)->rsp_prod;                                \
+    (_r)->req_cons = (_s)->req_prod;                                    \
+    (_r)->nr_ents = __RING_SIZE(_s, __size);                            \
+} while (0)
+
+/* How big is this ring? */
+#define RING_SIZE(_r)                                                   \
+    ((_r)->nr_ents)
+
+/* Number of free requests (for use on front side only). */
+#define RING_FREE_REQUESTS(_r)						\
+    (RING_SIZE(_r) - ((_r)->req_prod_pvt - (_r)->rsp_cons))
+
+/* Test if there is an empty slot available on the front ring.
+ * (This is only meaningful from the front. )
+ */
+#define RING_FULL(_r)                                                   \
+    (RING_FREE_REQUESTS(_r) == 0)
+
+/* Test if there are outstanding messages to be processed on a ring. */
+#define RING_HAS_UNCONSUMED_RESPONSES(_r)                               \
+    ((_r)->sring->rsp_prod - (_r)->rsp_cons)
+
+#define RING_HAS_UNCONSUMED_REQUESTS(_r)                                \
+    ({									\
+	unsigned int req = (_r)->sring->req_prod - (_r)->req_cons;	\
+	unsigned int rsp = RING_SIZE(_r) -				\
+			   ((_r)->req_cons - (_r)->rsp_prod_pvt);	\
+	req < rsp ? req : rsp;						\
+    })
+
+/* Direct access to individual ring elements, by index. */
+#define RING_GET_REQUEST(_r, _idx)                                      \
+    (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].req))
+
+#define RING_GET_RESPONSE(_r, _idx)                                     \
+    (&((_r)->sring->ring[((_idx) & (RING_SIZE(_r) - 1))].rsp))
+
+/* Loop termination condition: Would the specified index overflow the ring? */
+#define RING_REQUEST_CONS_OVERFLOW(_r, _cons)                           \
+    (((_cons) - (_r)->rsp_prod_pvt) >= RING_SIZE(_r))
+
+#define RING_PUSH_REQUESTS(_r) do {                                     \
+    wmb(); /* back sees requests /before/ updated producer index */     \
+    (_r)->sring->req_prod = (_r)->req_prod_pvt;                         \
+} while (0)
+
+#define RING_PUSH_RESPONSES(_r) do {                                    \
+    wmb(); /* front sees responses /before/ updated producer index */   \
+    (_r)->sring->rsp_prod = (_r)->rsp_prod_pvt;                         \
+} while (0)
+
+/*
+ * Notification hold-off (req_event and rsp_event):
+ *
+ * When queueing requests or responses on a shared ring, it may not always be
+ * necessary to notify the remote end. For example, if requests are in flight
+ * in a backend, the front may be able to queue further requests without
+ * notifying the back (if the back checks for new requests when it queues
+ * responses).
+ *
+ * When enqueuing requests or responses:
+ *
+ *  Use RING_PUSH_{REQUESTS,RESPONSES}_AND_CHECK_NOTIFY(). The second argument
+ *  is a boolean return value. True indicates that the receiver requires an
+ *  asynchronous notification.
+ *
+ * After dequeuing requests or responses (before sleeping the connection):
+ *
+ *  Use RING_FINAL_CHECK_FOR_REQUESTS() or RING_FINAL_CHECK_FOR_RESPONSES().
+ *  The second argument is a boolean return value. True indicates that there
+ *  are pending messages on the ring (i.e., the connection should not be put
+ *  to sleep).
+ *
+ *  These macros will set the req_event/rsp_event field to trigger a
+ *  notification on the very next message that is enqueued. If you want to
+ *  create batches of work (i.e., only receive a notification after several
+ *  messages have been enqueued) then you will need to create a customised
+ *  version of the FINAL_CHECK macro in your own code, which sets the event
+ *  field appropriately.
+ */
+
+#define RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(_r, _notify) do {           \
+    RING_IDX __old = (_r)->sring->req_prod;                             \
+    RING_IDX __new = (_r)->req_prod_pvt;                                \
+    wmb(); /* back sees requests /before/ updated producer index */     \
+    (_r)->sring->req_prod = __new;                                      \
+    mb(); /* back sees new requests /before/ we check req_event */      \
+    (_notify) = ((RING_IDX)(__new - (_r)->sring->req_event) <           \
+                 (RING_IDX)(__new - __old));                            \
+} while (0)
+
+#define RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(_r, _notify) do {          \
+    RING_IDX __old = (_r)->sring->rsp_prod;                             \
+    RING_IDX __new = (_r)->rsp_prod_pvt;                                \
+    wmb(); /* front sees responses /before/ updated producer index */   \
+    (_r)->sring->rsp_prod = __new;                                      \
+    mb(); /* front sees new responses /before/ we check rsp_event */    \
+    (_notify) = ((RING_IDX)(__new - (_r)->sring->rsp_event) <           \
+                 (RING_IDX)(__new - __old));                            \
+} while (0)
+
+#define RING_FINAL_CHECK_FOR_REQUESTS(_r, _work_to_do) do {             \
+    (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r);                   \
+    if (_work_to_do) break;                                             \
+    (_r)->sring->req_event = (_r)->req_cons + 1;                        \
+    mb();                                                               \
+    (_work_to_do) = RING_HAS_UNCONSUMED_REQUESTS(_r);                   \
+} while (0)
+
+#define RING_FINAL_CHECK_FOR_RESPONSES(_r, _work_to_do) do {            \
+    (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r);                  \
+    if (_work_to_do) break;                                             \
+    (_r)->sring->rsp_event = (_r)->rsp_cons + 1;                        \
+    mb();                                                               \
+    (_work_to_do) = RING_HAS_UNCONSUMED_RESPONSES(_r);                  \
+} while (0)
+
+#endif /* __XEN_PUBLIC_IO_RING_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/io/xenbus.h
@@ -0,0 +1,42 @@
+/*****************************************************************************
+ * xenbus.h
+ *
+ * Xenbus protocol details.
+ *
+ * Copyright (C) 2005 XenSource Ltd.
+ */
+
+#ifndef _XEN_PUBLIC_IO_XENBUS_H
+#define _XEN_PUBLIC_IO_XENBUS_H
+
+/* The state of either end of the Xenbus, i.e. the current communication
+   status of initialisation across the bus.  States here imply nothing about
+   the state of the connection between the driver and the kernel's device
+   layers.  */
+enum xenbus_state
+{
+  XenbusStateUnknown      = 0,
+  XenbusStateInitialising = 1,
+  XenbusStateInitWait     = 2,  /* Finished early initialisation, but waiting
+                                   for information from the peer or hotplug
+				   scripts. */
+  XenbusStateInitialised  = 3,  /* Initialised and waiting for a connection
+				   from the peer. */
+  XenbusStateConnected    = 4,
+  XenbusStateClosing      = 5,  /* The device is being closed due to an error
+				   or an unplug event. */
+  XenbusStateClosed       = 6
+
+};
+
+#endif /* _XEN_PUBLIC_IO_XENBUS_H */
+
+/*
+ * Local variables:
+ *  c-file-style: "linux"
+ *  indent-tabs-mode: t
+ *  c-indent-level: 8
+ *  c-basic-offset: 8
+ *  tab-width: 8
+ * End:
+ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/io/xs_wire.h
@@ -0,0 +1,87 @@
+/*
+ * Details of the "wire" protocol between Xen Store Daemon and client
+ * library or guest kernel.
+ * Copyright (C) 2005 Rusty Russell IBM Corporation
+ */
+
+#ifndef _XS_WIRE_H
+#define _XS_WIRE_H
+
+enum xsd_sockmsg_type
+{
+    XS_DEBUG,
+    XS_DIRECTORY,
+    XS_READ,
+    XS_GET_PERMS,
+    XS_WATCH,
+    XS_UNWATCH,
+    XS_TRANSACTION_START,
+    XS_TRANSACTION_END,
+    XS_INTRODUCE,
+    XS_RELEASE,
+    XS_GET_DOMAIN_PATH,
+    XS_WRITE,
+    XS_MKDIR,
+    XS_RM,
+    XS_SET_PERMS,
+    XS_WATCH_EVENT,
+    XS_ERROR,
+    XS_IS_DOMAIN_INTRODUCED
+};
+
+#define XS_WRITE_NONE "NONE"
+#define XS_WRITE_CREATE "CREATE"
+#define XS_WRITE_CREATE_EXCL "CREATE|EXCL"
+
+/* We hand errors as strings, for portability. */
+struct xsd_errors
+{
+    int errnum;
+    const char *errstring;
+};
+#define XSD_ERROR(x) { x, #x }
+static struct xsd_errors xsd_errors[] __attribute__((unused)) = {
+    XSD_ERROR(EINVAL),
+    XSD_ERROR(EACCES),
+    XSD_ERROR(EEXIST),
+    XSD_ERROR(EISDIR),
+    XSD_ERROR(ENOENT),
+    XSD_ERROR(ENOMEM),
+    XSD_ERROR(ENOSPC),
+    XSD_ERROR(EIO),
+    XSD_ERROR(ENOTEMPTY),
+    XSD_ERROR(ENOSYS),
+    XSD_ERROR(EROFS),
+    XSD_ERROR(EBUSY),
+    XSD_ERROR(EAGAIN),
+    XSD_ERROR(EISCONN)
+};
+
+struct xsd_sockmsg
+{
+    uint32_t type;  /* XS_??? */
+    uint32_t req_id;/* Request identifier, echoed in daemon's response.  */
+    uint32_t tx_id; /* Transaction id (0 if not related to a transaction). */
+    uint32_t len;   /* Length of data following this. */
+
+    /* Generally followed by nul-terminated string(s). */
+};
+
+enum xs_watch_type
+{
+    XS_WATCH_PATH = 0,
+    XS_WATCH_TOKEN
+};
+
+/* Inter-domain shared memory communications. */
+#define XENSTORE_RING_SIZE 1024
+typedef uint32_t XENSTORE_RING_IDX;
+#define MASK_XENSTORE_IDX(idx) ((idx) & (XENSTORE_RING_SIZE-1))
+struct xenstore_domain_interface {
+    char req[XENSTORE_RING_SIZE]; /* Requests to xenstore daemon. */
+    char rsp[XENSTORE_RING_SIZE]; /* Replies and async watch events. */
+    XENSTORE_RING_IDX req_cons, req_prod;
+    XENSTORE_RING_IDX rsp_cons, rsp_prod;
+};
+
+#endif /* _XS_WIRE_H */
===================================================================
--- /dev/null
+++ b/include/xen/interface/memory.h
@@ -0,0 +1,145 @@
+/******************************************************************************
+ * memory.h
+ *
+ * Memory reservation and information.
+ *
+ * Copyright (c) 2005, Keir Fraser <keir@xensource.com>
+ */
+
+#ifndef __XEN_PUBLIC_MEMORY_H__
+#define __XEN_PUBLIC_MEMORY_H__
+
+/*
+ * Increase or decrease the specified domain's memory reservation. Returns a
+ * -ve errcode on failure, or the # extents successfully allocated or freed.
+ * arg == addr of struct xen_memory_reservation.
+ */
+#define XENMEM_increase_reservation 0
+#define XENMEM_decrease_reservation 1
+#define XENMEM_populate_physmap     6
+struct xen_memory_reservation {
+
+    /*
+     * XENMEM_increase_reservation:
+     *   OUT: MFN (*not* GMFN) bases of extents that were allocated
+     * XENMEM_decrease_reservation:
+     *   IN:  GMFN bases of extents to free
+     * XENMEM_populate_physmap:
+     *   IN:  GPFN bases of extents to populate with memory
+     *   OUT: GMFN bases of extents that were allocated
+     *   (NB. This command also updates the mach_to_phys translation table)
+     */
+    GUEST_HANDLE(ulong) extent_start;
+
+    /* Number of extents, and size/alignment of each (2^extent_order pages). */
+    unsigned long  nr_extents;
+    unsigned int   extent_order;
+
+    /*
+     * Maximum # bits addressable by the user of the allocated region (e.g.,
+     * I/O devices often have a 32-bit limitation even in 64-bit systems). If
+     * zero then the user has no addressing restriction.
+     * This field is not used by XENMEM_decrease_reservation.
+     */
+    unsigned int   address_bits;
+
+    /*
+     * Domain whose reservation is being changed.
+     * Unprivileged domains can specify only DOMID_SELF.
+     */
+    domid_t        domid;
+
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_memory_reservation);
+
+/*
+ * Returns the maximum machine frame number of mapped RAM in this system.
+ * This command always succeeds (it never returns an error code).
+ * arg == NULL.
+ */
+#define XENMEM_maximum_ram_page     2
+
+/*
+ * Returns the current or maximum memory reservation, in pages, of the
+ * specified domain (may be DOMID_SELF). Returns -ve errcode on failure.
+ * arg == addr of domid_t.
+ */
+#define XENMEM_current_reservation  3
+#define XENMEM_maximum_reservation  4
+
+/*
+ * Returns a list of MFN bases of 2MB extents comprising the machine_to_phys
+ * mapping table. Architectures which do not have a m2p table do not implement
+ * this command.
+ * arg == addr of xen_machphys_mfn_list_t.
+ */
+#define XENMEM_machphys_mfn_list    5
+struct xen_machphys_mfn_list {
+    /*
+     * Size of the 'extent_start' array. Fewer entries will be filled if the
+     * machphys table is smaller than max_extents * 2MB.
+     */
+    unsigned int max_extents;
+
+    /*
+     * Pointer to buffer to fill with list of extent starts. If there are
+     * any large discontiguities in the machine address space, 2MB gaps in
+     * the machphys table will be represented by an MFN base of zero.
+     */
+    GUEST_HANDLE(ulong) extent_start;
+
+    /*
+     * Number of extents written to the above array. This will be smaller
+     * than 'max_extents' if the machphys table is smaller than max_e * 2MB.
+     */
+    unsigned int nr_extents;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_machphys_mfn_list);
+
+/*
+ * Sets the GPFN at which a particular page appears in the specified guest's
+ * pseudophysical address space.
+ * arg == addr of xen_add_to_physmap_t.
+ */
+#define XENMEM_add_to_physmap      7
+struct xen_add_to_physmap {
+    /* Which domain to change the mapping for. */
+    domid_t domid;
+
+    /* Source mapping space. */
+#define XENMAPSPACE_shared_info 0 /* shared info page */
+#define XENMAPSPACE_grant_table 1 /* grant table page */
+    unsigned int space;
+
+    /* Index into source mapping space. */
+    unsigned long idx;
+
+    /* GPFN where the source mapping page should appear. */
+    unsigned long gpfn;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_add_to_physmap);
+
+/*
+ * Translates a list of domain-specific GPFNs into MFNs. Returns a -ve error
+ * code on failure. This call only works for auto-translated guests.
+ */
+#define XENMEM_translate_gpfn_list  8
+struct xen_translate_gpfn_list {
+    /* Which domain to translate for? */
+    domid_t domid;
+
+    /* Length of list. */
+    unsigned long nr_gpfns;
+
+    /* List of GPFNs to translate. */
+    GUEST_HANDLE(ulong) gpfn_list;
+
+    /*
+     * Output list to contain MFN translations. May be the same as the input
+     * list (in which case each input GPFN is overwritten with the output MFN).
+     */
+    GUEST_HANDLE(ulong) mfn_list;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_translate_gpfn_list);
+
+#endif /* __XEN_PUBLIC_MEMORY_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/physdev.h
@@ -0,0 +1,61 @@
+
+#ifndef __XEN_PUBLIC_PHYSDEV_H__
+#define __XEN_PUBLIC_PHYSDEV_H__
+
+/* Commands to HYPERVISOR_physdev_op() */
+#define PHYSDEVOP_IRQ_UNMASK_NOTIFY     4
+#define PHYSDEVOP_IRQ_STATUS_QUERY      5
+#define PHYSDEVOP_SET_IOPL              6
+#define PHYSDEVOP_SET_IOBITMAP          7
+#define PHYSDEVOP_APIC_READ             8
+#define PHYSDEVOP_APIC_WRITE            9
+#define PHYSDEVOP_ASSIGN_VECTOR         10
+
+struct physdevop_irq_status_query {
+    /* IN */
+    uint32_t irq;
+    /* OUT */
+/* Need to call PHYSDEVOP_IRQ_UNMASK_NOTIFY when the IRQ has been serviced? */
+#define PHYSDEVOP_IRQ_NEEDS_UNMASK_NOTIFY (1<<0)
+    uint32_t flags;
+};
+
+struct physdevop_set_iopl {
+    /* IN */
+    uint32_t iopl;
+};
+
+struct physdevop_set_iobitmap {
+    /* IN */
+    uint8_t *bitmap;
+    uint32_t nr_ports;
+};
+
+struct physdevop_apic {
+    /* IN */
+    unsigned long apic_physbase;
+    uint32_t reg;
+    /* IN or OUT */
+    uint32_t value;
+};
+
+struct physdevop_irq {
+    /* IN */
+    uint32_t irq;
+    /* OUT */
+    uint32_t vector;
+};
+
+struct physdev_op {
+    uint32_t cmd;
+    union {
+        struct physdevop_irq_status_query      irq_status_query;
+        struct physdevop_set_iopl              set_iopl;
+        struct physdevop_set_iobitmap          set_iobitmap;
+        struct physdevop_apic                  apic_op;
+        struct physdevop_irq                   irq_op;
+    } u;
+};
+DEFINE_GUEST_HANDLE_STRUCT(physdev_op);
+
+#endif /* __XEN_PUBLIC_PHYSDEV_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/sched.h
@@ -0,0 +1,77 @@
+/******************************************************************************
+ * sched.h
+ *
+ * Scheduler state interactions
+ *
+ * Copyright (c) 2005, Keir Fraser <keir@xensource.com>
+ */
+
+#ifndef __XEN_PUBLIC_SCHED_H__
+#define __XEN_PUBLIC_SCHED_H__
+
+#include "event_channel.h"
+
+/*
+ * The prototype for this hypercall is:
+ *  long sched_op_new(int cmd, void *arg)
+ * @cmd == SCHEDOP_??? (scheduler operation).
+ * @arg == Operation-specific extra argument(s), as described below.
+ *
+ * **NOTE**:
+ * Versions of Xen prior to 3.0.2 provide only the following legacy version
+ * of this hypercall, supporting only the commands yield, block and shutdown:
+ *  long sched_op(int cmd, unsigned long arg)
+ * @cmd == SCHEDOP_??? (scheduler operation).
+ * @arg == 0               (SCHEDOP_yield and SCHEDOP_block)
+ *      == SHUTDOWN_* code (SCHEDOP_shutdown)
+ */
+
+/*
+ * Voluntarily yield the CPU.
+ * @arg == NULL.
+ */
+#define SCHEDOP_yield       0
+
+/*
+ * Block execution of this VCPU until an event is received for processing.
+ * If called with event upcalls masked, this operation will atomically
+ * reenable event delivery and check for pending events before blocking the
+ * VCPU. This avoids a "wakeup waiting" race.
+ * @arg == NULL.
+ */
+#define SCHEDOP_block       1
+
+/*
+ * Halt execution of this domain (all VCPUs) and notify the system controller.
+ * @arg == pointer to sched_shutdown structure.
+ */
+#define SCHEDOP_shutdown    2
+struct sched_shutdown {
+    unsigned int reason; /* SHUTDOWN_* */
+};
+DEFINE_GUEST_HANDLE_STRUCT(sched_shutdown);
+
+/*
+ * Poll a set of event-channel ports. Return when one or more are pending. An
+ * optional timeout may be specified.
+ * @arg == pointer to sched_poll structure.
+ */
+#define SCHEDOP_poll        3
+struct sched_poll {
+    GUEST_HANDLE(evtchn_port_t) ports;
+    unsigned int nr_ports;
+    uint64_t timeout;
+};
+DEFINE_GUEST_HANDLE_STRUCT(sched_poll);
+
+/*
+ * Reason codes for SCHEDOP_shutdown. These may be interpreted by control
+ * software to determine the appropriate action. For the most part, Xen does
+ * not care about the shutdown code.
+ */
+#define SHUTDOWN_poweroff   0  /* Domain exited normally. Clean up and kill. */
+#define SHUTDOWN_reboot     1  /* Clean up, kill, and then restart.          */
+#define SHUTDOWN_suspend    2  /* Clean up, save suspend info, kill.         */
+#define SHUTDOWN_crash      3  /* Tell controller we've crashed.             */
+
+#endif /* __XEN_PUBLIC_SCHED_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/vcpu.h
@@ -0,0 +1,164 @@
+/******************************************************************************
+ * vcpu.h
+ *
+ * VCPU initialisation, query, and hotplug.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Copyright (c) 2005, Keir Fraser <keir@xensource.com>
+ */
+
+#ifndef __XEN_PUBLIC_VCPU_H__
+#define __XEN_PUBLIC_VCPU_H__
+
+/*
+ * Prototype for this hypercall is:
+ *  int vcpu_op(int cmd, int vcpuid, void *extra_args)
+ * @cmd        == VCPUOP_??? (VCPU operation).
+ * @vcpuid     == VCPU to operate on.
+ * @extra_args == Operation-specific extra arguments (NULL if none).
+ */
+
+/*
+ * Initialise a VCPU. Each VCPU can be initialised only once. A
+ * newly-initialised VCPU will not run until it is brought up by VCPUOP_up.
+ *
+ * @extra_arg == pointer to vcpu_guest_context structure containing initial
+ *               state for the VCPU.
+ */
+#define VCPUOP_initialise            0
+
+/*
+ * Bring up a VCPU. This makes the VCPU runnable. This operation will fail
+ * if the VCPU has not been initialised (VCPUOP_initialise).
+ */
+#define VCPUOP_up                    1
+
+/*
+ * Bring down a VCPU (i.e., make it non-runnable).
+ * There are a few caveats that callers should observe:
+ *  1. This operation may return, and VCPU_is_up may return false, before the
+ *     VCPU stops running (i.e., the command is asynchronous). It is a good
+ *     idea to ensure that the VCPU has entered a non-critical loop before
+ *     bringing it down. Alternatively, this operation is guaranteed
+ *     synchronous if invoked by the VCPU itself.
+ *  2. After a VCPU is initialised, there is currently no way to drop all its
+ *     references to domain memory. Even a VCPU that is down still holds
+ *     memory references via its pagetable base pointer and GDT. It is good
+ *     practise to move a VCPU onto an 'idle' or default page table, LDT and
+ *     GDT before bringing it down.
+ */
+#define VCPUOP_down                  2
+
+/* Returns 1 if the given VCPU is up. */
+#define VCPUOP_is_up                 3
+
+/*
+ * Return information about the state and running time of a VCPU.
+ * @extra_arg == pointer to vcpu_runstate_info structure.
+ */
+#define VCPUOP_get_runstate_info     4
+struct vcpu_runstate_info {
+    /* VCPU's current state (RUNSTATE_*). */
+    int      state;
+    /* When was current state entered (system time, ns)? */
+    uint64_t state_entry_time;
+    /*
+     * Time spent in each RUNSTATE_* (ns). The sum of these times is
+     * guaranteed not to drift from system time.
+     */
+    uint64_t time[4];
+};
+
+/* VCPU is currently running on a physical CPU. */
+#define RUNSTATE_running  0
+
+/* VCPU is runnable, but not currently scheduled on any physical CPU. */
+#define RUNSTATE_runnable 1
+
+/* VCPU is blocked (a.k.a. idle). It is therefore not runnable. */
+#define RUNSTATE_blocked  2
+
+/*
+ * VCPU is not runnable, but it is not blocked.
+ * This is a 'catch all' state for things like hotplug and pauses by the
+ * system administrator (or for critical sections in the hypervisor).
+ * RUNSTATE_blocked dominates this state (it is the preferred state).
+ */
+#define RUNSTATE_offline  3
+
+/*
+ * Register a shared memory area from which the guest may obtain its own
+ * runstate information without needing to execute a hypercall.
+ * Notes:
+ *  1. The registered address may be virtual or physical, depending on the
+ *     platform. The virtual address should be registered on x86 systems.
+ *  2. Only one shared area may be registered per VCPU. The shared area is
+ *     updated by the hypervisor each time the VCPU is scheduled. Thus
+ *     runstate.state will always be RUNSTATE_running and
+ *     runstate.state_entry_time will indicate the system time at which the
+ *     VCPU was last scheduled to run.
+ * @extra_arg == pointer to vcpu_register_runstate_memory_area structure.
+ */
+#define VCPUOP_register_runstate_memory_area 5
+struct vcpu_register_runstate_memory_area {
+    union {
+        struct vcpu_runstate_info *v;
+        uint64_t p;
+    } addr;
+};
+
+/*
+ * Set or stop a VCPU's periodic timer. Every VCPU has one periodic timer
+ * which can be set via these commands. Periods smaller than one millisecond
+ * may not be supported.
+ */
+#define VCPUOP_set_periodic_timer    6 /* arg == vcpu_set_periodic_timer_t */
+#define VCPUOP_stop_periodic_timer   7 /* arg == NULL */
+struct vcpu_set_periodic_timer {
+    uint64_t period_ns;
+};
+
+/*
+ * Set or stop a VCPU's single-shot timer. Every VCPU has one single-shot
+ * timer which can be set via these commands.
+ */
+#define VCPUOP_set_singleshot_timer  8 /* arg == vcpu_set_singleshot_timer_t */
+#define VCPUOP_stop_singleshot_timer 9 /* arg == NULL */
+struct vcpu_set_singleshot_timer {
+    uint64_t timeout_abs_ns;
+    uint32_t flags;            /* VCPU_SSHOTTMR_??? */
+};
+
+/* Flags to VCPUOP_set_singleshot_timer. */
+ /* Require the timeout to be in the future (return -ETIME if it's passed). */
+#define _VCPU_SSHOTTMR_future (0)
+#define VCPU_SSHOTTMR_future  (1U << _VCPU_SSHOTTMR_future)
+
+#endif /* __XEN_PUBLIC_VCPU_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/version.h
@@ -0,0 +1,60 @@
+/******************************************************************************
+ * version.h
+ *
+ * Xen version, type, and compile information.
+ *
+ * Copyright (c) 2005, Nguyen Anh Quynh <aquynh@gmail.com>
+ * Copyright (c) 2005, Keir Fraser <keir@xensource.com>
+ */
+
+#ifndef __XEN_PUBLIC_VERSION_H__
+#define __XEN_PUBLIC_VERSION_H__
+
+/* NB. All ops return zero on success, except XENVER_version. */
+
+/* arg == NULL; returns major:minor (16:16). */
+#define XENVER_version      0
+
+/* arg == xen_extraversion_t. */
+#define XENVER_extraversion 1
+struct xen_extraversion {
+    char extraversion[16];
+};
+#define XEN_EXTRAVERSION_LEN (sizeof(struct xen_extraversion))
+
+/* arg == xen_compile_info_t. */
+#define XENVER_compile_info 2
+struct xen_compile_info {
+    char compiler[64];
+    char compile_by[16];
+    char compile_domain[32];
+    char compile_date[32];
+};
+
+#define XENVER_capabilities 3
+struct xen_capabilities_info {
+    char info[1024];
+};
+#define XEN_CAPABILITIES_INFO_LEN (sizeof(struct xen_capabilities_info))
+
+#define XENVER_changeset 4
+struct xen_changeset_info {
+    char info[64];
+};
+#define XEN_CHANGESET_INFO_LEN (sizeof(struct xen_changeset_info))
+
+#define XENVER_platform_parameters 5
+struct xen_platform_parameters {
+    unsigned long virt_start;
+};
+
+#define XENVER_get_features 6
+struct xen_feature_info {
+    unsigned int submap_idx;    /* IN: which 32-bit submap to return */
+    uint32_t     submap;        /* OUT: 32-bit submap */
+};
+
+/* Declares the features reported by XENVER_get_features. */
+#include "features.h"
+
+#endif /* __XEN_PUBLIC_VERSION_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/interface/xen.h
@@ -0,0 +1,446 @@
+/******************************************************************************
+ * xen.h
+ *
+ * Guest OS interface to Xen.
+ *
+ * Copyright (c) 2004, K A Fraser
+ */
+
+#ifndef __XEN_PUBLIC_XEN_H__
+#define __XEN_PUBLIC_XEN_H__
+
+#include <asm/xen/interface.h>
+
+/*
+ * XEN "SYSTEM CALLS" (a.k.a. HYPERCALLS).
+ */
+
+/*
+ * x86_32: EAX = vector; EBX, ECX, EDX, ESI, EDI = args 1, 2, 3, 4, 5.
+ *         EAX = return value
+ *         (argument registers may be clobbered on return)
+ * x86_64: RAX = vector; RDI, RSI, RDX, R10, R8, R9 = args 1, 2, 3, 4, 5, 6.
+ *         RAX = return value
+ *         (argument registers not clobbered on return; RCX, R11 are)
+ */
+#define __HYPERVISOR_set_trap_table        0
+#define __HYPERVISOR_mmu_update            1
+#define __HYPERVISOR_set_gdt               2
+#define __HYPERVISOR_stack_switch          3
+#define __HYPERVISOR_set_callbacks         4
+#define __HYPERVISOR_fpu_taskswitch        5
+#define __HYPERVISOR_sched_op              6
+#define __HYPERVISOR_dom0_op               7
+#define __HYPERVISOR_set_debugreg          8
+#define __HYPERVISOR_get_debugreg          9
+#define __HYPERVISOR_update_descriptor    10
+#define __HYPERVISOR_memory_op            12
+#define __HYPERVISOR_multicall            13
+#define __HYPERVISOR_update_va_mapping    14
+#define __HYPERVISOR_set_timer_op         15
+#define __HYPERVISOR_event_channel_op_compat 16
+#define __HYPERVISOR_xen_version          17
+#define __HYPERVISOR_console_io           18
+#define __HYPERVISOR_physdev_op_compat    19
+#define __HYPERVISOR_grant_table_op       20
+#define __HYPERVISOR_vm_assist            21
+#define __HYPERVISOR_update_va_mapping_otherdomain 22
+#define __HYPERVISOR_iret                 23 /* x86 only */
+#define __HYPERVISOR_vcpu_op              24
+#define __HYPERVISOR_set_segment_base     25 /* x86/64 only */
+#define __HYPERVISOR_mmuext_op            26
+#define __HYPERVISOR_acm_op               27
+#define __HYPERVISOR_nmi_op               28
+#define __HYPERVISOR_sched_op_new         29
+#define __HYPERVISOR_callback_op          30
+#define __HYPERVISOR_xenoprof_op          31
+#define __HYPERVISOR_event_channel_op     32
+#define __HYPERVISOR_physdev_op           33
+#define __HYPERVISOR_hvm_op               34
+
+/*
+ * VIRTUAL INTERRUPTS
+ *
+ * Virtual interrupts that a guest OS may receive from Xen.
+ */
+#define VIRQ_TIMER      0  /* Timebase update, and/or requested timeout.  */
+#define VIRQ_DEBUG      1  /* Request guest to dump debug info.           */
+#define VIRQ_CONSOLE    2  /* (DOM0) Bytes received on emergency console. */
+#define VIRQ_DOM_EXC    3  /* (DOM0) Exceptional event for some domain.   */
+#define VIRQ_DEBUGGER   6  /* (DOM0) A domain has paused for debugging.   */
+#define NR_VIRQS        8
+
+/*
+ * MMU-UPDATE REQUESTS
+ *
+ * HYPERVISOR_mmu_update() accepts a list of (ptr, val) pairs.
+ * A foreigndom (FD) can be specified (or DOMID_SELF for none).
+ * Where the FD has some effect, it is described below.
+ * ptr[1:0] specifies the appropriate MMU_* command.
+ *
+ * ptr[1:0] == MMU_NORMAL_PT_UPDATE:
+ * Updates an entry in a page table. If updating an L1 table, and the new
+ * table entry is valid/present, the mapped frame must belong to the FD, if
+ * an FD has been specified. If attempting to map an I/O page then the
+ * caller assumes the privilege of the FD.
+ * FD == DOMID_IO: Permit /only/ I/O mappings, at the priv level of the caller.
+ * FD == DOMID_XEN: Map restricted areas of Xen's heap space.
+ * ptr[:2]  -- Machine address of the page-table entry to modify.
+ * val      -- Value to write.
+ *
+ * ptr[1:0] == MMU_MACHPHYS_UPDATE:
+ * Updates an entry in the machine->pseudo-physical mapping table.
+ * ptr[:2]  -- Machine address within the frame whose mapping to modify.
+ *             The frame must belong to the FD, if one is specified.
+ * val      -- Value to write into the mapping entry.
+ */
+#define MMU_NORMAL_PT_UPDATE     0 /* checked '*ptr = val'. ptr is MA.       */
+#define MMU_MACHPHYS_UPDATE      1 /* ptr = MA of frame to modify entry for  */
+
+/*
+ * MMU EXTENDED OPERATIONS
+ *
+ * HYPERVISOR_mmuext_op() accepts a list of mmuext_op structures.
+ * A foreigndom (FD) can be specified (or DOMID_SELF for none).
+ * Where the FD has some effect, it is described below.
+ *
+ * cmd: MMUEXT_(UN)PIN_*_TABLE
+ * mfn: Machine frame number to be (un)pinned as a p.t. page.
+ *      The frame must belong to the FD, if one is specified.
+ *
+ * cmd: MMUEXT_NEW_BASEPTR
+ * mfn: Machine frame number of new page-table base to install in MMU.
+ *
+ * cmd: MMUEXT_NEW_USER_BASEPTR [x86/64 only]
+ * mfn: Machine frame number of new page-table base to install in MMU
+ *      when in user space.
+ *
+ * cmd: MMUEXT_TLB_FLUSH_LOCAL
+ * No additional arguments. Flushes local TLB.
+ *
+ * cmd: MMUEXT_INVLPG_LOCAL
+ * linear_addr: Linear address to be flushed from the local TLB.
+ *
+ * cmd: MMUEXT_TLB_FLUSH_MULTI
+ * vcpumask: Pointer to bitmap of VCPUs to be flushed.
+ *
+ * cmd: MMUEXT_INVLPG_MULTI
+ * linear_addr: Linear address to be flushed.
+ * vcpumask: Pointer to bitmap of VCPUs to be flushed.
+ *
+ * cmd: MMUEXT_TLB_FLUSH_ALL
+ * No additional arguments. Flushes all VCPUs' TLBs.
+ *
+ * cmd: MMUEXT_INVLPG_ALL
+ * linear_addr: Linear address to be flushed from all VCPUs' TLBs.
+ *
+ * cmd: MMUEXT_FLUSH_CACHE
+ * No additional arguments. Writes back and flushes cache contents.
+ *
+ * cmd: MMUEXT_SET_LDT
+ * linear_addr: Linear address of LDT base (NB. must be page-aligned).
+ * nr_ents: Number of entries in LDT.
+ */
+#define MMUEXT_PIN_L1_TABLE      0
+#define MMUEXT_PIN_L2_TABLE      1
+#define MMUEXT_PIN_L3_TABLE      2
+#define MMUEXT_PIN_L4_TABLE      3
+#define MMUEXT_UNPIN_TABLE       4
+#define MMUEXT_NEW_BASEPTR       5
+#define MMUEXT_TLB_FLUSH_LOCAL   6
+#define MMUEXT_INVLPG_LOCAL      7
+#define MMUEXT_TLB_FLUSH_MULTI   8
+#define MMUEXT_INVLPG_MULTI      9
+#define MMUEXT_TLB_FLUSH_ALL    10
+#define MMUEXT_INVLPG_ALL       11
+#define MMUEXT_FLUSH_CACHE      12
+#define MMUEXT_SET_LDT          13
+#define MMUEXT_NEW_USER_BASEPTR 15
+
+#ifndef __ASSEMBLY__
+struct mmuext_op {
+    unsigned int cmd;
+    union {
+        /* [UN]PIN_TABLE, NEW_BASEPTR, NEW_USER_BASEPTR */
+        unsigned long mfn;
+        /* INVLPG_LOCAL, INVLPG_ALL, SET_LDT */
+        unsigned long linear_addr;
+    } arg1;
+    union {
+        /* SET_LDT */
+        unsigned int nr_ents;
+        /* TLB_FLUSH_MULTI, INVLPG_MULTI */
+        void *vcpumask;
+    } arg2;
+};
+DEFINE_GUEST_HANDLE_STRUCT(mmuext_op);
+#endif
+
+/* These are passed as 'flags' to update_va_mapping. They can be ORed. */
+/* When specifying UVMF_MULTI, also OR in a pointer to a CPU bitmap.   */
+/* UVMF_LOCAL is merely UVMF_MULTI with a NULL bitmap pointer.         */
+#define UVMF_NONE               (0UL<<0) /* No flushing at all.   */
+#define UVMF_TLB_FLUSH          (1UL<<0) /* Flush entire TLB(s).  */
+#define UVMF_INVLPG             (2UL<<0) /* Flush only one entry. */
+#define UVMF_FLUSHTYPE_MASK     (3UL<<0)
+#define UVMF_MULTI              (0UL<<2) /* Flush subset of TLBs. */
+#define UVMF_LOCAL              (0UL<<2) /* Flush local TLB.      */
+#define UVMF_ALL                (1UL<<2) /* Flush all TLBs.       */
+
+/*
+ * Commands to HYPERVISOR_console_io().
+ */
+#define CONSOLEIO_write         0
+#define CONSOLEIO_read          1
+
+/*
+ * Commands to HYPERVISOR_vm_assist().
+ */
+#define VMASST_CMD_enable                0
+#define VMASST_CMD_disable               1
+#define VMASST_TYPE_4gb_segments         0
+#define VMASST_TYPE_4gb_segments_notify  1
+#define VMASST_TYPE_writable_pagetables  2
+#define VMASST_TYPE_pae_extended_cr3     3
+#define MAX_VMASST_TYPE 3
+
+#ifndef __ASSEMBLY__
+
+typedef uint16_t domid_t;
+
+/* Domain ids >= DOMID_FIRST_RESERVED cannot be used for ordinary domains. */
+#define DOMID_FIRST_RESERVED (0x7FF0U)
+
+/* DOMID_SELF is used in certain contexts to refer to oneself. */
+#define DOMID_SELF (0x7FF0U)
+
+/*
+ * DOMID_IO is used to restrict page-table updates to mapping I/O memory.
+ * Although no Foreign Domain need be specified to map I/O pages, DOMID_IO
+ * is useful to ensure that no mappings to the OS's own heap are accidentally
+ * installed. (e.g., in Linux this could cause havoc as reference counts
+ * aren't adjusted on the I/O-mapping code path).
+ * This only makes sense in MMUEXT_SET_FOREIGNDOM, but in that context can
+ * be specified by any calling domain.
+ */
+#define DOMID_IO   (0x7FF1U)
+
+/*
+ * DOMID_XEN is used to allow privileged domains to map restricted parts of
+ * Xen's heap space (e.g., the machine_to_phys table).
+ * This only makes sense in MMUEXT_SET_FOREIGNDOM, and is only permitted if
+ * the caller is privileged.
+ */
+#define DOMID_XEN  (0x7FF2U)
+
+/*
+ * Send an array of these to HYPERVISOR_mmu_update().
+ * NB. The fields are natural pointer/address size for this architecture.
+ */
+struct mmu_update {
+    uint64_t ptr;       /* Machine address of PTE. */
+    uint64_t val;       /* New contents of PTE.    */
+};
+DEFINE_GUEST_HANDLE_STRUCT(mmu_update);
+
+/*
+ * Send an array of these to HYPERVISOR_multicall().
+ * NB. The fields are natural register size for this architecture.
+ */
+struct multicall_entry {
+    unsigned long op;
+    long result;
+    unsigned long args[6];
+};
+DEFINE_GUEST_HANDLE_STRUCT(multicall_entry);
+
+/*
+ * Event channel endpoints per domain:
+ *  1024 if a long is 32 bits; 4096 if a long is 64 bits.
+ */
+#define NR_EVENT_CHANNELS (sizeof(unsigned long) * sizeof(unsigned long) * 64)
+
+struct vcpu_time_info {
+    /*
+     * Updates to the following values are preceded and followed by an
+     * increment of 'version'. The guest can therefore detect updates by
+     * looking for changes to 'version'. If the least-significant bit of
+     * the version number is set then an update is in progress and the guest
+     * must wait to read a consistent set of values.
+     * The correct way to interact with the version number is similar to
+     * Linux's seqlock: see the implementations of read_seqbegin/read_seqretry.
+     */
+    uint32_t version;
+    uint32_t pad0;
+    uint64_t tsc_timestamp;   /* TSC at last update of time vals.  */
+    uint64_t system_time;     /* Time, in nanosecs, since boot.    */
+    /*
+     * Current system time:
+     *   system_time + ((tsc - tsc_timestamp) << tsc_shift) * tsc_to_system_mul
+     * CPU frequency (Hz):
+     *   ((10^9 << 32) / tsc_to_system_mul) >> tsc_shift
+     */
+    uint32_t tsc_to_system_mul;
+    int8_t   tsc_shift;
+    int8_t   pad1[3];
+}; /* 32 bytes */
+
+struct vcpu_info {
+    /*
+     * 'evtchn_upcall_pending' is written non-zero by Xen to indicate
+     * a pending notification for a particular VCPU. It is then cleared
+     * by the guest OS /before/ checking for pending work, thus avoiding
+     * a set-and-check race. Note that the mask is only accessed by Xen
+     * on the CPU that is currently hosting the VCPU. This means that the
+     * pending and mask flags can be updated by the guest without special
+     * synchronisation (i.e., no need for the x86 LOCK prefix).
+     * This may seem suboptimal because if the pending flag is set by
+     * a different CPU then an IPI may be scheduled even when the mask
+     * is set. However, note:
+     *  1. The task of 'interrupt holdoff' is covered by the per-event-
+     *     channel mask bits. A 'noisy' event that is continually being
+     *     triggered can be masked at source at this very precise
+     *     granularity.
+     *  2. The main purpose of the per-VCPU mask is therefore to restrict
+     *     reentrant execution: whether for concurrency control, or to
+     *     prevent unbounded stack usage. Whatever the purpose, we expect
+     *     that the mask will be asserted only for short periods at a time,
+     *     and so the likelihood of a 'spurious' IPI is suitably small.
+     * The mask is read before making an event upcall to the guest: a
+     * non-zero mask therefore guarantees that the VCPU will not receive
+     * an upcall activation. The mask is cleared when the VCPU requests
+     * to block: this avoids wakeup-waiting races.
+     */
+    uint8_t evtchn_upcall_pending;
+    uint8_t evtchn_upcall_mask;
+    unsigned long evtchn_pending_sel;
+    struct arch_vcpu_info arch;
+    struct vcpu_time_info time;
+}; /* 64 bytes (x86) */
+
+/*
+ * Xen/kernel shared data -- pointer provided in start_info.
+ * NB. We expect that this struct is smaller than a page.
+ */
+struct shared_info {
+    struct vcpu_info vcpu_info[MAX_VIRT_CPUS];
+
+    /*
+     * A domain can create "event channels" on which it can send and receive
+     * asynchronous event notifications. There are three classes of event that
+     * are delivered by this mechanism:
+     *  1. Bi-directional inter- and intra-domain connections. Domains must
+     *     arrange out-of-band to set up a connection (usually by allocating
+     *     an unbound 'listener' port and avertising that via a storage service
+     *     such as xenstore).
+     *  2. Physical interrupts. A domain with suitable hardware-access
+     *     privileges can bind an event-channel port to a physical interrupt
+     *     source.
+     *  3. Virtual interrupts ('events'). A domain can bind an event-channel
+     *     port to a virtual interrupt source, such as the virtual-timer
+     *     device or the emergency console.
+     *
+     * Event channels are addressed by a "port index". Each channel is
+     * associated with two bits of information:
+     *  1. PENDING -- notifies the domain that there is a pending notification
+     *     to be processed. This bit is cleared by the guest.
+     *  2. MASK -- if this bit is clear then a 0->1 transition of PENDING
+     *     will cause an asynchronous upcall to be scheduled. This bit is only
+     *     updated by the guest. It is read-only within Xen. If a channel
+     *     becomes pending while the channel is masked then the 'edge' is lost
+     *     (i.e., when the channel is unmasked, the guest must manually handle
+     *     pending notifications as no upcall will be scheduled by Xen).
+     *
+     * To expedite scanning of pending notifications, any 0->1 pending
+     * transition on an unmasked channel causes a corresponding bit in a
+     * per-vcpu selector word to be set. Each bit in the selector covers a
+     * 'C long' in the PENDING bitfield array.
+     */
+    unsigned long evtchn_pending[sizeof(unsigned long) * 8];
+    unsigned long evtchn_mask[sizeof(unsigned long) * 8];
+
+    /*
+     * Wallclock time: updated only by control software. Guests should base
+     * their gettimeofday() syscall on this wallclock-base value.
+     */
+    uint32_t wc_version;      /* Version counter: see vcpu_time_info_t. */
+    uint32_t wc_sec;          /* Secs  00:00:00 UTC, Jan 1, 1970.  */
+    uint32_t wc_nsec;         /* Nsecs 00:00:00 UTC, Jan 1, 1970.  */
+
+    struct arch_shared_info arch;
+
+};
+
+/*
+ * Start-of-day memory layout for the initial domain (DOM0):
+ *  1. The domain is started within contiguous virtual-memory region.
+ *  2. The contiguous region begins and ends on an aligned 4MB boundary.
+ *  3. The region start corresponds to the load address of the OS image.
+ *     If the load address is not 4MB aligned then the address is rounded down.
+ *  4. This the order of bootstrap elements in the initial virtual region:
+ *      a. relocated kernel image
+ *      b. initial ram disk              [mod_start, mod_len]
+ *      c. list of allocated page frames [mfn_list, nr_pages]
+ *      d. start_info_t structure        [register ESI (x86)]
+ *      e. bootstrap page tables         [pt_base, CR3 (x86)]
+ *      f. bootstrap stack               [register ESP (x86)]
+ *  5. Bootstrap elements are packed together, but each is 4kB-aligned.
+ *  6. The initial ram disk may be omitted.
+ *  7. The list of page frames forms a contiguous 'pseudo-physical' memory
+ *     layout for the domain. In particular, the bootstrap virtual-memory
+ *     region is a 1:1 mapping to the first section of the pseudo-physical map.
+ *  8. All bootstrap elements are mapped read-writable for the guest OS. The
+ *     only exception is the bootstrap page table, which is mapped read-only.
+ *  9. There is guaranteed to be at least 512kB padding after the final
+ *     bootstrap element. If necessary, the bootstrap virtual region is
+ *     extended by an extra 4MB to ensure this.
+ */
+
+#define MAX_GUEST_CMDLINE 1024
+struct start_info {
+    /* THE FOLLOWING ARE FILLED IN BOTH ON INITIAL BOOT AND ON RESUME.    */
+    char magic[32];             /* "xen-<version>-<platform>".            */
+    unsigned long nr_pages;     /* Total pages allocated to this domain.  */
+    unsigned long shared_info;  /* MACHINE address of shared info struct. */
+    uint32_t flags;             /* SIF_xxx flags.                         */
+    unsigned long store_mfn;    /* MACHINE page number of shared page.    */
+    uint32_t store_evtchn;      /* Event channel for store communication. */
+    union {
+        struct {
+            unsigned long mfn;      /* MACHINE page number of console page.   */
+            uint32_t  evtchn;   /* Event channel for console page.        */
+        } domU;
+        struct {
+            uint32_t info_off;  /* Offset of console_info struct.         */
+            uint32_t info_size; /* Size of console_info struct from start.*/
+        } dom0;
+    } console;
+    /* THE FOLLOWING ARE ONLY FILLED IN ON INITIAL BOOT (NOT RESUME).     */
+    unsigned long pt_base;      /* VIRTUAL address of page directory.     */
+    unsigned long nr_pt_frames; /* Number of bootstrap p.t. frames.       */
+    unsigned long mfn_list;     /* VIRTUAL address of page-frame list.    */
+    unsigned long mod_start;    /* VIRTUAL address of pre-loaded module.  */
+    unsigned long mod_len;      /* Size (bytes) of pre-loaded module.     */
+    int8_t cmd_line[MAX_GUEST_CMDLINE];
+};
+
+/* These flags are passed in the 'flags' field of start_info_t. */
+#define SIF_PRIVILEGED    (1<<0)  /* Is the domain privileged? */
+#define SIF_INITDOMAIN    (1<<1)  /* Is this the initial control domain? */
+
+typedef uint64_t cpumap_t;
+
+typedef uint8_t xen_domain_handle_t[16];
+
+/* Turn a plain number into a C unsigned long constant. */
+#define __mk_unsigned_long(x) x ## UL
+#define mk_unsigned_long(x) __mk_unsigned_long(x)
+
+#else /* __ASSEMBLY__ */
+
+/* In assembly code we cannot use C numeric constant suffixes. */
+#define mk_unsigned_long(x) x
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __XEN_PUBLIC_XEN_H__ */

-- 

[PATCH 06/25] xen: Core Xen implementation

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-core.patch --]
[-- Type: text/plain, Size: 73145 bytes --]

Core Xen Implementation

This patch is a rollup of all the core pieces of the Xen
implementation, including booting, memory management, interrupts, time
and so on.

This adds a second entry point to head.S, which is jumped to when
booted by Xen.  This allows startup under Xen to be easily detected.

Because Xen starts the kernel in a fairly sane state, very little
setup is needed here; it just needs to jump into xen_start_kernel to
init the paravirt_ops structure, and then jump into start_kernel
proper.

This also makes a few small adjustments to the gdt tables to make them
properly suited to Xen.

This patch also contains an initial set of paravirt ops for Xen,
mostly ones which can just be implemented with the generic native_*
version.  At boot time, the global paravirt_ops structure is populated
with the Xen pointers in xen_start_kernel, which then jumps to the
standard start_kernel.

Also implements Xen pagetable handling, including the machinery to
implement direct pagetables.  This means that pte update operations
are intercepted so that pseudo-physical addresses can be converted to
machine addresses.  It also implements late pinning/early unpinning so
that pagetables are initialized while they're normal read-write memory
as much as possible, yet pinned to make cr3 reloads as efficient as
possible.

Xen implements interrupts in terms of event channels.  This patch maps
an event through an event channel to an irq, and then feeds it through
the normal interrupt path, via a Xen irq_chip implementation.

Context switches are optimised with the use of multicalls, so that the
multiple hypercalls needed to perform the switch can be implemented
with a single hypercall.  In order to simplify the source changes,
this is done via a generic multicall batching mechanism, which can be
used to batch arbitrary series of hypercalls into a multicall.

Time is implemented by using a clocksource which is driven from the
hypervisor's nanosecond timebase.  Xen implements time by
extrapolating from known timestamps using the tsc; the hypervisor is
responsible for making sure that the tsc is constant rate and
synchronized between vcpus.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Ian Pratt <ian.pratt@xensource.com>
Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Cc: Adrian Bunk <bunk@stusta.de>

---
 arch/i386/Makefile               |    3 
 arch/i386/kernel/entry.S         |   79 ++++
 arch/i386/kernel/head.S          |    5 
 arch/i386/kernel/paravirt.c      |    3 
 arch/i386/kernel/vmlinux.lds.S   |    1 
 arch/i386/xen/Kconfig            |    2 
 arch/i386/xen/Makefile           |    2 
 arch/i386/xen/enlighten.c        |  727 ++++++++++++++++++++++++++++++++++++++
 arch/i386/xen/events.c           |  487 +++++++++++++++++++++++++
 arch/i386/xen/features.c         |   29 +
 arch/i386/xen/mmu.c              |  377 +++++++++++++++++++
 arch/i386/xen/mmu.h              |   47 ++
 arch/i386/xen/multicalls.c       |   61 +++
 arch/i386/xen/multicalls.h       |   26 +
 arch/i386/xen/setup.c            |   93 ++++
 arch/i386/xen/time.c             |  393 ++++++++++++++++++++
 arch/i386/xen/xen-head.S         |   34 +
 arch/i386/xen/xen-ops.h          |   34 +
 include/asm-i386/irq.h           |    1 
 include/asm-i386/xen/hypercall.h |   18 
 include/xen/events.h             |   28 +
 include/xen/features.h           |   26 +
 include/xen/page.h               |  178 +++++++++
 23 files changed, 2650 insertions(+), 4 deletions(-)

===================================================================
--- a/arch/i386/Makefile
+++ b/arch/i386/Makefile
@@ -93,6 +93,9 @@ mcore-$(CONFIG_X86_ES7000)	:= mach-defau
 mcore-$(CONFIG_X86_ES7000)	:= mach-default
 core-$(CONFIG_X86_ES7000)	:= arch/i386/mach-es7000/
 
+# Xen paravirtualization support
+core-$(CONFIG_XEN)		+= arch/i386/xen/
+
 # default subarch .h files
 mflags-y += -Iinclude/asm-i386/mach-default
 
===================================================================
--- a/arch/i386/kernel/entry.S
+++ b/arch/i386/kernel/entry.S
@@ -1023,6 +1023,85 @@ ENTRY(kernel_thread_helper)
 	CFI_ENDPROC
 ENDPROC(kernel_thread_helper)
 
+#ifdef CONFIG_XEN
+/* Xen only supports sysenter/sysexit in ring0 guests,
+   and only if it the guest asks for it.  So for now,
+   this should never be used. */
+ENTRY(xen_sti_sysexit)
+	CFI_STARTPROC
+	ud2
+	CFI_ENDPROC
+ENDPROC(xen_sti_sysexit)
+
+ENTRY(xen_hypervisor_callback)
+	CFI_STARTPROC
+	pushl $0
+	CFI_ADJUST_CFA_OFFSET 4
+	SAVE_ALL
+	mov %esp, %eax
+	call xen_evtchn_do_upcall
+	jmp  ret_from_intr
+	CFI_ENDPROC
+ENDPROC(xen_hypervisor_callback)
+
+# Hypervisor uses this for application faults while it executes.
+# We get here for two reasons:
+#  1. Fault while reloading DS, ES, FS or GS
+#  2. Fault while executing IRET
+# Category 1 we fix up by reattempting the load, and zeroing the segment
+# register if the load fails.
+# Category 2 we fix up by jumping to do_iret_error. We cannot use the
+# normal Linux return path in this case because if we use the IRET hypercall
+# to pop the stack frame we end up in an infinite loop of failsafe callbacks.
+# We distinguish between categories by maintaining a status value in EAX.
+ENTRY(xen_failsafe_callback)
+	CFI_STARTPROC
+	pushl %eax
+	CFI_ADJUST_CFA_OFFSET 4
+	movl $1,%eax
+1:	mov 4(%esp),%ds
+2:	mov 8(%esp),%es
+3:	mov 12(%esp),%fs
+4:	mov 16(%esp),%gs
+	testl %eax,%eax
+	popl %eax
+	CFI_ADJUST_CFA_OFFSET -4
+	lea 16(%esp),%esp
+	CFI_ADJUST_CFA_OFFSET -16
+	jz 5f
+	addl $16,%esp
+	jmp iret_exc		# EAX != 0 => Category 2 (Bad IRET)
+5:	pushl $0		# EAX == 0 => Category 1 (Bad segment)
+	CFI_ADJUST_CFA_OFFSET 4
+	SAVE_ALL
+	jmp ret_from_exception
+	CFI_ENDPROC
+
+.section .fixup,"ax"
+6:	xorl %eax,%eax
+	movl %eax,4(%esp)
+	jmp 1b
+7:	xorl %eax,%eax
+	movl %eax,8(%esp)
+	jmp 2b
+8:	xorl %eax,%eax
+	movl %eax,12(%esp)
+	jmp 3b
+9:	xorl %eax,%eax
+	movl %eax,16(%esp)
+	jmp 4b
+.previous
+.section __ex_table,"a"
+	.align 4
+	.long 1b,6b
+	.long 2b,7b
+	.long 3b,8b
+	.long 4b,9b
+.previous
+ENDPROC(xen_failsafe_callback)
+
+#endif	/* CONFIG_XEN */
+
 .section .rodata,"a"
 #include "syscall_table.S"
 
===================================================================
--- a/arch/i386/kernel/head.S
+++ b/arch/i386/kernel/head.S
@@ -533,6 +533,8 @@ unhandled_paravirt:
 	ud2
 #endif
 
+#include "../xen/xen-head.S"
+
 /*
  * Real beginning of normal "text" segment
  */
@@ -542,7 +544,8 @@ ENTRY(_stext)
 /*
  * BSS section
  */
-.section ".bss.page_aligned","w"
+.section ".bss.page_aligned","wa"
+	.align PAGE_SIZE_asm
 ENTRY(swapper_pg_dir)
 	.fill 1024,4,0
 ENTRY(empty_zero_page)
===================================================================
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -292,6 +292,7 @@ struct paravirt_ops paravirt_ops = {
 	.apic_read = native_apic_read,
 	.setup_boot_clock = setup_boot_APIC_clock,
 	.setup_secondary_clock = setup_secondary_APIC_clock,
+	.startup_ipi_hook = paravirt_nop,
 #endif
 	.set_lazy_mode = paravirt_nop,
 
@@ -342,8 +343,6 @@ struct paravirt_ops paravirt_ops = {
 	.dup_mmap = paravirt_nop,
 	.exit_mmap = paravirt_nop,
 	.activate_mm = paravirt_nop,
-
-	.startup_ipi_hook = paravirt_nop,
 };
 
 /*
===================================================================
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -94,6 +94,7 @@ SECTIONS
 
   . = ALIGN(4096);
   .data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) {
+	*(.data.page_aligned)
 	*(.data.idt)
   }
 
===================================================================
--- a/arch/i386/xen/Kconfig
+++ b/arch/i386/xen/Kconfig
@@ -4,7 +4,7 @@
 
 config XEN
 	bool "Enable support for Xen hypervisor"
-	depends on PARAVIRT && HZ_100 && !PREEMPT && !NO_HZ
+	depends on PARAVIRT && !PREEMPT
 	default y
 	help
 	  This is the Linux Xen port.
===================================================================
--- /dev/null
+++ b/arch/i386/xen/Makefile
@@ -0,0 +1,2 @@
+obj-y		:= enlighten.o setup.o events.o time.o \
+			features.o mmu.o multicalls.o
===================================================================
--- /dev/null
+++ b/arch/i386/xen/enlighten.c
@@ -0,0 +1,727 @@
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/preempt.h>
+#include <linux/percpu.h>
+#include <linux/delay.h>
+#include <linux/start_kernel.h>
+#include <linux/sched.h>
+#include <linux/bootmem.h>
+#include <linux/module.h>
+
+#include <xen/interface/xen.h>
+#include <xen/features.h>
+#include <xen/page.h>
+
+#include <asm/paravirt.h>
+#include <asm/page.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/fixmap.h>
+#include <asm/processor.h>
+#include <asm/setup.h>
+#include <asm/desc.h>
+#include <asm/pgtable.h>
+
+#include "xen-ops.h"
+#include "mmu.h"
+#include "multicalls.h"
+
+EXPORT_SYMBOL_GPL(hypercall_page);
+
+DEFINE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode);
+
+DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
+DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
+DEFINE_PER_CPU(unsigned long, xen_cr3);
+
+/* Code defined in entry.S (not a function) */
+extern const char xen_sti_sysexit[];
+
+struct start_info *xen_start_info;
+EXPORT_SYMBOL_GPL(xen_start_info);
+
+static void xen_vcpu_setup(int cpu)
+{
+	per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+}
+
+static void __init xen_banner(void)
+{
+	printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
+	       paravirt_ops.name);
+	printk(KERN_INFO "Hypervisor signature: %s\n", xen_start_info->magic);
+}
+
+static void xen_cpuid(unsigned int *eax, unsigned int *ebx,
+		      unsigned int *ecx, unsigned int *edx)
+{
+	unsigned maskedx = ~0;
+	if (*eax == 1)
+		maskedx = ~((1 << X86_FEATURE_APIC) |
+			    (1 << X86_FEATURE_ACPI) |
+			    (1 << X86_FEATURE_ACC));
+
+	asm(XEN_EMULATE_PREFIX "cpuid"
+		: "=a" (*eax),
+		  "=b" (*ebx),
+		  "=c" (*ecx),
+		  "=d" (*edx)
+		: "0" (*eax), "2" (*ecx));
+	*edx &= maskedx;
+}
+
+static void xen_set_debugreg(int reg, unsigned long val)
+{
+	HYPERVISOR_set_debugreg(reg, val);
+}
+
+static unsigned long xen_get_debugreg(int reg)
+{
+	return HYPERVISOR_get_debugreg(reg);
+}
+
+static unsigned long xen_save_fl(void)
+{
+	struct vcpu_info *vcpu;
+	unsigned long flags;
+
+	preempt_disable();
+	vcpu = x86_read_percpu(xen_vcpu);
+	/* flag has opposite sense of mask */
+	flags = !vcpu->evtchn_upcall_mask;
+	preempt_enable();
+
+	/* convert to IF type flag
+	   -0 -> 0x00000000
+	   -1 -> 0xffffffff
+	*/
+	return (-flags) & X86_EFLAGS_IF;
+}
+
+static void xen_restore_fl(unsigned long flags)
+{
+	struct vcpu_info *vcpu;
+
+	preempt_disable();
+
+	/* convert from IF type flag */
+	flags = !(flags & X86_EFLAGS_IF);
+	vcpu = x86_read_percpu(xen_vcpu);
+	vcpu->evtchn_upcall_mask = flags;
+	if (flags == 0) {
+		barrier(); /* unmask then check (avoid races) */
+		if (unlikely(vcpu->evtchn_upcall_pending))
+			force_evtchn_callback();
+		preempt_enable();
+	} else
+		preempt_enable_no_resched();
+}
+
+static void xen_irq_disable(void)
+{
+	struct vcpu_info *vcpu;
+	preempt_disable();
+	vcpu = x86_read_percpu(xen_vcpu);
+	vcpu->evtchn_upcall_mask = 1;
+	preempt_enable_no_resched();
+}
+
+static void xen_irq_enable(void)
+{
+	struct vcpu_info *vcpu;
+
+	preempt_disable();
+	vcpu = x86_read_percpu(xen_vcpu);
+	vcpu->evtchn_upcall_mask = 0;
+	barrier(); /* unmask then check (avoid races) */
+	if (unlikely(vcpu->evtchn_upcall_pending))
+		force_evtchn_callback();
+	preempt_enable();
+}
+
+static void xen_safe_halt(void)
+{
+	/* Blocking includes an implicit local_irq_enable(). */
+	if (HYPERVISOR_sched_op(SCHEDOP_block, 0) != 0)
+		BUG();
+}
+
+static void xen_halt(void)
+{
+#if 0
+	if (irqs_disabled())
+		HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
+#endif
+}
+
+static void xen_set_lazy_mode(enum paravirt_lazy_mode mode)
+{
+	enum paravirt_lazy_mode *lazy = &get_cpu_var(xen_lazy_mode);
+
+	xen_mc_flush();
+
+	*lazy = mode;
+
+	put_cpu_var(xen_lazy_mode);
+}
+
+static unsigned long xen_store_tr(void)
+{
+	return 0;
+}
+
+static void xen_set_ldt(const void *addr, unsigned entries)
+{
+	unsigned long linear_addr = (unsigned long)addr;
+	struct mmuext_op *op;
+	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+	op = mcs.args;
+	op->cmd = MMUEXT_SET_LDT;
+	if (linear_addr) {
+		/* ldt my be vmalloced, use arbitrary_virt_to_machine */
+		xmaddr_t maddr;
+		maddr = arbitrary_virt_to_machine((unsigned long)addr);
+		linear_addr = (unsigned long)maddr.maddr;
+	}
+	op->arg1.linear_addr = linear_addr;
+	op->arg2.nr_ents = entries;
+
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue();
+}
+
+static void xen_load_gdt(const struct Xgt_desc_struct *dtr)
+{
+	unsigned long *frames;
+	unsigned long va = dtr->address;
+	unsigned int size = dtr->size + 1;
+	int f;
+	struct multicall_space mcs;
+
+	BUG_ON(size > 16*PAGE_SIZE);
+	BUG_ON(va & ~PAGE_MASK);
+
+	mcs = xen_mc_entry(sizeof(*frames) * (size/PAGE_SIZE));
+	frames = mcs.args;
+
+	for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
+		frames[f] = virt_to_mfn(va);
+		make_lowmem_page_readonly((void *)va);
+	}
+
+	MULTI_set_gdt(mcs.mc, frames, size/8);
+
+	xen_mc_issue();
+}
+
+static void load_TLS_descriptor(struct thread_struct *t,
+				unsigned int cpu, unsigned int i)
+{
+	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
+	xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
+	struct multicall_space mc = xen_mc_entry(0);
+
+	MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
+}
+
+static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
+{
+	load_TLS_descriptor(t, cpu, 0);
+	load_TLS_descriptor(t, cpu, 1);
+	load_TLS_descriptor(t, cpu, 2);
+
+	xen_mc_issue();
+}
+
+static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, u32 low, u32 high)
+{
+	unsigned long lp = (unsigned long)&dt[entrynum];
+	xmaddr_t mach_lp = virt_to_machine(lp);
+	u64 entry = (u64)high << 32 | low;
+
+	xen_mc_flush();
+	if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
+		BUG();
+}
+
+static int cvt_gate_to_trap(int vector, u32 low, u32 high, struct trap_info *info)
+{
+	u8 type, dpl;
+
+	type = (high >> 8) & 0x1f;
+	dpl = (high >> 13) & 3;
+
+	if (type != 0xf && type != 0xe)
+		return 0;
+
+	info->vector = vector;
+	info->address = (high & 0xffff0000) | (low & 0x0000ffff);
+	info->cs = low >> 16;
+	info->flags = dpl;
+	/* interrupt gates clear IF */
+	if (type == 0xe)
+		info->flags |= 4;
+
+	return 1;
+}
+
+/* Locations of each CPU's IDT */
+static DEFINE_PER_CPU(struct Xgt_desc_struct, idt_desc);
+
+/* Set an IDT entry.  If the entry is part of the current IDT, then
+   also update Xen. */
+static void xen_write_idt_entry(struct desc_struct *dt, int entrynum, u32 low, u32 high)
+{
+
+	int cpu = smp_processor_id();
+	unsigned long p = (unsigned long)&dt[entrynum];
+	unsigned long start = per_cpu(idt_desc, cpu).address;
+	unsigned long end = start + per_cpu(idt_desc, cpu).size + 1;
+
+	xen_mc_flush();
+
+	write_dt_entry(dt, entrynum, low, high);
+
+	if (p >= start && (p + 8) <= end) {
+		struct trap_info info[2];
+
+		info[1].address = 0;
+
+		if (cvt_gate_to_trap(entrynum, low, high, &info[0]))
+			if (HYPERVISOR_set_trap_table(info))
+				BUG();
+	}
+}
+
+/* Load a new IDT into Xen.  In principle this can be per-CPU, so we
+   hold a spinlock to protect the static traps[] array (static because
+   it avoids allocation, and saves stack space). */
+static void xen_load_idt(const struct Xgt_desc_struct *desc)
+{
+	static DEFINE_SPINLOCK(lock);
+	static struct trap_info traps[257];
+
+	int cpu = smp_processor_id();
+	unsigned in, out, count;
+
+	per_cpu(idt_desc, cpu) = *desc;
+
+	count = desc->size / 8;
+	BUG_ON(count > 256);
+
+	spin_lock(&lock);
+	for(in = out = 0; in < count; in++) {
+		const u32 *entry = (u32 *)(desc->address + in * 8);
+
+		if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out]))
+			out++;
+	}
+	traps[out].address = 0;
+
+	xen_mc_flush();
+	if (HYPERVISOR_set_trap_table(traps))
+		BUG();
+
+	spin_unlock(&lock);
+}
+
+/* Write a GDT descriptor entry.  Ignore LDT descriptors, since
+   they're handled differently. */
+static void xen_write_gdt_entry(struct desc_struct *dt, int entry, u32 low, u32 high)
+{
+	switch ((high >> 8) & 0xff) {
+	case DESCTYPE_LDT:
+	case DESCTYPE_TSS:
+		/* ignore */
+		break;
+
+	default: {
+		xmaddr_t maddr = virt_to_machine(&dt[entry]);
+		u64 desc = (u64)high << 32 | low;
+
+		xen_mc_flush();
+		if (HYPERVISOR_update_descriptor(maddr.maddr, desc))
+			BUG();
+	}
+
+	}
+}
+
+static void xen_load_esp0(struct tss_struct *tss,
+				   struct thread_struct *thread)
+{
+	if (xen_get_lazy_mode() != PARAVIRT_LAZY_CPU) {
+		if (HYPERVISOR_stack_switch(__KERNEL_DS, thread->esp0))
+			BUG();
+	} else {
+		struct multicall_space mcs = xen_mc_entry(0);
+		MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0);
+	}
+}
+
+static void xen_set_iopl_mask(unsigned mask)
+{
+#if 0
+	struct physdev_set_iopl set_iopl;
+
+	/* Force the change at ring 0. */
+	set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
+	HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+#endif
+}
+
+static void xen_io_delay(void)
+{
+}
+
+#ifdef CONFIG_X86_LOCAL_APIC
+static unsigned long xen_apic_read(unsigned long reg)
+{
+	return 0;
+}
+#endif
+
+static void xen_flush_tlb(void)
+{
+	struct mmuext_op op;
+
+	op.cmd = MMUEXT_TLB_FLUSH_LOCAL;
+	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+		BUG();
+}
+
+static void xen_flush_tlb_single(unsigned long addr)
+{
+	struct mmuext_op op;
+
+	op.cmd = MMUEXT_INVLPG_LOCAL;
+	op.arg1.linear_addr = addr & PAGE_MASK;
+	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+		BUG();
+}
+
+static unsigned long xen_read_cr2(void)
+{
+	return x86_read_percpu(xen_vcpu)->arch.cr2;
+}
+
+static void xen_write_cr4(unsigned long cr4)
+{
+	/* never allow TSC to be disabled */
+	native_write_cr4(cr4 & ~X86_CR4_TSD);
+}
+
+/*
+ * Page-directory addresses above 4GB do not fit into architectural %cr3.
+ * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
+ * must use the following accessor macros to pack/unpack valid MFNs.
+ */
+#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
+#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))
+
+static unsigned long xen_read_cr3(void)
+{
+	return x86_read_percpu(xen_cr3);
+}
+
+static void xen_write_cr3(unsigned long cr3)
+{
+	if (cr3 == x86_read_percpu(xen_cr3)) {
+		/* just a simple tlb flush */
+		xen_flush_tlb();
+		return;
+	}
+
+	x86_write_percpu(xen_cr3, cr3);
+
+
+	{
+		struct mmuext_op *op;
+		struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+		unsigned long mfn = pfn_to_mfn(PFN_DOWN(cr3));
+
+		op = mcs.args;
+		op->cmd = MMUEXT_NEW_BASEPTR;
+		op->arg1.mfn = mfn;
+
+		MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+		xen_mc_issue();
+	}
+}
+
+static void xen_alloc_pt(u32 pfn)
+{
+	/* XXX pfn isn't necessarily a lowmem page */
+	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+}
+
+static void xen_alloc_pd(u32 pfn)
+{
+	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+}
+
+static void xen_release_pd(u32 pfn)
+{
+	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static void xen_release_pt(u32 pfn)
+{
+	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+}
+
+static void xen_alloc_pd_clone(u32 pfn, u32 clonepfn,
+					u32 start, u32 count)
+{
+	xen_alloc_pd(pfn);
+}
+
+static __init void xen_pagetable_setup_start(pgd_t *base)
+{
+	pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base;
+
+	init_mm.pgd = base;
+	/*
+	 * copy top-level of Xen-supplied pagetable into place.	 For
+	 * !PAE we can use this as-is, but for PAE it is a stand-in
+	 * while we copy the pmd pages.
+	 */
+	memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t));
+
+	if (PTRS_PER_PMD > 1) {
+		int i;
+		/*
+		 * For PAE, need to allocate new pmds, rather than
+		 * share Xen's, since Xen doesn't like pmd's being
+		 * shared between address spaces.
+		 */
+		for(i = 0; i < PTRS_PER_PGD; i++) {
+			if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) {
+				pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+
+				memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]),
+				       PAGE_SIZE);
+
+				xen_alloc_pd(PFN_DOWN(__pa(pmd)));
+
+				set_pgd(&base[i], __pgd(1 + __pa(pmd)));
+			} else
+				pgd_clear(&base[i]);
+		}
+	}
+
+	/* make sure zero_page is mapped RO so we can use it in pagetables */
+	make_lowmem_page_readonly(empty_zero_page);
+	make_lowmem_page_readonly(base);
+	/*
+	 * Switch to new pagetable.  This is done before
+	 * pagetable_init has done anything so that the new pages
+	 * added to the table can be prepared properly for Xen.
+	 */
+	xen_write_cr3(__pa(base));
+}
+
+static __init void xen_pagetable_setup_done(pgd_t *base)
+{
+	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+		/*
+		 * Create a mapping for the shared info page.
+		 * Should be set_fixmap(), but shared_info is a machine
+		 * address with no corresponding pseudo-phys address.
+		 */
+		set_pte_mfn(fix_to_virt(FIX_PARAVIRT_BOOTMAP),
+			    PFN_DOWN(xen_start_info->shared_info),
+			    PAGE_KERNEL);
+
+		HYPERVISOR_shared_info =
+			(struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
+
+	} else
+		HYPERVISOR_shared_info =
+			(struct shared_info *)__va(xen_start_info->shared_info);
+
+	xen_pgd_pin(base);
+
+	xen_vcpu_setup(smp_processor_id());
+}
+
+static const struct paravirt_ops xen_paravirt_ops __initdata = {
+	.paravirt_enabled = 1,
+	.shared_kernel_pmd = 0,
+
+	.name = "Xen",
+	.banner = xen_banner,
+
+	.patch = paravirt_patch_default,
+
+	.memory_setup = xen_memory_setup,
+	.arch_setup = xen_arch_setup,
+	.init_IRQ = xen_init_IRQ,
+	.time_init = xen_time_init,
+
+	.cpuid = xen_cpuid,
+
+	.set_debugreg = xen_set_debugreg,
+	.get_debugreg = xen_get_debugreg,
+
+	.clts = native_clts,
+
+	.read_cr0 = native_read_cr0,
+	.write_cr0 = native_write_cr0,
+
+	.read_cr2 = xen_read_cr2,
+	.write_cr2 = native_write_cr2,
+
+	.read_cr3 = xen_read_cr3,
+	.write_cr3 = xen_write_cr3,
+
+	.read_cr4 = native_read_cr4,
+	.read_cr4_safe = native_read_cr4_safe,
+	.write_cr4 = xen_write_cr4,
+
+	.save_fl = xen_save_fl,
+	.restore_fl = xen_restore_fl,
+	.irq_disable = xen_irq_disable,
+	.irq_enable = xen_irq_enable,
+	.safe_halt = xen_safe_halt,
+	.halt = xen_halt,
+	.wbinvd = native_wbinvd,
+
+	.read_msr = native_read_msr_safe,
+	.write_msr = native_write_msr_safe,
+	.read_tsc = native_read_tsc,
+	.read_pmc = native_read_pmc,
+
+	.iret = (void *)&hypercall_page[__HYPERVISOR_iret],
+	.irq_enable_sysexit = (void *)xen_sti_sysexit,
+
+	.load_tr_desc = paravirt_nop,
+	.set_ldt = xen_set_ldt,
+	.load_gdt = xen_load_gdt,
+	.load_idt = xen_load_idt,
+	.load_tls = xen_load_tls,
+
+	.store_gdt = native_store_gdt,
+	.store_idt = native_store_idt,
+	.store_tr = xen_store_tr,
+
+	.write_ldt_entry = xen_write_ldt_entry,
+	.write_gdt_entry = xen_write_gdt_entry,
+	.write_idt_entry = xen_write_idt_entry,
+	.load_esp0 = xen_load_esp0,
+
+	.set_iopl_mask = xen_set_iopl_mask,
+	.io_delay = xen_io_delay,
+	.set_wallclock = xen_set_wallclock,
+	.get_wallclock = xen_get_wallclock,
+	.get_cpu_khz = xen_cpu_khz,
+	.sched_clock = xen_clocksource_read,
+
+#ifdef CONFIG_X86_LOCAL_APIC
+	.apic_write = paravirt_nop,
+	.apic_write_atomic = paravirt_nop,
+	.apic_read = xen_apic_read,
+	.setup_boot_clock = paravirt_nop,
+	.setup_secondary_clock = paravirt_nop,
+	.startup_ipi_hook = paravirt_nop,
+#endif
+
+	.flush_tlb_user = xen_flush_tlb,
+	.flush_tlb_kernel = xen_flush_tlb,
+	.flush_tlb_single = xen_flush_tlb_single,
+
+	.pte_update = paravirt_nop,
+	.pte_update_defer = paravirt_nop,
+
+	.pagetable_setup_start = xen_pagetable_setup_start,
+	.pagetable_setup_done = xen_pagetable_setup_done,
+	.activate_mm = xen_activate_mm,
+	.dup_mmap = xen_dup_mmap,
+	.exit_mmap = xen_exit_mmap,
+
+	.set_pte = xen_set_pte,
+	.set_pte_at = xen_set_pte_at,
+	.set_pmd = xen_set_pmd,
+
+	.alloc_pt = xen_alloc_pt,
+	.alloc_pd = xen_alloc_pd,
+	.alloc_pd_clone = xen_alloc_pd_clone,
+	.release_pd = xen_release_pd,
+	.release_pt = xen_release_pt,
+
+	.pte_val = xen_pte_val,
+	.pgd_val = xen_pgd_val,
+
+	.make_pte = xen_make_pte,
+	.make_pgd = xen_make_pgd,
+
+#ifdef CONFIG_X86_PAE
+	.set_pte_atomic = xen_set_pte_atomic,
+	.set_pte_present = xen_set_pte_at,
+	.set_pud = xen_set_pud,
+	.pte_clear = xen_pte_clear,
+	.pmd_clear = xen_pmd_clear,
+
+	.make_pmd = xen_make_pmd,
+	.pmd_val = xen_pmd_val,
+#endif	/* PAE */
+
+	.set_lazy_mode = xen_set_lazy_mode,
+};
+
+/* First C function to be called on Xen boot */
+static asmlinkage void __init xen_start_kernel(void)
+{
+	pgd_t *pgd;
+
+	if (!xen_start_info)
+		return;
+
+	BUG_ON(memcmp(xen_start_info->magic, "xen-3.0", 7) != 0);
+
+	/* Install Xen paravirt ops */
+	paravirt_ops = xen_paravirt_ops;
+
+	xen_setup_features();
+
+	/* Get mfn list */
+	if (!xen_feature(XENFEAT_auto_translated_physmap))
+		phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list;
+
+	pgd = (pgd_t *)xen_start_info->pt_base;
+
+	init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
+
+	init_mm.pgd = pgd; /* use the Xen pagetables to start */
+
+	/* keep using Xen gdt for now; no urgent need to change it */
+
+	x86_write_percpu(xen_cr3, __pa(pgd));
+	xen_vcpu_setup(0);
+
+	paravirt_ops.kernel_rpl = 1;
+	if (xen_feature(XENFEAT_supervisor_mode_kernel))
+		paravirt_ops.kernel_rpl = 0;
+
+	/* set the limit of our address space */
+	reserve_top_address(-HYPERVISOR_VIRT_START + 2 * PAGE_SIZE);
+
+	/* set up basic CPUID stuff */
+	cpu_detect(&new_cpu_data);
+	new_cpu_data.hard_math = 1;
+	new_cpu_data.x86_capability[0] = cpuid_edx(1);
+
+	/* Poke various useful things into boot_params */
+	LOADER_TYPE = (9 << 4) | 0;
+	INITRD_START = xen_start_info->mod_start ? __pa(xen_start_info->mod_start) : 0;
+	INITRD_SIZE = xen_start_info->mod_len;
+
+	/* Start the world */
+	start_kernel();
+}
+
+paravirt_probe(xen_start_kernel);
===================================================================
--- /dev/null
+++ b/arch/i386/xen/events.c
@@ -0,0 +1,487 @@
+#include <linux/linkage.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+#include <asm/ptrace.h>
+#include <asm/irq.h>
+#include <asm/sync_bitops.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/events.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+
+#include "xen-ops.h"
+
+/*
+ * This lock protects updates to the following mapping and reference-count
+ * arrays. The lock does not need to be acquired to read the mapping tables.
+ */
+static DEFINE_SPINLOCK(irq_mapping_update_lock);
+
+/* IRQ <-> VIRQ mapping. */
+static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1};
+
+/* Packed IRQ information: binding type, sub-type index, and event channel. */
+struct packed_irq
+{
+	unsigned short evtchn;
+	unsigned char index;
+	unsigned char type;
+};
+
+static struct packed_irq irq_info[NR_IRQS];
+
+/* Binding types. */
+enum { IRQT_UNBOUND, IRQT_PIRQ, IRQT_VIRQ, IRQT_IPI, IRQT_EVTCHN };
+
+/* Convenient shorthand for packed representation of an unbound IRQ. */
+#define IRQ_UNBOUND	mk_irq_info(IRQT_UNBOUND, 0, 0)
+
+static int evtchn_to_irq[NR_EVENT_CHANNELS] = {
+	[0 ... NR_EVENT_CHANNELS-1] = -1
+};
+static unsigned long cpu_evtchn_mask[NR_CPUS][NR_EVENT_CHANNELS/BITS_PER_LONG];
+static u8 cpu_evtchn[NR_EVENT_CHANNELS];
+
+/* Reference counts for bindings to IRQs. */
+static int irq_bindcount[NR_IRQS];
+
+/* Xen will never allocate port zero for any purpose. */
+#define VALID_EVTCHN(chn)	((chn) != 0)
+
+/*
+ * Force a proper event-channel callback from Xen after clearing the
+ * callback mask. We do this in a very simple manner, by making a call
+ * down into Xen. The pending flag will be checked by Xen on return.
+ */
+void force_evtchn_callback(void)
+{
+	(void)HYPERVISOR_xen_version(0, NULL);
+}
+EXPORT_SYMBOL_GPL(force_evtchn_callback);
+
+static struct irq_chip xen_dynamic_chip;
+
+/* Constructor for packed IRQ information. */
+static inline struct packed_irq mk_irq_info(u32 type, u32 index, u32 evtchn)
+{
+	return (struct packed_irq) { evtchn, index, type };
+}
+
+/*
+ * Accessors for packed IRQ information.
+ */
+static inline unsigned int evtchn_from_irq(int irq)
+{
+	return irq_info[irq].evtchn;
+}
+
+static inline unsigned int index_from_irq(int irq)
+{
+	return irq_info[irq].index;
+}
+
+static inline unsigned int type_from_irq(int irq)
+{
+	return irq_info[irq].type;
+}
+
+static inline unsigned long active_evtchns(unsigned int cpu,
+					   struct shared_info *sh,
+					   unsigned int idx)
+{
+	return (sh->evtchn_pending[idx] &
+		cpu_evtchn_mask[cpu][idx] &
+		~sh->evtchn_mask[idx]);
+}
+
+static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
+{
+	int irq = evtchn_to_irq[chn];
+
+	BUG_ON(irq == -1);
+#ifdef CONFIG_SMP
+	irq_desc[irq].affinity = cpumask_of_cpu(cpu);
+#endif
+
+	__clear_bit(chn, cpu_evtchn_mask[cpu_evtchn[chn]]);
+	__set_bit(chn, cpu_evtchn_mask[cpu]);
+
+	cpu_evtchn[chn] = cpu;
+}
+
+static void init_evtchn_cpu_bindings(void)
+{
+#ifdef CONFIG_SMP
+	int i;
+	/* By default all event channels notify CPU#0. */
+	for (i = 0; i < NR_IRQS; i++)
+		irq_desc[i].affinity = cpumask_of_cpu(0);
+#endif
+
+	memset(cpu_evtchn, 0, sizeof(cpu_evtchn));
+	memset(cpu_evtchn_mask[0], ~0, sizeof(cpu_evtchn_mask[0]));
+}
+
+static inline unsigned int cpu_from_evtchn(unsigned int evtchn)
+{
+	return cpu_evtchn[evtchn];
+}
+
+static inline void clear_evtchn(int port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_clear_bit(port, &s->evtchn_pending[0]);
+}
+
+static inline void set_evtchn(int port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_set_bit(port, &s->evtchn_pending[0]);
+}
+
+
+/**
+ * notify_remote_via_irq - send event to remote end of event channel via irq
+ * @irq: irq of event channel to send event to
+ *
+ * Unlike notify_remote_via_evtchn(), this is safe to use across
+ * save/restore. Notifications on a broken connection are silently
+ * dropped.
+ */
+void notify_remote_via_irq(int irq)
+{
+	int evtchn = evtchn_from_irq(irq);
+
+	if (VALID_EVTCHN(evtchn))
+		notify_remote_via_evtchn(evtchn);
+}
+EXPORT_SYMBOL_GPL(notify_remote_via_irq);
+
+static void mask_evtchn(int port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_set_bit(port, &s->evtchn_mask[0]);
+}
+
+static void unmask_evtchn(int port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	unsigned int cpu = get_cpu();
+
+	BUG_ON(!irqs_disabled());
+
+	/* Slow path (hypercall) if this is a non-local port. */
+	if (unlikely(cpu != cpu_from_evtchn(port))) {
+		struct evtchn_unmask unmask = { .port = port };
+		(void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
+	} else {
+		struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
+
+		sync_clear_bit(port, &s->evtchn_mask[0]);
+
+		/*
+		 * The following is basically the equivalent of
+		 * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
+		 * the interrupt edge' if the channel is masked.
+		 */
+		if (sync_test_bit(port, &s->evtchn_pending[0]) &&
+		    !sync_test_and_set_bit(port / BITS_PER_LONG,
+					   &vcpu_info->evtchn_pending_sel))
+			vcpu_info->evtchn_upcall_pending = 1;
+	}
+
+	put_cpu();
+}
+
+static int find_unbound_irq(void)
+{
+	int irq;
+
+	/* Only allocate from dynirq range */
+	for (irq = 0; irq < NR_IRQS; irq++)
+		if (irq_bindcount[irq] == 0)
+			break;
+
+	if (irq == NR_IRQS)
+		panic("No available IRQ to bind to: increase NR_IRQS!\n");
+
+	return irq;
+}
+
+static int bind_evtchn_to_irq(unsigned int evtchn)
+{
+	int irq;
+
+	spin_lock(&irq_mapping_update_lock);
+
+	irq = evtchn_to_irq[evtchn];
+
+	if (irq == -1) {
+		irq = find_unbound_irq();
+
+		dynamic_irq_init(irq);
+		set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
+					      handle_level_irq, "event");
+
+		evtchn_to_irq[evtchn] = irq;
+		irq_info[irq] = mk_irq_info(IRQT_EVTCHN, 0, evtchn);
+	}
+
+	irq_bindcount[irq]++;
+
+	spin_unlock(&irq_mapping_update_lock);
+
+	return irq;
+}
+
+static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
+{
+	struct evtchn_bind_virq bind_virq;
+	int evtchn, irq;
+
+	spin_lock(&irq_mapping_update_lock);
+
+	irq = per_cpu(virq_to_irq, cpu)[virq];
+
+	if (irq == -1) {
+		bind_virq.virq = virq;
+		bind_virq.vcpu = cpu;
+		if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
+						&bind_virq) != 0)
+			BUG();
+		evtchn = bind_virq.port;
+
+		irq = find_unbound_irq();
+
+		dynamic_irq_init(irq);
+		set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
+					      handle_level_irq, "virq");
+
+		evtchn_to_irq[evtchn] = irq;
+		irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn);
+
+		per_cpu(virq_to_irq, cpu)[virq] = irq;
+
+		bind_evtchn_to_cpu(evtchn, cpu);
+	}
+
+	irq_bindcount[irq]++;
+
+	spin_unlock(&irq_mapping_update_lock);
+
+	return irq;
+}
+
+static void unbind_from_irq(unsigned int irq)
+{
+	struct evtchn_close close;
+	int evtchn = evtchn_from_irq(irq);
+
+	spin_lock(&irq_mapping_update_lock);
+
+	if (VALID_EVTCHN(evtchn) && (--irq_bindcount[irq] == 0)) {
+		close.port = evtchn;
+		if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
+			BUG();
+
+		switch (type_from_irq(irq)) {
+		case IRQT_VIRQ:
+			per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))
+				[index_from_irq(irq)] = -1;
+			break;
+		default:
+			break;
+		}
+
+		/* Closed ports are implicitly re-bound to VCPU0. */
+		bind_evtchn_to_cpu(evtchn, 0);
+
+		evtchn_to_irq[evtchn] = -1;
+		irq_info[irq] = IRQ_UNBOUND;
+
+		dynamic_irq_init(irq);
+	}
+
+	spin_unlock(&irq_mapping_update_lock);
+}
+
+int bind_evtchn_to_irqhandler(unsigned int evtchn,
+			      irqreturn_t (*handler)(int, void *),
+			      unsigned long irqflags, const char *devname, void *dev_id)
+{
+	unsigned int irq;
+	int retval;
+
+	irq = bind_evtchn_to_irq(evtchn);
+	retval = request_irq(irq, handler, irqflags, devname, dev_id);
+	if (retval != 0) {
+		unbind_from_irq(irq);
+		return retval;
+	}
+
+	return irq;
+}
+EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
+
+int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
+			    irqreturn_t (*handler)(int, void *),
+			    unsigned long irqflags, const char *devname, void *dev_id)
+{
+	unsigned int irq;
+	int retval;
+
+	irq = bind_virq_to_irq(virq, cpu);
+	retval = request_irq(irq, handler, irqflags, devname, dev_id);
+	if (retval != 0) {
+		unbind_from_irq(irq);
+		return retval;
+	}
+
+	return irq;
+}
+EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
+
+void unbind_from_irqhandler(unsigned int irq, void *dev_id)
+{
+	free_irq(irq, dev_id);
+	unbind_from_irq(irq);
+}
+EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
+
+/*
+  Search the CPUs pending events bitmasks.  For each one found, map
+  the event number to an irq, and feed it into do_IRQ() for
+  handling.
+
+  Xen uses a two-level bitmap to speed searching.  The first level is
+  a bitset of words which contain pending event bits.  The second
+  level is a bitset of pending events themselves.
+*/
+fastcall void xen_evtchn_do_upcall(struct pt_regs *regs)
+{
+	int cpu = get_cpu();
+	struct shared_info *s = HYPERVISOR_shared_info;
+	struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
+	unsigned long pending_words;
+
+	vcpu_info->evtchn_upcall_pending = 0;
+
+	/* NB. No need for a barrier here -- XCHG is a barrier on x86. */
+	pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
+	while (pending_words != 0) {
+		unsigned long pending_bits;
+		int word_idx = __ffs(pending_words);
+		pending_words &= ~(1UL << word_idx);
+
+		while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) {
+			int bit_idx = __ffs(pending_bits);
+			int port = (word_idx * BITS_PER_LONG) + bit_idx;
+			int irq = evtchn_to_irq[port];
+
+			if (irq != -1) {
+				regs->orig_eax = ~irq;
+				do_IRQ(regs);
+			}
+		}
+	}
+
+	put_cpu();
+}
+
+/* Rebind an evtchn so that it gets delivered to a specific cpu */
+static void rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
+{
+	struct evtchn_bind_vcpu bind_vcpu;
+	int evtchn = evtchn_from_irq(irq);
+
+	if (!VALID_EVTCHN(evtchn))
+		return;
+
+	/* Send future instances of this interrupt to other vcpu. */
+	bind_vcpu.port = evtchn;
+	bind_vcpu.vcpu = tcpu;
+
+	/*
+	 * If this fails, it usually just indicates that we're dealing with a
+	 * virq or IPI channel, which don't actually need to be rebound. Ignore
+	 * it, but don't do the xenlinux-level rebind in that case.
+	 */
+	if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
+		bind_evtchn_to_cpu(evtchn, tcpu);
+}
+
+
+static void set_affinity_irq(unsigned irq, cpumask_t dest)
+{
+	unsigned tcpu = first_cpu(dest);
+	rebind_irq_to_cpu(irq, tcpu);
+}
+
+static void enable_dynirq(unsigned int irq)
+{
+	int evtchn = evtchn_from_irq(irq);
+
+	if (VALID_EVTCHN(evtchn))
+		unmask_evtchn(evtchn);
+}
+
+static void disable_dynirq(unsigned int irq)
+{
+	int evtchn = evtchn_from_irq(irq);
+
+	if (VALID_EVTCHN(evtchn))
+		mask_evtchn(evtchn);
+}
+
+static void ack_dynirq(unsigned int irq)
+{
+	int evtchn = evtchn_from_irq(irq);
+
+	move_native_irq(irq);
+
+	if (VALID_EVTCHN(evtchn))
+		clear_evtchn(evtchn);
+}
+
+static int retrigger_dynirq(unsigned int irq)
+{
+	int evtchn = evtchn_from_irq(irq);
+	int ret = 0;
+
+	if (VALID_EVTCHN(evtchn)) {
+		set_evtchn(evtchn);
+		ret = 1;
+	}
+
+	return ret;
+}
+
+static struct irq_chip xen_dynamic_chip __read_mostly = {
+	.name		= "xen-dyn",
+	.mask		= disable_dynirq,
+	.unmask		= enable_dynirq,
+	.ack		= ack_dynirq,
+	.set_affinity	= set_affinity_irq,
+	.retrigger	= retrigger_dynirq,
+};
+
+void __init xen_init_IRQ(void)
+{
+	int i;
+
+	init_evtchn_cpu_bindings();
+
+	/* No event channels are 'live' right now. */
+	for (i = 0; i < NR_EVENT_CHANNELS; i++)
+		mask_evtchn(i);
+
+	/* Dynamic IRQ space is currently unbound. Zero the refcnts. */
+	for (i = 0; i < NR_IRQS; i++)
+		irq_bindcount[i] = 0;
+
+	irq_ctx_init(smp_processor_id());
+}
===================================================================
--- /dev/null
+++ b/arch/i386/xen/features.c
@@ -0,0 +1,29 @@
+/******************************************************************************
+ * features.c
+ *
+ * Xen feature flags.
+ *
+ * Copyright (c) 2006, Ian Campbell, XenSource Inc.
+ */
+#include <linux/types.h>
+#include <linux/cache.h>
+#include <linux/module.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/features.h>
+
+u8 xen_features[XENFEAT_NR_SUBMAPS * 32] __read_mostly;
+EXPORT_SYMBOL_GPL(xen_features);
+
+void xen_setup_features(void)
+{
+	struct xen_feature_info fi;
+	int i, j;
+
+	for (i = 0; i < XENFEAT_NR_SUBMAPS; i++) {
+		fi.submap_idx = i;
+		if (HYPERVISOR_xen_version(XENVER_get_features, &fi) < 0)
+			break;
+		for (j=0; j<32; j++)
+			xen_features[i*32+j] = !!(fi.submap & 1<<j);
+	}
+}
===================================================================
--- /dev/null
+++ b/arch/i386/xen/mmu.c
@@ -0,0 +1,377 @@
+#include <asm/bug.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/paravirt.h>
+
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+
+#include "mmu.h"
+
+xmaddr_t arbitrary_virt_to_machine(unsigned long address)
+{
+	pte_t *pte = lookup_address(address);
+	unsigned offset = address & PAGE_MASK;
+
+	BUG_ON(pte == NULL);
+
+	return XMADDR((pte_mfn(*pte) << PAGE_SHIFT) + offset);
+}
+
+void make_lowmem_page_readonly(void *vaddr)
+{
+	pte_t *pte, ptev;
+	unsigned long address = (unsigned long)vaddr;
+
+	pte = lookup_address(address);
+	BUG_ON(pte == NULL);
+
+	ptev = pte_wrprotect(*pte);
+
+	if(HYPERVISOR_update_va_mapping(address, ptev, 0))
+		BUG();
+}
+
+void make_lowmem_page_readwrite(void *vaddr)
+{
+	pte_t *pte, ptev;
+	unsigned long address = (unsigned long)vaddr;
+
+	pte = lookup_address(address);
+	BUG_ON(pte == NULL);
+
+	ptev = pte_mkwrite(*pte);
+
+	if(HYPERVISOR_update_va_mapping(address, ptev, 0))
+		BUG();
+}
+
+
+void xen_set_pte(pte_t *ptep, pte_t pte)
+{
+	struct mmu_update u;
+
+	u.ptr = virt_to_machine(ptep).maddr;
+	u.val = pte_val_ma(pte);
+	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
+		BUG();
+}
+
+void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+	struct mmu_update u;
+
+	u.ptr = virt_to_machine(ptr).maddr;
+	u.val = pmd_val_ma(val);
+	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
+		BUG();
+}
+
+#ifdef CONFIG_X86_PAE
+void xen_set_pud(pud_t *ptr, pud_t val)
+{
+	struct mmu_update u;
+
+	u.ptr = virt_to_machine(ptr).maddr;
+	u.val = pud_val_ma(val);
+	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
+		BUG();
+}
+#endif
+
+/*
+ * Associate a virtual page frame with a given physical page frame
+ * and protection flags for that frame.
+ */
+void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	pgd = swapper_pg_dir + pgd_index(vaddr);
+	if (pgd_none(*pgd)) {
+		BUG();
+		return;
+	}
+	pud = pud_offset(pgd, vaddr);
+	if (pud_none(*pud)) {
+		BUG();
+		return;
+	}
+	pmd = pmd_offset(pud, vaddr);
+	if (pmd_none(*pmd)) {
+		BUG();
+		return;
+	}
+	pte = pte_offset_kernel(pmd, vaddr);
+	/* <mfn,flags> stored as-is, to permit clearing entries */
+	xen_set_pte(pte, mfn_pte(mfn, flags));
+
+	/*
+	 * It's enough to flush this one mapping.
+	 * (PGE mappings get flushed as well)
+	 */
+	__flush_tlb_one(vaddr);
+}
+
+void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
+		    pte_t *ptep, pte_t pteval)
+{
+	if ((mm != current->mm && mm != &init_mm) ||
+	    HYPERVISOR_update_va_mapping(addr, pteval, 0) != 0)
+		xen_set_pte(ptep, pteval);
+}
+
+#ifdef CONFIG_X86_PAE
+void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
+{
+	set_64bit((u64 *)ptep, pte_val_ma(pte));
+}
+
+void xen_pte_clear(struct mm_struct *mm, unsigned long addr,pte_t *ptep)
+{
+	ptep->pte_low = 0;
+	smp_wmb();
+	ptep->pte_high = 0;
+}
+
+void xen_pmd_clear(pmd_t *pmdp)
+{
+	xen_set_pmd(pmdp, __pmd(0));
+}
+
+unsigned long long xen_pte_val(pte_t pte)
+{
+	unsigned long long ret = 0;
+
+	if (pte.pte_low) {
+		ret = ((unsigned long long)pte.pte_high << 32) | pte.pte_low;
+		ret = machine_to_phys(XMADDR(ret)).paddr | 1;
+	}
+
+	return ret;
+}
+
+unsigned long long xen_pmd_val(pmd_t pmd)
+{
+	unsigned long long ret = pmd.pmd;
+	if (ret)
+		ret = machine_to_phys(XMADDR(ret)).paddr | 1;
+	return ret;
+}
+
+unsigned long long xen_pgd_val(pgd_t pgd)
+{
+	unsigned long long ret = pgd.pgd;
+	if (ret)
+		ret = machine_to_phys(XMADDR(ret)).paddr | 1;
+	return ret;
+}
+
+pte_t xen_make_pte(unsigned long long pte)
+{
+	if (pte & 1)
+		pte = phys_to_machine(XPADDR(pte)).maddr;
+
+	return (pte_t){ pte, pte >> 32 };
+}
+
+pmd_t xen_make_pmd(unsigned long long pmd)
+{
+	if (pmd & 1)
+		pmd = phys_to_machine(XPADDR(pmd)).maddr;
+
+	return (pmd_t){ pmd };
+}
+
+pgd_t xen_make_pgd(unsigned long long pgd)
+{
+	if (pgd & _PAGE_PRESENT)
+		pgd = phys_to_machine(XPADDR(pgd)).maddr;
+
+	return (pgd_t){ pgd };
+}
+#else  /* !PAE */
+unsigned long xen_pte_val(pte_t pte)
+{
+	unsigned long ret = pte.pte_low;
+
+	if (ret & _PAGE_PRESENT)
+		ret = machine_to_phys(XMADDR(ret)).paddr;
+
+	return ret;
+}
+
+unsigned long xen_pmd_val(pmd_t pmd)
+{
+	BUG();
+	return 0;
+}
+
+unsigned long xen_pgd_val(pgd_t pgd)
+{
+	unsigned long ret = pgd.pgd;
+	if (ret)
+		ret = machine_to_phys(XMADDR(ret)).paddr | 1;
+	return ret;
+}
+
+pte_t xen_make_pte(unsigned long pte)
+{
+	if (pte & _PAGE_PRESENT)
+		pte = phys_to_machine(XPADDR(pte)).maddr;
+
+	return (pte_t){ pte };
+}
+
+pmd_t xen_make_pmd(unsigned long pmd)
+{
+	BUG();
+	return __pmd(0);
+}
+
+pgd_t xen_make_pgd(unsigned long pgd)
+{
+	if (pgd & _PAGE_PRESENT)
+		pgd = phys_to_machine(XPADDR(pgd)).maddr;
+
+	return (pgd_t){ pgd };
+}
+#endif	/* CONFIG_X86_PAE */
+
+
+
+static void pgd_walk_set_prot(void *pt, pgprot_t flags)
+{
+	unsigned long pfn = PFN_DOWN(__pa(pt));
+
+	if (HYPERVISOR_update_va_mapping((unsigned long)pt,
+					 pfn_pte(pfn, flags), 0) < 0)
+		BUG();
+}
+
+static void pgd_walk(pgd_t *pgd_base, pgprot_t flags)
+{
+	pgd_t *pgd = pgd_base;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+	int    g, u, m;
+
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return;
+
+	for (g = 0; g < USER_PTRS_PER_PGD; g++, pgd++) {
+		if (pgd_none(*pgd))
+			continue;
+		pud = pud_offset(pgd, 0);
+
+		if (PTRS_PER_PUD > 1) /* not folded */
+			pgd_walk_set_prot(pud,flags);
+
+		for (u = 0; u < PTRS_PER_PUD; u++, pud++) {
+			if (pud_none(*pud))
+				continue;
+			pmd = pmd_offset(pud, 0);
+
+			if (PTRS_PER_PMD > 1) /* not folded */
+				pgd_walk_set_prot(pmd,flags);
+
+			for (m = 0; m < PTRS_PER_PMD; m++, pmd++) {
+				if (pmd_none(*pmd))
+					continue;
+
+				/* This can get called before mem_map
+				   is set up, so we assume nothing is
+				   highmem at that point. */
+				if (mem_map == NULL ||
+				    !PageHighMem(pmd_page(*pmd))) {
+					pte = pte_offset_kernel(pmd,0);
+					pgd_walk_set_prot(pte,flags);
+				}
+			}
+		}
+	}
+
+	if (HYPERVISOR_update_va_mapping((unsigned long)pgd_base,
+					 pfn_pte(PFN_DOWN(__pa(pgd_base)),
+						 flags),
+					 UVMF_TLB_FLUSH) < 0)
+		BUG();
+}
+
+
+/* This is called just after a mm has been duplicated from its parent,
+   but it has not been used yet.  We need to make sure that its
+   pagetable is all read-only, and can be pinned. */
+void xen_pgd_pin(pgd_t *pgd)
+{
+	struct mmuext_op op;
+
+	pgd_walk(pgd, PAGE_KERNEL_RO);
+
+#if defined(CONFIG_X86_PAE)
+	op.cmd = MMUEXT_PIN_L3_TABLE;
+#else
+	op.cmd = MMUEXT_PIN_L2_TABLE;
+#endif
+	op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
+	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF) < 0)
+		BUG();
+}
+
+/* Release a pagetables pages back as normal RW */
+void xen_pgd_unpin(pgd_t *pgd)
+{
+	struct mmuext_op op;
+
+	op.cmd = MMUEXT_UNPIN_TABLE;
+	op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
+
+	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF) < 0)
+		BUG();
+
+	pgd_walk(pgd, PAGE_KERNEL);
+}
+
+
+void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+	xen_pgd_pin(next->pgd);
+}
+
+void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
+{
+	xen_pgd_pin(mm->pgd);
+}
+
+void xen_exit_mmap(struct mm_struct *mm)
+{
+	struct task_struct *tsk = current;
+
+	task_lock(tsk);
+
+	/*
+	 * We aggressively remove defunct pgd from cr3. We execute unmap_vmas()
+	 * *much* faster this way, as no tlb flushes means bigger wrpt batches.
+	 */
+	if (tsk->active_mm == mm) {
+		tsk->active_mm = &init_mm;
+		atomic_inc(&init_mm.mm_count);
+
+		switch_mm(mm, &init_mm, tsk);
+
+		atomic_dec(&mm->mm_count);
+		BUG_ON(atomic_read(&mm->mm_count) == 0);
+	}
+
+	task_unlock(tsk);
+
+	xen_pgd_unpin(mm->pgd);
+}
===================================================================
--- /dev/null
+++ b/arch/i386/xen/mmu.h
@@ -0,0 +1,47 @@
+#ifndef _XEN_MMU_H
+
+#include <linux/linkage.h>
+#include <asm/page.h>
+
+void set_pte_mfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);
+
+void xen_set_pte(pte_t *ptep, pte_t pteval);
+void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
+		    pte_t *ptep, pte_t pteval);
+void xen_set_pmd(pmd_t *pmdp, pmd_t pmdval);
+
+void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next);
+void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm);
+void xen_exit_mmap(struct mm_struct *mm);
+
+void xen_pgd_pin(pgd_t *pgd);
+void xen_pgd_unpin(pgd_t *pgd);
+
+#ifdef CONFIG_X86_PAE
+unsigned long long xen_pte_val(pte_t);
+unsigned long long xen_pmd_val(pmd_t);
+unsigned long long xen_pgd_val(pgd_t);
+
+pte_t xen_make_pte(unsigned long long);
+pmd_t xen_make_pmd(unsigned long long);
+pgd_t xen_make_pgd(unsigned long long);
+
+void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
+		    pte_t *ptep, pte_t pteval);
+void xen_set_pte_atomic(pte_t *ptep, pte_t pte);
+void xen_set_pud(pud_t *ptr, pud_t val);
+void xen_pte_clear(struct mm_struct *mm, unsigned long addr,pte_t *ptep);
+void xen_pmd_clear(pmd_t *pmdp);
+
+
+#else
+unsigned long xen_pte_val(pte_t);
+unsigned long xen_pmd_val(pmd_t);
+unsigned long xen_pgd_val(pgd_t);
+
+pte_t xen_make_pte(unsigned long);
+pmd_t xen_make_pmd(unsigned long);
+pgd_t xen_make_pgd(unsigned long);
+#endif
+
+#endif	/* _XEN_MMU_H */
===================================================================
--- /dev/null
+++ b/arch/i386/xen/multicalls.c
@@ -0,0 +1,61 @@
+#include <linux/percpu.h>
+
+#include <asm/xen/hypercall.h>
+
+#include "multicalls.h"
+
+#define MC_BATCH	8
+#define MC_ARGS		(MC_BATCH * 32 / sizeof(u64))
+
+struct mc_buffer {
+	struct multicall_entry entries[MC_BATCH];
+	u64 args[MC_ARGS];
+	unsigned mcidx, argidx;
+};
+
+static DEFINE_PER_CPU(struct mc_buffer, mc_buffer);
+
+void xen_mc_flush(void)
+{
+	struct mc_buffer *b = &get_cpu_var(mc_buffer);
+	int ret = 0;
+
+	if (b->mcidx) {
+		int i;
+
+		if (HYPERVISOR_multicall(b->entries, b->mcidx) != 0)
+			BUG();
+		for(i = 0; i < b->mcidx; i++)
+			if (b->entries[i].result < 0)
+				ret++;
+		b->mcidx = 0;
+		b->argidx = 0;
+	} else
+		BUG_ON(b->argidx != 0);
+
+	put_cpu_var(mc_buffer);
+
+	BUG_ON(ret);
+}
+
+struct multicall_space xen_mc_entry(size_t args)
+{
+	struct mc_buffer *b = &get_cpu_var(mc_buffer);
+	struct multicall_space ret;
+	unsigned argspace = (args + sizeof(u64) - 1) / sizeof(u64);
+
+	BUG_ON(argspace > MC_ARGS);
+
+	if (b->mcidx == MC_BATCH ||
+	    (b->argidx + argspace) > MC_ARGS)
+		xen_mc_flush();
+
+	ret.mc = &b->entries[b->mcidx];
+	b->mcidx++;
+	ret.args = &b->args[b->argidx];
+	b->argidx += argspace;
+
+	put_cpu_var(mc_buffer);
+
+	return ret;
+}
===================================================================
--- /dev/null
+++ b/arch/i386/xen/multicalls.h
@@ -0,0 +1,26 @@
+#ifndef _XEN_MULTICALLS_H
+#define _XEN_MULTICALLS_H
+
+#include "xen-ops.h"
+
+/* Multicalls */
+struct multicall_space
+{
+	struct multicall_entry *mc;
+	void *args;
+};
+
+/* Allocate room for a multicall and its args */
+struct multicall_space xen_mc_entry(size_t args);
+
+/* Flush all pending multicalls */
+void xen_mc_flush(void);
+
+/* Issue a multicall if we're not in lazy mode */
+static inline void xen_mc_issue(void)
+{
+	if (xen_get_lazy_mode() == PARAVIRT_LAZY_NONE)
+		xen_mc_flush();
+}
+
+#endif /* _XEN_MULTICALLS_H */
===================================================================
--- /dev/null
+++ b/arch/i386/xen/setup.c
@@ -0,0 +1,93 @@
+/*
+ *	Machine specific setup for xen
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/pm.h>
+
+#include <asm/e820.h>
+#include <asm/setup.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/interface/physdev.h>
+#include <xen/features.h>
+
+#include "xen-ops.h"
+
+/* These are code, but not functions.  Defined in entry.S */
+extern const char xen_hypervisor_callback[];
+extern const char xen_failsafe_callback[];
+
+static __initdata struct shared_info init_shared;
+
+/*
+ * Point at some empty memory to start with. We map the real shared_info
+ * page as soon as fixmap is up and running.
+ */
+struct shared_info *HYPERVISOR_shared_info = &init_shared;
+
+unsigned long *phys_to_machine_mapping;
+EXPORT_SYMBOL(phys_to_machine_mapping);
+
+/**
+ * machine_specific_memory_setup - Hook for machine specific memory setup.
+ **/
+
+char * __init xen_memory_setup(void)
+{
+	unsigned long max_pfn = xen_start_info->nr_pages;
+
+	e820.nr_map = 0;
+	add_memory_region(0, PFN_PHYS(max_pfn), E820_RAM);
+
+	return "Xen";
+}
+
+static void xen_idle(void)
+{
+	local_irq_disable();
+
+	if (need_resched())
+		local_irq_enable();
+	else {
+		current_thread_info()->status &= ~TS_POLLING;
+		smp_mb__after_clear_bit();
+		safe_halt();
+		current_thread_info()->status |= TS_POLLING;
+	}
+}
+
+void __init xen_arch_setup(void)
+{
+	struct physdevop_set_iopl set_iopl;
+	int rc;
+
+	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
+	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
+
+	if (!xen_feature(XENFEAT_auto_translated_physmap))
+		HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_pae_extended_cr3);
+
+	HYPERVISOR_set_callbacks(__KERNEL_CS, (unsigned long)xen_hypervisor_callback,
+				 __KERNEL_CS, (unsigned long)xen_failsafe_callback);
+
+	set_iopl.iopl = 1;
+	rc = HYPERVISOR_physdev_op(PHYSDEVOP_SET_IOPL, &set_iopl);
+	if (rc != 0)
+		printk(KERN_INFO "physdev_op failed %d\n", rc);
+
+#ifdef CONFIG_ACPI
+	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
+		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
+		disable_acpi();
+	}
+#endif
+
+	memcpy(boot_command_line, xen_start_info->cmd_line,
+	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
+	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
+
+	pm_idle = xen_idle;
+}
===================================================================
--- /dev/null
+++ b/arch/i386/xen/time.c
@@ -0,0 +1,393 @@
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/events.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/vcpu.h>
+
+#include "xen-ops.h"
+
+#define XEN_SHIFT 22
+#define TIMER_SLOP	100000	/* Xen may fire a timer up to this many ns early */
+
+/* These are perodically updated in shared_info, and then copied here. */
+struct shadow_time_info {
+	u64 tsc_timestamp;     /* TSC at last update of time vals.  */
+	u64 system_timestamp;  /* Time, in nanosecs, since boot.    */
+	u32 tsc_to_nsec_mul;
+	int tsc_shift;
+	u32 version;
+};
+
+static DEFINE_PER_CPU(struct shadow_time_info, shadow_time);
+
+unsigned long xen_cpu_khz(void)
+{
+	u64 cpu_khz = 1000000ULL << 32;
+	const struct vcpu_time_info *info =
+		&HYPERVISOR_shared_info->vcpu_info[0].time;
+
+	do_div(cpu_khz, info->tsc_to_system_mul);
+	if (info->tsc_shift < 0)
+		cpu_khz <<= -info->tsc_shift;
+	else
+		cpu_khz >>= info->tsc_shift;
+
+	return cpu_khz;
+}
+
+/*
+ * Reads a consistent set of time-base values from Xen, into a shadow data
+ * area.
+ */
+static void get_time_values_from_xen(void)
+{
+	struct vcpu_time_info   *src;
+	struct shadow_time_info *dst;
+
+	preempt_disable();
+
+	src = &__get_cpu_var(xen_vcpu)->time;
+	dst = &__get_cpu_var(shadow_time);
+
+	do {
+		dst->version = src->version;
+		rmb();
+		dst->tsc_timestamp     = src->tsc_timestamp;
+		dst->system_timestamp  = src->system_time;
+		dst->tsc_to_nsec_mul   = src->tsc_to_system_mul;
+		dst->tsc_shift         = src->tsc_shift;
+		rmb();
+	} while ((src->version & 1) | (dst->version ^ src->version));
+
+	preempt_enable();
+}
+
+/*
+ * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
+ * yielding a 64-bit result.
+ */
+static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
+{
+	u64 product;
+#ifdef __i386__
+	u32 tmp1, tmp2;
+#endif
+
+	if (shift < 0)
+		delta >>= -shift;
+	else
+		delta <<= shift;
+
+#ifdef __i386__
+	__asm__ (
+		"mul  %5       ; "
+		"mov  %4,%%eax ; "
+		"mov  %%edx,%4 ; "
+		"mul  %5       ; "
+		"xor  %5,%5    ; "
+		"add  %4,%%eax ; "
+		"adc  %5,%%edx ; "
+		: "=A" (product), "=r" (tmp1), "=r" (tmp2)
+		: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
+#elif __x86_64__
+	__asm__ (
+		"mul %%rdx ; shrd $32,%%rdx,%%rax"
+		: "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
+#else
+#error implement me!
+#endif
+
+	return product;
+}
+
+static u64 get_nsec_offset(struct shadow_time_info *shadow)
+{
+	u64 now, delta;
+	rdtscll(now);
+	delta = now - shadow->tsc_timestamp;
+	return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift);
+}
+
+cycle_t xen_clocksource_read(void)
+{
+	struct shadow_time_info *shadow = &get_cpu_var(shadow_time);
+	cycle_t ret;
+
+	get_time_values_from_xen();
+
+	ret = shadow->system_timestamp + get_nsec_offset(shadow);
+
+	put_cpu_var(shadow_time);
+
+	return ret;
+}
+
+static void xen_read_wallclock(struct timespec *ts)
+{
+	const struct shared_info *s = HYPERVISOR_shared_info;
+	u32 version;
+	u64 delta;
+	struct timespec now;
+
+	/* get wallclock at system boot */
+	do {
+		version = s->wc_version;
+		rmb();
+		now.tv_sec  = s->wc_sec;
+		now.tv_nsec = s->wc_nsec;
+		rmb();
+	} while ((s->wc_version & 1) | (version ^ s->wc_version));
+
+	delta = xen_clocksource_read();	/* time since system boot */
+	delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec;
+
+	now.tv_nsec = do_div(delta, NSEC_PER_SEC);
+	now.tv_sec = delta;
+
+	set_normalized_timespec(ts, now.tv_sec, now.tv_nsec);
+}
+
+unsigned long xen_get_wallclock(void)
+{
+	struct timespec ts;
+
+	xen_read_wallclock(&ts);
+
+	return ts.tv_sec;
+}
+
+int xen_set_wallclock(unsigned long now)
+{
+	/* do nothing for domU */
+	return -1;
+}
+
+static struct clocksource xen_clocksource __read_mostly = {
+	.name = "xen",
+	.rating = 400,
+	.read = xen_clocksource_read,
+	.mask = ~0,
+	.mult = 1<<XEN_SHIFT,		/* time directly in nanoseconds */
+	.shift = XEN_SHIFT,
+	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+/*
+   Xen clockevent implementation
+
+   Xen has two clockevent implementations:
+
+   The old timer_op one works with all released versions of Xen prior
+   to version 3.0.4.  This version of the hypervisor provides a
+   single-shot timer with nanosecond resolution.  However, sharing the
+   same event channel is a 100Hz tick which is delivered while the
+   vcpu is running.  We don't care about or use this tick, but it will
+   cause the core time code to think the timer fired too soon, and
+   will end up resetting it each time.  It could be filtered, but
+   doing so has complications when the ktime clocksource is not yet
+   the xen clocksource (ie, at boot time).
+
+   The new vcpu_op-based timer interface allows the tick timer period
+   to be changed or turned off.  The tick timer is not useful as a
+   periodic timer because events are only delivered to running vcpus.
+   The one-shot timer can report when a timeout is in the past, so
+   set_next_event is capable of returning -ETIME when appropriate.
+   This interface is used when available.
+*/
+
+
+/*
+  Get a hypervisor absolute time.  In theory we could maintain an
+  offset between the kernel's time and the hypervisor's time, and
+  apply that to a kernel's absolute timeout.  Unfortunately the
+  hypervisor and kernel times can drift even if the kernel is using
+  the Xen clocksource, because ntp can warp the kernel's clocksource.
+*/
+static s64 get_abs_timeout(unsigned long delta)
+{
+	return xen_clocksource_read() + delta;
+}
+
+static void xen_timerop_set_mode(enum clock_event_mode mode,
+				 struct clock_event_device *evt)
+{
+	switch(mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		/* unsupported */
+		WARN_ON(1);
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+		break;
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		HYPERVISOR_set_timer_op(0);  /* cancel timeout */
+		break;
+	}
+}
+
+static int xen_timerop_set_next_event(unsigned long delta,
+				      struct clock_event_device *evt)
+{
+	WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT);
+
+	if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0)
+		BUG();
+
+	/* We may have missed the deadline, but there's no real way of
+	   knowing for sure.  If the event was in the past, then we'll
+	   get an immediate interrupt. */
+
+	return 0;
+}
+
+static const struct clock_event_device xen_timerop_clockevent = {
+	.name = "xen",
+	.features = CLOCK_EVT_FEAT_ONESHOT,
+
+	.max_delta_ns = 0xffffffff,
+	.min_delta_ns = TIMER_SLOP,
+
+	.mult = 1,
+	.shift = 0,
+	.rating = 500,
+
+	.set_mode = xen_timerop_set_mode,
+	.set_next_event = xen_timerop_set_next_event,
+};
+
+
+
+static void xen_vcpuop_set_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt)
+{
+	int cpu = smp_processor_id();
+
+	switch(mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		WARN_ON(1);	/* unsupported */
+		break;
+
+	case CLOCK_EVT_MODE_ONESHOT:
+		if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL))
+			BUG();
+		break;
+
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, cpu, NULL) ||
+		    HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL))
+			BUG();
+		break;
+	}
+}
+
+static int xen_vcpuop_set_next_event(unsigned long delta,
+				     struct clock_event_device *evt)
+{
+	int cpu = smp_processor_id();
+	struct vcpu_set_singleshot_timer single;
+	int ret;
+
+	WARN_ON(evt->mode != CLOCK_EVT_MODE_ONESHOT);
+
+	single.timeout_abs_ns = get_abs_timeout(delta);
+	single.flags = VCPU_SSHOTTMR_future;
+
+	ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, cpu, &single);
+
+	BUG_ON(ret != 0 && ret != -ETIME);
+
+	return ret;
+}
+
+static const struct clock_event_device xen_vcpuop_clockevent = {
+	.name = "xen",
+	.features = CLOCK_EVT_FEAT_ONESHOT,
+
+	.max_delta_ns = 0xffffffff,
+	.min_delta_ns = TIMER_SLOP,
+
+	.mult = 1,
+	.shift = 0,
+	.rating = 500,
+
+	.set_mode = xen_vcpuop_set_mode,
+	.set_next_event = xen_vcpuop_set_next_event,
+};
+
+static const struct clock_event_device *xen_clockevent =
+	&xen_timerop_clockevent;
+static DEFINE_PER_CPU(struct clock_event_device, xen_clock_events);
+
+static irqreturn_t xen_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = &__get_cpu_var(xen_clock_events);
+	irqreturn_t ret;
+
+	ret = IRQ_NONE;
+	if (evt->event_handler) {
+		evt->event_handler(evt);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static void xen_setup_timer(int cpu)
+{
+	const char *name;
+	struct clock_event_device *evt;
+	int irq;
+
+	printk("installing Xen timer for CPU %d\n", cpu);
+
+	name = kasprintf(GFP_KERNEL, "timer%d", cpu);
+	if (!name)
+		name = "<timer kasprintf failed>";
+
+	irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt,
+				      IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+				      name, NULL);
+
+	evt = &get_cpu_var(xen_clock_events);
+	memcpy(evt, xen_clockevent, sizeof(*evt));
+
+	evt->cpumask = cpumask_of_cpu(cpu);
+	evt->irq = irq;
+	clockevents_register_device(evt);
+
+	put_cpu_var(xen_clock_events);
+}
+
+__init void xen_time_init(void)
+{
+	int cpu = smp_processor_id();
+
+	get_time_values_from_xen();
+
+	clocksource_register(&xen_clocksource);
+
+	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) {
+		/* Successfully turned off 100hz tick, so we have the
+		   vcpuop-based timer interface */
+		printk(KERN_DEBUG "Xen: using vcpuop timer interface\n");
+		xen_clockevent = &xen_vcpuop_clockevent;
+	}
+
+	/* Set initial system time with full resolution */
+	xen_read_wallclock(&xtime);
+	set_normalized_timespec(&wall_to_monotonic,
+				-xtime.tv_sec, -xtime.tv_nsec);
+
+	tsc_disable = 0;
+
+	xen_setup_timer(cpu);
+}
===================================================================
--- /dev/null
+++ b/arch/i386/xen/xen-head.S
@@ -0,0 +1,34 @@
+/* Xen-specific pieces of head.S, intended to be included in the right
+	place in head.S */
+
+#ifdef CONFIG_XEN
+
+#include <linux/elfnote.h>
+#include <asm/boot.h>
+#include <xen/interface/elfnote.h>
+
+ENTRY(startup_xen)
+	movl %esi,xen_start_info
+	jmp startup_paravirt
+
+.pushsection ".bss.page_aligned"
+	.align PAGE_SIZE_asm
+ENTRY(hypercall_page)
+	.skip 0x1000
+.popsection
+
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz, "linux")
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz, "2.6")
+	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz, "xen-3.0")
+	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      .long,  __PAGE_OFFSET)
+	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .long,  startup_xen)
+	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .long,  hypercall_page)
+	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz, "!writable_page_tables|pae_pgdir_above_4gb")
+#ifdef CONFIG_X86_PAE
+	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz, "yes")
+#else
+	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz, "no")
+#endif
+	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz, "generic")
+
+#endif /*CONFIG_XEN */
===================================================================
--- /dev/null
+++ b/arch/i386/xen/xen-ops.h
@@ -0,0 +1,34 @@
+#ifndef XEN_OPS_H
+#define XEN_OPS_H
+
+#include <linux/init.h>
+#include <linux/clocksource.h>
+
+DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu);
+DECLARE_PER_CPU(unsigned long, xen_cr3);
+
+extern struct start_info *xen_start_info;
+extern struct shared_info *HYPERVISOR_shared_info;
+
+char * __init xen_memory_setup(void);
+void __init xen_arch_setup(void);
+void __init xen_init_IRQ(void);
+
+unsigned long xen_cpu_khz(void);
+void __init xen_time_init(void);
+unsigned long xen_get_wallclock(void);
+int xen_set_wallclock(unsigned long time);
+cycle_t xen_clocksource_read(void);
+
+DECLARE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode);
+
+static inline unsigned xen_get_lazy_mode(void)
+{
+	unsigned ret = get_cpu_var(xen_lazy_mode);
+	put_cpu_var(xen_lazy_mode);
+
+	return ret;
+}
+
+
+#endif /* XEN_OPS_H */
===================================================================
--- a/include/asm-i386/irq.h
+++ b/include/asm-i386/irq.h
@@ -41,6 +41,7 @@ extern void fixup_irqs(cpumask_t map);
 extern void fixup_irqs(cpumask_t map);
 #endif
 
+unsigned int do_IRQ(struct pt_regs *regs);
 void init_IRQ(void);
 void __init native_init_IRQ(void);
 
===================================================================
--- a/include/asm-i386/xen/hypercall.h
+++ b/include/asm-i386/xen/hypercall.h
@@ -410,4 +410,22 @@ MULTI_mmuext_op(struct multicall_entry *
 	mcl->args[2] = (unsigned long)success_count;
 	mcl->args[3] = domid;
 }
+
+static inline void
+MULTI_set_gdt(struct multicall_entry *mcl, unsigned long *frames, int entries)
+{
+	mcl->op = __HYPERVISOR_set_gdt;
+	mcl->args[0] = (unsigned long)frames;
+	mcl->args[1] = entries;
+}
+
+static inline void
+MULTI_stack_switch(struct multicall_entry *mcl,
+		   unsigned long ss, unsigned long esp)
+{
+	mcl->op = __HYPERVISOR_stack_switch;
+	mcl->args[0] = ss;
+	mcl->args[1] = esp;
+}
+
 #endif /* __HYPERCALL_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/events.h
@@ -0,0 +1,28 @@
+#ifndef _XEN_EVENTS_H
+#define _XEN_EVENTS_H
+
+#include <linux/irq.h>
+
+int bind_evtchn_to_irqhandler(unsigned int evtchn,
+			      irqreturn_t (*handler)(int, void *),
+			      unsigned long irqflags, const char *devname,
+			      void *dev_id);
+int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
+			    irqreturn_t (*handler)(int, void *),
+			    unsigned long irqflags, const char *devname, void *dev_id);
+
+/*
+ * Common unbind function for all event sources. Takes IRQ to unbind from.
+ * Automatically closes the underlying event channel (even for bindings
+ * made with bind_evtchn_to_irqhandler()).
+ */
+void unbind_from_irqhandler(unsigned int irq, void *dev_id);
+
+static inline void notify_remote_via_evtchn(int port)
+{
+	struct evtchn_send send = { .port = port };
+	(void)HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
+}
+
+extern void notify_remote_via_irq(int irq);
+#endif	/* _XEN_EVENTS_H */
===================================================================
--- /dev/null
+++ b/include/xen/features.h
@@ -0,0 +1,26 @@
+/******************************************************************************
+ * features.h
+ *
+ * Query the features reported by Xen.
+ *
+ * Copyright (c) 2006, Ian Campbell
+ */
+
+#ifndef __XEN_FEATURES_H__
+#define __XEN_FEATURES_H__
+
+#include <xen/interface/features.h>
+
+void xen_setup_features(void);
+
+extern u8 xen_features[XENFEAT_NR_SUBMAPS * 32];
+
+static inline int xen_feature(int flag)
+{
+	switch(flag) {
+	}
+
+	return xen_features[flag];
+}
+
+#endif /* __ASM_XEN_FEATURES_H__ */
===================================================================
--- /dev/null
+++ b/include/xen/page.h
@@ -0,0 +1,178 @@
+#ifndef __XEN_PAGE_H
+#define __XEN_PAGE_H
+
+#include <linux/pfn.h>
+
+#include <asm/uaccess.h>
+
+#include <xen/features.h>
+
+#ifdef CONFIG_X86_PAE
+/* Xen machine address */
+typedef struct xmaddr {
+	unsigned long long maddr;
+} xmaddr_t;
+
+/* Xen pseudo-physical address */
+typedef struct xpaddr {
+	unsigned long long paddr;
+} xpaddr_t;
+#else
+/* Xen machine address */
+typedef struct xmaddr {
+	unsigned long maddr;
+} xmaddr_t;
+
+/* Xen pseudo-physical address */
+typedef struct xpaddr {
+	unsigned long paddr;
+} xpaddr_t;
+#endif
+
+#define XMADDR(x)	((xmaddr_t) { .maddr = (x) })
+#define XPADDR(x)	((xpaddr_t) { .paddr = (x) })
+
+/**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
+#define INVALID_P2M_ENTRY	(~0UL)
+#define FOREIGN_FRAME_BIT	(1UL<<31)
+#define FOREIGN_FRAME(m)	((m) | FOREIGN_FRAME_BIT)
+
+extern unsigned long *phys_to_machine_mapping;
+
+static inline unsigned long pfn_to_mfn(unsigned long pfn)
+{
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return pfn;
+
+	return phys_to_machine_mapping[(unsigned int)(pfn)] &
+		~FOREIGN_FRAME_BIT;
+}
+
+static inline int phys_to_machine_mapping_valid(unsigned long pfn)
+{
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return 1;
+
+	return (phys_to_machine_mapping[pfn] != INVALID_P2M_ENTRY);
+}
+
+static inline unsigned long mfn_to_pfn(unsigned long mfn)
+{
+	unsigned long pfn;
+
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return mfn;
+
+#if 0
+	if (unlikely((mfn >> machine_to_phys_order) != 0))
+		return max_mapnr;
+#endif
+
+	pfn = 0;
+	/*
+	 * The array access can fail (e.g., device space beyond end of RAM).
+	 * In such cases it doesn't matter what we return (we return garbage),
+	 * but we must handle the fault without crashing!
+	 */
+	__get_user(pfn, &machine_to_phys_mapping[mfn]);
+
+	return pfn;
+}
+
+static inline xmaddr_t phys_to_machine(xpaddr_t phys)
+{
+	unsigned offset = phys.paddr & ~PAGE_MASK;
+	return XMADDR(PFN_PHYS((u64)pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
+}
+
+static inline xpaddr_t machine_to_phys(xmaddr_t machine)
+{
+	unsigned offset = machine.maddr & ~PAGE_MASK;
+	return XPADDR(PFN_PHYS((u64)mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
+}
+
+/*
+ * We detect special mappings in one of two ways:
+ *  1. If the MFN is an I/O page then Xen will set the m2p entry
+ *     to be outside our maximum possible pseudophys range.
+ *  2. If the MFN belongs to a different domain then we will certainly
+ *     not have MFN in our p2m table. Conversely, if the page is ours,
+ *     then we'll have p2m(m2p(MFN))==MFN.
+ * If we detect a special mapping then it doesn't have a 'struct page'.
+ * We force !pfn_valid() by returning an out-of-range pointer.
+ *
+ * NB. These checks require that, for any MFN that is not in our reservation,
+ * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
+ * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
+ * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
+ *
+ * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
+ *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
+ *      require. In all the cases we care about, the FOREIGN_FRAME bit is
+ *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
+ */
+static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
+{
+	extern unsigned long max_mapnr;
+	unsigned long pfn = mfn_to_pfn(mfn);
+	if ((pfn < max_mapnr)
+	    && !xen_feature(XENFEAT_auto_translated_physmap)
+	    && (phys_to_machine_mapping[pfn] != mfn))
+		return max_mapnr; /* force !pfn_valid() */
+	return pfn;
+}
+
+static inline void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+	if (xen_feature(XENFEAT_auto_translated_physmap)) {
+		BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
+		return;
+	}
+	phys_to_machine_mapping[pfn] = mfn;
+}
+
+/* VIRT <-> MACHINE conversion */
+#define virt_to_machine(v)	(phys_to_machine(XPADDR(__pa(v))))
+#define virt_to_mfn(v)		(pfn_to_mfn(PFN_DOWN(__pa(v))))
+#define mfn_to_virt(m)		(__va(mfn_to_pfn(m) << PAGE_SHIFT))
+
+#ifdef CONFIG_X86_PAE
+#define pte_mfn(_pte) (((_pte).pte_low >> PAGE_SHIFT) |\
+                       (((_pte).pte_high & 0xfff) << (32-PAGE_SHIFT)))
+
+static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
+{
+	pte_t pte;
+
+	pte.pte_high = (page_nr >> (32 - PAGE_SHIFT)) | (pgprot_val(pgprot) >> 32);
+	pte.pte_high &= (__supported_pte_mask >> 32);
+	pte.pte_low = ((page_nr << PAGE_SHIFT) | pgprot_val(pgprot));
+	pte.pte_low &= __supported_pte_mask;
+
+	return pte;
+}
+
+static inline unsigned long long pte_val_ma(pte_t x)
+{
+	return ((unsigned long long)x.pte_high << 32) | x.pte_low;
+}
+#define pmd_val_ma(v) ((v).pmd)
+#define pud_val_ma(v) ((v).pgd.pgd)
+#define __pte_ma(x)	((pte_t) { .pte_low=(x), .pte_high=(x)>>32 } )
+#define __pmd_ma(x)	((pmd_t) { (x) } )
+#else  /* !X86_PAE */
+#define pte_mfn(_pte) ((_pte).pte_low >> PAGE_SHIFT)
+#define mfn_pte(pfn, prot)	__pte_ma(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
+#define pte_val_ma(x)	((x).pte_low)
+#define pmd_val_ma(v)	((v).pud.pgd.pgd)
+#define __pte_ma(x)	((pte_t) { (x) } )
+#endif	/* CONFIG_X86_PAE */
+
+#define pgd_val_ma(x)	((x).pgd)
+
+
+xmaddr_t arbitrary_virt_to_machine(unsigned long address);
+void make_lowmem_page_readonly(void *vaddr);
+void make_lowmem_page_readwrite(void *vaddr);
+
+#endif /* __XEN_PAGE_H */

-- 

Re: [PATCH 06/25] xen: Core Xen implementation

[Andi Kleen]

On Monday 23 April 2007 23:56:44 Jeremy Fitzhardinge wrote:
> Core Xen Implementation
> 
> This patch is a rollup of all the core pieces of the Xen
> implementation, including booting, memory management, interrupts, time
> and so on.

The patch is definitely too big.

> +#ifdef CONFIG_XEN
> +/* Xen only supports sysenter/sysexit in ring0 guests,
> +   and only if it the guest asks for it.  So for now,
> +   this should never be used. */
> +ENTRY(xen_sti_sysexit)
> +	CFI_STARTPROC
> +	ud2
> +	CFI_ENDPROC
> +ENDPROC(xen_sti_sysexit)

Put that elsewhere? It doesn't need to be here.


> +++ b/arch/i386/xen/enlighten.c
> @@ -0,0 +1,727 @@

Comments describing what all the files do? 

> +	unsigned maskedx = ~0;
> +	if (*eax == 1)
> +		maskedx = ~((1 << X86_FEATURE_APIC) |
> +			    (1 << X86_FEATURE_ACPI) |
> +			    (1 << X86_FEATURE_ACC));

Why ACC? 

And why doesn't Xen mask those by itself?

And you got apic functions later which would be never called?
Why are the hooks needed then? 

> +
> +static unsigned long xen_save_fl(void)
> +{
> +	struct vcpu_info *vcpu;
> +	unsigned long flags;
> +
> +	preempt_disable();
> +	vcpu = x86_read_percpu(xen_vcpu);
> +	/* flag has opposite sense of mask */
> +	flags = !vcpu->evtchn_upcall_mask;
> +	preempt_enable();

If you use get_cpu/put_cpu it will be optimized away on PREEMPT && !SMP
(more occurrences)

> +static void xen_restore_fl(unsigned long flags)
> +{
> +	struct vcpu_info *vcpu;
> +
> +	preempt_disable();
> +
> +	/* convert from IF type flag */
> +	flags = !(flags & X86_EFLAGS_IF);
> +	vcpu = x86_read_percpu(xen_vcpu);
> +	vcpu->evtchn_upcall_mask = flags;
> +	if (flags == 0) {
> +		barrier(); /* unmask then check (avoid races) */

Don't you need a rmb() here then? The CPU could speculate reads
(more occurrences) 

> +		if (unlikely(vcpu->evtchn_upcall_pending))
> +			force_evtchn_callback();
> +		preempt_enable();
> +	} else
> +		preempt_enable_no_resched();
> +}
> +
> +static void xen_irq_disable(void)
> +{
> +	struct vcpu_info *vcpu;
> +	preempt_disable();
> +	vcpu = x86_read_percpu(xen_vcpu);
> +	vcpu->evtchn_upcall_mask = 1;
> +	preempt_enable_no_resched();

First with the new per cpu the preempt disable shouldn't be needed
anymore because the thing is atomic. In the worst case you do 
the change on the previous CPU, but that can happen anyways after
preempt_enable

And then when you have enabled who transfers the irq off state to the
new CPU? 


> +static void xen_halt(void)
> +{
> +#if 0
> +	if (irqs_disabled())
> +		HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
> +#endif
> +}

Who halts then?

> +static void xen_load_gdt(const struct Xgt_desc_struct *dtr)
> +{
> +	unsigned long *frames;
> +	unsigned long va = dtr->address;
> +	unsigned int size = dtr->size + 1;
> +	int f;
> +	struct multicall_space mcs;
> +
> +	BUG_ON(size > 16*PAGE_SIZE);

Why 16?

> +	count = desc->size / 8;
> +	BUG_ON(count > 256);

should be >= ?


> +static void xen_set_iopl_mask(unsigned mask)
> +{
> +#if 0
> +	struct physdev_set_iopl set_iopl;
> +
> +	/* Force the change at ring 0. */
> +	set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
> +	HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
> +#endif

And who does iopl then?


> + * Page-directory addresses above 4GB do not fit into architectural %cr3.
> + * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
> + * must use the following accessor macros to pack/unpack valid MFNs.
> + */
> +#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
> +#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))

Don't you lose bits >4GB here due to the casts before shift?

> +	BUG_ON(memcmp(xen_start_info->magic, "xen-3.0", 7) != 0);

Hopefully Xen 4.0 can handle this then.

> +
> +	/* Poke various useful things into boot_params */
> +	LOADER_TYPE = (9 << 4) | 0;

| 0 ? Probably should be something symbolic

> +unsigned long xen_pmd_val(pmd_t pmd)
> +{
> +	BUG();
> +	return 0;
> +}

Why do we have pmd_val hooks then?

> +pmd_t xen_make_pmd(unsigned long pmd)
> +{
> +	BUG();
> +	return __pmd(0);
> +}

and make_pmd hooks?

> --- /dev/null
> +++ b/arch/i386/xen/time.c

... will review the rest later.

Can you please split it up a bit?

-Andi

Re: [PATCH 06/25] xen: Core Xen implementation

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> On Monday 23 April 2007 23:56:44 Jeremy Fitzhardinge wrote:
>   
>> Core Xen Implementation
>>
>> This patch is a rollup of all the core pieces of the Xen
>> implementation, including booting, memory management, interrupts, time
>> and so on.
>>     
>
> The patch is definitely too big.
>   

Yes.  It was originally smaller patches, which I tried to keep in a
state where everything was incrementally buildable, but it got too hard
to keep it all together.

I guess I can break it down into functional groups, and put the config
stuff at the end.

>> +#ifdef CONFIG_XEN
>> +/* Xen only supports sysenter/sysexit in ring0 guests,
>> +   and only if it the guest asks for it.  So for now,
>> +   this should never be used. */
>> +ENTRY(xen_sti_sysexit)
>> +	CFI_STARTPROC
>> +	ud2
>> +	CFI_ENDPROC
>> +ENDPROC(xen_sti_sysexit)
>>     
>
> Put that elsewhere? It doesn't need to be here.
>   

Yes, I can drop it.  It's not needed in this kernel.

>> +++ b/arch/i386/xen/enlighten.c
>> @@ -0,0 +1,727 @@
>>     
>
> Comments describing what all the files do? 
>   

OK.

>> +	unsigned maskedx = ~0;
>> +	if (*eax == 1)
>> +		maskedx = ~((1 << X86_FEATURE_APIC) |
>> +			    (1 << X86_FEATURE_ACPI) |
>> +			    (1 << X86_FEATURE_ACC));
>>     
>
> Why ACC? 
>
> And why doesn't Xen mask those by itself?
>   

Because it doesn't care whether they're set or not.  I'm suppressing
them here to prevent the kernel from trying to use these features.  I
suppress ACC in particular to stop the P4 thermal interrupt code from
trying to do anything.

I'll comment it.

> And you got apic functions later which would be never called?
> Why are the hooks needed then? 
>   

They aren't.  They're only for VMI.  I've only got them to make sure
that there are no stray APIC usages.

>> +
>> +static unsigned long xen_save_fl(void)
>> +{
>> +	struct vcpu_info *vcpu;
>> +	unsigned long flags;
>> +
>> +	preempt_disable();
>> +	vcpu = x86_read_percpu(xen_vcpu);
>> +	/* flag has opposite sense of mask */
>> +	flags = !vcpu->evtchn_upcall_mask;
>> +	preempt_enable();
>>     
>
> If you use get_cpu/put_cpu it will be optimized away on PREEMPT && !SMP
> (more occurrences)
>   

Won't preempt_disable disappear as well?  I don't need the CPU number.

>> +static void xen_restore_fl(unsigned long flags)
>> +{
>> +	struct vcpu_info *vcpu;
>> +
>> +	preempt_disable();
>> +
>> +	/* convert from IF type flag */
>> +	flags = !(flags & X86_EFLAGS_IF);
>> +	vcpu = x86_read_percpu(xen_vcpu);
>> +	vcpu->evtchn_upcall_mask = flags;
>> +	if (flags == 0) {
>> +		barrier(); /* unmask then check (avoid races) */
>>     
>
> Don't you need a rmb() here then? The CPU could speculate reads
> (more occurrences) 
>   

OK.

>> +		if (unlikely(vcpu->evtchn_upcall_pending))
>> +			force_evtchn_callback();
>> +		preempt_enable();
>> +	} else
>> +		preempt_enable_no_resched();
>> +}
>> +
>> +static void xen_irq_disable(void)
>> +{
>> +	struct vcpu_info *vcpu;
>> +	preempt_disable();
>> +	vcpu = x86_read_percpu(xen_vcpu);
>> +	vcpu->evtchn_upcall_mask = 1;
>> +	preempt_enable_no_resched();
>>     
>
> First with the new per cpu the preempt disable shouldn't be needed
> anymore because the thing is atomic. In the worst case you do 
> the change on the previous CPU, but that can happen anyways after
> preempt_enable
>   

No, there's a one instruction preempt window there.  If I do:

    mov %fs:xen_vcpu, %eax
    movb $1,1(%eax)

and a preempt happens in between, then the interrupt will be disabled on
the wrong cpu.

Once we can put the vcpu structure into the percpu area directly, then I
can do:

    movb $1,%fs:xen_vcpu+1

which is preempt-safe, of course.

> And then when you have enabled who transfers the irq off state to the
> new CPU? 
>   

I don't follow you.

>> +static void xen_halt(void)
>> +{
>> +#if 0
>> +	if (irqs_disabled())
>> +		HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
>> +#endif
>> +}
>>     
>
> Who halts then?
>   

I fix this up in the xen-machine-ops.patch.

>> +static void xen_load_gdt(const struct Xgt_desc_struct *dtr)
>> +{
>> +	unsigned long *frames;
>> +	unsigned long va = dtr->address;
>> +	unsigned int size = dtr->size + 1;
>> +	int f;
>> +	struct multicall_space mcs;
>> +
>> +	BUG_ON(size > 16*PAGE_SIZE);
>>     
>
> Why 16?
>   

I'll make it more explicit.  It's 64k of GDT entries == 16 pages.

>> +	count = desc->size / 8;
>> +	BUG_ON(count > 256);
>>     
>
> should be >= ?
>   

I think 256 idt entries is OK, but it should be (desc->size+1) / 8.

>> +static void xen_set_iopl_mask(unsigned mask)
>> +{
>> +#if 0
>> +	struct physdev_set_iopl set_iopl;
>> +
>> +	/* Force the change at ring 0. */
>> +	set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
>> +	HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
>> +#endif
>>     
>
> And who does iopl then?
>   

Nobody at the moment.  I don't think there's much need for it in an
unprivileged Xen domU.  I could just nop it out for now.

>> + * Page-directory addresses above 4GB do not fit into architectural %cr3.
>> + * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
>> + * must use the following accessor macros to pack/unpack valid MFNs.
>> + */
>> +#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
>> +#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))
>>     
>
> Don't you lose bits >4GB here due to the casts before shift?
>   

Erm, good point.

>> +	BUG_ON(memcmp(xen_start_info->magic, "xen-3.0", 7) != 0);
>>     
>
> Hopefully Xen 4.0 can handle this then.
>   

It would probably present xen-3 guests a xen-3 signature.

>> +
>> +	/* Poke various useful things into boot_params */
>> +	LOADER_TYPE = (9 << 4) | 0;
>>     
>
> | 0 ? Probably should be something symbolic
>   

0 is the version number.  I don't think there are symbols for the
bootloader types.

>> +unsigned long xen_pmd_val(pmd_t pmd)
>> +{
>> +	BUG();
>> +	return 0;
>> +}
>>     
>
> Why do we have pmd_val hooks then?
>
>   
>> +pmd_t xen_make_pmd(unsigned long pmd)
>> +{
>> +	BUG();
>> +	return __pmd(0);
>> +}
>>     
>
> and make_pmd hooks?
>   

That's the !PAE case, so we expect to never have any PMD calls.  The
hooks exist for !PAE because I didn't want to have more ifdefs.

>> --- /dev/null
>> +++ b/arch/i386/xen/time.c
>>     
>
> ... will review the rest later.
>
> Can you please split it up a bit?
>   

OK.

    J

Re: [PATCH 06/25] xen: Core Xen implementation

[Andi Kleen]

> ... will review the rest later.

Rest is ok

-Andi

 

Re: [PATCH 06/25] xen: Core Xen implementation

[Jeremy Fitzhardinge]

Andi Kleen wrote:
>> ... will review the rest later.
>>     
>
> Rest is ok
>   

Thanks for looking at it.  I'll try to separate xen-core into more
digestable pieces.

    J

Re: [PATCH 06/25] xen: Core Xen implementation

[Andi Kleen]

On Wednesday 25 April 2007 21:41:23 Jeremy Fitzhardinge wrote:
> Andi Kleen wrote:
> >> ... will review the rest later.
> >>     
> >
> > Rest is ok
> >   
> 
> Thanks for looking at it.  I'll try to separate xen-core into more
> digestable pieces.

For me you don't need anymore, but possibly for others.

To summarize the outstanding issues are:
- fixing sched_clock first
- hopefully more review of the core pieces by others
- what i commented (minor stuff mostly)
- review of xenbus and drivers
[i did upto the grant table code, but not more] 


-Andi

Re: [PATCH 06/25] xen: Core Xen implementation II

[Andi Kleen]

> To summarize the outstanding issues are:
> - fixing sched_clock first
> - hopefully more review of the core pieces by others
> - what i commented (minor stuff mostly)
> - review of xenbus and drivers
> [i did upto the grant table code, but not more] 

- and more testing by other people (forgot that earlier)

-Andi

Re: [PATCH 06/25] xen: Core Xen implementation

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> For me you don't need anymore, but possibly for others.
>   

Hm.  I'm not a fan of the great big monolithic patch myself, but on the
other hand I don't like the idea of patches which are not self-contained
steps from working->working state.  Xen-core.patch is currently the
(more or less) minimal set of stuff which needs to be in place to get
working Xen guest up, and so from that perspective I don't think there's
a good way of splitting it up.

> To summarize the outstanding issues are:
> - fixing sched_clock first
>   

What was the sched_clock problem?  I don't remember and outstanding
issues with it.  I noticed you didn't take paravirt-sched_clock.

> - hopefully more review of the core pieces by others
> - what i commented (minor stuff mostly)
>   

I just rebased onto your newest patches, so I'll address your comments
and repost.

> - review of xenbus and drivers

Yes, not much response there.

    J

Re: [PATCH 06/25] xen: Core Xen implementation

[Andi Kleen]

> > To summarize the outstanding issues are:
> > - fixing sched_clock first
> >   
> 
> What was the sched_clock problem?  I don't remember and outstanding
> issues with it.  I noticed you didn't take paravirt-sched_clock.

The major problem was that it didn't compile on x86-64.
And a few uglities in there so I was not too unhappy to drop.

-Andi

Re: [PATCH 06/25] xen: Core Xen implementation

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> The major problem was that it didn't compile on x86-64.
>   

Ah, OK.  I don't think you mentioned that.  I'll fix that up.

> And a few uglities in there
>   

Such as?

    J

Re: [PATCH 06/25] xen: Core Xen implementation

[Jeremy Fitzhardinge]

Andi Kleen wrote:
>> +	/* convert from IF type flag */
>> +	flags = !(flags & X86_EFLAGS_IF);
>> +	vcpu = x86_read_percpu(xen_vcpu);
>> +	vcpu->evtchn_upcall_mask = flags;
>> +	if (flags == 0) {
>> +		barrier(); /* unmask then check (avoid races) */
>>     
>
> Don't you need a rmb() here then? The CPU could speculate reads
> (more occurrences) 
>   

Is rmb() sufficient?  It will stop a speculative read on the pending
flag, but will it make sure the write has happened by then?  Ie, is it a
write-vs-read barrier, or just a read-vs-read? 
Documentation/memory-barriers.txt suggests not.

    J

Re: [PATCH 06/25] xen: Core Xen implementation

[Keir Fraser]

On 27/4/07 08:08, "Jeremy Fitzhardinge" <jeremy@goop.org> wrote:

>> Don't you need a rmb() here then? The CPU could speculate reads
>> (more occurrences)
>>   
> 
> Is rmb() sufficient?  It will stop a speculative read on the pending
> flag, but will it make sure the write has happened by then?  Ie, is it a
> write-vs-read barrier, or just a read-vs-read?
> Documentation/memory-barriers.txt suggests not.

The barrier() is sufficient. We are racing against Xen checking
evtchn_upcall_mask *on the local cpu*. Which means an interrupt has to
occur, which squashes speculative stuff.

Yeah, I know, it needs a better comment. :-)

 -- Keir

[PATCH 07/25] xen: Complete pagetable pinning for Xen

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-pinned-pagetables.patch --]
[-- Type: text/plain, Size: 21951 bytes --]

Xen has a notion of pinned pagetables, which are pagetables that
remain read-only to the guest and are validated by the hypervisor.
This makes context switches much cheaper, because the hypervisor
doesn't need to revalidate the pagetable each time.

This patch adds a PG_pinned flag for pagetable pages so we can tell if
it has been pinned or not.  This allows various pagetable update
optimisations.

This also adds a mm parameter to the alloc_pt pv_op, so that Xen can
see if we're adding a page to a pinned pagetable.  This is not
necessary for alloc_pd or release_p[dt], which is fortunate because it
isn't available at all callsites.

This also adds a new paravirt hook which is called during setup once
the zones and memory allocator have been initialized.  When the
init_mm pagetable is first built, the struct page array does not yet
exist, and so there's nowhere to put he init_mm pagetable's PG_pinned
flags.  Once the zones are initialized and the struct page array
exists, we can set the PG_pinned flags for those pages.

This patch also adds the Xen support for pte pages allocated out of
highmem (highpte), principly by implementing xen_kmap_atomic_pte.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Zach Amsden <zach@vmware.com>

---
 arch/i386/kernel/setup.c    |    3 
 arch/i386/kernel/vmi.c      |    2 
 arch/i386/mm/init.c         |    2 
 arch/i386/mm/pageattr.c     |    2 
 arch/i386/xen/enlighten.c   |  105 +++++++++++-----
 arch/i386/xen/mmu.c         |  280 +++++++++++++++++++++++++++----------------
 arch/i386/xen/mmu.h         |    2 
 arch/i386/xen/xen-ops.h     |    2 
 include/asm-i386/paravirt.h |   16 +-
 include/asm-i386/pgalloc.h  |    6 
 include/asm-i386/setup.h    |    4 
 include/linux/page-flags.h  |    5 
 12 files changed, 289 insertions(+), 140 deletions(-)

===================================================================
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -607,9 +607,12 @@ void __init setup_arch(char **cmdline_p)
 	sparse_init();
 	zone_sizes_init();
 
+
 	/*
 	 * NOTE: at this point the bootmem allocator is fully available.
 	 */
+
+	paravirt_post_allocator_init();
 
 	dmi_scan_machine();
 
===================================================================
--- a/arch/i386/kernel/vmi.c
+++ b/arch/i386/kernel/vmi.c
@@ -361,7 +361,7 @@ static void *vmi_kmap_atomic_pte(struct 
 }
 #endif
 
-static void vmi_allocate_pt(u32 pfn)
+static void vmi_allocate_pt(struct mm_struct *mm, u32 pfn)
 {
 	vmi_set_page_type(pfn, VMI_PAGE_L1);
 	vmi_ops.allocate_page(pfn, VMI_PAGE_L1, 0, 0, 0);
===================================================================
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -87,7 +87,7 @@ static pte_t * __init one_page_table_ini
 	if (pmd_none(*pmd)) {
 		pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 
-		paravirt_alloc_pt(__pa(page_table) >> PAGE_SHIFT);
+		paravirt_alloc_pt(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 		BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 	}
===================================================================
--- a/arch/i386/mm/pageattr.c
+++ b/arch/i386/mm/pageattr.c
@@ -60,7 +60,7 @@ static struct page *split_large_page(uns
 	address = __pa(address);
 	addr = address & LARGE_PAGE_MASK; 
 	pbase = (pte_t *)page_address(base);
-	paravirt_alloc_pt(page_to_pfn(base));
+	paravirt_alloc_pt(&init_mm, page_to_pfn(base));
 	for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE) {
                set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT,
                                           addr == address ? prot : ref_prot));
===================================================================
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -8,6 +8,9 @@
 #include <linux/sched.h>
 #include <linux/bootmem.h>
 #include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/page-flags.h>
+#include <linux/highmem.h>
 
 #include <xen/interface/xen.h>
 #include <xen/features.h>
@@ -453,32 +456,59 @@ static void xen_write_cr3(unsigned long 
 	}
 }
 
-static void xen_alloc_pt(u32 pfn)
-{
-	/* XXX pfn isn't necessarily a lowmem page */
+/* Early in boot, while setting up the initial pagetable, assume
+   everything is pinned. */
+static void xen_alloc_pt_init(struct mm_struct *mm, u32 pfn)
+{
+	BUG_ON(mem_map);	/* should only be used early */
 	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
 }
 
-static void xen_alloc_pd(u32 pfn)
-{
-	make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
-}
-
-static void xen_release_pd(u32 pfn)
-{
-	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
-}
-
+/* This needs to make sure the new pte page is pinned iff its being
+   attached to a pinned pagetable. */
+static void xen_alloc_pt(struct mm_struct *mm, u32 pfn)
+{
+	struct page *page = pfn_to_page(pfn);
+
+	if (PagePinned(virt_to_page(mm->pgd))) {
+		SetPagePinned(page);
+
+		if (!PageHighMem(page))
+			make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+		else
+			/* make sure there are no stray mappings of
+			   this page */
+			kmap_flush_unused();
+	}
+}
+
+/* This should never happen until we're OK to use struct page */
 static void xen_release_pt(u32 pfn)
 {
-	make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
-}
-
-static void xen_alloc_pd_clone(u32 pfn, u32 clonepfn,
-					u32 start, u32 count)
-{
-	xen_alloc_pd(pfn);
-}
+	struct page *page = pfn_to_page(pfn);
+
+	if (PagePinned(page)) {
+		if (!PageHighMem(page))
+			make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+	}
+}
+
+#ifdef CONFIG_HIGHPTE
+static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
+{
+	pgprot_t prot = PAGE_KERNEL;
+
+	if (PagePinned(page))
+		prot = PAGE_KERNEL_RO;
+
+	if (0 && PageHighMem(page))
+		printk("mapping highpte %lx type %d prot %s\n",
+		       page_to_pfn(page), type,
+		       (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");
+
+	return kmap_atomic_prot(page, type, prot);
+}
+#endif
 
 static __init void xen_pagetable_setup_start(pgd_t *base)
 {
@@ -506,7 +536,7 @@ static __init void xen_pagetable_setup_s
 				memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]),
 				       PAGE_SIZE);
 
-				xen_alloc_pd(PFN_DOWN(__pa(pmd)));
+				make_lowmem_page_readonly(pmd);
 
 				set_pgd(&base[i], __pgd(1 + __pa(pmd)));
 			} else
@@ -527,6 +557,10 @@ static __init void xen_pagetable_setup_s
 
 static __init void xen_pagetable_setup_done(pgd_t *base)
 {
+	/* This will work as long as patching hasn't happened yet
+	   (which it hasn't) */
+	paravirt_ops.alloc_pt = xen_alloc_pt;
+
 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
 		/*
 		 * Create a mapping for the shared info page.
@@ -544,7 +578,19 @@ static __init void xen_pagetable_setup_d
 		HYPERVISOR_shared_info =
 			(struct shared_info *)__va(xen_start_info->shared_info);
 
-	xen_pgd_pin(base);
+	/* Actually pin the pagetable down, but we can't set PG_pinned
+	   yet because the page structures don't exist yet. */
+	{
+		struct mmuext_op op;
+#ifdef CONFIG_X86_PAE
+		op.cmd = MMUEXT_PIN_L3_TABLE;
+#else
+		op.cmd = MMUEXT_PIN_L3_TABLE;
+#endif
+		op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(base)));
+		if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+			BUG();
+	}
 
 	xen_vcpu_setup(smp_processor_id());
 }
@@ -562,6 +608,7 @@ static const struct paravirt_ops xen_par
 	.arch_setup = xen_arch_setup,
 	.init_IRQ = xen_init_IRQ,
 	.time_init = xen_time_init,
+	.post_allocator_init = xen_mark_init_mm_pinned,
 
 	.cpuid = xen_cpuid,
 
@@ -647,11 +694,15 @@ static const struct paravirt_ops xen_par
 	.set_pte_at = xen_set_pte_at,
 	.set_pmd = xen_set_pmd,
 
-	.alloc_pt = xen_alloc_pt,
-	.alloc_pd = xen_alloc_pd,
-	.alloc_pd_clone = xen_alloc_pd_clone,
-	.release_pd = xen_release_pd,
+	.alloc_pt = xen_alloc_pt_init,
 	.release_pt = xen_release_pt,
+	.alloc_pd = paravirt_nop,
+	.alloc_pd_clone = paravirt_nop,
+	.release_pd = paravirt_nop,
+
+#ifdef CONFIG_HIGHPTE
+	.kmap_atomic_pte = xen_kmap_atomic_pte,
+#endif
 
 	.pte_val = xen_pte_val,
 	.pgd_val = xen_pgd_val,
===================================================================
--- a/arch/i386/xen/mmu.c
+++ b/arch/i386/xen/mmu.c
@@ -1,15 +1,19 @@
+#include <linux/highmem.h>
+
 #include <asm/bug.h>
-
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 
 #include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
 #include <asm/paravirt.h>
 
 #include <xen/page.h>
 #include <xen/interface/xen.h>
 
+#include "multicalls.h"
+
 #include "mmu.h"
 
 xmaddr_t arbitrary_virt_to_machine(unsigned long address)
@@ -47,17 +51,6 @@ void make_lowmem_page_readwrite(void *va
 	ptev = pte_mkwrite(*pte);
 
 	if(HYPERVISOR_update_va_mapping(address, ptev, 0))
-		BUG();
-}
-
-
-void xen_set_pte(pte_t *ptep, pte_t pte)
-{
-	struct mmu_update u;
-
-	u.ptr = virt_to_machine(ptep).maddr;
-	u.val = pte_val_ma(pte);
-	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
 		BUG();
 }
 
@@ -70,18 +63,6 @@ void xen_set_pmd(pmd_t *ptr, pmd_t val)
 	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
 		BUG();
 }
-
-#ifdef CONFIG_X86_PAE
-void xen_set_pud(pud_t *ptr, pud_t val)
-{
-	struct mmu_update u;
-
-	u.ptr = virt_to_machine(ptr).maddr;
-	u.val = pud_val_ma(val);
-	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
-		BUG();
-}
-#endif
 
 /*
  * Associate a virtual page frame with a given physical page frame
@@ -129,12 +110,29 @@ void xen_set_pte_at(struct mm_struct *mm
 }
 
 #ifdef CONFIG_X86_PAE
+void xen_set_pud(pud_t *ptr, pud_t val)
+{
+	struct mmu_update u;
+
+	u.ptr = virt_to_machine(ptr).maddr;
+	u.val = pud_val_ma(val);
+	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
+		BUG();
+}
+
+void xen_set_pte(pte_t *ptep, pte_t pte)
+{
+	ptep->pte_high = pte.pte_high;
+	smp_wmb();
+	ptep->pte_low = pte.pte_low;
+}
+
 void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
 {
 	set_64bit((u64 *)ptep, pte_val_ma(pte));
 }
 
-void xen_pte_clear(struct mm_struct *mm, unsigned long addr,pte_t *ptep)
+void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 {
 	ptep->pte_low = 0;
 	smp_wmb();
@@ -198,6 +196,11 @@ pgd_t xen_make_pgd(unsigned long long pg
 	return (pgd_t){ pgd };
 }
 #else  /* !PAE */
+void xen_set_pte(pte_t *ptep, pte_t pte)
+{
+	*ptep = pte;
+}
+
 unsigned long xen_pte_val(pte_t pte)
 {
 	unsigned long ret = pte.pte_low;
@@ -206,12 +209,6 @@ unsigned long xen_pte_val(pte_t pte)
 		ret = machine_to_phys(XMADDR(ret)).paddr;
 
 	return ret;
-}
-
-unsigned long xen_pmd_val(pmd_t pmd)
-{
-	BUG();
-	return 0;
 }
 
 unsigned long xen_pgd_val(pgd_t pgd)
@@ -230,12 +227,6 @@ pte_t xen_make_pte(unsigned long pte)
 	return (pte_t){ pte };
 }
 
-pmd_t xen_make_pmd(unsigned long pmd)
-{
-	BUG();
-	return __pmd(0);
-}
-
 pgd_t xen_make_pgd(unsigned long pgd)
 {
 	if (pgd & _PAGE_PRESENT)
@@ -246,109 +237,194 @@ pgd_t xen_make_pgd(unsigned long pgd)
 #endif	/* CONFIG_X86_PAE */
 
 
-
-static void pgd_walk_set_prot(void *pt, pgprot_t flags)
-{
-	unsigned long pfn = PFN_DOWN(__pa(pt));
-
-	if (HYPERVISOR_update_va_mapping((unsigned long)pt,
-					 pfn_pte(pfn, flags), 0) < 0)
-		BUG();
-}
-
-static void pgd_walk(pgd_t *pgd_base, pgprot_t flags)
+/*
+  (Yet another) pagetable walker.  This one is intended for pinning a
+  pagetable.  This means that it walks a pagetable and calls the
+  callback function on each page it finds making up the page table,
+  at every level.  It walks the entire pagetable, but it only bothers
+  pinning pte pages which are below pte_limit.  In the normal case
+  this will be TASK_SIZE, but at boot we need to pin up to
+  FIXADDR_TOP.  But the important bit is that we don't pin beyond
+  there, because then we start getting into Xen's ptes.
+*/
+static int pgd_walk(pgd_t *pgd_base, int (*func)(struct page *, unsigned),
+		    unsigned long limit)
 {
 	pgd_t *pgd = pgd_base;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-	int    g, u, m;
+	int flush = 0;
+	unsigned long addr = 0;
+	unsigned long pgd_next;
+
+	BUG_ON(limit > FIXADDR_TOP);
 
 	if (xen_feature(XENFEAT_auto_translated_physmap))
-		return;
-
-	for (g = 0; g < USER_PTRS_PER_PGD; g++, pgd++) {
-		if (pgd_none(*pgd))
+		return 0;
+
+	for (; addr != FIXADDR_TOP; pgd++, addr = pgd_next) {
+		pud_t *pud;
+		unsigned long pud_limit, pud_next;
+
+		pgd_next = pud_limit = pgd_addr_end(addr, FIXADDR_TOP);
+
+		if (!pgd_val(*pgd))
 			continue;
+
 		pud = pud_offset(pgd, 0);
 
 		if (PTRS_PER_PUD > 1) /* not folded */
-			pgd_walk_set_prot(pud,flags);
-
-		for (u = 0; u < PTRS_PER_PUD; u++, pud++) {
+			flush |= (*func)(virt_to_page(pud), 0);
+
+		for (; addr != pud_limit; pud++, addr = pud_next) {
+			pmd_t *pmd;
+			unsigned long pmd_limit;
+
+			pud_next = pud_addr_end(addr, pud_limit);
+
+			if (pud_next < limit)
+				pmd_limit = pud_next;
+			else
+				pmd_limit = limit;
+
 			if (pud_none(*pud))
 				continue;
+
 			pmd = pmd_offset(pud, 0);
 
 			if (PTRS_PER_PMD > 1) /* not folded */
-				pgd_walk_set_prot(pmd,flags);
-
-			for (m = 0; m < PTRS_PER_PMD; m++, pmd++) {
+				flush |= (*func)(virt_to_page(pmd), 0);
+
+			for (; addr != pmd_limit; pmd++) {
+				addr += (PAGE_SIZE * PTRS_PER_PTE);
+				if ((pmd_limit-1) < (addr-1)) {
+					addr = pmd_limit;
+					break;
+				}
+
 				if (pmd_none(*pmd))
 					continue;
 
-				/* This can get called before mem_map
-				   is set up, so we assume nothing is
-				   highmem at that point. */
-				if (mem_map == NULL ||
-				    !PageHighMem(pmd_page(*pmd))) {
-					pte = pte_offset_kernel(pmd,0);
-					pgd_walk_set_prot(pte,flags);
-				}
+				flush |= (*func)(pmd_page(*pmd), 0);
 			}
 		}
 	}
 
-	if (HYPERVISOR_update_va_mapping((unsigned long)pgd_base,
-					 pfn_pte(PFN_DOWN(__pa(pgd_base)),
-						 flags),
-					 UVMF_TLB_FLUSH) < 0)
-		BUG();
-}
-
-
-/* This is called just after a mm has been duplicated from its parent,
-   but it has not been used yet.  We need to make sure that its
-   pagetable is all read-only, and can be pinned. */
+	flush |= (*func)(virt_to_page(pgd_base), UVMF_TLB_FLUSH);
+
+	return flush;
+}
+
+static int pin_page(struct page *page, unsigned flags)
+{
+	unsigned pgfl = test_and_set_bit(PG_pinned, &page->flags);
+	int flush;
+
+	if (pgfl)
+		flush = 0;		/* already pinned */
+	else if (PageHighMem(page))
+		/* kmaps need flushing if we found an unpinned
+		   highpage */
+		flush = 1;
+	else {
+		void *pt = lowmem_page_address(page);
+		unsigned long pfn = page_to_pfn(page);
+		struct multicall_space mcs = xen_mc_entry(0);
+
+		flush = 0;
+
+		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+					pfn_pte(pfn, PAGE_KERNEL_RO),
+					flags);
+	}
+
+	return flush;
+}
+
+/* This is called just after a mm has been created, but it has not
+   been used yet.  We need to make sure that its pagetable is all
+   read-only, and can be pinned. */
 void xen_pgd_pin(pgd_t *pgd)
 {
-	struct mmuext_op op;
-
-	pgd_walk(pgd, PAGE_KERNEL_RO);
-
-#if defined(CONFIG_X86_PAE)
-	op.cmd = MMUEXT_PIN_L3_TABLE;
+	struct multicall_space mcs;
+	struct mmuext_op *op;
+
+	if (pgd_walk(pgd, pin_page, TASK_SIZE))
+		kmap_flush_unused();
+
+	mcs = xen_mc_entry(sizeof(*op));
+	op = mcs.args;
+
+#ifdef CONFIG_X86_PAE
+	op->cmd = MMUEXT_PIN_L3_TABLE;
 #else
-	op.cmd = MMUEXT_PIN_L2_TABLE;
+	op->cmd = MMUEXT_PIN_L2_TABLE;
 #endif
-	op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
-	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF) < 0)
-		BUG();
+	op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_flush();
+}
+
+/* The init_mm pagetable is really pinned as soon as its created, but
+   that's before we have page structures to store the bits.  So do all
+   the book-keeping now. */
+static __init int mark_pinned(struct page *page, unsigned flags)
+{
+	SetPagePinned(page);
+	return 0;
+}
+
+void __init xen_mark_init_mm_pinned(void)
+{
+	pgd_walk(init_mm.pgd, mark_pinned, FIXADDR_TOP);
+}
+
+static int unpin_page(struct page *page, unsigned flags)
+{
+	unsigned pgfl = test_and_clear_bit(PG_pinned, &page->flags);
+
+	if (pgfl && !PageHighMem(page)) {
+		void *pt = lowmem_page_address(page);
+		unsigned long pfn = page_to_pfn(page);
+		struct multicall_space mcs = xen_mc_entry(0);
+
+		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
+					pfn_pte(pfn, PAGE_KERNEL),
+					flags);
+	}
+
+	return 0;		/* never need to flush on unpin */
 }
 
 /* Release a pagetables pages back as normal RW */
-void xen_pgd_unpin(pgd_t *pgd)
-{
-	struct mmuext_op op;
-
-	op.cmd = MMUEXT_UNPIN_TABLE;
-	op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
-
-	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF) < 0)
-		BUG();
-
-	pgd_walk(pgd, PAGE_KERNEL);
+static void xen_pgd_unpin(pgd_t *pgd)
+{
+	struct mmuext_op *op;
+	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+	op = mcs.args;
+	op->cmd = MMUEXT_UNPIN_TABLE;
+	op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
+
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	pgd_walk(pgd, unpin_page, TASK_SIZE);
+
+	xen_mc_flush();
 }
 
 
 void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next)
 {
+	spin_lock(&next->page_table_lock);
 	xen_pgd_pin(next->pgd);
+	spin_unlock(&next->page_table_lock);
 }
 
 void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
 {
+	spin_lock(&mm->page_table_lock);
 	xen_pgd_pin(mm->pgd);
+	spin_unlock(&mm->page_table_lock);
 }
 
 void xen_exit_mmap(struct mm_struct *mm)
===================================================================
--- a/arch/i386/xen/mmu.h
+++ b/arch/i386/xen/mmu.h
@@ -15,7 +15,7 @@ void xen_exit_mmap(struct mm_struct *mm)
 void xen_exit_mmap(struct mm_struct *mm);
 
 void xen_pgd_pin(pgd_t *pgd);
-void xen_pgd_unpin(pgd_t *pgd);
+//void xen_pgd_unpin(pgd_t *pgd);
 
 #ifdef CONFIG_X86_PAE
 unsigned long long xen_pte_val(pte_t);
===================================================================
--- a/arch/i386/xen/xen-ops.h
+++ b/arch/i386/xen/xen-ops.h
@@ -20,6 +20,8 @@ int xen_set_wallclock(unsigned long time
 int xen_set_wallclock(unsigned long time);
 cycle_t xen_clocksource_read(void);
 
+void xen_mark_init_mm_pinned(void);
+
 DECLARE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode);
 
 static inline unsigned xen_get_lazy_mode(void)
===================================================================
--- a/include/asm-i386/paravirt.h
+++ b/include/asm-i386/paravirt.h
@@ -52,6 +52,8 @@ struct paravirt_ops
 	/* Basic arch-specific setup */
 	void (*arch_setup)(void);
 	char *(*memory_setup)(void);
+	void (*post_allocator_init)(void);
+
 	void (*init_IRQ)(void);
 	void (*time_init)(void);
 
@@ -173,7 +175,7 @@ struct paravirt_ops
 				 unsigned long va);
 
 	/* Hooks for allocating/releasing pagetable pages */
-	void (*alloc_pt)(u32 pfn);
+	void (*alloc_pt)(struct mm_struct *mm, u32 pfn);
 	void (*alloc_pd)(u32 pfn);
 	void (*alloc_pd_clone)(u32 pfn, u32 clonepfn, u32 start, u32 count);
 	void (*release_pt)(u32 pfn);
@@ -682,6 +684,12 @@ static inline void setup_secondary_clock
 }
 #endif
 
+static inline void paravirt_post_allocator_init(void)
+{
+	if (paravirt_ops.post_allocator_init)
+		(*paravirt_ops.post_allocator_init)();
+}
+
 static inline void paravirt_pagetable_setup_start(pgd_t *base)
 {
 	if (paravirt_ops.pagetable_setup_start)
@@ -738,9 +746,9 @@ static inline void flush_tlb_others(cpum
 	PVOP_VCALL3(flush_tlb_others, &cpumask, mm, va);
 }
 
-static inline void paravirt_alloc_pt(unsigned pfn)
-{
-	PVOP_VCALL1(alloc_pt, pfn);
+static inline void paravirt_alloc_pt(struct mm_struct *mm, unsigned pfn)
+{
+	PVOP_VCALL2(alloc_pt, mm, pfn);
 }
 static inline void paravirt_release_pt(unsigned pfn)
 {
===================================================================
--- a/include/asm-i386/pgalloc.h
+++ b/include/asm-i386/pgalloc.h
@@ -7,7 +7,7 @@
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else
-#define paravirt_alloc_pt(pfn) do { } while (0)
+#define paravirt_alloc_pt(mm, pfn) do { } while (0)
 #define paravirt_alloc_pd(pfn) do { } while (0)
 #define paravirt_alloc_pd(pfn) do { } while (0)
 #define paravirt_alloc_pd_clone(pfn, clonepfn, start, count) do { } while (0)
@@ -17,13 +17,13 @@
 
 #define pmd_populate_kernel(mm, pmd, pte)			\
 do {								\
-	paravirt_alloc_pt(__pa(pte) >> PAGE_SHIFT);		\
+	paravirt_alloc_pt(mm, __pa(pte) >> PAGE_SHIFT);		\
 	set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(pte)));		\
 } while (0)
 
 #define pmd_populate(mm, pmd, pte) 				\
 do {								\
-	paravirt_alloc_pt(page_to_pfn(pte));			\
+	paravirt_alloc_pt(mm, page_to_pfn(pte));		\
 	set_pmd(pmd, __pmd(_PAGE_TABLE +			\
 		((unsigned long long)page_to_pfn(pte) <<	\
 			(unsigned long long) PAGE_SHIFT)));	\
===================================================================
--- a/include/asm-i386/setup.h
+++ b/include/asm-i386/setup.h
@@ -79,6 +79,10 @@ void __init add_memory_region(unsigned l
 
 extern unsigned long init_pg_tables_end;
 
+#ifndef CONFIG_PARAVIRT
+#define paravirt_post_allocator_init()	do {} while(0)
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif  /*  __KERNEL__  */
===================================================================
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -93,6 +93,7 @@
 
 /* PG_owner_priv_1 users should have descriptive aliases */
 #define PG_checked		PG_owner_priv_1 /* Used by some filesystems */
+#define PG_pinned		PG_owner_priv_1	/* Xen pinned pagetable */
 
 #if (BITS_PER_LONG > 32)
 /*
@@ -170,6 +171,10 @@ static inline void SetPageUptodate(struc
 #define PageChecked(page)	test_bit(PG_checked, &(page)->flags)
 #define SetPageChecked(page)	set_bit(PG_checked, &(page)->flags)
 #define ClearPageChecked(page)	clear_bit(PG_checked, &(page)->flags)
+
+#define PagePinned(page)	test_bit(PG_pinned, &(page)->flags)
+#define SetPagePinned(page)	set_bit(PG_pinned, &(page)->flags)
+#define ClearPagePinned(page)	clear_bit(PG_pinned, &(page)->flags)
 
 #define PageReserved(page)	test_bit(PG_reserved, &(page)->flags)
 #define SetPageReserved(page)	set_bit(PG_reserved, &(page)->flags)

-- 

[PATCH 08/25] xen: xen: fix multicall batching

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-fix-multicall.patch --]
[-- Type: text/plain, Size: 7805 bytes --]

Disable interrupts between allocating a multicall entry and actually
issuing it, to prevent an interrupt from coming in, allocating and
initializing further multicall entries, and then issuing them all,
including the partially completed one.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/xen/enlighten.c  |   44 +++++++++++++++++++++++++++-----------------
 arch/i386/xen/mmu.c        |   18 ++++++++++++------
 arch/i386/xen/multicalls.c |    9 ++++++++-
 arch/i386/xen/multicalls.h |   27 +++++++++++++++++++++++----
 arch/i386/xen/xen-ops.h    |    5 +----
 5 files changed, 71 insertions(+), 32 deletions(-)

===================================================================
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -160,13 +160,25 @@ static void xen_halt(void)
 
 static void xen_set_lazy_mode(enum paravirt_lazy_mode mode)
 {
-	enum paravirt_lazy_mode *lazy = &get_cpu_var(xen_lazy_mode);
+	switch(mode) {
+	case PARAVIRT_LAZY_NONE:
+		BUG_ON(x86_read_percpu(xen_lazy_mode) == PARAVIRT_LAZY_NONE);
+		break;
+
+	case PARAVIRT_LAZY_MMU:
+	case PARAVIRT_LAZY_CPU:
+		BUG_ON(x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE);
+		break;
+
+	case PARAVIRT_LAZY_FLUSH:
+		/* flush if necessary, but don't change state */
+		if (x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE)
+			xen_mc_flush();
+		return;
+	}
 
 	xen_mc_flush();
-
-	*lazy = mode;
-
-	put_cpu_var(xen_lazy_mode);
+	x86_write_percpu(xen_lazy_mode, mode);
 }
 
 static unsigned long xen_store_tr(void)
@@ -193,7 +208,7 @@ static void xen_set_ldt(const void *addr
 
 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 
-	xen_mc_issue();
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
 }
 
 static void xen_load_gdt(const struct Xgt_desc_struct *dtr)
@@ -217,7 +232,7 @@ static void xen_load_gdt(const struct Xg
 
 	MULTI_set_gdt(mcs.mc, frames, size/8);
 
-	xen_mc_issue();
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
 }
 
 static void load_TLS_descriptor(struct thread_struct *t,
@@ -225,18 +240,20 @@ static void load_TLS_descriptor(struct t
 {
 	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 	xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
-	struct multicall_space mc = xen_mc_entry(0);
+	struct multicall_space mc = __xen_mc_entry(0);
 
 	MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
 }
 
 static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
 {
+	xen_mc_batch();
+
 	load_TLS_descriptor(t, cpu, 0);
 	load_TLS_descriptor(t, cpu, 1);
 	load_TLS_descriptor(t, cpu, 2);
 
-	xen_mc_issue();
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
 }
 
 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, u32 low, u32 high)
@@ -356,13 +373,9 @@ static void xen_load_esp0(struct tss_str
 static void xen_load_esp0(struct tss_struct *tss,
 				   struct thread_struct *thread)
 {
-	if (xen_get_lazy_mode() != PARAVIRT_LAZY_CPU) {
-		if (HYPERVISOR_stack_switch(__KERNEL_DS, thread->esp0))
-			BUG();
-	} else {
-		struct multicall_space mcs = xen_mc_entry(0);
-		MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0);
-	}
+	struct multicall_space mcs = xen_mc_entry(0);
+	MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0);
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
 }
 
 static void xen_set_iopl_mask(unsigned mask)
@@ -452,7 +465,7 @@ static void xen_write_cr3(unsigned long 
 
 		MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 
-		xen_mc_issue();
+		xen_mc_issue(PARAVIRT_LAZY_CPU);
 	}
 }
 
===================================================================
--- a/arch/i386/xen/mmu.c
+++ b/arch/i386/xen/mmu.c
@@ -344,7 +344,7 @@ static int pin_page(struct page *page, u
 	else {
 		void *pt = lowmem_page_address(page);
 		unsigned long pfn = page_to_pfn(page);
-		struct multicall_space mcs = xen_mc_entry(0);
+		struct multicall_space mcs = __xen_mc_entry(0);
 
 		flush = 0;
 
@@ -364,10 +364,12 @@ void xen_pgd_pin(pgd_t *pgd)
 	struct multicall_space mcs;
 	struct mmuext_op *op;
 
+	xen_mc_batch();
+
 	if (pgd_walk(pgd, pin_page, TASK_SIZE))
 		kmap_flush_unused();
 
-	mcs = xen_mc_entry(sizeof(*op));
+	mcs = __xen_mc_entry(sizeof(*op));
 	op = mcs.args;
 
 #ifdef CONFIG_X86_PAE
@@ -378,7 +380,7 @@ void xen_pgd_pin(pgd_t *pgd)
 	op->arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(pgd)));
 	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
 
-	xen_mc_flush();
+	xen_mc_issue(0);
 }
 
 /* The init_mm pagetable is really pinned as soon as its created, but
@@ -402,7 +404,7 @@ static int unpin_page(struct page *page,
 	if (pgfl && !PageHighMem(page)) {
 		void *pt = lowmem_page_address(page);
 		unsigned long pfn = page_to_pfn(page);
-		struct multicall_space mcs = xen_mc_entry(0);
+		struct multicall_space mcs = __xen_mc_entry(0);
 
 		MULTI_update_va_mapping(mcs.mc, (unsigned long)pt,
 					pfn_pte(pfn, PAGE_KERNEL),
@@ -416,7 +418,11 @@ static void xen_pgd_unpin(pgd_t *pgd)
 static void xen_pgd_unpin(pgd_t *pgd)
 {
 	struct mmuext_op *op;
-	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+	struct multicall_space mcs;
+
+	xen_mc_batch();
+
+	mcs = __xen_mc_entry(sizeof(*op));
 
 	op = mcs.args;
 	op->cmd = MMUEXT_UNPIN_TABLE;
@@ -426,7 +432,7 @@ static void xen_pgd_unpin(pgd_t *pgd)
 
 	pgd_walk(pgd, unpin_page, TASK_SIZE);
 
-	xen_mc_flush();
+	xen_mc_issue(0);
 }
 
 
===================================================================
--- a/arch/i386/xen/multicalls.c
+++ b/arch/i386/xen/multicalls.c
@@ -14,11 +14,17 @@ struct mc_buffer {
 };
 
 static DEFINE_PER_CPU(struct mc_buffer, mc_buffer);
+DEFINE_PER_CPU(unsigned long, xen_mc_irq_flags);
 
 void xen_mc_flush(void)
 {
 	struct mc_buffer *b = &get_cpu_var(mc_buffer);
 	int ret = 0;
+	unsigned long flags;
+
+	/* Disable interrupts in case someone comes in and queues
+	   something in the middle */
+	local_irq_save(flags);
 
 	if (b->mcidx) {
 		int i;
@@ -34,11 +40,12 @@ void xen_mc_flush(void)
 		BUG_ON(b->argidx != 0);
 
 	put_cpu_var(mc_buffer);
+	local_irq_restore(flags);
 
 	BUG_ON(ret);
 }
 
-struct multicall_space xen_mc_entry(size_t args)
+struct multicall_space __xen_mc_entry(size_t args)
 {
 	struct mc_buffer *b = &get_cpu_var(mc_buffer);
 	struct multicall_space ret;
===================================================================
--- a/arch/i386/xen/multicalls.h
+++ b/arch/i386/xen/multicalls.h
@@ -11,16 +11,35 @@ struct multicall_space
 };
 
 /* Allocate room for a multicall and its args */
-struct multicall_space xen_mc_entry(size_t args);
+struct multicall_space __xen_mc_entry(size_t args);
+
+DECLARE_PER_CPU(unsigned long, xen_mc_irq_flags);
+
+/* Call to start a batch of multiple __xen_mc_entry()s.  Must be
+   paired with xen_mc_issue() */
+static inline void xen_mc_batch(void)
+{
+	/* need to disable interrupts until this entry is complete */
+	local_irq_save(__get_cpu_var(xen_mc_irq_flags));
+}
+
+static inline struct multicall_space xen_mc_entry(size_t args)
+{
+	xen_mc_batch();
+	return __xen_mc_entry(args);
+}
 
 /* Flush all pending multicalls */
 void xen_mc_flush(void);
 
-/* Issue a multicall if we're not in lazy mode */
-static inline void xen_mc_issue(void)
+/* Issue a multicall if we're not in a lazy mode */
+static inline void xen_mc_issue(unsigned mode)
 {
-	if (xen_get_lazy_mode() == PARAVIRT_LAZY_NONE)
+	if ((xen_get_lazy_mode() & mode) == 0)
 		xen_mc_flush();
+
+	/* restore flags saved in xen_mc_batch */
+	local_irq_restore(x86_read_percpu(xen_mc_irq_flags));
 }
 
 #endif /* _XEN_MULTICALLS_H */
===================================================================
--- a/arch/i386/xen/xen-ops.h
+++ b/arch/i386/xen/xen-ops.h
@@ -26,10 +26,7 @@ DECLARE_PER_CPU(enum paravirt_lazy_mode,
 
 static inline unsigned xen_get_lazy_mode(void)
 {
-	unsigned ret = get_cpu_var(xen_lazy_mode);
-	put_cpu_var(xen_lazy_mode);
-
-	return ret;
+	return x86_read_percpu(xen_lazy_mode);
 }
 
 

-- 

[PATCH 09/25] xen: Account for time stolen by Xen

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-stolen-time.patch --]
[-- Type: text/plain, Size: 4588 bytes --]

This accounts for the time Xen steals from our VCPUs.  This accounting
gets run on each timer interrupt, just as a way to get it run
relatively often, and when interesting things are going on.

Stolen time is not really used by much in the kernel; it is reported
in /proc/stats, and that's about it.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: john stultz <johnstul@us.ibm.com>

---
 arch/i386/xen/time.c |  101 +++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 100 insertions(+), 1 deletion(-)

===================================================================
--- a/arch/i386/xen/time.c
+++ b/arch/i386/xen/time.c
@@ -2,6 +2,7 @@
 #include <linux/interrupt.h>
 #include <linux/clocksource.h>
 #include <linux/clockchips.h>
+#include <linux/kernel_stat.h>
 
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
@@ -14,6 +15,7 @@
 
 #define XEN_SHIFT 22
 #define TIMER_SLOP	100000	/* Xen may fire a timer up to this many ns early */
+#define NS_PER_TICK	(1000000000ll / HZ)
 
 /* These are perodically updated in shared_info, and then copied here. */
 struct shadow_time_info {
@@ -26,6 +28,99 @@ struct shadow_time_info {
 
 static DEFINE_PER_CPU(struct shadow_time_info, shadow_time);
 
+/* runstate info updated by Xen */
+static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
+
+/* snapshots of runstate info */
+static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate_snapshot);
+
+/* unused ns of stolen and blocked time */
+static DEFINE_PER_CPU(u64, residual_stolen);
+static DEFINE_PER_CPU(u64, residual_blocked);
+
+/*
+ * Runstate accounting
+ */
+static void get_runstate_snapshot(struct vcpu_runstate_info *res)
+{
+	u64 state_time;
+	struct vcpu_runstate_info *state;
+
+	preempt_disable();
+
+	state = &__get_cpu_var(runstate);
+
+	do {
+		state_time = state->state_entry_time;
+		barrier();
+		*res = *state;
+		barrier();
+	} while(state->state_entry_time != state_time);
+
+	preempt_enable();
+}
+
+static void setup_runstate_info(void)
+{
+	struct vcpu_register_runstate_memory_area area;
+
+	area.addr.v = &__get_cpu_var(runstate);
+
+	if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area,
+			       smp_processor_id(), &area))
+		BUG();
+
+	get_runstate_snapshot(&__get_cpu_var(runstate_snapshot));
+}
+
+static void do_stolen_accounting(void)
+{
+	struct vcpu_runstate_info state;
+	struct vcpu_runstate_info *snap;
+	u64 blocked, runnable, offline, stolen;
+	cputime_t ticks;
+
+	get_runstate_snapshot(&state);
+
+	WARN_ON(state.state != RUNSTATE_running);
+
+	snap = &__get_cpu_var(runstate_snapshot);
+
+	/* work out how much time the VCPU has not been runn*ing*  */
+	blocked = state.time[RUNSTATE_blocked] - snap->time[RUNSTATE_blocked];
+	runnable = state.time[RUNSTATE_runnable] - snap->time[RUNSTATE_runnable];
+	offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline];
+
+	*snap = state;
+
+	/* Add the appropriate number of ticks of stolen time,
+	   including any left-overs from last time.  Passing NULL to
+	   account_steal_time accounts the time as stolen. */
+	stolen = runnable + offline + __get_cpu_var(residual_stolen);
+	ticks = 0;
+	while(stolen >= NS_PER_TICK) {
+		ticks++;
+		stolen -= NS_PER_TICK;
+	}
+	__get_cpu_var(residual_stolen) = stolen;
+	account_steal_time(NULL, ticks);
+
+	/* Add the appropriate number of ticks of blocked time,
+	   including any left-overs from last time.  Passing idle to
+	   account_steal_time accounts the time as idle/wait. */
+	blocked += __get_cpu_var(residual_blocked);
+	ticks = 0;
+	while(blocked >= NS_PER_TICK) {
+		ticks++;
+		blocked -= NS_PER_TICK;
+	}
+	__get_cpu_var(residual_blocked) = blocked;
+	account_steal_time(idle_task(smp_processor_id()), ticks);
+}
+
+
+
+/* Get the CPU speed from Xen */
 unsigned long xen_cpu_khz(void)
 {
 	u64 cpu_khz = 1000000ULL << 32;
@@ -338,6 +433,8 @@ static irqreturn_t xen_timer_interrupt(i
 		ret = IRQ_HANDLED;
 	}
 
+	do_stolen_accounting();
+
 	return ret;
 }
 
@@ -363,6 +460,8 @@ static void xen_setup_timer(int cpu)
 	evt->irq = irq;
 	clockevents_register_device(evt);
 
+	setup_runstate_info();
+
 	put_cpu_var(xen_clock_events);
 }
 
@@ -375,7 +474,7 @@ __init void xen_time_init(void)
 	clocksource_register(&xen_clocksource);
 
 	if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) {
-		/* Successfully turned off 100hz tick, so we have the
+		/* Successfully turned off 100Hz tick, so we have the
 		   vcpuop-based timer interface */
 		printk(KERN_DEBUG "Xen: using vcpuop timer interface\n");
 		xen_clockevent = &xen_vcpuop_clockevent;

-- 

Re: [PATCH 09/25] xen: Account for time stolen by Xen

[Andi Kleen]

> +
> +	do {
> +		state_time = state->state_entry_time;
> +		barrier();

Should be likely rmb

-Andi

Re: [PATCH 09/25] xen: Account for time stolen by Xen

[Jeremy Fitzhardinge]

Andi Kleen wrote:
>> +
>> +	do {
>> +		state_time = state->state_entry_time;
>> +		barrier();
>>     
>
> Should be likely rmb

We discussed this, and decided that it wasn't necessary.  The state is
always updated by the current CPU, so if it changes under our feet it
will be because we were preempted, and so that should shoot down any
speculated reads.

    J

Re: [PATCH 09/25] xen: Account for time stolen by Xen

[Andi Kleen]

On Wednesday 25 April 2007 20:13:34 Jeremy Fitzhardinge wrote:
> Andi Kleen wrote:
> >> +
> >> +	do {
> >> +		state_time = state->state_entry_time;
> >> +		barrier();
> >>     
> >
> > Should be likely rmb
> 
> We discussed this, and decided that it wasn't necessary.  The state is
> always updated by the current CPU, so if it changes under our feet it
> will be because we were preempted, and so that should shoot down any
> speculated reads.

Then the barrier shouldn't be needed at all? 

Anyways needs comments

-Andi

Re: [PATCH 09/25] xen: Account for time stolen by Xen

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> Then the barrier shouldn't be needed at all? 
>   

We still need to prevent compiler reordering.

> Anyways needs comments
>   

Yep.

    J

[PATCH 10/25] xen: Implement xen_sched_clock

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-sched-clock.patch --]
[-- Type: text/plain, Size: 2876 bytes --]

Implement xen_sched_clock, which returns the number of ns the current
vcpu has been actually in the running state (vs blocked,
runnable-but-not-running, or offline) since boot.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: john stultz <johnstul@us.ibm.com>

---
 arch/i386/xen/enlighten.c |    2 +-
 arch/i386/xen/time.c      |   22 +++++++++++++++++++++-
 arch/i386/xen/xen-ops.h   |    3 +--
 3 files changed, 23 insertions(+), 4 deletions(-)

===================================================================
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -676,7 +676,7 @@ static const struct paravirt_ops xen_par
 	.set_wallclock = xen_set_wallclock,
 	.get_wallclock = xen_get_wallclock,
 	.get_cpu_khz = xen_cpu_khz,
-	.sched_clock = xen_clocksource_read,
+	.sched_clock = xen_sched_clock,
 
 #ifdef CONFIG_X86_LOCAL_APIC
 	.apic_write = paravirt_nop,
===================================================================
--- a/arch/i386/xen/time.c
+++ b/arch/i386/xen/time.c
@@ -16,6 +16,8 @@
 #define XEN_SHIFT 22
 #define TIMER_SLOP	100000	/* Xen may fire a timer up to this many ns early */
 #define NS_PER_TICK	(1000000000ll / HZ)
+
+static cycle_t xen_clocksource_read(void);
 
 /* These are perodically updated in shared_info, and then copied here. */
 struct shadow_time_info {
@@ -118,6 +120,24 @@ static void do_stolen_accounting(void)
 	account_steal_time(idle_task(smp_processor_id()), ticks);
 }
 
+/*
+ * Xen sched_clock implementation.  Returns the number of unstolen
+ * nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED
+ * states.
+ */
+unsigned long long xen_sched_clock(void)
+{
+	struct vcpu_runstate_info state;
+	cycle_t now = xen_clocksource_read();
+
+	get_runstate_snapshot(&state);
+
+	WARN_ON(state.state != RUNSTATE_running);
+
+	return state.time[RUNSTATE_blocked] +
+		state.time[RUNSTATE_running] +
+		(now - state.state_entry_time);
+}
 
 
 /* Get the CPU speed from Xen */
@@ -209,7 +229,7 @@ static u64 get_nsec_offset(struct shadow
 	return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift);
 }
 
-cycle_t xen_clocksource_read(void)
+static cycle_t xen_clocksource_read(void)
 {
 	struct shadow_time_info *shadow = &get_cpu_var(shadow_time);
 	cycle_t ret;
===================================================================
--- a/arch/i386/xen/xen-ops.h
+++ b/arch/i386/xen/xen-ops.h
@@ -2,7 +2,6 @@
 #define XEN_OPS_H
 
 #include <linux/init.h>
-#include <linux/clocksource.h>
 
 DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu);
 DECLARE_PER_CPU(unsigned long, xen_cr3);
@@ -18,7 +17,7 @@ void __init xen_time_init(void);
 void __init xen_time_init(void);
 unsigned long xen_get_wallclock(void);
 int xen_set_wallclock(unsigned long time);
-cycle_t xen_clocksource_read(void);
+unsigned long long xen_sched_clock(void);
 
 void xen_mark_init_mm_pinned(void);
 

-- 

[PATCH 11/25] xen: Xen SMP guest support

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-smp.patch --]
[-- Type: text/plain, Size: 31379 bytes --]

This is a fairly straightforward Xen implementation of smp_ops.  One
thing this must to is carefully set up all the various sibling and
core maps so that the smp scheduler setup works properly (the setup is
very simple, since vcpus don't have any siblings or multiple cores).

Xen has its own IPI mechanisms, and has no dependency on any
APIC-based IPI.  The smp_ops hooks and the flush_tlb_others pv_op
allow a Xen guest to avoid all APIC code in arch/i386 (the only apic
operation is a single apic_read for the apic version number).

One subtle point which needs to be addressed is unpinning pagetables
when another cpu may have a lazy tlb reference to the pagetable. Xen
will not allow an in-use pagetable to be unpinned, so we must find any
other cpus with a reference to the pagetable and get them to shoot
down their references.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andi Kleen <ak@suse.de>

---
 arch/i386/kernel/smp.c                             |   16 
 arch/i386/kernel/smpboot.c                         |    4 
 arch/i386/xen/Makefile                             |    6 
 arch/i386/xen/enlighten.c                          |  118 ++++-
 arch/i386/xen/events.c                             |   78 +++
 arch/i386/xen/mmu.c                                |   66 ++-
 arch/i386/xen/mmu.h                                |    9 
 arch/i386/xen/setup.c                              |    9 
 arch/i386/xen/smp.c                                |  419 ++++++++++++++++++++
 arch/i386/xen/time.c                               |    9 
 arch/i386/xen/xen-ops.h                            |   25 +
 include/asm-i386/mach-default/irq_vectors_limits.h |    2 
 include/asm-i386/mmu_context.h                     |   17 
 include/asm-i386/processor.h                       |    1 
 include/asm-i386/smp.h                             |    2 
 include/xen/events.h                               |   27 +
 16 files changed, 730 insertions(+), 78 deletions(-)

===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -23,6 +23,7 @@
 
 #include <asm/mtrr.h>
 #include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
 #include <mach_apic.h>
 
 /*
@@ -256,21 +257,6 @@ static struct mm_struct * flush_mm;
 static struct mm_struct * flush_mm;
 static unsigned long flush_va;
 static DEFINE_SPINLOCK(tlbstate_lock);
-
-/*
- * We cannot call mmdrop() because we are in interrupt context, 
- * instead update mm->cpu_vm_mask.
- *
- * We need to reload %cr3 since the page tables may be going
- * away from under us..
- */
-static inline void leave_mm (unsigned long cpu)
-{
-	if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
-		BUG();
-	cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).active_mm->cpu_vm_mask);
-	load_cr3(swapper_pg_dir);
-}
 
 /*
  *
===================================================================
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -151,7 +151,7 @@ void __init smp_alloc_memory(void)
  * a given CPU
  */
 
-static void __cpuinit smp_store_cpu_info(int id)
+void __cpuinit smp_store_cpu_info(int id)
 {
 	struct cpuinfo_x86 *c = cpu_data + id;
 
@@ -785,7 +785,7 @@ static inline struct task_struct * alloc
 /* Initialize the CPU's GDT.  This is either the boot CPU doing itself
    (still using the master per-cpu area), or a CPU doing it for a
    secondary which will soon come up. */
-static __cpuinit void init_gdt(int cpu)
+__cpuinit void init_gdt(int cpu)
 {
 	struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 
===================================================================
--- a/arch/i386/xen/Makefile
+++ b/arch/i386/xen/Makefile
@@ -1,2 +1,4 @@ obj-y		:= enlighten.o setup.o events.o t
-obj-y		:= enlighten.o setup.o events.o time.o \
-			features.o mmu.o multicalls.o
+obj-y	:= enlighten.o setup.o events.o time.o \
+		features.o mmu.o multicalls.o
+
+obj-$(CONFIG_SMP)	+= smp.o
===================================================================
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -13,6 +13,7 @@
 #include <linux/highmem.h>
 
 #include <xen/interface/xen.h>
+#include <xen/interface/vcpu.h>
 #include <xen/features.h>
 #include <xen/page.h>
 
@@ -25,6 +26,8 @@
 #include <asm/setup.h>
 #include <asm/desc.h>
 #include <asm/pgtable.h>
+#include <asm/smp.h>
+#include <asm/tlbflush.h>
 
 #include "xen-ops.h"
 #include "mmu.h"
@@ -44,7 +47,7 @@ struct start_info *xen_start_info;
 struct start_info *xen_start_info;
 EXPORT_SYMBOL_GPL(xen_start_info);
 
-static void xen_vcpu_setup(int cpu)
+void xen_vcpu_setup(int cpu)
 {
 	per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
 }
@@ -152,10 +155,10 @@ static void xen_safe_halt(void)
 
 static void xen_halt(void)
 {
-#if 0
 	if (irqs_disabled())
 		HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
-#endif
+	else
+		xen_safe_halt();
 }
 
 static void xen_set_lazy_mode(enum paravirt_lazy_mode mode)
@@ -313,6 +316,32 @@ static void xen_write_idt_entry(struct d
 	}
 }
 
+static void xen_convert_trap_info(const struct Xgt_desc_struct *desc,
+				  struct trap_info *traps)
+{
+	unsigned in, out, count;
+
+	count = desc->size / 8;
+	BUG_ON(count > 256);
+
+	for(in = out = 0; in < count; in++) {
+		const u32 *entry = (u32 *)(desc->address + in * 8);
+
+		if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out]))
+			out++;
+	}
+	traps[out].address = 0;
+}
+
+void xen_copy_trap_info(struct trap_info *traps)
+{
+	const struct Xgt_desc_struct *desc = &get_cpu_var(idt_desc);
+
+	xen_convert_trap_info(desc, traps);
+
+	put_cpu_var(idt_desc);
+}
+
 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
    hold a spinlock to protect the static traps[] array (static because
    it avoids allocation, and saves stack space). */
@@ -320,23 +349,13 @@ static void xen_load_idt(const struct Xg
 {
 	static DEFINE_SPINLOCK(lock);
 	static struct trap_info traps[257];
-
 	int cpu = smp_processor_id();
-	unsigned in, out, count;
 
 	per_cpu(idt_desc, cpu) = *desc;
 
-	count = desc->size / 8;
-	BUG_ON(count > 256);
-
 	spin_lock(&lock);
-	for(in = out = 0; in < count; in++) {
-		const u32 *entry = (u32 *)(desc->address + in * 8);
-
-		if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out]))
-			out++;
-	}
-	traps[out].address = 0;
+
+	xen_convert_trap_info(desc, traps);
 
 	xen_mc_flush();
 	if (HYPERVISOR_set_trap_table(traps))
@@ -393,7 +412,13 @@ static void xen_io_delay(void)
 #ifdef CONFIG_X86_LOCAL_APIC
 static unsigned long xen_apic_read(unsigned long reg)
 {
+	WARN_ON(1);
 	return 0;
+}
+
+static void xen_apic_write(unsigned long reg, unsigned long val)
+{
+	WARN_ON(1);
 }
 #endif
 
@@ -416,6 +441,40 @@ static void xen_flush_tlb_single(unsigne
 		BUG();
 }
 
+static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm,
+				 unsigned long va)
+{
+	struct mmuext_op op;
+	cpumask_t cpumask = *cpus;
+
+	/*
+	 * A couple of (to be removed) sanity checks:
+	 *
+	 * - current CPU must not be in mask
+	 * - mask must exist :)
+	 */
+	BUG_ON(cpus_empty(cpumask));
+	BUG_ON(cpu_isset(smp_processor_id(), cpumask));
+	BUG_ON(!mm);
+
+	/* If a CPU which we ran on has gone down, OK. */
+	cpus_and(cpumask, cpumask, cpu_online_map);
+	if (cpus_empty(cpumask))
+		return;
+
+	if (va == TLB_FLUSH_ALL) {
+		op.cmd = MMUEXT_TLB_FLUSH_MULTI;
+		op.arg2.vcpumask = (void *)cpus;
+	} else {
+		op.cmd = MMUEXT_INVLPG_MULTI;
+		op.arg1.linear_addr = va;
+		op.arg2.vcpumask = (void *)cpus;
+	}
+
+	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+		BUG();
+}
+
 static unsigned long xen_read_cr2(void)
 {
 	return x86_read_percpu(xen_vcpu)->arch.cr2;
@@ -426,14 +485,6 @@ static void xen_write_cr4(unsigned long 
 	/* never allow TSC to be disabled */
 	native_write_cr4(cr4 & ~X86_CR4_TSD);
 }
-
-/*
- * Page-directory addresses above 4GB do not fit into architectural %cr3.
- * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
- * must use the following accessor macros to pack/unpack valid MFNs.
- */
-#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
-#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))
 
 static unsigned long xen_read_cr3(void)
 {
@@ -679,8 +730,8 @@ static const struct paravirt_ops xen_par
 	.sched_clock = xen_sched_clock,
 
 #ifdef CONFIG_X86_LOCAL_APIC
-	.apic_write = paravirt_nop,
-	.apic_write_atomic = paravirt_nop,
+	.apic_write = xen_apic_write,
+	.apic_write_atomic = xen_apic_write,
 	.apic_read = xen_apic_read,
 	.setup_boot_clock = paravirt_nop,
 	.setup_secondary_clock = paravirt_nop,
@@ -690,6 +741,7 @@ static const struct paravirt_ops xen_par
 	.flush_tlb_user = xen_flush_tlb,
 	.flush_tlb_kernel = xen_flush_tlb,
 	.flush_tlb_single = xen_flush_tlb_single,
+	.flush_tlb_others = xen_flush_tlb_others,
 
 	.pte_update = paravirt_nop,
 	.pte_update_defer = paravirt_nop,
@@ -734,6 +786,19 @@ static const struct paravirt_ops xen_par
 	.set_lazy_mode = xen_set_lazy_mode,
 };
 
+#ifdef CONFIG_SMP
+static const struct smp_ops xen_smp_ops __initdata = {
+	.smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
+	.smp_prepare_cpus = xen_smp_prepare_cpus,
+	.cpu_up = xen_cpu_up,
+	.smp_cpus_done = xen_smp_cpus_done,
+
+	.smp_send_stop = xen_smp_send_stop,
+	.smp_send_reschedule = xen_smp_send_reschedule,
+	.smp_call_function_mask = xen_smp_call_function_mask,
+};
+#endif	/* CONFIG_SMP */
+
 /* First C function to be called on Xen boot */
 static asmlinkage void __init xen_start_kernel(void)
 {
@@ -746,6 +811,9 @@ static asmlinkage void __init xen_start_
 
 	/* Install Xen paravirt ops */
 	paravirt_ops = xen_paravirt_ops;
+#ifdef CONFIG_SMP
+	smp_ops = xen_smp_ops;
+#endif
 
 	xen_setup_features();
 
===================================================================
--- a/arch/i386/xen/events.c
+++ b/arch/i386/xen/events.c
@@ -24,6 +24,9 @@ static DEFINE_SPINLOCK(irq_mapping_updat
 /* IRQ <-> VIRQ mapping. */
 static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1};
 
+/* IRQ <-> IPI mapping */
+static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -1};
+
 /* Packed IRQ information: binding type, sub-type index, and event channel. */
 struct packed_irq
 {
@@ -35,7 +38,13 @@ static struct packed_irq irq_info[NR_IRQ
 static struct packed_irq irq_info[NR_IRQS];
 
 /* Binding types. */
-enum { IRQT_UNBOUND, IRQT_PIRQ, IRQT_VIRQ, IRQT_IPI, IRQT_EVTCHN };
+enum {
+	IRQT_UNBOUND,
+	IRQT_PIRQ,
+	IRQT_VIRQ,
+	IRQT_IPI,
+	IRQT_EVTCHN
+};
 
 /* Convenient shorthand for packed representation of an unbound IRQ. */
 #define IRQ_UNBOUND	mk_irq_info(IRQT_UNBOUND, 0, 0)
@@ -238,6 +247,43 @@ static int bind_evtchn_to_irq(unsigned i
 	return irq;
 }
 
+static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
+{
+	struct evtchn_bind_ipi bind_ipi;
+	int evtchn, irq;
+
+	spin_lock(&irq_mapping_update_lock);
+
+	if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1) {
+		if ((irq = find_unbound_irq()) < 0)
+			goto out;
+
+		dynamic_irq_init(irq);
+		set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
+					      handle_level_irq, "ipi");
+
+		bind_ipi.vcpu = cpu;
+		if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
+						&bind_ipi) != 0)
+			BUG();
+		evtchn = bind_ipi.port;
+
+		evtchn_to_irq[evtchn] = irq;
+		irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn);
+
+		per_cpu(ipi_to_irq, cpu)[ipi] = irq;
+
+		bind_evtchn_to_cpu(evtchn, cpu);
+	}
+
+	irq_bindcount[irq]++;
+
+ out:
+	spin_unlock(&irq_mapping_update_lock);
+	return irq;
+}
+
+
 static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 {
 	struct evtchn_bind_virq bind_virq;
@@ -345,12 +391,42 @@ int bind_virq_to_irqhandler(unsigned int
 }
 EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
 
+int bind_ipi_to_irqhandler(enum ipi_vector ipi,
+			   unsigned int cpu,
+			   irq_handler_t handler,
+			   unsigned long irqflags,
+			   const char *devname,
+			   void *dev_id)
+{
+	int irq, retval;
+
+	irq = bind_ipi_to_irq(ipi, cpu);
+	if (irq < 0)
+		return irq;
+
+	retval = request_irq(irq, handler, irqflags, devname, dev_id);
+	if (retval != 0) {
+		unbind_from_irq(irq);
+		return retval;
+	}
+
+	return irq;
+}
+
 void unbind_from_irqhandler(unsigned int irq, void *dev_id)
 {
 	free_irq(irq, dev_id);
 	unbind_from_irq(irq);
 }
 EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
+
+void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
+{
+	int irq = per_cpu(ipi_to_irq, cpu)[vector];
+	BUG_ON(irq < 0);
+	notify_remote_via_irq(irq);
+}
+
 
 /*
   Search the CPUs pending events bitmasks.  For each one found, map
===================================================================
--- a/arch/i386/xen/mmu.c
+++ b/arch/i386/xen/mmu.c
@@ -349,8 +349,12 @@ void xen_pgd_pin(pgd_t *pgd)
 
 	xen_mc_batch();
 
-	if (pgd_walk(pgd, pin_page, TASK_SIZE))
+	if (pgd_walk(pgd, pin_page, TASK_SIZE)) {
+		/* re-enable interrupts for kmap_flush_unused */
+		xen_mc_issue(0);
 		kmap_flush_unused();
+		xen_mc_batch();
+	}
 
 	mcs = __xen_mc_entry(sizeof(*op));
 	op = mcs.args;
@@ -433,27 +437,49 @@ void xen_dup_mmap(struct mm_struct *oldm
 	spin_unlock(&mm->page_table_lock);
 }
 
+
+#ifdef CONFIG_SMP
+/*
+ * While a process runs, Xen pins its pagetables, which means that the
+ * hypervisor forces it to be read-only, and it controls all updates
+ * to it.  This means that all pagetable updates have to go via the
+ * hypervisor, which is moderately expensive.
+ *
+ * Since we're pulling the pagetable down, we switch to use init_mm,
+ * unpin old process pagetable and mark it all read-write, which
+ * allows further operations on it to be simple memory accesses.
+ *
+ * The only subtle point is that another CPU may be still using the
+ * pagetable because of lazy tlb flushing.  This means we need need to
+ * switch all CPUs off this pagetable before we can unpin it.
+ */
+static void drop_mm_ref(void *info)
+{
+	struct mm_struct *mm = info;
+
+	if (__get_cpu_var(cpu_tlbstate).active_mm == mm)
+		leave_mm(smp_processor_id());
+}
+#endif
+
 void xen_exit_mmap(struct mm_struct *mm)
 {
-	struct task_struct *tsk = current;
-
-	task_lock(tsk);
-
-	/*
-	 * We aggressively remove defunct pgd from cr3. We execute unmap_vmas()
-	 * *much* faster this way, as no tlb flushes means bigger wrpt batches.
-	 */
-	if (tsk->active_mm == mm) {
-		tsk->active_mm = &init_mm;
-		atomic_inc(&init_mm.mm_count);
-
-		switch_mm(mm, &init_mm, tsk);
-
-		atomic_dec(&mm->mm_count);
-		BUG_ON(atomic_read(&mm->mm_count) == 0);
-	}
-
-	task_unlock(tsk);
+	preempt_disable();
+
+	if (current->active_mm == mm) {
+		if (current->mm == mm)
+			load_cr3(swapper_pg_dir);
+		else
+			leave_mm(smp_processor_id());
+	}
+
+#ifdef CONFIG_SMP
+	if (!cpus_empty(mm->cpu_vm_mask))
+		xen_smp_call_function_mask(mm->cpu_vm_mask, drop_mm_ref,
+					   mm, 1);
+#endif	/* CONFIG_SMP */
+
+	preempt_enable();
 
 	xen_pgd_unpin(mm->pgd);
 }
===================================================================
--- a/arch/i386/xen/mmu.h
+++ b/arch/i386/xen/mmu.h
@@ -2,6 +2,15 @@
 
 #include <linux/linkage.h>
 #include <asm/page.h>
+
+/*
+ * Page-directory addresses above 4GB do not fit into architectural %cr3.
+ * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
+ * must use the following accessor macros to pack/unpack valid MFNs.
+ */
+#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
+#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))
+
 
 void set_pte_mfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);
 
===================================================================
--- a/arch/i386/xen/setup.c
+++ b/arch/i386/xen/setup.c
@@ -15,10 +15,6 @@
 #include <xen/features.h>
 
 #include "xen-ops.h"
-
-/* These are code, but not functions.  Defined in entry.S */
-extern const char xen_hypervisor_callback[];
-extern const char xen_failsafe_callback[];
 
 static __initdata struct shared_info init_shared;
 
@@ -90,4 +86,9 @@ void __init xen_arch_setup(void)
 	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 
 	pm_idle = xen_idle;
+
+#ifdef CONFIG_SMP
+	/* fill cpus_possible with all available cpus */
+	xen_fill_possible_map();
+#endif
 }
===================================================================
--- /dev/null
+++ b/arch/i386/xen/smp.c
@@ -0,0 +1,419 @@
+#include <linux/sched.h>
+#include <linux/err.h>
+
+#include <asm/paravirt.h>
+#include <asm/smp.h>
+#include <asm/desc.h>
+#include <asm/pgtable.h>
+#include <asm/cpu.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/vcpu.h>
+
+#include <asm/xen/interface.h>
+#include <asm/xen/hypercall.h>
+
+#include <xen/page.h>
+#include <xen/events.h>
+
+#include "xen-ops.h"
+#include "mmu.h"
+
+static cpumask_t cpu_initialized_map;
+static DEFINE_PER_CPU(int, resched_irq);
+static DEFINE_PER_CPU(int, callfunc_irq);
+
+/*
+ * Structure and data for smp_call_function(). This is designed to minimise
+ * static memory requirements. It also looks cleaner.
+ */
+static DEFINE_SPINLOCK(call_lock);
+
+struct call_data_struct {
+	void (*func) (void *info);
+	void *info;
+	atomic_t started;
+	atomic_t finished;
+	int wait;
+};
+
+static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
+
+static struct call_data_struct *call_data;
+
+/*
+ * Reschedule call back. Nothing to do,
+ * all the work is done automatically when
+ * we return from the interrupt.
+ */
+static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
+{
+	return IRQ_HANDLED;
+}
+
+/* VCPUs are single-cored, and have no siblings */
+static void set_cpu_sibling_map(int cpu)
+{
+	struct cpuinfo_x86 *c = &cpu_data[cpu];
+
+	cpu_set(cpu, cpu_sibling_map[cpu]);
+	cpu_set(cpu, c->llc_shared_map);
+	cpu_core_map[cpu] = cpu_sibling_map[cpu];
+	c->booted_cores = 1;
+}
+
+static void remove_siblinginfo(int cpu)
+{
+	struct cpuinfo_x86 *c = &cpu_data[cpu];
+
+	cpus_clear(cpu_sibling_map[cpu]);
+	cpus_clear(cpu_core_map[cpu]);
+	c->booted_cores = 0;
+	c->phys_proc_id = 0;
+	c->cpu_core_id = 0;
+}
+
+static __cpuinit void cpu_bringup_and_idle(void)
+{
+	int cpu = smp_processor_id();
+
+	cpu_init();
+	xen_setup_timer();
+
+	preempt_disable();
+	per_cpu(cpu_state, cpu) = CPU_ONLINE;
+
+	/* We can take interrupts now: we're officially "up". */
+	local_irq_enable();
+
+	wmb();
+	cpu_idle();
+}
+
+static int xen_smp_intr_init(unsigned int cpu)
+{
+	int rc;
+	const char *resched_name, *callfunc_name;
+
+	per_cpu(resched_irq, cpu) = per_cpu(callfunc_irq, cpu) = -1;
+
+	resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
+	rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
+				    cpu,
+				    xen_reschedule_interrupt,
+				    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+				    resched_name,
+				    NULL);
+	if (rc < 0)
+		goto fail;
+	per_cpu(resched_irq, cpu) = rc;
+
+	callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
+	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
+				    cpu,
+				    xen_call_function_interrupt,
+				    IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
+				    callfunc_name,
+				    NULL);
+	if (rc < 0)
+		goto fail;
+	per_cpu(callfunc_irq, cpu) = rc;
+
+	return 0;
+
+ fail:
+	if (per_cpu(resched_irq, cpu) >= 0)
+		unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL);
+	if (per_cpu(callfunc_irq, cpu) >= 0)
+		unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL);
+	return rc;
+}
+
+void __init xen_fill_possible_map(void)
+{
+	int i, rc;
+
+	for_each_possible_cpu(i)
+	    if (i != smp_processor_id())
+		return;
+
+	for (i = 0; i < NR_CPUS; i++) {
+		rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
+		if (rc >= 0)
+			cpu_set(i, cpu_possible_map);
+	}
+}
+
+void __init xen_smp_prepare_boot_cpu(void)
+{
+	int cpu;
+
+	BUG_ON(smp_processor_id() != 0);
+	native_smp_prepare_boot_cpu();
+
+	xen_vcpu_setup(0);
+
+	/* We've switched to the "real" per-cpu gdt, so make sure the
+	   old memory can be recycled */
+	make_lowmem_page_readwrite(&per_cpu__gdt_page);
+
+	for (cpu = 0; cpu < NR_CPUS; cpu++) {
+		cpus_clear(cpu_sibling_map[cpu]);
+		cpus_clear(cpu_core_map[cpu]);
+	}
+
+	xen_fill_possible_map();  /* should already be done */
+}
+
+void __init xen_smp_prepare_cpus(unsigned int max_cpus)
+{
+	unsigned cpu;
+
+	for (cpu = 0; cpu < NR_CPUS; cpu++) {
+		cpus_clear(cpu_sibling_map[cpu]);
+		cpus_clear(cpu_core_map[cpu]);
+	}
+
+	smp_store_cpu_info(0);
+	set_cpu_sibling_map(0);
+
+	if (xen_smp_intr_init(0))
+		BUG();
+
+	cpu_initialized_map = cpumask_of_cpu(0);
+
+	/* Restrict the possible_map according to max_cpus. */
+	while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
+		for (cpu = NR_CPUS-1; !cpu_isset(cpu, cpu_possible_map); cpu--)
+			continue;
+		cpu_clear(cpu, cpu_possible_map);
+	}
+
+	for_each_possible_cpu (cpu) {
+		struct task_struct *idle;
+
+		if (cpu == 0)
+			continue;
+
+		idle = fork_idle(cpu);
+		if (IS_ERR(idle))
+			panic("failed fork for CPU %d", cpu);
+
+		cpu_set(cpu, cpu_present_map);
+	}
+
+	//init_xenbus_allowed_cpumask();
+}
+
+static __cpuinit int
+cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
+{
+	struct vcpu_guest_context *ctxt;
+	struct gdt_page *gdt = &per_cpu(gdt_page, cpu);
+
+	if (cpu_test_and_set(cpu, cpu_initialized_map))
+		return 0;
+
+	ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
+	if (ctxt == NULL)
+		return -ENOMEM;
+
+	ctxt->flags = VGCF_IN_KERNEL;
+	ctxt->user_regs.ds = __USER_DS;
+	ctxt->user_regs.es = __USER_DS;
+	ctxt->user_regs.fs = __KERNEL_PERCPU;
+	ctxt->user_regs.gs = 0;
+	ctxt->user_regs.ss = __KERNEL_DS;
+	ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
+	ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
+
+	memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
+
+	xen_copy_trap_info(ctxt->trap_ctxt);
+
+	ctxt->ldt_ents = 0;
+
+	BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK);
+	make_lowmem_page_readonly(gdt->gdt);
+
+	ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt);
+	ctxt->gdt_ents      = ARRAY_SIZE(gdt->gdt);
+
+	ctxt->user_regs.cs = __KERNEL_CS;
+	ctxt->user_regs.esp = idle->thread.esp0 - sizeof(struct pt_regs);
+
+	ctxt->kernel_ss = __KERNEL_DS;
+	ctxt->kernel_sp = idle->thread.esp0;
+
+	ctxt->event_callback_cs     = __KERNEL_CS;
+	ctxt->event_callback_eip    = (unsigned long)xen_hypervisor_callback;
+	ctxt->failsafe_callback_cs  = __KERNEL_CS;
+	ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
+
+	per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
+	ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
+
+	if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
+		BUG();
+
+	kfree(ctxt);
+	return 0;
+}
+
+int __cpuinit xen_cpu_up(unsigned int cpu)
+{
+	struct task_struct *idle = idle_task(cpu);
+	int rc;
+
+#if 0
+	rc = cpu_up_check(cpu);
+	if (rc)
+		return rc;
+#endif
+
+	init_gdt(cpu);
+	per_cpu(current_task, cpu) = idle;
+	xen_vcpu_setup(cpu);
+	irq_ctx_init(cpu);
+
+	/* make sure interrupts start blocked */
+	per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
+
+	rc = cpu_initialize_context(cpu, idle);
+	if (rc)
+		return rc;
+
+	if (num_online_cpus() == 1)
+		alternatives_smp_switch(1);
+
+	/* This must be done before setting cpu_online_map */
+	smp_store_cpu_info(cpu);
+	set_cpu_sibling_map(cpu);
+	wmb();
+
+	rc = xen_smp_intr_init(cpu);
+	if (rc) {
+		remove_siblinginfo(cpu);
+		return rc;
+	}
+
+	cpu_set(cpu, cpu_online_map);
+
+	rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
+	BUG_ON(rc);
+
+	return 0;
+}
+
+void xen_smp_cpus_done(unsigned int max_cpus)
+{
+}
+
+static void stop_self(void *v)
+{
+	int cpu = smp_processor_id();
+
+	/* make sure we're not pinning something down */
+	load_cr3(swapper_pg_dir);
+	/* should set up a minimal gdt */
+
+	HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
+	BUG();
+}
+
+void xen_smp_send_stop(void)
+{
+	cpumask_t mask = cpu_online_map;
+	cpu_clear(smp_processor_id(), mask);
+	xen_smp_call_function_mask(mask, stop_self, NULL, 0);
+}
+
+void xen_smp_send_reschedule(int cpu)
+{
+	xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
+}
+
+
+static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector)
+{
+	unsigned cpu;
+
+	cpus_and(mask, mask, cpu_online_map);
+
+	for_each_cpu_mask(cpu, mask)
+		xen_send_IPI_one(cpu, vector);
+}
+
+static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
+{
+	void (*func) (void *info) = call_data->func;
+	void *info = call_data->info;
+	int wait = call_data->wait;
+
+	/*
+	 * Notify initiating CPU that I've grabbed the data and am
+	 * about to execute the function
+	 */
+	mb();
+	atomic_inc(&call_data->started);
+	/*
+	 * At this point the info structure may be out of scope unless wait==1
+	 */
+	irq_enter();
+	(*func)(info);
+	irq_exit();
+
+	if (wait) {
+		mb();
+		atomic_inc(&call_data->finished);
+	}
+
+	return IRQ_HANDLED;
+}
+
+int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
+			       void *info, int wait)
+{
+	struct call_data_struct data;
+	int cpus;
+
+	/* Holding any lock stops cpus from going down. */
+	spin_lock(&call_lock);
+
+	cpu_clear(smp_processor_id(), mask);
+
+	cpus = cpus_weight(mask);
+	if (!cpus) {
+		spin_unlock(&call_lock);
+		return 0;
+	}
+
+	/* Can deadlock when called with interrupts disabled */
+	WARN_ON(irqs_disabled());
+
+	data.func = func;
+	data.info = info;
+	atomic_set(&data.started, 0);
+	data.wait = wait;
+	if (wait)
+		atomic_set(&data.finished, 0);
+
+	call_data = &data;
+	mb();
+
+	/* Send a message to other CPUs and wait for them to respond */
+	xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
+
+	/* Make sure other vcpus get a chance to run.
+	   XXX too severe?  Maybe we should check the other CPU's states? */
+	HYPERVISOR_sched_op(SCHEDOP_yield, 0);
+
+	/* Wait for response */
+	while (atomic_read(&data.started) != cpus ||
+	       (wait && atomic_read(&data.finished) != cpus))
+		cpu_relax();
+
+	spin_unlock(&call_lock);
+
+	return 0;
+}
===================================================================
--- a/arch/i386/xen/time.c
+++ b/arch/i386/xen/time.c
@@ -452,8 +452,9 @@ static irqreturn_t xen_timer_interrupt(i
 	return ret;
 }
 
-static void xen_setup_timer(int cpu)
-{
+void xen_setup_timer(void)
+{
+	int cpu = smp_processor_id();
 	const char *name;
 	struct clock_event_device *evt;
 	int irq;
@@ -502,5 +503,5 @@ __init void xen_time_init(void)
 
 	tsc_disable = 0;
 
-	xen_setup_timer(cpu);
-}
+	xen_setup_timer();
+}
===================================================================
--- a/arch/i386/xen/xen-ops.h
+++ b/arch/i386/xen/xen-ops.h
@@ -2,6 +2,13 @@
 #define XEN_OPS_H
 
 #include <linux/init.h>
+#include <linux/percpu.h>
+
+/* These are code, but not functions.  Defined in entry.S */
+extern const char xen_hypervisor_callback[];
+extern const char xen_failsafe_callback[];
+
+void xen_copy_trap_info(struct trap_info *traps);
 
 DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu);
 DECLARE_PER_CPU(unsigned long, xen_cr3);
@@ -18,6 +25,7 @@ unsigned long xen_get_wallclock(void);
 unsigned long xen_get_wallclock(void);
 int xen_set_wallclock(unsigned long time);
 unsigned long long xen_sched_clock(void);
+void xen_setup_timer(void);
 
 void xen_mark_init_mm_pinned(void);
 
@@ -28,5 +36,22 @@ static inline unsigned xen_get_lazy_mode
 	return x86_read_percpu(xen_lazy_mode);
 }
 
+void __init xen_fill_possible_map(void);
+
+void xen_vcpu_setup(int cpu);
+void xen_smp_prepare_boot_cpu(void);
+void xen_smp_prepare_cpus(unsigned int max_cpus);
+int xen_cpu_up(unsigned int cpu);
+void xen_smp_cpus_done(unsigned int max_cpus);
+
+void xen_smp_send_stop(void);
+void xen_smp_send_reschedule(int cpu);
+int xen_smp_call_function (void (*func) (void *info), void *info, int nonatomic,
+			   int wait);
+int xen_smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+				 int nonatomic, int wait);
+
+int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
+			       void *info, int wait);
 
 #endif /* XEN_OPS_H */
===================================================================
--- a/include/asm-i386/mach-default/irq_vectors_limits.h
+++ b/include/asm-i386/mach-default/irq_vectors_limits.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_IRQ_VECTORS_LIMITS_H
 #define _ASM_IRQ_VECTORS_LIMITS_H
 
-#ifdef CONFIG_X86_IO_APIC
+#if defined(CONFIG_X86_IO_APIC) || defined(CONFIG_PARAVIRT)
 #define NR_IRQS 224
 # if (224 >= 32 * NR_CPUS)
 # define NR_IRQ_VECTORS NR_IRQS
===================================================================
--- a/include/asm-i386/mmu_context.h
+++ b/include/asm-i386/mmu_context.h
@@ -30,6 +30,23 @@ static inline void enter_lazy_tlb(struct
 	if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
 		per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_LAZY;
 #endif
+}
+
+/*
+ * We cannot call mmdrop() because we are in interrupt context,
+ * instead update mm->cpu_vm_mask.
+ *
+ * We need to reload %cr3 since the page tables may be going
+ * away from under us..
+ */
+static inline void leave_mm (unsigned long cpu)
+{
+#ifdef CONFIG_SMP
+	if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
+		BUG();
+	cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).active_mm->cpu_vm_mask);
+#endif
+	load_cr3(swapper_pg_dir);
 }
 
 static inline void switch_mm(struct mm_struct *prev,
===================================================================
--- a/include/asm-i386/processor.h
+++ b/include/asm-i386/processor.h
@@ -752,6 +752,7 @@ extern void cpu_set_gdt(int);
 extern void cpu_set_gdt(int);
 extern void switch_to_new_gdt(void);
 extern void cpu_init(void);
+extern void init_gdt(int cpu);
 
 extern int force_mwait;
 
===================================================================
--- a/include/asm-i386/smp.h
+++ b/include/asm-i386/smp.h
@@ -143,6 +143,8 @@ extern void __cpu_die(unsigned int cpu);
 extern void __cpu_die(unsigned int cpu);
 extern unsigned int num_processors;
 
+void __cpuinit smp_store_cpu_info(int id);
+
 #endif /* !__ASSEMBLY__ */
 
 #else /* CONFIG_SMP */
===================================================================
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -1,15 +1,32 @@
 #ifndef _XEN_EVENTS_H
 #define _XEN_EVENTS_H
 
-#include <linux/irq.h>
+#include <linux/interrupt.h>
+
+#include <xen/interface/event_channel.h>
+#include <asm/xen/hypercall.h>
+
+enum ipi_vector {
+	XEN_RESCHEDULE_VECTOR,
+	XEN_CALL_FUNCTION_VECTOR,
+
+	XEN_NR_IPIS,
+};
 
 int bind_evtchn_to_irqhandler(unsigned int evtchn,
-			      irqreturn_t (*handler)(int, void *),
+			      irq_handler_t handler,
 			      unsigned long irqflags, const char *devname,
 			      void *dev_id);
 int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
-			    irqreturn_t (*handler)(int, void *),
-			    unsigned long irqflags, const char *devname, void *dev_id);
+			    irq_handler_t handler,
+			    unsigned long irqflags, const char *devname,
+			    void *dev_id);
+int bind_ipi_to_irqhandler(enum ipi_vector ipi,
+			   unsigned int cpu,
+			   irq_handler_t handler,
+			   unsigned long irqflags,
+			   const char *devname,
+			   void *dev_id);
 
 /*
  * Common unbind function for all event sources. Takes IRQ to unbind from.
@@ -17,6 +34,8 @@ int bind_virq_to_irqhandler(unsigned int
  * made with bind_evtchn_to_irqhandler()).
  */
 void unbind_from_irqhandler(unsigned int irq, void *dev_id);
+
+void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector);
 
 static inline void notify_remote_via_evtchn(int port)
 {

-- 

Re: [PATCH 11/25] xen: Xen SMP guest support

[Andi Kleen]

>  #ifdef CONFIG_X86_LOCAL_APIC
>  static unsigned long xen_apic_read(unsigned long reg)

Can't you just make them all NULL? Crashing here should be correct.


  
> +#ifdef CONFIG_SMP
> +static const struct smp_ops xen_smp_ops __initdata = {

Why __initdata? 

> +/* VCPUs are single-cored, and have no siblings */
> +static void set_cpu_sibling_map(int cpu)

Can you put this somewhere generic and use it everywhere? Don't want
duplication of this code.

> +{
> +	struct cpuinfo_x86 *c = &cpu_data[cpu];
> +
> +	cpu_set(cpu, cpu_sibling_map[cpu]);
> +	cpu_set(cpu, c->llc_shared_map);
> +	cpu_core_map[cpu] = cpu_sibling_map[cpu];
> +	c->booted_cores = 1;
> +}
> +
> +static void remove_siblinginfo(int cpu)

Similar.

> +void __init xen_fill_possible_map(void)
> +{
> +	int i, rc;
> +
> +	for_each_possible_cpu(i)
> +	    if (i != smp_processor_id())
> +		return;

Strange check?

> +
> + * We need to reload %cr3 since the page tables may be going
> + * away from under us..
> + */
> +static inline void leave_mm (unsigned long cpu)
> +{
> +#ifdef CONFIG_SMP
> +	if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
> +		BUG();
> +	cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).active_mm->cpu_vm_mask);
> +#endif
> +	load_cr3(swapper_pg_dir);
>  }

Should be out of line


-Andi

Re: [PATCH 11/25] xen: Xen SMP guest support

[Jeremy Fitzhardinge]

Andi Kleen wrote:
>   
>>  #ifdef CONFIG_X86_LOCAL_APIC
>>  static unsigned long xen_apic_read(unsigned long reg)
>>     
>
> Can't you just make them all NULL? Crashing here should be correct.
>   

No.  The APIC setup code does at least one unconditional read to get the
APIC version before deciding the APIC is disabled/not present.  In my
testing that's the only access to the APIC which happens under Xen, but
it wouldn't surprise me if there were other stray accesses with
different configurations (like the P4_THERMAL stuff).

>> +#ifdef CONFIG_SMP
>> +static const struct smp_ops xen_smp_ops __initdata = {
>>     
>
> Why __initdata? 
>   

It gets copied into the real smp_ops early on, so it isn't needed after
that.

>> +/* VCPUs are single-cored, and have no siblings */
>> +static void set_cpu_sibling_map(int cpu)
>>     
>
> Can you put this somewhere generic and use it everywhere? Don't want
> duplication of this code.
>   

OK.

> Strange check?
>   

Er, yes, that does look odd.

>> +
>> + * We need to reload %cr3 since the page tables may be going
>> + * away from under us..
>> + */
>> +static inline void leave_mm (unsigned long cpu)
>> +{
>> +#ifdef CONFIG_SMP
>> +	if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
>> +		BUG();
>> +	cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).active_mm->cpu_vm_mask);
>> +#endif
>> +	load_cr3(swapper_pg_dir);
>>  }
>>     
>
> Should be out of line
>   

OK.

    J

Re: [PATCH 11/25] xen: Xen SMP guest support

[Jeremy Fitzhardinge]

Andi Kleen wrote:
>> +/* VCPUs are single-cored, and have no siblings */
>> +static void set_cpu_sibling_map(int cpu)
>>     
>
> Can you put this somewhere generic and use it everywhere? Don't want
> duplication of this code.
>   

Are there any other users?  This is a very cutdown version of the code
in kernel/smpboot.c; under Xen all CPUs are considered to be
single-cored and single-threaded, so there's not a lot to do here.

    J

Re: [PATCH 11/25] xen: Xen SMP guest support

[Andi Kleen]

On Friday 27 April 2007 08:46:19 Jeremy Fitzhardinge wrote:
> Andi Kleen wrote:
> >> +/* VCPUs are single-cored, and have no siblings */
> >> +static void set_cpu_sibling_map(int cpu)
> >>     
> >
> > Can you put this somewhere generic and use it everywhere? Don't want
> > duplication of this code.
> >   
> 
> Are there any other users?  This is a very cutdown version of the code
> in kernel/smpboot.c; under Xen all CPUs are considered to be
> single-cored and single-threaded, so there's not a lot to do here.

I would like to have a single place to set that up, with xen calling
it with single arguments and the normal code with complex ones

-Andi

[PATCH 12/25] xen: Add support for preemption

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-preempt.patch --]
[-- Type: text/plain, Size: 9359 bytes --]

Add Xen support for preemption.  This is mostly a cleanup of existing
preempt_enable/disable calls, or just comments to explain the current
usage.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/xen/Kconfig      |    2 
 arch/i386/xen/enlighten.c  |   93 ++++++++++++++++++++++++++++----------------
 arch/i386/xen/mmu.c        |    4 +
 arch/i386/xen/multicalls.c |   11 ++---
 arch/i386/xen/time.c       |   22 ++++++++--
 5 files changed, 88 insertions(+), 44 deletions(-)

===================================================================
--- a/arch/i386/xen/Kconfig
+++ b/arch/i386/xen/Kconfig
@@ -4,7 +4,7 @@
 
 config XEN
 	bool "Enable support for Xen hypervisor"
-	depends on PARAVIRT && !PREEMPT
+	depends on PARAVIRT
 	default y
 	help
 	  This is the Linux Xen port.
===================================================================
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -2,6 +2,7 @@
 #include <linux/init.h>
 #include <linux/smp.h>
 #include <linux/preempt.h>
+#include <linux/hardirq.h>
 #include <linux/percpu.h>
 #include <linux/delay.h>
 #include <linux/start_kernel.h>
@@ -92,11 +93,10 @@ static unsigned long xen_save_fl(void)
 	struct vcpu_info *vcpu;
 	unsigned long flags;
 
-	preempt_disable();
 	vcpu = x86_read_percpu(xen_vcpu);
+
 	/* flag has opposite sense of mask */
 	flags = !vcpu->evtchn_upcall_mask;
-	preempt_enable();
 
 	/* convert to IF type flag
 	   -0 -> 0x00000000
@@ -109,41 +109,56 @@ static void xen_restore_fl(unsigned long
 {
 	struct vcpu_info *vcpu;
 
-	preempt_disable();
-
 	/* convert from IF type flag */
 	flags = !(flags & X86_EFLAGS_IF);
+
+	/* There's a one instruction preempt window here.  We need to
+	   make sure we're don't switch CPUs between getting the vcpu
+	   pointer and updating the mask. */
+	preempt_disable();
 	vcpu = x86_read_percpu(xen_vcpu);
 	vcpu->evtchn_upcall_mask = flags;
+	preempt_enable_no_resched();
+
+	/* Doesn't matter if we get preempted here, because any
+	   pending event will get dealt with anyway. */
+
 	if (flags == 0) {
+		preempt_check_resched();
 		barrier(); /* unmask then check (avoid races) */
 		if (unlikely(vcpu->evtchn_upcall_pending))
 			force_evtchn_callback();
-		preempt_enable();
-	} else
-		preempt_enable_no_resched();
+	}
 }
 
 static void xen_irq_disable(void)
 {
+	/* There's a one instruction preempt window here.  We need to
+	   make sure we're don't switch CPUs between getting the vcpu
+	   pointer and updating the mask. */
+	preempt_disable();
+	x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1;
+	preempt_enable_no_resched();
+}
+
+static void xen_irq_enable(void)
+{
 	struct vcpu_info *vcpu;
-	preempt_disable();
-	vcpu = x86_read_percpu(xen_vcpu);
-	vcpu->evtchn_upcall_mask = 1;
-	preempt_enable_no_resched();
-}
-
-static void xen_irq_enable(void)
-{
-	struct vcpu_info *vcpu;
-
+
+	/* There's a one instruction preempt window here.  We need to
+	   make sure we're don't switch CPUs between getting the vcpu
+	   pointer and updating the mask. */
 	preempt_disable();
 	vcpu = x86_read_percpu(xen_vcpu);
 	vcpu->evtchn_upcall_mask = 0;
+	preempt_enable_no_resched();
+
+	/* Doesn't matter if we get preempted here, because any
+	   pending event will get dealt with anyway. */
+
 	barrier(); /* unmask then check (avoid races) */
 	if (unlikely(vcpu->evtchn_upcall_pending))
 		force_evtchn_callback();
-	preempt_enable();
 }
 
 static void xen_safe_halt(void)
@@ -163,6 +178,8 @@ static void xen_halt(void)
 
 static void xen_set_lazy_mode(enum paravirt_lazy_mode mode)
 {
+	BUG_ON(preemptible());
+
 	switch(mode) {
 	case PARAVIRT_LAZY_NONE:
 		BUG_ON(x86_read_percpu(xen_lazy_mode) == PARAVIRT_LAZY_NONE);
@@ -262,12 +279,17 @@ static void xen_write_ldt_entry(struct d
 	xmaddr_t mach_lp = virt_to_machine(lp);
 	u64 entry = (u64)high << 32 | low;
 
+	preempt_disable();
+
 	xen_mc_flush();
 	if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
 		BUG();
-}
-
-static int cvt_gate_to_trap(int vector, u32 low, u32 high, struct trap_info *info)
+
+	preempt_enable();
+}
+
+static int cvt_gate_to_trap(int vector, u32 low, u32 high,
+			    struct trap_info *info)
 {
 	u8 type, dpl;
 
@@ -295,11 +317,13 @@ static DEFINE_PER_CPU(struct Xgt_desc_st
    also update Xen. */
 static void xen_write_idt_entry(struct desc_struct *dt, int entrynum, u32 low, u32 high)
 {
-
-	int cpu = smp_processor_id();
 	unsigned long p = (unsigned long)&dt[entrynum];
-	unsigned long start = per_cpu(idt_desc, cpu).address;
-	unsigned long end = start + per_cpu(idt_desc, cpu).size + 1;
+	unsigned long start, end;
+
+	preempt_disable();
+
+	start = __get_cpu_var(idt_desc).address;
+	end = start + __get_cpu_var(idt_desc).size + 1;
 
 	xen_mc_flush();
 
@@ -314,6 +338,8 @@ static void xen_write_idt_entry(struct d
 			if (HYPERVISOR_set_trap_table(info))
 				BUG();
 	}
+
+	preempt_enable();
 }
 
 static void xen_convert_trap_info(const struct Xgt_desc_struct *desc,
@@ -335,11 +361,9 @@ static void xen_convert_trap_info(const 
 
 void xen_copy_trap_info(struct trap_info *traps)
 {
-	const struct Xgt_desc_struct *desc = &get_cpu_var(idt_desc);
+	const struct Xgt_desc_struct *desc = &__get_cpu_var(idt_desc);
 
 	xen_convert_trap_info(desc, traps);
-
-	put_cpu_var(idt_desc);
 }
 
 /* Load a new IDT into Xen.  In principle this can be per-CPU, so we
@@ -349,11 +373,10 @@ static void xen_load_idt(const struct Xg
 {
 	static DEFINE_SPINLOCK(lock);
 	static struct trap_info traps[257];
-	int cpu = smp_processor_id();
-
-	per_cpu(idt_desc, cpu) = *desc;
 
 	spin_lock(&lock);
+
+	__get_cpu_var(idt_desc) = *desc;
 
 	xen_convert_trap_info(desc, traps);
 
@@ -368,6 +391,8 @@ static void xen_load_idt(const struct Xg
    they're handled differently. */
 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, u32 low, u32 high)
 {
+	preempt_disable();
+
 	switch ((high >> 8) & 0xff) {
 	case DESCTYPE_LDT:
 	case DESCTYPE_TSS:
@@ -384,10 +409,12 @@ static void xen_write_gdt_entry(struct d
 	}
 
 	}
+
+	preempt_enable();
 }
 
 static void xen_load_esp0(struct tss_struct *tss,
-				   struct thread_struct *thread)
+			  struct thread_struct *thread)
 {
 	struct multicall_space mcs = xen_mc_entry(0);
 	MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0);
@@ -493,6 +520,8 @@ static unsigned long xen_read_cr3(void)
 
 static void xen_write_cr3(unsigned long cr3)
 {
+	BUG_ON(preemptible());
+
 	if (cr3 == x86_read_percpu(xen_cr3)) {
 		/* just a simple tlb flush */
 		xen_flush_tlb();
===================================================================
--- a/arch/i386/xen/mmu.c
+++ b/arch/i386/xen/mmu.c
@@ -481,5 +481,7 @@ void xen_exit_mmap(struct mm_struct *mm)
 
 	preempt_enable();
 
+	spin_lock(&mm->page_table_lock);
 	xen_pgd_unpin(mm->pgd);
-}
+	spin_unlock(&mm->page_table_lock);
+}
===================================================================
--- a/arch/i386/xen/multicalls.c
+++ b/arch/i386/xen/multicalls.c
@@ -1,4 +1,5 @@
 #include <linux/percpu.h>
+#include <linux/hardirq.h>
 
 #include <asm/xen/hypercall.h>
 
@@ -18,9 +19,11 @@ DEFINE_PER_CPU(unsigned long, xen_mc_irq
 
 void xen_mc_flush(void)
 {
-	struct mc_buffer *b = &get_cpu_var(mc_buffer);
+	struct mc_buffer *b = &__get_cpu_var(mc_buffer);
 	int ret = 0;
 	unsigned long flags;
+
+	BUG_ON(preemptible());
 
 	/* Disable interrupts in case someone comes in and queues
 	   something in the middle */
@@ -39,7 +42,6 @@ void xen_mc_flush(void)
 	} else
 		BUG_ON(b->argidx != 0);
 
-	put_cpu_var(mc_buffer);
 	local_irq_restore(flags);
 
 	BUG_ON(ret);
@@ -47,10 +49,11 @@ void xen_mc_flush(void)
 
 struct multicall_space __xen_mc_entry(size_t args)
 {
-	struct mc_buffer *b = &get_cpu_var(mc_buffer);
+	struct mc_buffer *b = &__get_cpu_var(mc_buffer);
 	struct multicall_space ret;
 	unsigned argspace = (args + sizeof(u64) - 1) / sizeof(u64);
 
+	BUG_ON(preemptible());
 	BUG_ON(argspace > MC_ARGS);
 
 	if (b->mcidx == MC_BATCH ||
@@ -62,7 +65,5 @@ struct multicall_space __xen_mc_entry(si
 	ret.args = &b->args[b->argidx];
 	b->argidx += argspace;
 
-	put_cpu_var(mc_buffer);
-
 	return ret;
 }
===================================================================
--- a/arch/i386/xen/time.c
+++ b/arch/i386/xen/time.c
@@ -48,7 +48,7 @@ static void get_runstate_snapshot(struct
 	u64 state_time;
 	struct vcpu_runstate_info *state;
 
-	preempt_disable();
+	BUG_ON(preemptible());
 
 	state = &__get_cpu_var(runstate);
 
@@ -58,8 +58,6 @@ static void get_runstate_snapshot(struct
 		*res = *state;
 		barrier();
 	} while(state->state_entry_time != state_time);
-
-	preempt_enable();
 }
 
 static void setup_runstate_info(void)
@@ -128,15 +126,29 @@ unsigned long long xen_sched_clock(void)
 unsigned long long xen_sched_clock(void)
 {
 	struct vcpu_runstate_info state;
-	cycle_t now = xen_clocksource_read();
+	cycle_t now;
+	unsigned long long ret;
+
+	/*
+	 * Ideally sched_clock should be called on a per-cpu basis
+	 * anyway, so preempt should already be disabled, but that's
+	 * not current practice at the moment.
+	 */
+	preempt_disable();
+
+	now = xen_clocksource_read();
 
 	get_runstate_snapshot(&state);
 
 	WARN_ON(state.state != RUNSTATE_running);
 
-	return state.time[RUNSTATE_blocked] +
+	ret = state.time[RUNSTATE_blocked] +
 		state.time[RUNSTATE_running] +
 		(now - state.state_entry_time);
+
+	preempt_enable();
+
+	return ret;
 }
 
 

-- 

[PATCH 13/25] xen: xen: lazy-mmu operations

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-lazy-mmu.patch --]
[-- Type: text/plain, Size: 5098 bytes --]

This patch uses the lazy-mmu hooks to batch mmu operations where
possible.  This is primarily useful for batching operations applied to
active pagetables, which happens during mprotect, munmap, mremap and
the like (mmap does not do bulk pagetable operations, so it isn't
helped).

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/xen/enlighten.c  |   56 +++++++++++++++++++++++++++-----------------
 arch/i386/xen/mmu.c        |   56 ++++++++++++++++++++++++++++++++------------
 arch/i386/xen/multicalls.c |    4 +--
 3 files changed, 78 insertions(+), 38 deletions(-)

===================================================================
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -451,28 +451,38 @@ static void xen_apic_write(unsigned long
 
 static void xen_flush_tlb(void)
 {
-	struct mmuext_op op;
-
-	op.cmd = MMUEXT_TLB_FLUSH_LOCAL;
-	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
-		BUG();
+	struct mmuext_op *op;
+	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+	op = mcs.args;
+	op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
 }
 
 static void xen_flush_tlb_single(unsigned long addr)
 {
-	struct mmuext_op op;
-
-	op.cmd = MMUEXT_INVLPG_LOCAL;
-	op.arg1.linear_addr = addr & PAGE_MASK;
-	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
-		BUG();
+	struct mmuext_op *op;
+	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+	op = mcs.args;
+	op->cmd = MMUEXT_INVLPG_LOCAL;
+	op->arg1.linear_addr = addr & PAGE_MASK;
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
 }
 
 static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm,
 				 unsigned long va)
 {
-	struct mmuext_op op;
+	struct {
+		struct mmuext_op op;
+		cpumask_t mask;
+	} *args;
 	cpumask_t cpumask = *cpus;
+	struct multicall_space mcs;
 
 	/*
 	 * A couple of (to be removed) sanity checks:
@@ -489,17 +499,21 @@ static void xen_flush_tlb_others(const c
 	if (cpus_empty(cpumask))
 		return;
 
+	mcs = xen_mc_entry(sizeof(*args));
+	args = mcs.args;
+	args->mask = cpumask;
+	args->op.arg2.vcpumask = &args->mask;
+
 	if (va == TLB_FLUSH_ALL) {
-		op.cmd = MMUEXT_TLB_FLUSH_MULTI;
-		op.arg2.vcpumask = (void *)cpus;
+		args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
 	} else {
-		op.cmd = MMUEXT_INVLPG_MULTI;
-		op.arg1.linear_addr = va;
-		op.arg2.vcpumask = (void *)cpus;
-	}
-
-	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
-		BUG();
+		args->op.cmd = MMUEXT_INVLPG_MULTI;
+		args->op.arg1.linear_addr = va;
+	}
+
+	MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
 }
 
 static unsigned long xen_read_cr2(void)
===================================================================
--- a/arch/i386/xen/mmu.c
+++ b/arch/i386/xen/mmu.c
@@ -56,12 +56,20 @@ void make_lowmem_page_readwrite(void *va
 
 void xen_set_pmd(pmd_t *ptr, pmd_t val)
 {
-	struct mmu_update u;
-
-	u.ptr = virt_to_machine(ptr).maddr;
-	u.val = pmd_val_ma(val);
-	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
-		BUG();
+	struct multicall_space mcs;
+	struct mmu_update *u;
+
+	preempt_disable();
+
+	mcs = xen_mc_entry(sizeof(*u));
+	u = mcs.args;
+	u->ptr = virt_to_machine(ptr).maddr;
+	u->val = pmd_val_ma(val);
+	MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
 }
 
 /*
@@ -104,20 +112,38 @@ void xen_set_pte_at(struct mm_struct *mm
 void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
 		    pte_t *ptep, pte_t pteval)
 {
-	if ((mm != current->mm && mm != &init_mm) ||
-	    HYPERVISOR_update_va_mapping(addr, pteval, 0) != 0)
-		xen_set_pte(ptep, pteval);
+	if (mm == current->mm || mm == &init_mm) {
+		if (xen_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
+			struct multicall_space mcs;
+			mcs = xen_mc_entry(0);
+
+			MULTI_update_va_mapping(mcs.mc, addr, pteval, 0);
+			xen_mc_issue(PARAVIRT_LAZY_MMU);
+			return;
+		} else
+			if (HYPERVISOR_update_va_mapping(addr, pteval, 0) == 0)
+				return;
+	}
+	xen_set_pte(ptep, pteval);
 }
 
 #ifdef CONFIG_X86_PAE
 void xen_set_pud(pud_t *ptr, pud_t val)
 {
-	struct mmu_update u;
-
-	u.ptr = virt_to_machine(ptr).maddr;
-	u.val = pud_val_ma(val);
-	if (HYPERVISOR_mmu_update(&u, 1, NULL, DOMID_SELF) < 0)
-		BUG();
+	struct multicall_space mcs;
+	struct mmu_update *u;
+
+	preempt_disable();
+
+	mcs = xen_mc_entry(sizeof(*u));
+	u = mcs.args;
+	u->ptr = virt_to_machine(ptr).maddr;
+	u->val = pud_val_ma(val);
+	MULTI_mmu_update(mcs.mc, u, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_MMU);
+
+	preempt_enable();
 }
 
 void xen_set_pte(pte_t *ptep, pte_t pte)
===================================================================
--- a/arch/i386/xen/multicalls.c
+++ b/arch/i386/xen/multicalls.c
@@ -5,8 +5,8 @@
 
 #include "multicalls.h"
 
-#define MC_BATCH	8
-#define MC_ARGS		(MC_BATCH * 32 / sizeof(u64))
+#define MC_BATCH	32
+#define MC_ARGS		(MC_BATCH * 16 / sizeof(u64))
 
 struct mc_buffer {
 	struct multicall_entry entries[MC_BATCH];

-- 

[PATCH 14/25] xen: xen: deal with negative stolen time

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-signed-time.patch --]
[-- Type: text/plain, Size: 2009 bytes --]

Stolen time should never be negative; if it ever is, it probably
indicates some other bug.  However, if it does happen, then its better
to just clamp it at zero, rather than trying to account for it as a
huge positive number.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/xen/time.c |   19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

===================================================================
--- a/arch/i386/xen/time.c
+++ b/arch/i386/xen/time.c
@@ -77,7 +77,7 @@ static void do_stolen_accounting(void)
 {
 	struct vcpu_runstate_info state;
 	struct vcpu_runstate_info *snap;
-	u64 blocked, runnable, offline, stolen;
+	s64 blocked, runnable, offline, stolen;
 	cputime_t ticks;
 
 	get_runstate_snapshot(&state);
@@ -97,6 +97,10 @@ static void do_stolen_accounting(void)
 	   including any left-overs from last time.  Passing NULL to
 	   account_steal_time accounts the time as stolen. */
 	stolen = runnable + offline + __get_cpu_var(residual_stolen);
+
+	if (stolen < 0)
+		stolen = 0;
+
 	ticks = 0;
 	while(stolen >= NS_PER_TICK) {
 		ticks++;
@@ -109,6 +113,10 @@ static void do_stolen_accounting(void)
 	   including any left-overs from last time.  Passing idle to
 	   account_steal_time accounts the time as idle/wait. */
 	blocked += __get_cpu_var(residual_blocked);
+
+	if (blocked < 0)
+		blocked = 0;
+
 	ticks = 0;
 	while(blocked >= NS_PER_TICK) {
 		ticks++;
@@ -127,7 +135,8 @@ unsigned long long xen_sched_clock(void)
 {
 	struct vcpu_runstate_info state;
 	cycle_t now;
-	unsigned long long ret;
+	u64 ret;
+	s64 offset;
 
 	/*
 	 * Ideally sched_clock should be called on a per-cpu basis
@@ -142,9 +151,13 @@ unsigned long long xen_sched_clock(void)
 
 	WARN_ON(state.state != RUNSTATE_running);
 
+	offset = now - state.state_entry_time;
+	if (offset < 0)
+		offset = 0;
+
 	ret = state.time[RUNSTATE_blocked] +
 		state.time[RUNSTATE_running] +
-		(now - state.state_entry_time);
+		offset;
 
 	preempt_enable();
 

-- 

[PATCH 15/25] xen: xen time fixups

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-time-fixups.patch --]
[-- Type: text/plain, Size: 5808 bytes --]

1. make sure timer state is set up before bringing up CPU
2. make sure snapshot of 64-bit time values is atomic

Be sure, however, that the clockevent source is registered on its home
CPU.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/xen/smp.c     |    4 +-
 arch/i386/xen/time.c    |   93 +++++++++++++++++++++++++++++++----------------
 arch/i386/xen/xen-ops.h |    3 +
 3 files changed, 67 insertions(+), 33 deletions(-)

===================================================================
--- a/arch/i386/xen/smp.c
+++ b/arch/i386/xen/smp.c
@@ -78,10 +78,11 @@ static __cpuinit void cpu_bringup_and_id
 	int cpu = smp_processor_id();
 
 	cpu_init();
-	xen_setup_timer();
 
 	preempt_disable();
 	per_cpu(cpu_state, cpu) = CPU_ONLINE;
+
+	xen_setup_cpu_clockevents();
 
 	/* We can take interrupts now: we're officially "up". */
 	local_irq_enable();
@@ -275,6 +276,7 @@ int __cpuinit xen_cpu_up(unsigned int cp
 	per_cpu(current_task, cpu) = idle;
 	xen_vcpu_setup(cpu);
 	irq_ctx_init(cpu);
+	xen_setup_timer(cpu);
 
 	/* make sure interrupts start blocked */
 	per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
===================================================================
--- a/arch/i386/xen/time.c
+++ b/arch/i386/xen/time.c
@@ -40,6 +40,35 @@ static DEFINE_PER_CPU(u64, residual_stol
 static DEFINE_PER_CPU(u64, residual_stolen);
 static DEFINE_PER_CPU(u64, residual_blocked);
 
+/* return an consistent snapshot of 64-bit time/counter value */
+static u64 get64(const u64 *p)
+{
+	u64 ret;
+
+	if (BITS_PER_LONG < 64) {
+		u32 *p32 = (u32 *)p;
+		u32 h, l;
+
+		/*
+		 * Read high then low, and then make sure high is
+		 * still the same; this will only loop if low wraps
+		 * and carries into high.
+		 * XXX some clean way to make this endian-proof?
+		 */
+		do {
+			h = p32[1];
+			barrier();
+			l = p32[0];
+			barrier();
+		} while (p32[1] != h);
+
+		ret = (((u64)h) << 32) | l;
+	} else
+		ret = *p;
+
+	return ret;
+}
+
 /*
  * Runstate accounting
  */
@@ -53,24 +82,22 @@ static void get_runstate_snapshot(struct
 	state = &__get_cpu_var(runstate);
 
 	do {
-		state_time = state->state_entry_time;
+		state_time = get64(&state->state_entry_time);
 		barrier();
 		*res = *state;
 		barrier();
-	} while(state->state_entry_time != state_time);
-}
-
-static void setup_runstate_info(void)
+	} while(get64(&state->state_entry_time) != state_time);
+}
+
+static void setup_runstate_info(int cpu)
 {
 	struct vcpu_register_runstate_memory_area area;
 
-	area.addr.v = &__get_cpu_var(runstate);
+	area.addr.v = &per_cpu(runstate, cpu);
 
 	if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area,
-			       smp_processor_id(), &area))
+			       cpu, &area))
 		BUG();
-
-	get_runstate_snapshot(&__get_cpu_var(runstate_snapshot));
 }
 
 static void do_stolen_accounting(void)
@@ -185,12 +212,10 @@ unsigned long xen_cpu_khz(void)
  * Reads a consistent set of time-base values from Xen, into a shadow data
  * area.
  */
-static void get_time_values_from_xen(void)
+static unsigned get_time_values_from_xen(void)
 {
 	struct vcpu_time_info   *src;
 	struct shadow_time_info *dst;
-
-	preempt_disable();
 
 	src = &__get_cpu_var(xen_vcpu)->time;
 	dst = &__get_cpu_var(shadow_time);
@@ -205,7 +230,7 @@ static void get_time_values_from_xen(voi
 		rmb();
 	} while ((src->version & 1) | (dst->version ^ src->version));
 
-	preempt_enable();
+	return dst->version;
 }
 
 /*
@@ -249,7 +274,7 @@ static u64 get_nsec_offset(struct shadow
 static u64 get_nsec_offset(struct shadow_time_info *shadow)
 {
 	u64 now, delta;
-	rdtscll(now);
+	now = native_read_tsc();
 	delta = now - shadow->tsc_timestamp;
 	return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift);
 }
@@ -258,10 +283,14 @@ static cycle_t xen_clocksource_read(void
 {
 	struct shadow_time_info *shadow = &get_cpu_var(shadow_time);
 	cycle_t ret;
-
-	get_time_values_from_xen();
-
-	ret = shadow->system_timestamp + get_nsec_offset(shadow);
+	unsigned version;
+
+	do {
+		version = get_time_values_from_xen();
+		barrier();
+		ret = shadow->system_timestamp + get_nsec_offset(shadow);
+		barrier();
+	} while(version != __get_cpu_var(xen_vcpu)->time.version);
 
 	put_cpu_var(shadow_time);
 
@@ -483,9 +512,8 @@ static irqreturn_t xen_timer_interrupt(i
 	return ret;
 }
 
-void xen_setup_timer(void)
-{
-	int cpu = smp_processor_id();
+void xen_setup_timer(int cpu)
+{
 	const char *name;
 	struct clock_event_device *evt;
 	int irq;
@@ -500,23 +528,25 @@ void xen_setup_timer(void)
 				      IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
 				      name, NULL);
 
-	evt = &get_cpu_var(xen_clock_events);
+	evt = &per_cpu(xen_clock_events, cpu);
 	memcpy(evt, xen_clockevent, sizeof(*evt));
 
 	evt->cpumask = cpumask_of_cpu(cpu);
 	evt->irq = irq;
-	clockevents_register_device(evt);
-
-	setup_runstate_info();
-
-	put_cpu_var(xen_clock_events);
+
+	setup_runstate_info(cpu);
+}
+
+void xen_setup_cpu_clockevents(void)
+{
+	BUG_ON(preemptible());
+
+	clockevents_register_device(&__get_cpu_var(xen_clock_events));
 }
 
 __init void xen_time_init(void)
 {
 	int cpu = smp_processor_id();
-
-	get_time_values_from_xen();
 
 	clocksource_register(&xen_clocksource);
 
@@ -534,5 +564,6 @@ __init void xen_time_init(void)
 
 	tsc_disable = 0;
 
-	xen_setup_timer();
-}
+	xen_setup_timer(cpu);
+	xen_setup_cpu_clockevents();
+}
===================================================================
--- a/arch/i386/xen/xen-ops.h
+++ b/arch/i386/xen/xen-ops.h
@@ -25,7 +25,8 @@ unsigned long xen_get_wallclock(void);
 unsigned long xen_get_wallclock(void);
 int xen_set_wallclock(unsigned long time);
 unsigned long long xen_sched_clock(void);
-void xen_setup_timer(void);
+void xen_setup_timer(int cpu);
+void xen_setup_cpu_clockevents(void);
 
 void xen_mark_init_mm_pinned(void);
 

-- 

[PATCH 16/25] xen: Use the hvc console infrastructure for Xen console

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-hvc-console.patch --]
[-- Type: text/plain, Size: 5647 bytes --]

Implement a Xen back-end for hvc console.

From: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/xen/Kconfig     |    1 
 arch/i386/xen/events.c    |    3 -
 drivers/Makefile          |    3 +
 drivers/xen/Makefile      |    1 
 drivers/xen/hvc-console.c |  134 +++++++++++++++++++++++++++++++++++++++++++++
 include/xen/events.h      |    1 
 6 files changed, 142 insertions(+), 1 deletion(-)

===================================================================
--- a/arch/i386/xen/Kconfig
+++ b/arch/i386/xen/Kconfig
@@ -5,6 +5,7 @@ config XEN
 config XEN
 	bool "Enable support for Xen hypervisor"
 	depends on PARAVIRT
+	select HVC_DRIVER
 	default y
 	help
 	  This is the Linux Xen port.
===================================================================
--- a/arch/i386/xen/events.c
+++ b/arch/i386/xen/events.c
@@ -219,7 +219,7 @@ static int find_unbound_irq(void)
 	return irq;
 }
 
-static int bind_evtchn_to_irq(unsigned int evtchn)
+int bind_evtchn_to_irq(unsigned int evtchn)
 {
 	int irq;
 
@@ -244,6 +244,7 @@ static int bind_evtchn_to_irq(unsigned i
 
 	return irq;
 }
+EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
 
 static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
 {
===================================================================
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -14,6 +14,9 @@ obj-$(CONFIG_ACPI)		+= acpi/
 # was used and do nothing if so
 obj-$(CONFIG_PNP)		+= pnp/
 obj-$(CONFIG_ARM_AMBA)		+= amba/
+
+# Xen is the default console when running as a guest
+obj-$(CONFIG_XEN)		+= xen/
 
 # char/ comes before serial/ etc so that the VT console is the boot-time
 # default.
===================================================================
--- /dev/null
+++ b/drivers/xen/Makefile
@@ -0,0 +1,1 @@
+obj-y	+= hvc-console.o
===================================================================
--- /dev/null
+++ b/drivers/xen/hvc-console.c
@@ -0,0 +1,134 @@
+/*
+ * xen console driver interface to hvc_console.c
+ *
+ * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/types.h>
+
+#include <asm/xen/hypervisor.h>
+#include <xen/page.h>
+#include <xen/events.h>
+#include <xen/interface/io/console.h>
+
+#include "../char/hvc_console.h"
+
+#define HVC_COOKIE   0x58656e /* "Xen" in hex */
+
+static struct hvc_struct *hvc;
+static int xencons_irq;
+
+/* ------------------------------------------------------------------ */
+
+static inline struct xencons_interface *xencons_interface(void)
+{
+	return mfn_to_virt(xen_start_info->console.domU.mfn);
+}
+
+static inline void notify_daemon(void)
+{
+	/* Use evtchn: this is called early, before irq is set up. */
+	notify_remote_via_evtchn(xen_start_info->console.domU.evtchn);
+}
+
+static int write_console(uint32_t vtermno, const char *data, int len)
+{
+	struct xencons_interface *intf = xencons_interface();
+	XENCONS_RING_IDX cons, prod;
+	int sent = 0;
+
+	cons = intf->out_cons;
+	prod = intf->out_prod;
+	mb();
+	BUG_ON((prod - cons) > sizeof(intf->out));
+
+	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
+		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
+
+	wmb();
+	intf->out_prod = prod;
+
+	notify_daemon();
+	return sent;
+}
+
+static int read_console(uint32_t vtermno, char *buf, int len)
+{
+	struct xencons_interface *intf = xencons_interface();
+	XENCONS_RING_IDX cons, prod;
+	int recv = 0;
+
+	cons = intf->in_cons;
+	prod = intf->in_prod;
+	mb();
+	BUG_ON((prod - cons) > sizeof(intf->in));
+
+	while (cons != prod && recv < len)
+		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++,intf->in)];
+
+	mb();
+	intf->in_cons = cons;
+
+	notify_daemon();
+	return recv;
+}
+
+static struct hv_ops hvc_ops = {
+	.get_chars = read_console,
+	.put_chars = write_console,
+};
+
+static int __init xen_init(void)
+{
+	struct hvc_struct *hp;
+
+	if (!is_running_on_xen())
+		return 0;
+
+	xencons_irq = bind_evtchn_to_irq(xen_start_info->console.domU.evtchn);
+	if (xencons_irq < 0)
+		xencons_irq = 0 /* NO_IRQ */;
+	hp = hvc_alloc(HVC_COOKIE, xencons_irq, &hvc_ops, 256);
+	if (IS_ERR(hp))
+		return PTR_ERR(hp);
+
+	hvc = hp;
+	return 0;
+}
+
+static void __exit xen_fini(void)
+{
+	if (hvc)
+		hvc_remove(hvc);
+}
+
+static int xen_cons_init(void)
+{
+	if (!is_running_on_xen())
+		return 0;
+
+	hvc_instantiate(HVC_COOKIE, 0, &hvc_ops);
+	return 0;
+}
+
+module_init(xen_init);
+module_exit(xen_fini);
+console_initcall(xen_cons_init);
===================================================================
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -13,6 +13,7 @@ enum ipi_vector {
 	XEN_NR_IPIS,
 };
 
+int bind_evtchn_to_irq(unsigned int evtchn);
 int bind_evtchn_to_irqhandler(unsigned int evtchn,
 			      irq_handler_t handler,
 			      unsigned long irqflags, const char *devname,

-- 

Re: [PATCH 16/25] xen: Use the hvc console infrastructure for Xen console

[Olof Johansson]

On Mon, Apr 23, 2007 at 02:56:54PM -0700, Jeremy Fitzhardinge wrote:
> Implement a Xen back-end for hvc console.
> 
> From: Gerd Hoffmann <kraxel@suse.de>
> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
> 
> ---
>  arch/i386/xen/Kconfig     |    1 
>  arch/i386/xen/events.c    |    3 -
>  drivers/Makefile          |    3 +
>  drivers/xen/Makefile      |    1 
>  drivers/xen/hvc-console.c |  134 +++++++++++++++++++++++++++++++++++++++++++++
>  include/xen/events.h      |    1 
>  6 files changed, 142 insertions(+), 1 deletion(-)

If you move the driver to drivers/char/hvc_xen.c instead, you won't have to do...

> +#include "../char/hvc_console.h"

...this.

Other single-platform backend hvc drivers are under drivers/char already.


-Olof

Re: [PATCH 16/25] xen: Use the hvc console infrastructure for Xen console

[Jeremy Fitzhardinge]

Olof Johansson wrote:
> On Mon, Apr 23, 2007 at 02:56:54PM -0700, Jeremy Fitzhardinge wrote:
>   
>> Implement a Xen back-end for hvc console.
>>
>> From: Gerd Hoffmann <kraxel@suse.de>
>> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
>>
>> ---
>>  arch/i386/xen/Kconfig     |    1 
>>  arch/i386/xen/events.c    |    3 -
>>  drivers/Makefile          |    3 +
>>  drivers/xen/Makefile      |    1 
>>  drivers/xen/hvc-console.c |  134 +++++++++++++++++++++++++++++++++++++++++++++
>>  include/xen/events.h      |    1 
>>  6 files changed, 142 insertions(+), 1 deletion(-)
>>     
>
> If you move the driver to drivers/char/hvc_xen.c instead, you won't have to do...
>
>   
>> +#include "../char/hvc_console.h"
>>     
>
> ...this.
>
> Other single-platform backend hvc drivers are under drivers/char already.

Good point.

    J

[PATCH 17/25] xen: Add early printk support via hvc console

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-hvc-earlyprintk.patch --]
[-- Type: text/plain, Size: 2330 bytes --]

Add early printk support via hvc console, enable using
"earlyprintk=xen" on the kernel command line.

From: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Acked-by: Ingo Molnar <mingo@elte.hu>

---
 arch/x86_64/kernel/early_printk.c |    5 +++++
 drivers/xen/hvc-console.c         |   25 +++++++++++++++++++++++++
 include/xen/hvc-console.h         |    6 ++++++
 3 files changed, 36 insertions(+)

===================================================================
--- a/arch/x86_64/kernel/early_printk.c
+++ b/arch/x86_64/kernel/early_printk.c
@@ -6,6 +6,7 @@
 #include <asm/io.h>
 #include <asm/processor.h>
 #include <asm/fcntl.h>
+#include <xen/hvc-console.h>
 
 /* Simple VGA output */
 
@@ -243,6 +244,10 @@ static int __init setup_early_printk(cha
  		simnow_init(buf + 6);
  		early_console = &simnow_console;
  		keep_early = 1;
+#ifdef CONFIG_XEN
+	} else if (!strncmp(buf, "xen", 3)) {
+ 		early_console = &xenboot_console;
+#endif
 	}
 	register_console(early_console);
 	return 0;
===================================================================
--- a/drivers/xen/hvc-console.c
+++ b/drivers/xen/hvc-console.c
@@ -28,6 +28,7 @@
 #include <xen/page.h>
 #include <xen/events.h>
 #include <xen/interface/io/console.h>
+#include <xen/hvc-console.h>
 
 #include "../char/hvc_console.h"
 
@@ -132,3 +133,27 @@ module_init(xen_init);
 module_init(xen_init);
 module_exit(xen_fini);
 console_initcall(xen_cons_init);
+
+static void xenboot_write_console(struct console *console, const char *string,
+				  unsigned len)
+{
+	unsigned int linelen, off = 0;
+	const char *pos;
+
+	while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
+		linelen = pos-string+off;
+		if (off + linelen > len)
+			break;
+		write_console(0, string+off, linelen);
+		write_console(0, "\r\n", 2);
+		off += linelen + 1;
+	}
+	if (off < len)
+		write_console(0, string+off, len-off);
+}
+
+struct console xenboot_console = {
+	.name		= "xenboot",
+	.write		= xenboot_write_console,
+	.flags		= CON_PRINTBUFFER | CON_BOOT,
+};
===================================================================
--- /dev/null
+++ b/include/xen/hvc-console.h
@@ -0,0 +1,6 @@
+#ifndef XEN_HVC_CONSOLE_H
+#define XEN_HVC_CONSOLE_H
+
+extern struct console xenboot_console;
+
+#endif	/* XEN_HVC_CONSOLE_H */

-- 

[PATCH 18/25] xen: Add Xen grant table support

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-grant-table.patch --]
[-- Type: text/plain, Size: 29298 bytes --]

Add Xen 'grant table' driver which allows granting of access to
selected local memory pages by other virtual machines and,
symmetrically, the mapping of remote memory pages which other virtual
machines have granted access to.

This driver is a prerequisite for many of the Xen virtual device
drivers, which grant the 'device driver domain' restricted and
temporary access to only those memory pages that are currently
involved in I/O operations.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
 drivers/xen/Makefile                |    1 
 drivers/xen/grant-table.c           |  576 +++++++++++++++++++++++++++++++++++
 include/xen/grant_table.h           |  107 ++++++
 include/xen/interface/grant_table.h |  112 +++++-
 4 files changed, 777 insertions(+), 19 deletions(-)

===================================================================
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -1,1 +1,2 @@ obj-y	+= hvc-console.o
+obj-y	+= grant-table.o
 obj-y	+= hvc-console.o
===================================================================
--- /dev/null
+++ b/drivers/xen/grant-table.c
@@ -0,0 +1,576 @@
+/******************************************************************************
+ * grant_table.c
+ *
+ * Granting foreign access to our memory reservation.
+ *
+ * Copyright (c) 2005-2006, Christopher Clark
+ * Copyright (c) 2004-2005, K A Fraser
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+
+#include <xen/interface/xen.h>
+#include <xen/page.h>
+#include <xen/grant_table.h>
+
+#include <asm/pgtable.h>
+#include <asm/uaccess.h>
+#include <asm/sync_bitops.h>
+
+
+/* External tools reserve first few grant table entries. */
+#define NR_RESERVED_ENTRIES 8
+#define GNTTAB_LIST_END 0xffffffff
+#define GREFS_PER_GRANT_FRAME (PAGE_SIZE / sizeof(struct grant_entry))
+
+static grant_ref_t **gnttab_list;
+static unsigned int nr_grant_frames;
+static unsigned int boot_max_nr_grant_frames;
+static int gnttab_free_count;
+static grant_ref_t gnttab_free_head;
+static DEFINE_SPINLOCK(gnttab_list_lock);
+
+static struct grant_entry *shared;
+
+static struct gnttab_free_callback *gnttab_free_callback_list;
+
+static int gnttab_expand(unsigned int req_entries);
+
+#define RPP (PAGE_SIZE / sizeof(grant_ref_t))
+#define gnttab_entry(entry) (gnttab_list[(entry) / RPP][(entry) % RPP])
+
+static int get_free_entries(int count)
+{
+	unsigned long flags;
+	int ref, rc;
+	grant_ref_t head;
+
+	spin_lock_irqsave(&gnttab_list_lock, flags);
+
+	if ((gnttab_free_count < count) &&
+	    ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) {
+		spin_unlock_irqrestore(&gnttab_list_lock, flags);
+		return rc;
+	}
+
+	ref = head = gnttab_free_head;
+	gnttab_free_count -= count;
+	while (count-- > 1)
+		head = gnttab_entry(head);
+ 	gnttab_free_head = gnttab_entry(head);
+	gnttab_entry(head) = GNTTAB_LIST_END;
+
+	spin_unlock_irqrestore(&gnttab_list_lock, flags);
+
+	return ref;
+}
+
+#define get_free_entry() get_free_entries(1)
+
+static void do_free_callbacks(void)
+{
+	struct gnttab_free_callback *callback, *next;
+
+	callback = gnttab_free_callback_list;
+	gnttab_free_callback_list = NULL;
+
+	while (callback != NULL) {
+		next = callback->next;
+		if (gnttab_free_count >= callback->count) {
+			callback->next = NULL;
+			callback->fn(callback->arg);
+		} else {
+			callback->next = gnttab_free_callback_list;
+			gnttab_free_callback_list = callback;
+		}
+		callback = next;
+	}
+}
+
+static inline void check_free_callbacks(void)
+{
+	if (unlikely(gnttab_free_callback_list))
+		do_free_callbacks();
+}
+
+static void put_free_entry(grant_ref_t ref)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&gnttab_list_lock, flags);
+	gnttab_entry(ref) = gnttab_free_head;
+	gnttab_free_head = ref;
+	gnttab_free_count++;
+	check_free_callbacks();
+	spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+
+static void update_grant_entry(grant_ref_t ref, domid_t domid,
+			       unsigned long frame, unsigned flags)
+{
+	/*
+	 * Introducing a valid entry into the grant table:
+	 *  1. Write ent->domid.
+	 *  2. Write ent->frame:
+	 *      GTF_permit_access:   Frame to which access is permitted.
+	 *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new
+	 *                           frame, or zero if none.
+	 *  3. Write memory barrier (WMB).
+	 *  4. Write ent->flags, inc. valid type.
+	 */
+	shared[ref].frame = frame;
+	shared[ref].domid = domid;
+	wmb();
+	shared[ref].flags = flags;
+}
+
+/*
+ * Public grant-issuing interface functions
+ */
+void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
+				     unsigned long frame, int readonly)
+{
+	update_grant_entry(ref, domid, frame,
+			   GTF_permit_access | (readonly ? GTF_readonly : 0));
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref);
+
+int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
+				int readonly)
+{
+	int ref;
+
+	if (unlikely((ref = get_free_entry()) < 0))
+		return -ENOSPC;
+
+	gnttab_grant_foreign_access_ref(ref, domid, frame, readonly);
+
+	return ref;
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
+
+int gnttab_query_foreign_access(grant_ref_t ref)
+{
+	u16 nflags;
+
+	nflags = shared[ref].flags;
+
+	return (nflags & (GTF_reading|GTF_writing));
+}
+EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
+
+int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly)
+{
+	u16 flags, nflags;
+
+	nflags = shared[ref].flags;
+	do {
+		if ((flags = nflags) & (GTF_reading|GTF_writing)) {
+			printk(KERN_ALERT "WARNING: g.e. still in use!\n");
+			return 0;
+		}
+	} while ((nflags = sync_cmpxchg(&shared[ref].flags, flags, 0)) !=
+		 flags);
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref);
+
+void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
+			       unsigned long page)
+{
+	if (gnttab_end_foreign_access_ref(ref, readonly)) {
+		put_free_entry(ref);
+		if (page != 0)
+			free_page(page);
+	} else {
+		/* XXX This needs to be fixed so that the ref and page are
+		   placed on a list to be freed up later. */
+		printk(KERN_WARNING
+		       "WARNING: leaking g.e. and page still in use!\n");
+	}
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);
+
+int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)
+{
+	int ref;
+
+	if (unlikely((ref = get_free_entry()) < 0))
+		return -ENOSPC;
+	gnttab_grant_foreign_transfer_ref(ref, domid, pfn);
+
+	return ref;
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);
+
+void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,
+				       unsigned long pfn)
+{
+	update_grant_entry(ref, domid, pfn, GTF_accept_transfer);
+}
+EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);
+
+unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)
+{
+	unsigned long frame;
+	u16           flags;
+
+	/*
+	 * If a transfer is not even yet started, try to reclaim the grant
+	 * reference and return failure (== 0).
+	 */
+	while (!((flags = shared[ref].flags) & GTF_transfer_committed)) {
+		if (sync_cmpxchg(&shared[ref].flags, flags, 0) == flags)
+			return 0;
+		cpu_relax();
+	}
+
+	/* If a transfer is in progress then wait until it is completed. */
+	while (!(flags & GTF_transfer_completed)) {
+		flags = shared[ref].flags;
+		cpu_relax();
+	}
+
+	rmb();	/* Read the frame number /after/ reading completion status. */
+	frame = shared[ref].frame;
+	BUG_ON(frame == 0);
+
+	return frame;
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);
+
+unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)
+{
+	unsigned long frame = gnttab_end_foreign_transfer_ref(ref);
+	put_free_entry(ref);
+	return frame;
+}
+EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);
+
+void gnttab_free_grant_reference(grant_ref_t ref)
+{
+	put_free_entry(ref);
+}
+EXPORT_SYMBOL_GPL(gnttab_free_grant_reference);
+
+void gnttab_free_grant_references(grant_ref_t head)
+{
+	grant_ref_t ref;
+	unsigned long flags;
+	int count = 1;
+	if (head == GNTTAB_LIST_END)
+		return;
+	spin_lock_irqsave(&gnttab_list_lock, flags);
+	ref = head;
+	while (gnttab_entry(ref) != GNTTAB_LIST_END) {
+		ref = gnttab_entry(ref);
+		count++;
+	}
+	gnttab_entry(ref) = gnttab_free_head;
+	gnttab_free_head = head;
+	gnttab_free_count += count;
+	check_free_callbacks();
+	spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gnttab_free_grant_references);
+
+int gnttab_alloc_grant_references(u16 count, grant_ref_t *head)
+{
+	int h = get_free_entries(count);
+
+	if (h < 0)
+		return -ENOSPC;
+
+	*head = h;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references);
+
+int gnttab_empty_grant_references(const grant_ref_t *private_head)
+{
+	return (*private_head == GNTTAB_LIST_END);
+}
+EXPORT_SYMBOL_GPL(gnttab_empty_grant_references);
+
+int gnttab_claim_grant_reference(grant_ref_t *private_head)
+{
+	grant_ref_t g = *private_head;
+	if (unlikely(g == GNTTAB_LIST_END))
+		return -ENOSPC;
+	*private_head = gnttab_entry(g);
+	return g;
+}
+EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference);
+
+void gnttab_release_grant_reference(grant_ref_t *private_head,
+				    grant_ref_t release)
+{
+	gnttab_entry(release) = *private_head;
+	*private_head = release;
+}
+EXPORT_SYMBOL_GPL(gnttab_release_grant_reference);
+
+void gnttab_request_free_callback(struct gnttab_free_callback *callback,
+				  void (*fn)(void *), void *arg, u16 count)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&gnttab_list_lock, flags);
+	if (callback->next)
+		goto out;
+	callback->fn = fn;
+	callback->arg = arg;
+	callback->count = count;
+	callback->next = gnttab_free_callback_list;
+	gnttab_free_callback_list = callback;
+	check_free_callbacks();
+out:
+	spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gnttab_request_free_callback);
+
+void gnttab_cancel_free_callback(struct gnttab_free_callback *callback)
+{
+	struct gnttab_free_callback **pcb;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gnttab_list_lock, flags);
+	for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) {
+		if (*pcb == callback) {
+			*pcb = callback->next;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&gnttab_list_lock, flags);
+}
+EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback);
+
+static int grow_gnttab_list(unsigned int more_frames)
+{
+	unsigned int new_nr_grant_frames, extra_entries, i;
+
+	new_nr_grant_frames = nr_grant_frames + more_frames;
+	extra_entries       = more_frames * GREFS_PER_GRANT_FRAME;
+
+	for (i = nr_grant_frames; i < new_nr_grant_frames; i++)
+	{
+		gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC);
+		if (!gnttab_list[i])
+			goto grow_nomem;
+	}
+
+
+	for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames;
+	     i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++)
+		gnttab_entry(i) = i + 1;
+
+	gnttab_entry(i) = gnttab_free_head;
+	gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames;
+	gnttab_free_count += extra_entries;
+
+	nr_grant_frames = new_nr_grant_frames;
+
+	check_free_callbacks();
+
+	return 0;
+
+grow_nomem:
+	for ( ; i >= nr_grant_frames; i--)
+		free_page((unsigned long) gnttab_list[i]);
+	return -ENOMEM;
+}
+
+static unsigned int __max_nr_grant_frames(void)
+{
+	struct gnttab_query_size query;
+	int rc;
+
+	query.dom = DOMID_SELF;
+
+	rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1);
+	if ((rc < 0) || (query.status != GNTST_okay))
+		return 4; /* Legacy max supported number of frames */
+
+	return query.max_nr_frames;
+}
+
+static inline unsigned int max_nr_grant_frames(void)
+{
+	unsigned int xen_max = __max_nr_grant_frames();
+
+	if (xen_max > boot_max_nr_grant_frames)
+		return boot_max_nr_grant_frames;
+	return xen_max;
+}
+
+static int map_pte_fn(pte_t *pte, struct page *pmd_page,
+		      unsigned long addr, void *data)
+{
+	unsigned long **frames = (unsigned long **)data;
+
+	set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL));
+	(*frames)++;
+	return 0;
+}
+
+static int unmap_pte_fn(pte_t *pte, struct page *pmd_page,
+			unsigned long addr, void *data)
+{
+
+	set_pte_at(&init_mm, addr, pte, __pte(0));
+	return 0;
+}
+
+static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
+{
+	struct gnttab_setup_table setup;
+	unsigned long *frames;
+	unsigned int nr_gframes = end_idx + 1;
+	int rc;
+
+	frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC);
+	if (!frames)
+		return -ENOMEM;
+
+	setup.dom        = DOMID_SELF;
+	setup.nr_frames  = nr_gframes;
+	setup.frame_list = frames;
+
+	rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1);
+	if (rc == -ENOSYS) {
+		kfree(frames);
+		return -ENOSYS;
+	}
+
+	BUG_ON(rc || setup.status);
+
+	if (shared == NULL) {
+		struct vm_struct *area;
+		area = alloc_vm_area(PAGE_SIZE * max_nr_grant_frames());
+		BUG_ON(area == NULL);
+		shared = area->addr;
+	}
+	rc = apply_to_page_range(&init_mm, (unsigned long)shared,
+				 PAGE_SIZE * nr_gframes,
+				 map_pte_fn, &frames);
+	BUG_ON(rc);
+	frames -= nr_gframes; /* adjust after map_pte_fn() */
+
+	kfree(frames);
+
+	return 0;
+}
+
+int gnttab_resume(void)
+{
+	if (max_nr_grant_frames() < nr_grant_frames)
+		return -ENOSYS;
+	return gnttab_map(0, nr_grant_frames - 1);
+}
+
+int gnttab_suspend(void)
+{
+	apply_to_page_range(&init_mm, (unsigned long)shared,
+			    PAGE_SIZE * nr_grant_frames,
+			    unmap_pte_fn, NULL);
+
+	return 0;
+}
+
+static int gnttab_expand(unsigned int req_entries)
+{
+	int rc;
+	unsigned int cur, extra;
+
+	cur = nr_grant_frames;
+	extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) /
+		 GREFS_PER_GRANT_FRAME);
+	if (cur + extra > max_nr_grant_frames())
+		return -ENOSPC;
+
+	if ((rc = gnttab_map(cur, cur + extra - 1)) == 0)
+		rc = grow_gnttab_list(extra);
+
+	return rc;
+}
+
+static int __devinit gnttab_init(void)
+{
+	int i;
+	unsigned int max_nr_glist_frames;
+	unsigned int nr_init_grefs;
+
+	if (!is_running_on_xen())
+		return -ENODEV;
+
+	nr_grant_frames = 1;
+	boot_max_nr_grant_frames = __max_nr_grant_frames();
+
+	/* Determine the maximum number of frames required for the
+	 * grant reference free list on the current hypervisor.
+	 */
+	max_nr_glist_frames = (boot_max_nr_grant_frames *
+			       GREFS_PER_GRANT_FRAME /
+			       (PAGE_SIZE / sizeof(grant_ref_t)));
+
+	gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *),
+			      GFP_KERNEL);
+	if (gnttab_list == NULL)
+		return -ENOMEM;
+
+	for (i = 0; i < nr_grant_frames; i++) {
+		gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL);
+		if (gnttab_list[i] == NULL)
+			goto ini_nomem;
+	}
+
+	if (gnttab_resume() < 0)
+		return -ENODEV;
+
+	nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME;
+
+	for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++)
+		gnttab_entry(i) = i + 1;
+
+	gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END;
+	gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES;
+	gnttab_free_head  = NR_RESERVED_ENTRIES;
+
+	printk("Grant table initialized\n");
+	return 0;
+
+ ini_nomem:
+	for (i--; i >= 0; i--)
+		free_page((unsigned long)gnttab_list[i]);
+	kfree(gnttab_list);
+	return -ENOMEM;
+}
+
+core_initcall(gnttab_init);
===================================================================
--- /dev/null
+++ b/include/xen/grant_table.h
@@ -0,0 +1,107 @@
+/******************************************************************************
+ * grant_table.h
+ *
+ * Two sets of functionality:
+ * 1. Granting foreign access to our memory reservation.
+ * 2. Accessing others' memory reservations via grant references.
+ * (i.e., mechanisms for both sender and recipient of grant references)
+ *
+ * Copyright (c) 2004-2005, K A Fraser
+ * Copyright (c) 2005, Christopher Clark
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __ASM_GNTTAB_H__
+#define __ASM_GNTTAB_H__
+
+#include <asm/xen/hypervisor.h>
+#include <xen/interface/grant_table.h>
+
+/* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
+#define NR_GRANT_FRAMES 4
+
+struct gnttab_free_callback {
+	struct gnttab_free_callback *next;
+	void (*fn)(void *);
+	void *arg;
+	u16 count;
+};
+
+int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
+				int readonly);
+
+/*
+ * End access through the given grant reference, iff the grant entry is no
+ * longer in use.  Return 1 if the grant entry was freed, 0 if it is still in
+ * use.
+ */
+int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly);
+
+/*
+ * Eventually end access through the given grant reference, and once that
+ * access has been ended, free the given page too.  Access will be ended
+ * immediately iff the grant entry is not in use, otherwise it will happen
+ * some time later.  page may be 0, in which case no freeing will occur.
+ */
+void gnttab_end_foreign_access(grant_ref_t ref, int readonly,
+			       unsigned long page);
+
+int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);
+
+unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);
+unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);
+
+int gnttab_query_foreign_access(grant_ref_t ref);
+
+/*
+ * operations on reserved batches of grant references
+ */
+int gnttab_alloc_grant_references(u16 count, grant_ref_t *pprivate_head);
+
+void gnttab_free_grant_reference(grant_ref_t ref);
+
+void gnttab_free_grant_references(grant_ref_t head);
+
+int gnttab_empty_grant_references(const grant_ref_t *pprivate_head);
+
+int gnttab_claim_grant_reference(grant_ref_t *pprivate_head);
+
+void gnttab_release_grant_reference(grant_ref_t *private_head,
+				    grant_ref_t release);
+
+void gnttab_request_free_callback(struct gnttab_free_callback *callback,
+				  void (*fn)(void *), void *arg, u16 count);
+void gnttab_cancel_free_callback(struct gnttab_free_callback *callback);
+
+void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid,
+				     unsigned long frame, int readonly);
+
+void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,
+				       unsigned long pfn);
+
+#define gnttab_map_vaddr(map) ((void *)(map.host_virt_addr))
+
+#endif /* __ASM_GNTTAB_H__ */
===================================================================
--- a/include/xen/interface/grant_table.h
+++ b/include/xen/interface/grant_table.h
@@ -1,8 +1,26 @@
 /******************************************************************************
  * grant_table.h
- *
+ *
  * Interface for granting foreign access to page frames, and receiving
  * page-ownership transfers.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
  *
  * Copyright (c) 2004, K A Fraser
  */
@@ -17,11 +35,11 @@
 
 /* Some rough guidelines on accessing and updating grant-table entries
  * in a concurrency-safe manner. For more information, Linux contains a
- * reference implementation for guest OSes (arch/i386/mach-xen/grant_table.c).
- *
+ * reference implementation for guest OSes (arch/xen/kernel/grant_table.c).
+ *
  * NB. WMB is a no-op on current-generation x86 processors. However, a
  *     compiler barrier will still be required.
- *
+ *
  * Introducing a valid entry into the grant table:
  *  1. Write ent->domid.
  *  2. Write ent->frame:
@@ -30,7 +48,7 @@
  *                           frame, or zero if none.
  *  3. Write memory barrier (WMB).
  *  4. Write ent->flags, inc. valid type.
- *
+ *
  * Invalidating an unused GTF_permit_access entry:
  *  1. flags = ent->flags.
  *  2. Observe that !(flags & (GTF_reading|GTF_writing)).
@@ -42,7 +60,7 @@
  *  This cannot be done directly. Request assistance from the domain controller
  *  which can set a timeout on the use of a grant entry and take necessary
  *  action. (NB. This is not yet implemented!).
- *
+ *
  * Invalidating an unused GTF_accept_transfer entry:
  *  1. flags = ent->flags.
  *  2. Observe that !(flags & GTF_transfer_committed). [*]
@@ -60,7 +78,7 @@
  *
  * Changing a GTF_permit_access from writable to read-only:
  *  Use SMP-safe CMPXCHG to set GTF_readonly, while checking !GTF_writing.
- *
+ *
  * Changing a GTF_permit_access from read-only to writable:
  *  Use SMP-safe bit-setting instruction.
  */
@@ -144,12 +162,12 @@ typedef uint32_t grant_handle_t;
  * that must be presented later to destroy the mapping(s). On error, <handle>
  * is a negative status code.
  * NOTES:
- *  1. If GNTPIN_map_for_dev is specified then <dev_bus_addr> is the address
+ *  1. If GNTMAP_device_map is specified then <dev_bus_addr> is the address
  *     via which I/O devices may access the granted frame.
- *  2. If GNTPIN_map_for_host is specified then a mapping will be added at
+ *  2. If GNTMAP_host_map is specified then a mapping will be added at
  *     either a host virtual address in the current address space, or at
  *     a PTE at the specified machine address.  The type of mapping to
- *     perform is selected through the GNTMAP_contains_pte flag, and the
+ *     perform is selected through the GNTMAP_contains_pte flag, and the
  *     address is specified in <host_addr>.
  *  3. Mappings should only be destroyed via GNTTABOP_unmap_grant_ref. If a
  *     host mapping is destroyed by other means then it is *NOT* guaranteed
@@ -167,7 +185,6 @@ struct gnttab_map_grant_ref {
     grant_handle_t handle;
     uint64_t dev_bus_addr;
 };
-DEFINE_GUEST_HANDLE_STRUCT(gnttab_map_grant_ref);
 
 /*
  * GNTTABOP_unmap_grant_ref: Destroy one or more grant-reference mappings
@@ -189,7 +206,6 @@ struct gnttab_unmap_grant_ref {
     /* OUT parameters. */
     int16_t  status;              /* GNTST_* */
 };
-DEFINE_GUEST_HANDLE_STRUCT(gnttab_unmap_grant_ref);
 
 /*
  * GNTTABOP_setup_table: Set up a grant table for <dom> comprising at least
@@ -207,9 +223,8 @@ struct gnttab_setup_table {
     uint32_t nr_frames;
     /* OUT parameters. */
     int16_t  status;              /* GNTST_* */
-    GUEST_HANDLE(ulong) frame_list;
-};
-DEFINE_GUEST_HANDLE_STRUCT(gnttab_setup_table);
+    ulong *frame_list;
+};
 
 /*
  * GNTTABOP_dump_table: Dump the contents of the grant table to the
@@ -222,13 +237,12 @@ struct gnttab_dump_table {
     /* OUT parameters. */
     int16_t status;               /* GNTST_* */
 };
-DEFINE_GUEST_HANDLE_STRUCT(gnttab_dump_table);
 
 /*
  * GNTTABOP_transfer_grant_ref: Transfer <frame> to a foreign domain. The
  * foreign domain has previously registered its interest in the transfer via
  * <domid, ref>.
- *
+ *
  * Note that, even if the transfer fails, the specified page no longer belongs
  * to the calling domain *unless* the error is GNTST_bad_page.
  */
@@ -241,7 +255,65 @@ struct gnttab_transfer {
     /* OUT parameters. */
     int16_t       status;
 };
-DEFINE_GUEST_HANDLE_STRUCT(gnttab_transfer);
+
+
+/*
+ * GNTTABOP_copy: Hypervisor based copy
+ * source and destinations can be eithers MFNs or, for foreign domains,
+ * grant references. the foreign domain has to grant read/write access
+ * in its grant table.
+ *
+ * The flags specify what type source and destinations are (either MFN
+ * or grant reference).
+ *
+ * Note that this can also be used to copy data between two domains
+ * via a third party if the source and destination domains had previously
+ * grant appropriate access to their pages to the third party.
+ *
+ * source_offset specifies an offset in the source frame, dest_offset
+ * the offset in the target frame and  len specifies the number of
+ * bytes to be copied.
+ */
+
+#define _GNTCOPY_source_gref      (0)
+#define GNTCOPY_source_gref       (1<<_GNTCOPY_source_gref)
+#define _GNTCOPY_dest_gref        (1)
+#define GNTCOPY_dest_gref         (1<<_GNTCOPY_dest_gref)
+
+#define GNTTABOP_copy                 5
+struct gnttab_copy {
+    /* IN parameters. */
+    struct {
+        union {
+            grant_ref_t ref;
+            unsigned long   gmfn;
+        } u;
+        domid_t  domid;
+        uint16_t offset;
+    } source, dest;
+    uint16_t      len;
+    uint16_t      flags;          /* GNTCOPY_* */
+    /* OUT parameters. */
+    int16_t       status;
+};
+
+/*
+ * GNTTABOP_query_size: Query the current and maximum sizes of the shared
+ * grant table.
+ * NOTES:
+ *  1. <dom> may be specified as DOMID_SELF.
+ *  2. Only a sufficiently-privileged domain may specify <dom> != DOMID_SELF.
+ */
+#define GNTTABOP_query_size           6
+struct gnttab_query_size {
+    /* IN parameters. */
+    domid_t  dom;
+    /* OUT parameters. */
+    uint32_t nr_frames;
+    uint32_t max_nr_frames;
+    int16_t  status;              /* GNTST_* */
+};
+
 
 /*
  * Bitfield values for update_pin_status.flags.
@@ -284,6 +356,7 @@ DEFINE_GUEST_HANDLE_STRUCT(gnttab_transf
 #define GNTST_no_device_space  (-7) /* Out of space in I/O MMU.              */
 #define GNTST_permission_denied (-8) /* Not enough privilege for operation.  */
 #define GNTST_bad_page         (-9) /* Specified page was invalid for op.    */
+#define GNTST_bad_copy_arg    (-10) /* copy arguments cross page boundary */
 
 #define GNTTABOP_error_msgs {                   \
     "okay",                                     \
@@ -295,7 +368,8 @@ DEFINE_GUEST_HANDLE_STRUCT(gnttab_transf
     "invalid device address",                   \
     "no spare translation slot in the I/O MMU", \
     "permission denied",                        \
-    "bad page"                                  \
+    "bad page",                                 \
+    "copy arguments cross page boundary"        \
 }
 
 #endif /* __XEN_PUBLIC_GRANT_TABLE_H__ */

-- 

[PATCH 19/25] xen: Add the Xenbus sysfs and virtual device hotplug driver.

[Jeremy Fitzhardinge]

[-- Attachment #1: xenbus.patch --]
[-- Type: text/plain, Size: 90999 bytes --]

This communicates with the machine control software via a registry
residing in a controlling virtual machine. This allows dynamic
creation, destruction and modification of virtual device
configurations (network devices, block devices and CPUS, to name some
examples).

[ Greg, would you mind giving this a review?  Thanks -J ]

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Greg KH <greg@kroah.com>
---
 drivers/xen/Makefile                      |    1 
 drivers/xen/xenbus/Makefile               |    9 
 drivers/xen/xenbus/xenbus_client.c        |  563 +++++++++++++++++
 drivers/xen/xenbus/xenbus_comms.c         |  233 +++++++
 drivers/xen/xenbus/xenbus_comms.h         |   46 +
 drivers/xen/xenbus/xenbus_probe.c         |  919 +++++++++++++++++++++++++++++
 drivers/xen/xenbus/xenbus_probe.h         |   72 ++
 drivers/xen/xenbus/xenbus_probe_backend.c |  265 ++++++++
 drivers/xen/xenbus/xenbus_xs.c            |  861 +++++++++++++++++++++++++++
 include/asm-i386/xen/hypervisor.h         |    1 
 include/xen/xenbus.h                      |  211 ++++++
 11 files changed, 3181 insertions(+)

===================================================================
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -1,2 +1,3 @@ obj-y	+= grant-table.o
 obj-y	+= grant-table.o
 obj-y	+= hvc-console.o
+obj-y	+= xenbus/
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/Makefile
@@ -0,0 +1,9 @@
+obj-y	+= xenbus.o
+
+xenbus-objs =
+xenbus-objs += xenbus_client.o
+xenbus-objs += xenbus_comms.o
+xenbus-objs += xenbus_xs.o
+xenbus-objs += xenbus_probe.o
+
+obj-$(CONFIG_XEN_BACKEND) += xenbus_probe_backend.o
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -0,0 +1,563 @@
+/******************************************************************************
+ * Client-facing interface for the Xenbus driver.  In other words, the
+ * interface between the Xenbus and the device-specific code, be it the
+ * frontend or the backend of that driver.
+ *
+ * Copyright (C) 2005 XenSource Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+#include <xen/events.h>
+#include <xen/grant_table.h>
+#include <xen/xenbus.h>
+
+const char *xenbus_strstate(enum xenbus_state state)
+{
+	static const char *const name[] = {
+		[ XenbusStateUnknown      ] = "Unknown",
+		[ XenbusStateInitialising ] = "Initialising",
+		[ XenbusStateInitWait     ] = "InitWait",
+		[ XenbusStateInitialised  ] = "Initialised",
+		[ XenbusStateConnected    ] = "Connected",
+		[ XenbusStateClosing      ] = "Closing",
+		[ XenbusStateClosed	  ] = "Closed",
+	};
+	return (state < ARRAY_SIZE(name)) ? name[state] : "INVALID";
+}
+EXPORT_SYMBOL_GPL(xenbus_strstate);
+
+/**
+ * xenbus_watch_path - register a watch
+ * @dev: xenbus device
+ * @path: path to watch
+ * @watch: watch to register
+ * @callback: callback to register
+ *
+ * Register a @watch on the given path, using the given xenbus_watch structure
+ * for storage, and the given @callback function as the callback.  Return 0 on
+ * success, or -errno on error.  On success, the given @path will be saved as
+ * @watch->node, and remains the caller's to free.  On error, @watch->node will
+ * be NULL, the device will switch to %XenbusStateClosing, and the error will
+ * be saved in the store.
+ */
+int xenbus_watch_path(struct xenbus_device *dev, const char *path,
+		      struct xenbus_watch *watch,
+		      void (*callback)(struct xenbus_watch *,
+				       const char **, unsigned int))
+{
+	int err;
+
+	watch->node = path;
+	watch->callback = callback;
+
+	err = register_xenbus_watch(watch);
+
+	if (err) {
+		watch->node = NULL;
+		watch->callback = NULL;
+		xenbus_dev_fatal(dev, err, "adding watch on %s", path);
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_watch_path);
+
+
+/**
+ * xenbus_watch_path2 - register a watch on path/path2
+ * @dev: xenbus device
+ * @path: first half of path to watch
+ * @path2: second half of path to watch
+ * @watch: watch to register
+ * @callback: callback to register
+ *
+ * Register a watch on the given @path/@path2, using the given xenbus_watch
+ * structure for storage, and the given @callback function as the callback.
+ * Return 0 on success, or -errno on error.  On success, the watched path
+ * (@path/@path2) will be saved as @watch->node, and becomes the caller's to
+ * kfree().  On error, watch->node will be NULL, so the caller has nothing to
+ * free, the device will switch to %XenbusStateClosing, and the error will be
+ * saved in the store.
+ */
+int xenbus_watch_path2(struct xenbus_device *dev, const char *path,
+		       const char *path2, struct xenbus_watch *watch,
+		       void (*callback)(struct xenbus_watch *,
+					const char **, unsigned int))
+{
+	int err;
+	char *state = kasprintf(GFP_KERNEL, "%s/%s", path, path2);
+	if (!state) {
+		xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
+		return -ENOMEM;
+	}
+	err = xenbus_watch_path(dev, state, watch, callback);
+
+	if (err)
+		kfree(state);
+	return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_watch_path2);
+
+
+/**
+ * xenbus_switch_state
+ * @dev: xenbus device
+ * @xbt: transaction handle
+ * @state: new state
+ *
+ * Advertise in the store a change of the given driver to the given new_state.
+ * Return 0 on success, or -errno on error.  On error, the device will switch
+ * to XenbusStateClosing, and the error will be saved in the store.
+ */
+int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
+{
+	/* We check whether the state is currently set to the given value, and
+	   if not, then the state is set.  We don't want to unconditionally
+	   write the given state, because we don't want to fire watches
+	   unnecessarily.  Furthermore, if the node has gone, we don't write
+	   to it, as the device will be tearing down, and we don't want to
+	   resurrect that directory.
+
+	   Note that, because of this cached value of our state, this function
+	   will not work inside a Xenstore transaction (something it was
+	   trying to in the past) because dev->state would not get reset if
+	   the transaction was aborted.
+
+	 */
+
+	int current_state;
+	int err;
+
+	if (state == dev->state)
+		return 0;
+
+	err = xenbus_scanf(XBT_NIL, dev->nodename, "state", "%d",
+			   &current_state);
+	if (err != 1)
+		return 0;
+
+	err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%d", state);
+	if (err) {
+		if (state != XenbusStateClosing) /* Avoid looping */
+			xenbus_dev_fatal(dev, err, "writing new state");
+		return err;
+	}
+
+	dev->state = state;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_switch_state);
+
+int xenbus_frontend_closed(struct xenbus_device *dev)
+{
+	xenbus_switch_state(dev, XenbusStateClosed);
+	complete(&dev->down);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_frontend_closed);
+
+/**
+ * Return the path to the error node for the given device, or NULL on failure.
+ * If the value returned is non-NULL, then it is the caller's to kfree.
+ */
+static char *error_path(struct xenbus_device *dev)
+{
+	return kasprintf(GFP_KERNEL, "error/%s", dev->nodename);
+}
+
+
+static void xenbus_va_dev_error(struct xenbus_device *dev, int err,
+				const char *fmt, va_list ap)
+{
+	int ret;
+	unsigned int len;
+	char *printf_buffer = NULL;
+	char *path_buffer = NULL;
+
+#define PRINTF_BUFFER_SIZE 4096
+	printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
+	if (printf_buffer == NULL)
+		goto fail;
+
+	len = sprintf(printf_buffer, "%i ", -err);
+	ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap);
+
+	BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1);
+
+	dev_err(&dev->dev, "%s\n", printf_buffer);
+
+	path_buffer = error_path(dev);
+
+	if (path_buffer == NULL) {
+		dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
+		       dev->nodename, printf_buffer);
+		goto fail;
+	}
+
+	if (xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer) != 0) {
+		dev_err(&dev->dev, "failed to write error node for %s (%s)\n",
+		       dev->nodename, printf_buffer);
+		goto fail;
+	}
+
+fail:
+	kfree(printf_buffer);
+	kfree(path_buffer);
+}
+
+
+/**
+ * xenbus_dev_error
+ * @dev: xenbus device
+ * @err: error to report
+ * @fmt: error message format
+ *
+ * Report the given negative errno into the store, along with the given
+ * formatted message.
+ */
+void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	xenbus_va_dev_error(dev, err, fmt, ap);
+	va_end(ap);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_error);
+
+/**
+ * xenbus_dev_fatal
+ * @dev: xenbus device
+ * @err: error to report
+ * @fmt: error message format
+ *
+ * Equivalent to xenbus_dev_error(dev, err, fmt, args), followed by
+ * xenbus_switch_state(dev, NULL, XenbusStateClosing) to schedule an orderly
+ * closedown of this driver and its peer.
+ */
+
+void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	xenbus_va_dev_error(dev, err, fmt, ap);
+	va_end(ap);
+
+	xenbus_switch_state(dev, XenbusStateClosing);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
+
+/**
+ * xenbus_grant_ring
+ * @dev: xenbus device
+ * @ring_mfn: mfn of ring to grant
+
+ * Grant access to the given @ring_mfn to the peer of the given device.  Return
+ * 0 on success, or -errno on error.  On error, the device will switch to
+ * XenbusStateClosing, and the error will be saved in the store.
+ */
+int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
+{
+	int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
+	if (err < 0)
+		xenbus_dev_fatal(dev, err, "granting access to ring page");
+	return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_grant_ring);
+
+
+/**
+ * Allocate an event channel for the given xenbus_device, assigning the newly
+ * created local port to *port.  Return 0 on success, or -errno on error.  On
+ * error, the device will switch to XenbusStateClosing, and the error will be
+ * saved in the store.
+ */
+int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
+{
+	struct evtchn_alloc_unbound alloc_unbound;
+	int err;
+
+	alloc_unbound.dom = DOMID_SELF;
+	alloc_unbound.remote_dom = dev->otherend_id;
+
+	err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
+					  &alloc_unbound);
+	if (err)
+		xenbus_dev_fatal(dev, err, "allocating event channel");
+	else
+		*port = alloc_unbound.port;
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
+
+
+/**
+ * Bind to an existing interdomain event channel in another domain. Returns 0
+ * on success and stores the local port in *port. On error, returns -errno,
+ * switches the device to XenbusStateClosing, and saves the error in XenStore.
+ */
+int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port)
+{
+	struct evtchn_bind_interdomain bind_interdomain;
+	int err;
+
+	bind_interdomain.remote_dom = dev->otherend_id;
+	bind_interdomain.remote_port = remote_port;
+
+	err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
+					  &bind_interdomain);
+	if (err)
+		xenbus_dev_fatal(dev, err,
+				 "binding to event channel %d from domain %d",
+				 remote_port, dev->otherend_id);
+	else
+		*port = bind_interdomain.local_port;
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_bind_evtchn);
+
+
+/**
+ * Free an existing event channel. Returns 0 on success or -errno on error.
+ */
+int xenbus_free_evtchn(struct xenbus_device *dev, int port)
+{
+	struct evtchn_close close;
+	int err;
+
+	close.port = port;
+
+	err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
+	if (err)
+		xenbus_dev_error(dev, err, "freeing event channel %d", port);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
+
+
+/**
+ * xenbus_map_ring_valloc
+ * @dev: xenbus device
+ * @gnt_ref: grant reference
+ * @vaddr: pointer to address to be filled out by mapping
+ *
+ * Based on Rusty Russell's skeleton driver's map_page.
+ * Map a page of memory into this domain from another domain's grant table.
+ * xenbus_map_ring_valloc allocates a page of virtual address space, maps the
+ * page to that address, and sets *vaddr to that address.
+ * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
+ * or -ENOMEM on error. If an error is returned, device will switch to
+ * XenbusStateClosing and the error message will be saved in XenStore.
+ */
+int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
+{
+	struct gnttab_map_grant_ref op = {
+		.flags = GNTMAP_host_map,
+		.ref   = gnt_ref,
+		.dom   = dev->otherend_id,
+	};
+	struct vm_struct *area;
+
+	*vaddr = NULL;
+
+	area = alloc_vm_area(PAGE_SIZE);
+	if (!area)
+		return -ENOMEM;
+
+	op.host_addr = (unsigned long)area->addr;
+
+	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
+		BUG();
+
+	if (op.status != GNTST_okay) {
+		free_vm_area(area);
+		xenbus_dev_fatal(dev, op.status,
+				 "mapping in shared page %d from domain %d",
+				 gnt_ref, dev->otherend_id);
+		return op.status;
+	}
+
+	/* Stuff the handle in an unused field */
+	area->phys_addr = (unsigned long)op.handle;
+
+	*vaddr = area->addr;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
+
+
+/**
+ * xenbus_map_ring
+ * @dev: xenbus device
+ * @gnt_ref: grant reference
+ * @handle: pointer to grant handle to be filled
+ * @vaddr: address to be mapped to
+ *
+ * Map a page of memory into this domain from another domain's grant table.
+ * xenbus_map_ring does not allocate the virtual address space (you must do
+ * this yourself!). It only maps in the page to the specified address.
+ * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
+ * or -ENOMEM on error. If an error is returned, device will switch to
+ * XenbusStateClosing and the error message will be saved in XenStore.
+ */
+int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
+		    grant_handle_t *handle, void *vaddr)
+{
+	struct gnttab_map_grant_ref op = {
+		.host_addr = (unsigned long)vaddr,
+		.flags     = GNTMAP_host_map,
+		.ref       = gnt_ref,
+		.dom       = dev->otherend_id,
+	};
+
+	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
+		BUG();
+
+	if (op.status != GNTST_okay) {
+		xenbus_dev_fatal(dev, op.status,
+				 "mapping in shared page %d from domain %d",
+				 gnt_ref, dev->otherend_id);
+	} else
+		*handle = op.handle;
+
+	return op.status;
+}
+EXPORT_SYMBOL_GPL(xenbus_map_ring);
+
+
+/**
+ * xenbus_unmap_ring_vfree
+ * @dev: xenbus device
+ * @vaddr: addr to unmap
+ *
+ * Based on Rusty Russell's skeleton driver's unmap_page.
+ * Unmap a page of memory in this domain that was imported from another domain.
+ * Use xenbus_unmap_ring_vfree if you mapped in your memory with
+ * xenbus_map_ring_valloc (it will free the virtual address space).
+ * Returns 0 on success and returns GNTST_* on error
+ * (see xen/include/interface/grant_table.h).
+ */
+int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
+{
+	struct vm_struct *area;
+	struct gnttab_unmap_grant_ref op = {
+		.host_addr = (unsigned long)vaddr,
+	};
+
+	/* It'd be nice if linux/vmalloc.h provided a find_vm_area(void *addr)
+	 * method so that we don't have to muck with vmalloc internals here.
+	 * We could force the user to hang on to their struct vm_struct from
+	 * xenbus_map_ring_valloc, but these 6 lines considerably simplify
+	 * this API.
+	 */
+	read_lock(&vmlist_lock);
+	for (area = vmlist; area != NULL; area = area->next) {
+		if (area->addr == vaddr)
+			break;
+	}
+	read_unlock(&vmlist_lock);
+
+	if (!area) {
+		xenbus_dev_error(dev, -ENOENT,
+				 "can't find mapped virtual address %p", vaddr);
+		return GNTST_bad_virt_addr;
+	}
+
+	op.handle = (grant_handle_t)area->phys_addr;
+
+	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+		BUG();
+
+	if (op.status == GNTST_okay)
+		free_vm_area(area);
+	else
+		xenbus_dev_error(dev, op.status,
+				 "unmapping page at handle %d error %d",
+				 (int16_t)area->phys_addr, op.status);
+
+	return op.status;
+}
+EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
+
+
+/**
+ * xenbus_unmap_ring
+ * @dev: xenbus device
+ * @handle: grant handle
+ * @vaddr: addr to unmap
+ *
+ * Unmap a page of memory in this domain that was imported from another domain.
+ * Returns 0 on success and returns GNTST_* on error
+ * (see xen/include/interface/grant_table.h).
+ */
+int xenbus_unmap_ring(struct xenbus_device *dev,
+		      grant_handle_t handle, void *vaddr)
+{
+	struct gnttab_unmap_grant_ref op = {
+		.host_addr = (unsigned long)vaddr,
+		.handle    = handle,
+	};
+
+	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+		BUG();
+
+	if (op.status != GNTST_okay)
+		xenbus_dev_error(dev, op.status,
+				 "unmapping page at handle %d error %d",
+				 handle, op.status);
+
+	return op.status;
+}
+EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
+
+
+/**
+ * xenbus_read_driver_state
+ * @path: path for driver
+ *
+ * Return the state of the driver rooted at the given store path, or
+ * XenbusStateUnknown if no state can be read.
+ */
+enum xenbus_state xenbus_read_driver_state(const char *path)
+{
+	enum xenbus_state result;
+	int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
+	if (err)
+		result = XenbusStateUnknown;
+
+	return result;
+}
+EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -0,0 +1,233 @@
+/******************************************************************************
+ * xenbus_comms.c
+ *
+ * Low level code to talks to Xen Store: ringbuffer and event channel.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/wait.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/err.h>
+#include <xen/xenbus.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/events.h>
+#include <xen/page.h>
+#include "xenbus_comms.h"
+
+static int xenbus_irq;
+
+static DECLARE_WORK(probe_work, xenbus_probe);
+
+static DECLARE_WAIT_QUEUE_HEAD(xb_waitq);
+
+static irqreturn_t wake_waiting(int irq, void *unused)
+{
+	if (unlikely(xenstored_ready == 0)) {
+		xenstored_ready = 1;
+		schedule_work(&probe_work);
+	}
+
+	wake_up(&xb_waitq);
+	return IRQ_HANDLED;
+}
+
+static int check_indexes(XENSTORE_RING_IDX cons, XENSTORE_RING_IDX prod)
+{
+	return ((prod - cons) <= XENSTORE_RING_SIZE);
+}
+
+static void *get_output_chunk(XENSTORE_RING_IDX cons,
+			      XENSTORE_RING_IDX prod,
+			      char *buf, uint32_t *len)
+{
+	*len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod);
+	if ((XENSTORE_RING_SIZE - (prod - cons)) < *len)
+		*len = XENSTORE_RING_SIZE - (prod - cons);
+	return buf + MASK_XENSTORE_IDX(prod);
+}
+
+static const void *get_input_chunk(XENSTORE_RING_IDX cons,
+				   XENSTORE_RING_IDX prod,
+				   const char *buf, uint32_t *len)
+{
+	*len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons);
+	if ((prod - cons) < *len)
+		*len = prod - cons;
+	return buf + MASK_XENSTORE_IDX(cons);
+}
+
+/**
+ * xb_write - low level write
+ * @data: buffer to send
+ * @len: length of buffer
+ *
+ * Returns 0 on success, error otherwise.
+ */
+int xb_write(const void *data, unsigned len)
+{
+	struct xenstore_domain_interface *intf = xen_store_interface;
+	XENSTORE_RING_IDX cons, prod;
+	int rc;
+
+	while (len != 0) {
+		void *dst;
+		unsigned int avail;
+
+		rc = wait_event_interruptible(
+			xb_waitq,
+			(intf->req_prod - intf->req_cons) !=
+			XENSTORE_RING_SIZE);
+		if (rc < 0)
+			return rc;
+
+		/* Read indexes, then verify. */
+		cons = intf->req_cons;
+		prod = intf->req_prod;
+		if (!check_indexes(cons, prod)) {
+			intf->req_cons = intf->req_prod = 0;
+			return -EIO;
+		}
+
+		dst = get_output_chunk(cons, prod, intf->req, &avail);
+		if (avail == 0)
+			continue;
+		if (avail > len)
+			avail = len;
+
+		/* Must write data /after/ reading the consumer index. */
+		mb();
+
+		memcpy(dst, data, avail);
+		data += avail;
+		len -= avail;
+
+		/* Other side must not see new producer until data is there. */
+		wmb();
+		intf->req_prod += avail;
+
+		/* Implies mb(): other side will see the updated producer. */
+		notify_remote_via_evtchn(xen_store_evtchn);
+	}
+
+	return 0;
+}
+
+int xb_data_to_read(void)
+{
+	struct xenstore_domain_interface *intf = xen_store_interface;
+	return (intf->rsp_cons != intf->rsp_prod);
+}
+
+int xb_wait_for_data_to_read(void)
+{
+	return wait_event_interruptible(xb_waitq, xb_data_to_read());
+}
+
+int xb_read(void *data, unsigned len)
+{
+	struct xenstore_domain_interface *intf = xen_store_interface;
+	XENSTORE_RING_IDX cons, prod;
+	int rc;
+
+	while (len != 0) {
+		unsigned int avail;
+		const char *src;
+
+		rc = xb_wait_for_data_to_read();
+		if (rc < 0)
+			return rc;
+
+		/* Read indexes, then verify. */
+		cons = intf->rsp_cons;
+		prod = intf->rsp_prod;
+		if (!check_indexes(cons, prod)) {
+			intf->rsp_cons = intf->rsp_prod = 0;
+			return -EIO;
+		}
+
+		src = get_input_chunk(cons, prod, intf->rsp, &avail);
+		if (avail == 0)
+			continue;
+		if (avail > len)
+			avail = len;
+
+		/* Must read data /after/ reading the producer index. */
+		rmb();
+
+		memcpy(data, src, avail);
+		data += avail;
+		len -= avail;
+
+		/* Other side must not see free space until we've copied out */
+		mb();
+		intf->rsp_cons += avail;
+
+		pr_debug("Finished read of %i bytes (%i to go)\n", avail, len);
+
+		/* Implies mb(): other side will see the updated consumer. */
+		notify_remote_via_evtchn(xen_store_evtchn);
+	}
+
+	return 0;
+}
+
+/**
+ * xb_init_comms - Set up interrupt handler off store event channel.
+ */
+int xb_init_comms(void)
+{
+	struct xenstore_domain_interface *intf = xen_store_interface;
+	int err;
+
+	if (intf->req_prod != intf->req_cons)
+		printk(KERN_ERR "XENBUS request ring is not quiescent "
+		       "(%08x:%08x)!\n", intf->req_cons, intf->req_prod);
+
+	if (intf->rsp_prod != intf->rsp_cons) {
+		printk(KERN_WARNING "XENBUS response ring is not quiescent "
+		       "(%08x:%08x): fixing up\n",
+		       intf->rsp_cons, intf->rsp_prod);
+		intf->rsp_cons = intf->rsp_prod;
+	}
+
+	if (xenbus_irq)
+		unbind_from_irqhandler(xenbus_irq, &xb_waitq);
+
+	err = bind_evtchn_to_irqhandler(
+		xen_store_evtchn, wake_waiting,
+		0, "xenbus", &xb_waitq);
+	if (err <= 0) {
+		printk(KERN_ERR "XENBUS request irq failed %i\n", err);
+		return err;
+	}
+
+	xenbus_irq = err;
+
+	return 0;
+}
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_comms.h
@@ -0,0 +1,46 @@
+/*
+ * Private include for xenbus communications.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _XENBUS_COMMS_H
+#define _XENBUS_COMMS_H
+
+int xs_init(void);
+int xb_init_comms(void);
+
+/* Low level routines. */
+int xb_write(const void *data, unsigned len);
+int xb_read(void *data, unsigned len);
+int xb_data_to_read(void);
+int xb_wait_for_data_to_read(void);
+int xs_input_avail(void);
+extern struct xenstore_domain_interface *xen_store_interface;
+extern int xen_store_evtchn;
+
+#endif /* _XENBUS_COMMS_H */
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -0,0 +1,919 @@
+/******************************************************************************
+ * Talks to Xen Store to figure out what devices we have.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ * Copyright (C) 2005 Mike Wray, Hewlett-Packard
+ * Copyright (C) 2005, 2006 XenSource Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define DPRINTK(fmt, args...)				\
+	pr_debug("xenbus_probe (%s:%d) " fmt ".\n",	\
+		 __FUNCTION__, __LINE__, ##args)
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/notifier.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+
+#include <asm/io.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/xenbus.h>
+#include <xen/events.h>
+#include <xen/page.h>
+
+#include "xenbus_comms.h"
+#include "xenbus_probe.h"
+
+int xen_store_evtchn;
+struct xenstore_domain_interface *xen_store_interface;
+static unsigned long xen_store_mfn;
+
+static BLOCKING_NOTIFIER_HEAD(xenstore_chain);
+
+static void wait_for_devices(struct xenbus_driver *xendrv);
+
+static int xenbus_probe_frontend(const char *type, const char *name);
+
+static void xenbus_dev_shutdown(struct device *_dev);
+
+/* If something in array of ids matches this device, return it. */
+static const struct xenbus_device_id *
+match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev)
+{
+	for (; *arr->devicetype != '\0'; arr++) {
+		if (!strcmp(arr->devicetype, dev->devicetype))
+			return arr;
+	}
+	return NULL;
+}
+
+int xenbus_match(struct device *_dev, struct device_driver *_drv)
+{
+	struct xenbus_driver *drv = to_xenbus_driver(_drv);
+
+	if (!drv->ids)
+		return 0;
+
+	return match_device(drv->ids, to_xenbus_device(_dev)) != NULL;
+}
+
+/* device/<type>/<id> => <type>-<id> */
+static int frontend_bus_id(char bus_id[BUS_ID_SIZE], const char *nodename)
+{
+	nodename = strchr(nodename, '/');
+	if (!nodename || strlen(nodename + 1) >= BUS_ID_SIZE) {
+		printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename);
+		return -EINVAL;
+	}
+
+	strlcpy(bus_id, nodename + 1, BUS_ID_SIZE);
+	if (!strchr(bus_id, '/')) {
+		printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id);
+		return -EINVAL;
+	}
+	*strchr(bus_id, '/') = '-';
+	return 0;
+}
+
+
+static void free_otherend_details(struct xenbus_device *dev)
+{
+	kfree(dev->otherend);
+	dev->otherend = NULL;
+}
+
+
+static void free_otherend_watch(struct xenbus_device *dev)
+{
+	if (dev->otherend_watch.node) {
+		unregister_xenbus_watch(&dev->otherend_watch);
+		kfree(dev->otherend_watch.node);
+		dev->otherend_watch.node = NULL;
+	}
+}
+
+
+int read_otherend_details(struct xenbus_device *xendev,
+				 char *id_node, char *path_node)
+{
+	int err = xenbus_gather(XBT_NIL, xendev->nodename,
+				id_node, "%i", &xendev->otherend_id,
+				path_node, NULL, &xendev->otherend,
+				NULL);
+	if (err) {
+		xenbus_dev_fatal(xendev, err,
+				 "reading other end details from %s",
+				 xendev->nodename);
+		return err;
+	}
+	if (strlen(xendev->otherend) == 0 ||
+	    !xenbus_exists(XBT_NIL, xendev->otherend, "")) {
+		xenbus_dev_fatal(xendev, -ENOENT,
+				 "unable to read other end from %s.  "
+				 "missing or inaccessible.",
+				 xendev->nodename);
+		free_otherend_details(xendev);
+		return -ENOENT;
+	}
+
+	return 0;
+}
+
+
+static int read_backend_details(struct xenbus_device *xendev)
+{
+	return read_otherend_details(xendev, "backend-id", "backend");
+}
+
+
+/* Bus type for frontend drivers. */
+static struct xen_bus_type xenbus_frontend = {
+	.root = "device",
+	.levels = 2, 		/* device/type/<id> */
+	.get_bus_id = frontend_bus_id,
+	.probe = xenbus_probe_frontend,
+	.bus = {
+		.name     = "xen",
+		.match    = xenbus_match,
+		.probe    = xenbus_dev_probe,
+		.remove   = xenbus_dev_remove,
+		.shutdown = xenbus_dev_shutdown,
+	},
+};
+
+static void otherend_changed(struct xenbus_watch *watch,
+			     const char **vec, unsigned int len)
+{
+	struct xenbus_device *dev =
+		container_of(watch, struct xenbus_device, otherend_watch);
+	struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
+	enum xenbus_state state;
+
+	/* Protect us against watches firing on old details when the otherend
+	   details change, say immediately after a resume. */
+	if (!dev->otherend ||
+	    strncmp(dev->otherend, vec[XS_WATCH_PATH],
+		    strlen(dev->otherend))) {
+		dev_dbg(&dev->dev, "Ignoring watch at %s", vec[XS_WATCH_PATH]);
+		return;
+	}
+
+	state = xenbus_read_driver_state(dev->otherend);
+
+	dev_dbg(&dev->dev, "state is %d, (%s), %s, %s",
+		state, xenbus_strstate(state), dev->otherend_watch.node,
+		vec[XS_WATCH_PATH]);
+
+	/*
+	 * Ignore xenbus transitions during shutdown. This prevents us doing
+	 * work that can fail e.g., when the rootfs is gone.
+	 */
+	if (system_state > SYSTEM_RUNNING) {
+		struct xen_bus_type *bus = bus;
+		bus = container_of(dev->dev.bus, struct xen_bus_type, bus);
+		/* If we're frontend, drive the state machine to Closed. */
+		/* This should cause the backend to release our resources. */
+		if ((bus == &xenbus_frontend) && (state == XenbusStateClosing))
+			xenbus_frontend_closed(dev);
+		return;
+	}
+
+	if (drv->otherend_changed)
+		drv->otherend_changed(dev, state);
+}
+
+
+static int talk_to_otherend(struct xenbus_device *dev)
+{
+	struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver);
+
+	free_otherend_watch(dev);
+	free_otherend_details(dev);
+
+	return drv->read_otherend_details(dev);
+}
+
+
+static int watch_otherend(struct xenbus_device *dev)
+{
+	return xenbus_watch_path2(dev, dev->otherend, "state",
+				  &dev->otherend_watch, otherend_changed);
+}
+
+
+int xenbus_dev_probe(struct device *_dev)
+{
+	struct xenbus_device *dev = to_xenbus_device(_dev);
+	struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
+	const struct xenbus_device_id *id;
+	int err;
+
+	DPRINTK("%s", dev->nodename);
+
+	if (!drv->probe) {
+		err = -ENODEV;
+		goto fail;
+	}
+
+	id = match_device(drv->ids, dev);
+	if (!id) {
+		err = -ENODEV;
+		goto fail;
+	}
+
+	err = talk_to_otherend(dev);
+	if (err) {
+		dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n",
+			 dev->nodename);
+		return err;
+	}
+
+	err = drv->probe(dev, id);
+	if (err)
+		goto fail;
+
+	err = watch_otherend(dev);
+	if (err) {
+		dev_warn(&dev->dev, "watch_otherend on %s failed.\n",
+		       dev->nodename);
+		return err;
+	}
+
+	return 0;
+fail:
+	xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename);
+	xenbus_switch_state(dev, XenbusStateClosed);
+	return -ENODEV;
+}
+
+int xenbus_dev_remove(struct device *_dev)
+{
+	struct xenbus_device *dev = to_xenbus_device(_dev);
+	struct xenbus_driver *drv = to_xenbus_driver(_dev->driver);
+
+	DPRINTK("%s", dev->nodename);
+
+	free_otherend_watch(dev);
+	free_otherend_details(dev);
+
+	if (drv->remove)
+		drv->remove(dev);
+
+	xenbus_switch_state(dev, XenbusStateClosed);
+	return 0;
+}
+
+static void xenbus_dev_shutdown(struct device *_dev)
+{
+	struct xenbus_device *dev = to_xenbus_device(_dev);
+	unsigned long timeout = 5*HZ;
+
+	DPRINTK("%s", dev->nodename);
+
+	get_device(&dev->dev);
+	if (dev->state != XenbusStateConnected) {
+		printk("%s: %s: %s != Connected, skipping\n", __FUNCTION__,
+		       dev->nodename, xenbus_strstate(dev->state));
+		goto out;
+	}
+	xenbus_switch_state(dev, XenbusStateClosing);
+	timeout = wait_for_completion_timeout(&dev->down, timeout);
+	if (!timeout)
+		printk("%s: %s timeout closing device\n", __FUNCTION__, dev->nodename);
+ out:
+	put_device(&dev->dev);
+}
+
+int xenbus_register_driver_common(struct xenbus_driver *drv,
+				  struct xen_bus_type *bus)
+{
+	drv->driver.name = drv->name;
+	drv->driver.bus = &bus->bus;
+	drv->driver.owner = drv->owner;
+
+	return driver_register(&drv->driver);
+}
+
+int xenbus_register_frontend(struct xenbus_driver *drv)
+{
+	int ret;
+
+	drv->read_otherend_details = read_backend_details;
+
+	ret = xenbus_register_driver_common(drv, &xenbus_frontend);
+	if (ret)
+		return ret;
+
+	/* If this driver is loaded as a module wait for devices to attach. */
+	wait_for_devices(drv);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_register_frontend);
+
+void xenbus_unregister_driver(struct xenbus_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(xenbus_unregister_driver);
+
+struct xb_find_info
+{
+	struct xenbus_device *dev;
+	const char *nodename;
+};
+
+static int cmp_dev(struct device *dev, void *data)
+{
+	struct xenbus_device *xendev = to_xenbus_device(dev);
+	struct xb_find_info *info = data;
+
+	if (!strcmp(xendev->nodename, info->nodename)) {
+		info->dev = xendev;
+		get_device(dev);
+		return 1;
+	}
+	return 0;
+}
+
+struct xenbus_device *xenbus_device_find(const char *nodename,
+					 struct bus_type *bus)
+{
+	struct xb_find_info info = { .dev = NULL, .nodename = nodename };
+
+	bus_for_each_dev(bus, NULL, &info, cmp_dev);
+	return info.dev;
+}
+
+static int cleanup_dev(struct device *dev, void *data)
+{
+	struct xenbus_device *xendev = to_xenbus_device(dev);
+	struct xb_find_info *info = data;
+	int len = strlen(info->nodename);
+
+	DPRINTK("%s", info->nodename);
+
+	/* Match the info->nodename path, or any subdirectory of that path. */
+	if (strncmp(xendev->nodename, info->nodename, len))
+		return 0;
+
+	/* If the node name is longer, ensure it really is a subdirectory. */
+	if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/'))
+		return 0;
+
+	info->dev = xendev;
+	get_device(dev);
+	return 1;
+}
+
+static void xenbus_cleanup_devices(const char *path, struct bus_type *bus)
+{
+	struct xb_find_info info = { .nodename = path };
+
+	do {
+		info.dev = NULL;
+		bus_for_each_dev(bus, NULL, &info, cleanup_dev);
+		if (info.dev) {
+			device_unregister(&info.dev->dev);
+			put_device(&info.dev->dev);
+		}
+	} while (info.dev);
+}
+
+static void xenbus_dev_release(struct device *dev)
+{
+	if (dev)
+		kfree(to_xenbus_device(dev));
+}
+
+static ssize_t xendev_show_nodename(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename);
+}
+DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL);
+
+static ssize_t xendev_show_devtype(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype);
+}
+DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL);
+
+
+int xenbus_probe_node(struct xen_bus_type *bus,
+		      const char *type,
+		      const char *nodename)
+{
+	int err;
+	struct xenbus_device *xendev;
+	size_t stringlen;
+	char *tmpstring;
+
+	enum xenbus_state state = xenbus_read_driver_state(nodename);
+
+	if (state != XenbusStateInitialising) {
+		/* Device is not new, so ignore it.  This can happen if a
+		   device is going away after switching to Closed.  */
+		return 0;
+	}
+
+	stringlen = strlen(nodename) + 1 + strlen(type) + 1;
+	xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL);
+	if (!xendev)
+		return -ENOMEM;
+
+	xendev->state = XenbusStateInitialising;
+
+	/* Copy the strings into the extra space. */
+
+	tmpstring = (char *)(xendev + 1);
+	strcpy(tmpstring, nodename);
+	xendev->nodename = tmpstring;
+
+	tmpstring += strlen(tmpstring) + 1;
+	strcpy(tmpstring, type);
+	xendev->devicetype = tmpstring;
+	init_completion(&xendev->down);
+
+	xendev->dev.bus = &bus->bus;
+	xendev->dev.release = xenbus_dev_release;
+
+	err = bus->get_bus_id(xendev->dev.bus_id, xendev->nodename);
+	if (err)
+		goto fail;
+
+	/* Register with generic device framework. */
+	err = device_register(&xendev->dev);
+	if (err)
+		goto fail;
+
+	device_create_file(&xendev->dev, &dev_attr_nodename);
+	device_create_file(&xendev->dev, &dev_attr_devtype);
+
+	return 0;
+fail:
+	kfree(xendev);
+	return err;
+}
+
+/* device/<typename>/<name> */
+static int xenbus_probe_frontend(const char *type, const char *name)
+{
+	char *nodename;
+	int err;
+
+	nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", xenbus_frontend.root, type, name);
+	if (!nodename)
+		return -ENOMEM;
+
+	DPRINTK("%s", nodename);
+
+	err = xenbus_probe_node(&xenbus_frontend, type, nodename);
+	kfree(nodename);
+	return err;
+}
+
+static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type)
+{
+	int err = 0;
+	char **dir;
+	unsigned int dir_n = 0;
+	int i;
+
+	dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n);
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
+
+	for (i = 0; i < dir_n; i++) {
+		err = bus->probe(type, dir[i]);
+		if (err)
+			break;
+	}
+	kfree(dir);
+	return err;
+}
+
+int xenbus_probe_devices(struct xen_bus_type *bus)
+{
+	int err = 0;
+	char **dir;
+	unsigned int i, dir_n;
+
+	dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n);
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
+
+	for (i = 0; i < dir_n; i++) {
+		err = xenbus_probe_device_type(bus, dir[i]);
+		if (err)
+			break;
+	}
+	kfree(dir);
+	return err;
+}
+
+static unsigned int char_count(const char *str, char c)
+{
+	unsigned int i, ret = 0;
+
+	for (i = 0; str[i]; i++)
+		if (str[i] == c)
+			ret++;
+	return ret;
+}
+
+static int strsep_len(const char *str, char c, unsigned int len)
+{
+	unsigned int i;
+
+	for (i = 0; str[i]; i++)
+		if (str[i] == c) {
+			if (len == 0)
+				return i;
+			len--;
+		}
+	return (len == 0) ? i : -ERANGE;
+}
+
+void dev_changed(const char *node, struct xen_bus_type *bus)
+{
+	int exists, rootlen;
+	struct xenbus_device *dev;
+	char type[BUS_ID_SIZE];
+	const char *p, *root;
+
+	if (char_count(node, '/') < 2)
+ 		return;
+
+	exists = xenbus_exists(XBT_NIL, node, "");
+	if (!exists) {
+		xenbus_cleanup_devices(node, &bus->bus);
+		return;
+	}
+
+	/* backend/<type>/... or device/<type>/... */
+	p = strchr(node, '/') + 1;
+	snprintf(type, BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p);
+	type[BUS_ID_SIZE-1] = '\0';
+
+	rootlen = strsep_len(node, '/', bus->levels);
+	if (rootlen < 0)
+		return;
+	root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node);
+	if (!root)
+		return;
+
+	dev = xenbus_device_find(root, &bus->bus);
+	if (!dev)
+		xenbus_probe_node(bus, type, root);
+	else
+		put_device(&dev->dev);
+
+	kfree(root);
+}
+
+static void frontend_changed(struct xenbus_watch *watch,
+			     const char **vec, unsigned int len)
+{
+	DPRINTK("");
+
+	dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend);
+}
+
+/* We watch for devices appearing and vanishing. */
+static struct xenbus_watch fe_watch = {
+	.node = "device",
+	.callback = frontend_changed,
+};
+
+static int suspend_dev(struct device *dev, void *data)
+{
+	int err = 0;
+	struct xenbus_driver *drv;
+	struct xenbus_device *xdev;
+
+	DPRINTK("");
+
+	if (dev->driver == NULL)
+		return 0;
+	drv = to_xenbus_driver(dev->driver);
+	xdev = container_of(dev, struct xenbus_device, dev);
+	if (drv->suspend)
+		err = drv->suspend(xdev);
+	if (err)
+		printk(KERN_WARNING
+		       "xenbus: suspend %s failed: %i\n", dev->bus_id, err);
+	return 0;
+}
+
+static int suspend_cancel_dev(struct device *dev, void *data)
+{
+	int err = 0;
+	struct xenbus_driver *drv;
+	struct xenbus_device *xdev;
+
+	DPRINTK("");
+
+	if (dev->driver == NULL)
+		return 0;
+	drv = to_xenbus_driver(dev->driver);
+	xdev = container_of(dev, struct xenbus_device, dev);
+	if (drv->suspend_cancel)
+		err = drv->suspend_cancel(xdev);
+	if (err)
+		printk(KERN_WARNING
+		       "xenbus: suspend_cancel %s failed: %i\n",
+		       dev->bus_id, err);
+	return 0;
+}
+
+static int resume_dev(struct device *dev, void *data)
+{
+	int err;
+	struct xenbus_driver *drv;
+	struct xenbus_device *xdev;
+
+	DPRINTK("");
+
+	if (dev->driver == NULL)
+		return 0;
+
+	drv = to_xenbus_driver(dev->driver);
+	xdev = container_of(dev, struct xenbus_device, dev);
+
+	err = talk_to_otherend(xdev);
+	if (err) {
+		printk(KERN_WARNING
+		       "xenbus: resume (talk_to_otherend) %s failed: %i\n",
+		       dev->bus_id, err);
+		return err;
+	}
+
+	xdev->state = XenbusStateInitialising;
+
+	if (drv->resume) {
+		err = drv->resume(xdev);
+		if (err) {
+			printk(KERN_WARNING
+			       "xenbus: resume %s failed: %i\n",
+			       dev->bus_id, err);
+			return err;
+		}
+	}
+
+	err = watch_otherend(xdev);
+	if (err) {
+		printk(KERN_WARNING
+		       "xenbus_probe: resume (watch_otherend) %s failed: "
+		       "%d.\n", dev->bus_id, err);
+		return err;
+	}
+
+	return 0;
+}
+
+void xenbus_suspend(void)
+{
+	DPRINTK("");
+
+	bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_dev);
+	xenbus_backend_suspend(suspend_dev);
+	xs_suspend();
+}
+EXPORT_SYMBOL_GPL(xenbus_suspend);
+
+void xenbus_resume(void)
+{
+	xb_init_comms();
+	xs_resume();
+	bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, resume_dev);
+	xenbus_backend_resume(resume_dev);
+}
+EXPORT_SYMBOL_GPL(xenbus_resume);
+
+void xenbus_suspend_cancel(void)
+{
+	xs_suspend_cancel();
+	bus_for_each_dev(&xenbus_frontend.bus, NULL, NULL, suspend_cancel_dev);
+	xenbus_backend_resume(suspend_cancel_dev);
+}
+EXPORT_SYMBOL_GPL(xenbus_suspend_cancel);
+
+/* A flag to determine if xenstored is 'ready' (i.e. has started) */
+int xenstored_ready = 0;
+
+
+int register_xenstore_notifier(struct notifier_block *nb)
+{
+	int ret = 0;
+
+	if (xenstored_ready > 0)
+		ret = nb->notifier_call(nb, 0, NULL);
+	else
+		blocking_notifier_chain_register(&xenstore_chain, nb);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_xenstore_notifier);
+
+void unregister_xenstore_notifier(struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&xenstore_chain, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_xenstore_notifier);
+
+void xenbus_probe(struct work_struct *unused)
+{
+	BUG_ON((xenstored_ready <= 0));
+
+	/* Enumerate devices in xenstore and watch for changes. */
+	xenbus_probe_devices(&xenbus_frontend);
+	register_xenbus_watch(&fe_watch);
+	xenbus_backend_probe_and_watch();
+
+	/* Notify others that xenstore is up */
+	blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
+}
+
+static int __init xenbus_probe_init(void)
+{
+	int err = 0;
+
+	DPRINTK("");
+
+	err = -ENODEV;
+	if (!is_running_on_xen())
+		goto out_error;
+
+	/* Register ourselves with the kernel bus subsystem */
+	err = bus_register(&xenbus_frontend.bus);
+	if (err)
+		goto out_error;
+
+	err = xenbus_backend_bus_register();
+	if (err)
+		goto out_unreg_front;
+
+	/*
+	 * Domain0 doesn't have a store_evtchn or store_mfn yet.
+	 */
+	if (is_initial_xendomain()) {
+		/* dom0 not yet supported */
+	} else {
+		xenstored_ready = 1;
+		xen_store_evtchn = xen_start_info->store_evtchn;
+		xen_store_mfn = xen_start_info->store_mfn;
+	}
+	xen_store_interface = mfn_to_virt(xen_store_mfn);
+
+	/* Initialize the interface to xenstore. */
+	err = xs_init();
+	if (err) {
+		printk(KERN_WARNING
+		       "XENBUS: Error initializing xenstore comms: %i\n", err);
+		goto out_unreg_back;
+	}
+
+	if (!is_initial_xendomain())
+		xenbus_probe(NULL);
+
+	return 0;
+
+  out_unreg_back:
+	xenbus_backend_bus_unregister();
+
+  out_unreg_front:
+	bus_unregister(&xenbus_frontend.bus);
+
+  out_error:
+	return err;
+}
+
+postcore_initcall(xenbus_probe_init);
+
+MODULE_LICENSE("Dual BSD/GPL");
+
+static int is_disconnected_device(struct device *dev, void *data)
+{
+	struct xenbus_device *xendev = to_xenbus_device(dev);
+	struct device_driver *drv = data;
+
+	/*
+	 * A device with no driver will never connect. We care only about
+	 * devices which should currently be in the process of connecting.
+	 */
+	if (!dev->driver)
+		return 0;
+
+	/* Is this search limited to a particular driver? */
+	if (drv && (dev->driver != drv))
+		return 0;
+
+	return (xendev->state != XenbusStateConnected);
+}
+
+static int exists_disconnected_device(struct device_driver *drv)
+{
+	return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
+				is_disconnected_device);
+}
+
+static int print_device_status(struct device *dev, void *data)
+{
+	struct xenbus_device *xendev = to_xenbus_device(dev);
+	struct device_driver *drv = data;
+
+	/* Is this operation limited to a particular driver? */
+	if (drv && (dev->driver != drv))
+		return 0;
+
+	if (!dev->driver) {
+		/* Information only: is this too noisy? */
+		printk(KERN_INFO "XENBUS: Device with no driver: %s\n",
+		       xendev->nodename);
+	} else if (xendev->state != XenbusStateConnected) {
+		printk(KERN_WARNING "XENBUS: Timeout connecting "
+		       "to device: %s (state %d)\n",
+		       xendev->nodename, xendev->state);
+	}
+
+	return 0;
+}
+
+/* We only wait for device setup after most initcalls have run. */
+static int ready_to_wait_for_devices;
+
+/*
+ * On a 10 second timeout, wait for all devices currently configured.  We need
+ * to do this to guarantee that the filesystems and / or network devices
+ * needed for boot are available, before we can allow the boot to proceed.
+ *
+ * This needs to be on a late_initcall, to happen after the frontend device
+ * drivers have been initialised, but before the root fs is mounted.
+ *
+ * A possible improvement here would be to have the tools add a per-device
+ * flag to the store entry, indicating whether it is needed at boot time.
+ * This would allow people who knew what they were doing to accelerate their
+ * boot slightly, but of course needs tools or manual intervention to set up
+ * those flags correctly.
+ */
+static void wait_for_devices(struct xenbus_driver *xendrv)
+{
+	unsigned long timeout = jiffies + 10*HZ;
+	struct device_driver *drv = xendrv ? &xendrv->driver : NULL;
+
+	if (!ready_to_wait_for_devices || !is_running_on_xen())
+		return;
+
+	while (exists_disconnected_device(drv)) {
+		if (time_after(jiffies, timeout))
+			break;
+		schedule_timeout_interruptible(HZ/10);
+	}
+
+	bus_for_each_dev(&xenbus_frontend.bus, NULL, drv,
+			 print_device_status);
+}
+
+#ifndef MODULE
+static int __init boot_wait_for_devices(void)
+{
+	ready_to_wait_for_devices = 1;
+	wait_for_devices(NULL);
+	return 0;
+}
+
+late_initcall(boot_wait_for_devices);
+#endif
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_probe.h
@@ -0,0 +1,72 @@
+/******************************************************************************
+ * xenbus_probe.h
+ *
+ * Talks to Xen Store to figure out what devices we have.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ * Copyright (C) 2005 XenSource Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _XENBUS_PROBE_H
+#define _XENBUS_PROBE_H
+
+#ifdef CONFIG_XEN_BACKEND
+extern void xenbus_backend_suspend(int (*fn)(struct device *, void *));
+extern void xenbus_backend_resume(int (*fn)(struct device *, void *));
+extern void xenbus_backend_probe_and_watch(void);
+extern int xenbus_backend_bus_register(void);
+extern void xenbus_backend_bus_unregister(void);
+#else
+static inline void xenbus_backend_suspend(int (*fn)(struct device *, void *)) {}
+static inline void xenbus_backend_resume(int (*fn)(struct device *, void *)) {}
+static inline void xenbus_backend_probe_and_watch(void) {}
+static inline int xenbus_backend_bus_register(void) {return 0;}
+static inline void xenbus_backend_bus_unregister(void) {}
+#endif
+
+struct xen_bus_type
+{
+	char *root;
+	unsigned int levels;
+	int (*get_bus_id)(char bus_id[BUS_ID_SIZE], const char *nodename);
+	int (*probe)(const char *type, const char *dir);
+	struct bus_type bus;
+};
+
+extern int xenbus_match(struct device *_dev, struct device_driver *_drv);
+extern int xenbus_dev_probe(struct device *_dev);
+extern int xenbus_dev_remove(struct device *_dev);
+extern int xenbus_register_driver_common(struct xenbus_driver *drv,
+					 struct xen_bus_type *bus);
+extern int xenbus_probe_node(struct xen_bus_type *bus,
+			     const char *type,
+			     const char *nodename);
+extern int xenbus_probe_devices(struct xen_bus_type *bus);
+
+extern void dev_changed(const char *node, struct xen_bus_type *bus);
+
+#endif
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -0,0 +1,265 @@
+/******************************************************************************
+ * Talks to Xen Store to figure out what devices we have (backend half).
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ * Copyright (C) 2005 Mike Wray, Hewlett-Packard
+ * Copyright (C) 2005, 2006 XenSource Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define DPRINTK(fmt, args...)				\
+	pr_debug("xenbus_probe (%s:%d) " fmt ".\n",	\
+		 __FUNCTION__, __LINE__, ##args)
+
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/notifier.h>
+#include <linux/kthread.h>
+
+#include <asm/io.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/xenbus.h>
+#include <xen/features.h>
+
+#include "xenbus_comms.h"
+#include "xenbus_probe.h"
+
+#ifdef HAVE_XEN_PLATFORM_COMPAT_H
+#include <xen/platform-compat.h>
+#endif
+
+static int xenbus_uevent_backend(struct device *dev, char **envp,
+				 int num_envp, char *buffer, int buffer_size);
+static int xenbus_probe_backend(const char *type, const char *domid);
+
+extern int read_otherend_details(struct xenbus_device *xendev,
+				 char *id_node, char *path_node);
+
+static int read_frontend_details(struct xenbus_device *xendev)
+{
+	return read_otherend_details(xendev, "frontend-id", "frontend");
+}
+
+/* backend/<type>/<fe-uuid>/<id> => <type>-<fe-domid>-<id> */
+static int backend_bus_id(char bus_id[BUS_ID_SIZE], const char *nodename)
+{
+	int domid, err;
+	const char *devid, *type, *frontend;
+	unsigned int typelen;
+
+	type = strchr(nodename, '/');
+	if (!type)
+		return -EINVAL;
+	type++;
+	typelen = strcspn(type, "/");
+	if (!typelen || type[typelen] != '/')
+		return -EINVAL;
+
+	devid = strrchr(nodename, '/') + 1;
+
+	err = xenbus_gather(XBT_NIL, nodename, "frontend-id", "%i", &domid,
+			    "frontend", NULL, &frontend,
+			    NULL);
+	if (err)
+		return err;
+	if (strlen(frontend) == 0)
+		err = -ERANGE;
+	if (!err && !xenbus_exists(XBT_NIL, frontend, ""))
+		err = -ENOENT;
+
+	kfree(frontend);
+
+	if (err)
+		return err;
+
+	if (snprintf(bus_id, BUS_ID_SIZE,
+		     "%.*s-%i-%s", typelen, type, domid, devid) >= BUS_ID_SIZE)
+		return -ENOSPC;
+	return 0;
+}
+
+static struct xen_bus_type xenbus_backend = {
+	.root = "backend",
+	.levels = 3, 		/* backend/type/<frontend>/<id> */
+	.get_bus_id = backend_bus_id,
+	.probe = xenbus_probe_backend,
+	.bus = {
+		.name     = "xen-backend",
+		.match    = xenbus_match,
+		.probe    = xenbus_dev_probe,
+		.remove   = xenbus_dev_remove,
+		.shutdown = xenbus_dev_shutdown,
+		.uevent   = xenbus_uevent_backend,
+	},
+};
+
+static int xenbus_uevent_backend(struct device *dev, char **envp,
+				 int num_envp, char *buffer, int buffer_size)
+{
+	struct xenbus_device *xdev;
+	struct xenbus_driver *drv;
+	int i = 0;
+	int length = 0;
+
+	DPRINTK("");
+
+	if (dev == NULL)
+		return -ENODEV;
+
+	xdev = to_xenbus_device(dev);
+	if (xdev == NULL)
+		return -ENODEV;
+
+	/* stuff we want to pass to /sbin/hotplug */
+	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
+		       "XENBUS_TYPE=%s", xdev->devicetype);
+
+	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
+		       "XENBUS_PATH=%s", xdev->nodename);
+
+	add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
+		       "XENBUS_BASE_PATH=%s", xenbus_backend.root);
+
+	/* terminate, set to next free slot, shrink available space */
+	envp[i] = NULL;
+	envp = &envp[i];
+	num_envp -= i;
+	buffer = &buffer[length];
+	buffer_size -= length;
+
+	if (dev->driver) {
+		drv = to_xenbus_driver(dev->driver);
+		if (drv && drv->uevent)
+			return drv->uevent(xdev, envp, num_envp, buffer,
+					   buffer_size);
+	}
+
+	return 0;
+}
+
+int xenbus_register_backend(struct xenbus_driver *drv)
+{
+	drv->read_otherend_details = read_frontend_details;
+
+	return xenbus_register_driver_common(drv, &xenbus_backend);
+}
+EXPORT_SYMBOL_GPL(xenbus_register_backend);
+
+/* backend/<typename>/<frontend-uuid>/<name> */
+static int xenbus_probe_backend_unit(const char *dir,
+				     const char *type,
+				     const char *name)
+{
+	char *nodename;
+	int err;
+
+	nodename = kasprintf(GFP_KERNEL, "%s/%s", dir, name);
+	if (!nodename)
+		return -ENOMEM;
+
+	DPRINTK("%s\n", nodename);
+
+	err = xenbus_probe_node(&xenbus_backend, type, nodename);
+	kfree(nodename);
+	return err;
+}
+
+/* backend/<typename>/<frontend-domid> */
+static int xenbus_probe_backend(const char *type, const char *domid)
+{
+	char *nodename;
+	int err = 0;
+	char **dir;
+	unsigned int i, dir_n = 0;
+
+	DPRINTK("");
+
+	nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", xenbus_backend.root, type, domid);
+	if (!nodename)
+		return -ENOMEM;
+
+	dir = xenbus_directory(XBT_NIL, nodename, "", &dir_n);
+	if (IS_ERR(dir)) {
+		kfree(nodename);
+		return PTR_ERR(dir);
+	}
+
+	for (i = 0; i < dir_n; i++) {
+		err = xenbus_probe_backend_unit(nodename, type, dir[i]);
+		if (err)
+			break;
+	}
+	kfree(dir);
+	kfree(nodename);
+	return err;
+}
+
+static void backend_changed(struct xenbus_watch *watch,
+			    const char **vec, unsigned int len)
+{
+	DPRINTK("");
+
+	dev_changed(vec[XS_WATCH_PATH], &xenbus_backend);
+}
+
+static struct xenbus_watch be_watch = {
+	.node = "backend",
+	.callback = backend_changed,
+};
+
+void xenbus_backend_suspend(int (*fn)(struct device *, void *))
+{
+	DPRINTK("");
+	bus_for_each_dev(&xenbus_backend.bus, NULL, NULL, fn);
+}
+
+void xenbus_backend_resume(int (*fn)(struct device *, void *))
+{
+	DPRINTK("");
+	bus_for_each_dev(&xenbus_backend.bus, NULL, NULL, fn);
+}
+
+void xenbus_backend_probe_and_watch(void)
+{
+	xenbus_probe_devices(&xenbus_backend);
+	register_xenbus_watch(&be_watch);
+}
+
+int xenbus_backend_bus_register(void)
+{
+	return bus_register(&xenbus_backend.bus);
+}
+
+void xenbus_backend_bus_unregister(void)
+{
+	bus_unregister(&xenbus_backend.bus);
+}
===================================================================
--- /dev/null
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -0,0 +1,861 @@
+/******************************************************************************
+ * xenbus_xs.c
+ *
+ * This is the kernel equivalent of the "xs" library.  We don't need everything
+ * and we use xenbus_comms for communication.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/unistd.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/uio.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/fcntl.h>
+#include <linux/kthread.h>
+#include <linux/rwsem.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <xen/xenbus.h>
+#include "xenbus_comms.h"
+
+struct xs_stored_msg {
+	struct list_head list;
+
+	struct xsd_sockmsg hdr;
+
+	union {
+		/* Queued replies. */
+		struct {
+			char *body;
+		} reply;
+
+		/* Queued watch events. */
+		struct {
+			struct xenbus_watch *handle;
+			char **vec;
+			unsigned int vec_size;
+		} watch;
+	} u;
+};
+
+struct xs_handle {
+	/* A list of replies. Currently only one will ever be outstanding. */
+	struct list_head reply_list;
+	spinlock_t reply_lock;
+	wait_queue_head_t reply_waitq;
+
+	/*
+	 * Mutex ordering: transaction_mutex -> watch_mutex -> request_mutex.
+	 * response_mutex is never taken simultaneously with the other three.
+	 */
+
+	/* One request at a time. */
+	struct mutex request_mutex;
+
+	/* Protect xenbus reader thread against save/restore. */
+	struct mutex response_mutex;
+
+	/* Protect transactions against save/restore. */
+	struct rw_semaphore transaction_mutex;
+
+	/* Protect watch (de)register against save/restore. */
+	struct rw_semaphore watch_mutex;
+};
+
+static struct xs_handle xs_state;
+
+/* List of registered watches, and a lock to protect it. */
+static LIST_HEAD(watches);
+static DEFINE_SPINLOCK(watches_lock);
+
+/* List of pending watch callback events, and a lock to protect it. */
+static LIST_HEAD(watch_events);
+static DEFINE_SPINLOCK(watch_events_lock);
+
+/*
+ * Details of the xenwatch callback kernel thread. The thread waits on the
+ * watch_events_waitq for work to do (queued on watch_events list). When it
+ * wakes up it acquires the xenwatch_mutex before reading the list and
+ * carrying out work.
+ */
+static pid_t xenwatch_pid;
+static DEFINE_MUTEX(xenwatch_mutex);
+static DECLARE_WAIT_QUEUE_HEAD(watch_events_waitq);
+
+static int get_error(const char *errorstring)
+{
+	unsigned int i;
+
+	for (i = 0; strcmp(errorstring, xsd_errors[i].errstring) != 0; i++) {
+		if (i == ARRAY_SIZE(xsd_errors) - 1) {
+			printk(KERN_WARNING
+			       "XENBUS xen store gave: unknown error %s",
+			       errorstring);
+			return EINVAL;
+		}
+	}
+	return xsd_errors[i].errnum;
+}
+
+static void *read_reply(enum xsd_sockmsg_type *type, unsigned int *len)
+{
+	struct xs_stored_msg *msg;
+	char *body;
+
+	spin_lock(&xs_state.reply_lock);
+
+	while (list_empty(&xs_state.reply_list)) {
+		spin_unlock(&xs_state.reply_lock);
+		/* XXX FIXME: Avoid synchronous wait for response here. */
+		wait_event(xs_state.reply_waitq,
+			   !list_empty(&xs_state.reply_list));
+		spin_lock(&xs_state.reply_lock);
+	}
+
+	msg = list_entry(xs_state.reply_list.next,
+			 struct xs_stored_msg, list);
+	list_del(&msg->list);
+
+	spin_unlock(&xs_state.reply_lock);
+
+	*type = msg->hdr.type;
+	if (len)
+		*len = msg->hdr.len;
+	body = msg->u.reply.body;
+
+	kfree(msg);
+
+	return body;
+}
+
+void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
+{
+	void *ret;
+	struct xsd_sockmsg req_msg = *msg;
+	int err;
+
+	if (req_msg.type == XS_TRANSACTION_START)
+		down_read(&xs_state.transaction_mutex);
+
+	mutex_lock(&xs_state.request_mutex);
+
+	err = xb_write(msg, sizeof(*msg) + msg->len);
+	if (err) {
+		msg->type = XS_ERROR;
+		ret = ERR_PTR(err);
+	} else
+		ret = read_reply(&msg->type, &msg->len);
+
+	mutex_unlock(&xs_state.request_mutex);
+
+	if ((msg->type == XS_TRANSACTION_END) ||
+	    ((req_msg.type == XS_TRANSACTION_START) &&
+	     (msg->type == XS_ERROR)))
+		up_read(&xs_state.transaction_mutex);
+
+	return ret;
+}
+
+/* Send message to xs, get kmalloc'ed reply.  ERR_PTR() on error. */
+static void *xs_talkv(struct xenbus_transaction t,
+		      enum xsd_sockmsg_type type,
+		      const struct kvec *iovec,
+		      unsigned int num_vecs,
+		      unsigned int *len)
+{
+	struct xsd_sockmsg msg;
+	void *ret = NULL;
+	unsigned int i;
+	int err;
+
+	msg.tx_id = t.id;
+	msg.req_id = 0;
+	msg.type = type;
+	msg.len = 0;
+	for (i = 0; i < num_vecs; i++)
+		msg.len += iovec[i].iov_len;
+
+	mutex_lock(&xs_state.request_mutex);
+
+	err = xb_write(&msg, sizeof(msg));
+	if (err) {
+		mutex_unlock(&xs_state.request_mutex);
+		return ERR_PTR(err);
+	}
+
+	for (i = 0; i < num_vecs; i++) {
+		err = xb_write(iovec[i].iov_base, iovec[i].iov_len);;
+		if (err) {
+			mutex_unlock(&xs_state.request_mutex);
+			return ERR_PTR(err);
+		}
+	}
+
+	ret = read_reply(&msg.type, len);
+
+	mutex_unlock(&xs_state.request_mutex);
+
+	if (IS_ERR(ret))
+		return ret;
+
+	if (msg.type == XS_ERROR) {
+		err = get_error(ret);
+		kfree(ret);
+		return ERR_PTR(-err);
+	}
+
+	if (msg.type != type) {
+		if (printk_ratelimit())
+			printk(KERN_WARNING
+			       "XENBUS unexpected type [%d], expected [%d]\n",
+			       msg.type, type);
+		kfree(ret);
+		return ERR_PTR(-EINVAL);
+	}
+	return ret;
+}
+
+/* Simplified version of xs_talkv: single message. */
+static void *xs_single(struct xenbus_transaction t,
+		       enum xsd_sockmsg_type type,
+		       const char *string,
+		       unsigned int *len)
+{
+	struct kvec iovec;
+
+	iovec.iov_base = (void *)string;
+	iovec.iov_len = strlen(string) + 1;
+	return xs_talkv(t, type, &iovec, 1, len);
+}
+
+/* Many commands only need an ack, don't care what it says. */
+static int xs_error(char *reply)
+{
+	if (IS_ERR(reply))
+		return PTR_ERR(reply);
+	kfree(reply);
+	return 0;
+}
+
+static unsigned int count_strings(const char *strings, unsigned int len)
+{
+	unsigned int num;
+	const char *p;
+
+	for (p = strings, num = 0; p < strings + len; p += strlen(p) + 1)
+		num++;
+
+	return num;
+}
+
+/* Return the path to dir with /name appended. Buffer must be kfree()'ed. */
+static char *join(const char *dir, const char *name)
+{
+	char *buffer;
+
+	if (strlen(name) == 0)
+		buffer = kasprintf(GFP_KERNEL, "%s", dir);
+	else
+		buffer = kasprintf(GFP_KERNEL, "%s/%s", dir, name);
+	return (!buffer) ? ERR_PTR(-ENOMEM) : buffer;
+}
+
+static char **split(char *strings, unsigned int len, unsigned int *num)
+{
+	char *p, **ret;
+
+	/* Count the strings. */
+	*num = count_strings(strings, len);
+
+	/* Transfer to one big alloc for easy freeing. */
+	ret = kmalloc(*num * sizeof(char *) + len, GFP_KERNEL);
+	if (!ret) {
+		kfree(strings);
+		return ERR_PTR(-ENOMEM);
+	}
+	memcpy(&ret[*num], strings, len);
+	kfree(strings);
+
+	strings = (char *)&ret[*num];
+	for (p = strings, *num = 0; p < strings + len; p += strlen(p) + 1)
+		ret[(*num)++] = p;
+
+	return ret;
+}
+
+char **xenbus_directory(struct xenbus_transaction t,
+			const char *dir, const char *node, unsigned int *num)
+{
+	char *strings, *path;
+	unsigned int len;
+
+	path = join(dir, node);
+	if (IS_ERR(path))
+		return (char **)path;
+
+	strings = xs_single(t, XS_DIRECTORY, path, &len);
+	kfree(path);
+	if (IS_ERR(strings))
+		return (char **)strings;
+
+	return split(strings, len, num);
+}
+EXPORT_SYMBOL_GPL(xenbus_directory);
+
+/* Check if a path exists. Return 1 if it does. */
+int xenbus_exists(struct xenbus_transaction t,
+		  const char *dir, const char *node)
+{
+	char **d;
+	int dir_n;
+
+	d = xenbus_directory(t, dir, node, &dir_n);
+	if (IS_ERR(d))
+		return 0;
+	kfree(d);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(xenbus_exists);
+
+/* Get the value of a single file.
+ * Returns a kmalloced value: call free() on it after use.
+ * len indicates length in bytes.
+ */
+void *xenbus_read(struct xenbus_transaction t,
+		  const char *dir, const char *node, unsigned int *len)
+{
+	char *path;
+	void *ret;
+
+	path = join(dir, node);
+	if (IS_ERR(path))
+		return (void *)path;
+
+	ret = xs_single(t, XS_READ, path, len);
+	kfree(path);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_read);
+
+/* Write the value of a single file.
+ * Returns -err on failure.
+ */
+int xenbus_write(struct xenbus_transaction t,
+		 const char *dir, const char *node, const char *string)
+{
+	const char *path;
+	struct kvec iovec[2];
+	int ret;
+
+	path = join(dir, node);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	iovec[0].iov_base = (void *)path;
+	iovec[0].iov_len = strlen(path) + 1;
+	iovec[1].iov_base = (void *)string;
+	iovec[1].iov_len = strlen(string);
+
+	ret = xs_error(xs_talkv(t, XS_WRITE, iovec, ARRAY_SIZE(iovec), NULL));
+	kfree(path);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_write);
+
+/* Create a new directory. */
+int xenbus_mkdir(struct xenbus_transaction t,
+		 const char *dir, const char *node)
+{
+	char *path;
+	int ret;
+
+	path = join(dir, node);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	ret = xs_error(xs_single(t, XS_MKDIR, path, NULL));
+	kfree(path);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_mkdir);
+
+/* Destroy a file or directory (directories must be empty). */
+int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node)
+{
+	char *path;
+	int ret;
+
+	path = join(dir, node);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	ret = xs_error(xs_single(t, XS_RM, path, NULL));
+	kfree(path);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_rm);
+
+/* Start a transaction: changes by others will not be seen during this
+ * transaction, and changes will not be visible to others until end.
+ */
+int xenbus_transaction_start(struct xenbus_transaction *t)
+{
+	char *id_str;
+
+	down_read(&xs_state.transaction_mutex);
+
+	id_str = xs_single(XBT_NIL, XS_TRANSACTION_START, "", NULL);
+	if (IS_ERR(id_str)) {
+		up_read(&xs_state.transaction_mutex);
+		return PTR_ERR(id_str);
+	}
+
+	t->id = simple_strtoul(id_str, NULL, 0);
+	kfree(id_str);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_transaction_start);
+
+/* End a transaction.
+ * If abandon is true, transaction is discarded instead of committed.
+ */
+int xenbus_transaction_end(struct xenbus_transaction t, int abort)
+{
+	char abortstr[2];
+	int err;
+
+	if (abort)
+		strcpy(abortstr, "F");
+	else
+		strcpy(abortstr, "T");
+
+	err = xs_error(xs_single(t, XS_TRANSACTION_END, abortstr, NULL));
+
+	up_read(&xs_state.transaction_mutex);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_transaction_end);
+
+/* Single read and scanf: returns -errno or num scanned. */
+int xenbus_scanf(struct xenbus_transaction t,
+		 const char *dir, const char *node, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+	char *val;
+
+	val = xenbus_read(t, dir, node, NULL);
+	if (IS_ERR(val))
+		return PTR_ERR(val);
+
+	va_start(ap, fmt);
+	ret = vsscanf(val, fmt, ap);
+	va_end(ap);
+	kfree(val);
+	/* Distinctive errno. */
+	if (ret == 0)
+		return -ERANGE;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_scanf);
+
+/* Single printf and write: returns -errno or 0. */
+int xenbus_printf(struct xenbus_transaction t,
+		  const char *dir, const char *node, const char *fmt, ...)
+{
+	va_list ap;
+	int ret;
+#define PRINTF_BUFFER_SIZE 4096
+	char *printf_buffer;
+
+	printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
+	if (printf_buffer == NULL)
+		return -ENOMEM;
+
+	va_start(ap, fmt);
+	ret = vsnprintf(printf_buffer, PRINTF_BUFFER_SIZE, fmt, ap);
+	va_end(ap);
+
+	BUG_ON(ret > PRINTF_BUFFER_SIZE-1);
+	ret = xenbus_write(t, dir, node, printf_buffer);
+
+	kfree(printf_buffer);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_printf);
+
+/* Takes tuples of names, scanf-style args, and void **, NULL terminated. */
+int xenbus_gather(struct xenbus_transaction t, const char *dir, ...)
+{
+	va_list ap;
+	const char *name;
+	int ret = 0;
+
+	va_start(ap, dir);
+	while (ret == 0 && (name = va_arg(ap, char *)) != NULL) {
+		const char *fmt = va_arg(ap, char *);
+		void *result = va_arg(ap, void *);
+		char *p;
+
+		p = xenbus_read(t, dir, name, NULL);
+		if (IS_ERR(p)) {
+			ret = PTR_ERR(p);
+			break;
+		}
+		if (fmt) {
+			if (sscanf(p, fmt, result) == 0)
+				ret = -EINVAL;
+			kfree(p);
+		} else
+			*(char **)result = p;
+	}
+	va_end(ap);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(xenbus_gather);
+
+static int xs_watch(const char *path, const char *token)
+{
+	struct kvec iov[2];
+
+	iov[0].iov_base = (void *)path;
+	iov[0].iov_len = strlen(path) + 1;
+	iov[1].iov_base = (void *)token;
+	iov[1].iov_len = strlen(token) + 1;
+
+	return xs_error(xs_talkv(XBT_NIL, XS_WATCH, iov,
+				 ARRAY_SIZE(iov), NULL));
+}
+
+static int xs_unwatch(const char *path, const char *token)
+{
+	struct kvec iov[2];
+
+	iov[0].iov_base = (char *)path;
+	iov[0].iov_len = strlen(path) + 1;
+	iov[1].iov_base = (char *)token;
+	iov[1].iov_len = strlen(token) + 1;
+
+	return xs_error(xs_talkv(XBT_NIL, XS_UNWATCH, iov,
+				 ARRAY_SIZE(iov), NULL));
+}
+
+static struct xenbus_watch *find_watch(const char *token)
+{
+	struct xenbus_watch *i, *cmp;
+
+	cmp = (void *)simple_strtoul(token, NULL, 16);
+
+	list_for_each_entry(i, &watches, list)
+		if (i == cmp)
+			return i;
+
+	return NULL;
+}
+
+/* Register callback to watch this node. */
+int register_xenbus_watch(struct xenbus_watch *watch)
+{
+	/* Pointer in ascii is the token. */
+	char token[sizeof(watch) * 2 + 1];
+	int err;
+
+	sprintf(token, "%lX", (long)watch);
+
+	down_read(&xs_state.watch_mutex);
+
+	spin_lock(&watches_lock);
+	BUG_ON(find_watch(token));
+	list_add(&watch->list, &watches);
+	spin_unlock(&watches_lock);
+
+	err = xs_watch(watch->node, token);
+
+	/* Ignore errors due to multiple registration. */
+	if ((err != 0) && (err != -EEXIST)) {
+		spin_lock(&watches_lock);
+		list_del(&watch->list);
+		spin_unlock(&watches_lock);
+	}
+
+	up_read(&xs_state.watch_mutex);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(register_xenbus_watch);
+
+void unregister_xenbus_watch(struct xenbus_watch *watch)
+{
+	struct xs_stored_msg *msg, *tmp;
+	char token[sizeof(watch) * 2 + 1];
+	int err;
+
+	sprintf(token, "%lX", (long)watch);
+
+	down_read(&xs_state.watch_mutex);
+
+	spin_lock(&watches_lock);
+	BUG_ON(!find_watch(token));
+	list_del(&watch->list);
+	spin_unlock(&watches_lock);
+
+	err = xs_unwatch(watch->node, token);
+	if (err)
+		printk(KERN_WARNING
+		       "XENBUS Failed to release watch %s: %i\n",
+		       watch->node, err);
+
+	up_read(&xs_state.watch_mutex);
+
+	/* Make sure there are no callbacks running currently (unless
+	   its us) */
+	if (current->pid != xenwatch_pid)
+		mutex_lock(&xenwatch_mutex);
+
+	/* Cancel pending watch events. */
+	spin_lock(&watch_events_lock);
+	list_for_each_entry_safe(msg, tmp, &watch_events, list) {
+		if (msg->u.watch.handle != watch)
+			continue;
+		list_del(&msg->list);
+		kfree(msg->u.watch.vec);
+		kfree(msg);
+	}
+	spin_unlock(&watch_events_lock);
+
+	if (current->pid != xenwatch_pid)
+		mutex_unlock(&xenwatch_mutex);
+}
+EXPORT_SYMBOL_GPL(unregister_xenbus_watch);
+
+void xs_suspend(void)
+{
+	down_write(&xs_state.transaction_mutex);
+	down_write(&xs_state.watch_mutex);
+	mutex_lock(&xs_state.request_mutex);
+	mutex_lock(&xs_state.response_mutex);
+}
+
+void xs_resume(void)
+{
+	struct xenbus_watch *watch;
+	char token[sizeof(watch) * 2 + 1];
+
+	mutex_unlock(&xs_state.response_mutex);
+	mutex_unlock(&xs_state.request_mutex);
+	up_write(&xs_state.transaction_mutex);
+
+	/* No need for watches_lock: the watch_mutex is sufficient. */
+	list_for_each_entry(watch, &watches, list) {
+		sprintf(token, "%lX", (long)watch);
+		xs_watch(watch->node, token);
+	}
+
+	up_write(&xs_state.watch_mutex);
+}
+
+void xs_suspend_cancel(void)
+{
+	mutex_unlock(&xs_state.response_mutex);
+	mutex_unlock(&xs_state.request_mutex);
+	up_write(&xs_state.watch_mutex);
+	up_write(&xs_state.transaction_mutex);
+}
+
+static int xenwatch_thread(void *unused)
+{
+	struct list_head *ent;
+	struct xs_stored_msg *msg;
+
+	for (;;) {
+		wait_event_interruptible(watch_events_waitq,
+					 !list_empty(&watch_events));
+
+		if (kthread_should_stop())
+			break;
+
+		mutex_lock(&xenwatch_mutex);
+
+		spin_lock(&watch_events_lock);
+		ent = watch_events.next;
+		if (ent != &watch_events)
+			list_del(ent);
+		spin_unlock(&watch_events_lock);
+
+		if (ent != &watch_events) {
+			msg = list_entry(ent, struct xs_stored_msg, list);
+			msg->u.watch.handle->callback(
+				msg->u.watch.handle,
+				(const char **)msg->u.watch.vec,
+				msg->u.watch.vec_size);
+			kfree(msg->u.watch.vec);
+			kfree(msg);
+		}
+
+		mutex_unlock(&xenwatch_mutex);
+	}
+
+	return 0;
+}
+
+static int process_msg(void)
+{
+	struct xs_stored_msg *msg;
+	char *body;
+	int err;
+
+	/*
+	 * We must disallow save/restore while reading a xenstore message.
+	 * A partial read across s/r leaves us out of sync with xenstored.
+	 */
+	for (;;) {
+		err = xb_wait_for_data_to_read();
+		if (err)
+			return err;
+		mutex_lock(&xs_state.response_mutex);
+		if (xb_data_to_read())
+			break;
+		/* We raced with save/restore: pending data 'disappeared'. */
+		mutex_unlock(&xs_state.response_mutex);
+	}
+
+
+	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
+	if (msg == NULL) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = xb_read(&msg->hdr, sizeof(msg->hdr));
+	if (err) {
+		kfree(msg);
+		goto out;
+	}
+
+	body = kmalloc(msg->hdr.len + 1, GFP_KERNEL);
+	if (body == NULL) {
+		kfree(msg);
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = xb_read(body, msg->hdr.len);
+	if (err) {
+		kfree(body);
+		kfree(msg);
+		goto out;
+	}
+	body[msg->hdr.len] = '\0';
+
+	if (msg->hdr.type == XS_WATCH_EVENT) {
+		msg->u.watch.vec = split(body, msg->hdr.len,
+					 &msg->u.watch.vec_size);
+		if (IS_ERR(msg->u.watch.vec)) {
+			kfree(msg);
+			err = PTR_ERR(msg->u.watch.vec);
+			goto out;
+		}
+
+		spin_lock(&watches_lock);
+		msg->u.watch.handle = find_watch(
+			msg->u.watch.vec[XS_WATCH_TOKEN]);
+		if (msg->u.watch.handle != NULL) {
+			spin_lock(&watch_events_lock);
+			list_add_tail(&msg->list, &watch_events);
+			wake_up(&watch_events_waitq);
+			spin_unlock(&watch_events_lock);
+		} else {
+			kfree(msg->u.watch.vec);
+			kfree(msg);
+		}
+		spin_unlock(&watches_lock);
+	} else {
+		msg->u.reply.body = body;
+		spin_lock(&xs_state.reply_lock);
+		list_add_tail(&msg->list, &xs_state.reply_list);
+		spin_unlock(&xs_state.reply_lock);
+		wake_up(&xs_state.reply_waitq);
+	}
+
+ out:
+	mutex_unlock(&xs_state.response_mutex);
+	return err;
+}
+
+static int xenbus_thread(void *unused)
+{
+	int err;
+
+	for (;;) {
+		err = process_msg();
+		if (err)
+			printk(KERN_WARNING "XENBUS error %d while reading "
+			       "message\n", err);
+		if (kthread_should_stop())
+			break;
+	}
+
+	return 0;
+}
+
+int xs_init(void)
+{
+	int err;
+	struct task_struct *task;
+
+	INIT_LIST_HEAD(&xs_state.reply_list);
+	spin_lock_init(&xs_state.reply_lock);
+	init_waitqueue_head(&xs_state.reply_waitq);
+
+	mutex_init(&xs_state.request_mutex);
+	mutex_init(&xs_state.response_mutex);
+	init_rwsem(&xs_state.transaction_mutex);
+	init_rwsem(&xs_state.watch_mutex);
+
+	/* Initialize the shared memory rings to talk to xenstored */
+	err = xb_init_comms();
+	if (err)
+		return err;
+
+	task = kthread_run(xenwatch_thread, NULL, "xenwatch");
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+	xenwatch_pid = task->pid;
+
+	task = kthread_run(xenbus_thread, NULL, "xenbus");
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+
+	return 0;
+}
===================================================================
--- a/include/asm-i386/xen/hypervisor.h
+++ b/include/asm-i386/xen/hypervisor.h
@@ -42,6 +42,7 @@
 
 #include <asm/ptrace.h>
 #include <asm/page.h>
+#include <asm/desc.h>
 #if defined(__i386__)
 #  ifdef CONFIG_X86_PAE
 #   include <asm-generic/pgtable-nopud.h>
===================================================================
--- /dev/null
+++ b/include/xen/xenbus.h
@@ -0,0 +1,211 @@
+/******************************************************************************
+ * xenbus.h
+ *
+ * Talks to Xen Store to figure out what devices we have.
+ *
+ * Copyright (C) 2005 Rusty Russell, IBM Corporation
+ * Copyright (C) 2005 XenSource Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _XEN_XENBUS_H
+#define _XEN_XENBUS_H
+
+#include <linux/device.h>
+#include <linux/notifier.h>
+#include <linux/mutex.h>
+#include <linux/completion.h>
+#include <linux/init.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/grant_table.h>
+#include <xen/interface/io/xenbus.h>
+#include <xen/interface/io/xs_wire.h>
+
+/* Register callback to watch this node. */
+struct xenbus_watch
+{
+	struct list_head list;
+
+	/* Path being watched. */
+	const char *node;
+
+	/* Callback (executed in a process context with no locks held). */
+	void (*callback)(struct xenbus_watch *,
+			 const char **vec, unsigned int len);
+};
+
+
+/* A xenbus device. */
+struct xenbus_device {
+	const char *devicetype;
+	const char *nodename;
+	const char *otherend;
+	int otherend_id;
+	struct xenbus_watch otherend_watch;
+	struct device dev;
+	enum xenbus_state state;
+	struct completion down;
+};
+
+static inline struct xenbus_device *to_xenbus_device(struct device *dev)
+{
+	return container_of(dev, struct xenbus_device, dev);
+}
+
+struct xenbus_device_id
+{
+	/* .../device/<device_type>/<identifier> */
+	char devicetype[32]; 	/* General class of device. */
+};
+
+/* A xenbus driver. */
+struct xenbus_driver {
+	char *name;
+	struct module *owner;
+	const struct xenbus_device_id *ids;
+	int (*probe)(struct xenbus_device *dev,
+		     const struct xenbus_device_id *id);
+	void (*otherend_changed)(struct xenbus_device *dev,
+				 enum xenbus_state backend_state);
+	int (*remove)(struct xenbus_device *dev);
+	int (*suspend)(struct xenbus_device *dev);
+	int (*suspend_cancel)(struct xenbus_device *dev);
+	int (*resume)(struct xenbus_device *dev);
+	int (*uevent)(struct xenbus_device *, char **, int, char *, int);
+	struct device_driver driver;
+	int (*read_otherend_details)(struct xenbus_device *dev);
+};
+
+static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)
+{
+	return container_of(drv, struct xenbus_driver, driver);
+}
+
+int xenbus_register_frontend(struct xenbus_driver *drv);
+int xenbus_register_backend(struct xenbus_driver *drv);
+void xenbus_unregister_driver(struct xenbus_driver *drv);
+
+struct xenbus_transaction
+{
+	u32 id;
+};
+
+/* Nil transaction ID. */
+#define XBT_NIL ((struct xenbus_transaction) { 0 })
+
+int __init xenbus_dev_init(void);
+
+char **xenbus_directory(struct xenbus_transaction t,
+			const char *dir, const char *node, unsigned int *num);
+void *xenbus_read(struct xenbus_transaction t,
+		  const char *dir, const char *node, unsigned int *len);
+int xenbus_write(struct xenbus_transaction t,
+		 const char *dir, const char *node, const char *string);
+int xenbus_mkdir(struct xenbus_transaction t,
+		 const char *dir, const char *node);
+int xenbus_exists(struct xenbus_transaction t,
+		  const char *dir, const char *node);
+int xenbus_rm(struct xenbus_transaction t, const char *dir, const char *node);
+int xenbus_transaction_start(struct xenbus_transaction *t);
+int xenbus_transaction_end(struct xenbus_transaction t, int abort);
+
+/* Single read and scanf: returns -errno or num scanned if > 0. */
+int xenbus_scanf(struct xenbus_transaction t,
+		 const char *dir, const char *node, const char *fmt, ...)
+	__attribute__((format(scanf, 4, 5)));
+
+/* Single printf and write: returns -errno or 0. */
+int xenbus_printf(struct xenbus_transaction t,
+		  const char *dir, const char *node, const char *fmt, ...)
+	__attribute__((format(printf, 4, 5)));
+
+/* Generic read function: NULL-terminated triples of name,
+ * sprintf-style type string, and pointer. Returns 0 or errno.*/
+int xenbus_gather(struct xenbus_transaction t, const char *dir, ...);
+
+/* notifer routines for when the xenstore comes up */
+extern int xenstored_ready;
+int register_xenstore_notifier(struct notifier_block *nb);
+void unregister_xenstore_notifier(struct notifier_block *nb);
+
+int register_xenbus_watch(struct xenbus_watch *watch);
+void unregister_xenbus_watch(struct xenbus_watch *watch);
+void xs_suspend(void);
+void xs_resume(void);
+void xs_suspend_cancel(void);
+
+/* Used by xenbus_dev to borrow kernel's store connection. */
+void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg);
+
+/* Prepare for domain suspend: then resume or cancel the suspend. */
+void xenbus_suspend(void);
+void xenbus_resume(void);
+void xenbus_probe(struct work_struct *);
+void xenbus_suspend_cancel(void);
+
+#define XENBUS_IS_ERR_READ(str) ({			\
+	if (!IS_ERR(str) && strlen(str) == 0) {		\
+		kfree(str);				\
+		str = ERR_PTR(-ERANGE);			\
+	}						\
+	IS_ERR(str);					\
+})
+
+#define XENBUS_EXIST_ERR(err) ((err) == -ENOENT || (err) == -ERANGE)
+
+int xenbus_watch_path(struct xenbus_device *dev, const char *path,
+		      struct xenbus_watch *watch,
+		      void (*callback)(struct xenbus_watch *,
+				       const char **, unsigned int));
+int xenbus_watch_path2(struct xenbus_device *dev, const char *path,
+		       const char *path2, struct xenbus_watch *watch,
+		       void (*callback)(struct xenbus_watch *,
+					const char **, unsigned int));
+int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
+int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
+int xenbus_map_ring_valloc(struct xenbus_device *dev,
+			   int gnt_ref, void **vaddr);
+int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
+			   grant_handle_t *handle, void *vaddr);
+
+int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
+int xenbus_unmap_ring(struct xenbus_device *dev,
+		      grant_handle_t handle, void *vaddr);
+
+int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
+int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port);
+int xenbus_free_evtchn(struct xenbus_device *dev, int port);
+
+enum xenbus_state xenbus_read_driver_state(const char *path);
+
+void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt, ...);
+void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt, ...);
+
+const char *xenbus_strstate(enum xenbus_state state);
+int xenbus_dev_is_online(struct xenbus_device *dev);
+int xenbus_frontend_closed(struct xenbus_device *dev);
+
+#endif /* _XEN_XENBUS_H */

-- 

[PATCH 20/25] xen: Add Xen virtual block device driver.

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-blockfront.patch --]
[-- Type: text/plain, Size: 36061 bytes --]

The block device frontend driver allows the kernel to access block
devices exported exported by a virtual machine containing a physical
block device driver.

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <axboe@kernel.dk>
---
 drivers/block/Kconfig        |    1 
 drivers/block/Makefile       |    1 
 drivers/block/xen/Kconfig    |   14 
 drivers/block/xen/Makefile   |    5 
 drivers/block/xen/blkfront.c |  844 ++++++++++++++++++++++++++++++++++++++++++
 drivers/block/xen/block.h    |  135 ++++++
 drivers/block/xen/vbd.c      |  229 +++++++++++
 include/linux/major.h        |    2 
 8 files changed, 1231 insertions(+)

===================================================================
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -445,6 +445,7 @@ config CDROM_PKTCDVD_WCACHE
 	  don't do deferred write error handling yet.
 
 source "drivers/s390/block/Kconfig"
+source "drivers/block/xen/Kconfig"
 
 config ATA_OVER_ETH
 	tristate "ATA over Ethernet support"
===================================================================
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -29,3 +29,4 @@ obj-$(CONFIG_BLK_DEV_SX8)	+= sx8.o
 obj-$(CONFIG_BLK_DEV_SX8)	+= sx8.o
 obj-$(CONFIG_BLK_DEV_UB)	+= ub.o
 
+obj-$(CONFIG_XEN)		+= xen/
===================================================================
--- /dev/null
+++ b/drivers/block/xen/Kconfig
@@ -0,0 +1,14 @@
+menu "Xen block device drivers"
+        depends on XEN
+
+config XEN_BLKDEV_FRONTEND
+	tristate "Block device frontend driver"
+	depends on XEN
+	default y
+	help
+	  The block device frontend driver allows the kernel to access block
+	  devices exported from a device driver virtual machine. Unless you
+	  are building a dedicated device driver virtual machine, then you
+	  almost certainly want to say Y here.
+
+endmenu
===================================================================
--- /dev/null
+++ b/drivers/block/xen/Makefile
@@ -0,0 +1,5 @@
+
+obj-$(CONFIG_XEN_BLKDEV_FRONTEND)	:= xenblk.o
+
+xenblk-objs := blkfront.o vbd.o
+
===================================================================
--- /dev/null
+++ b/drivers/block/xen/blkfront.c
@@ -0,0 +1,844 @@
+/******************************************************************************
+ * blkfront.c
+ *
+ * XenLinux virtual block device driver.
+ *
+ * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
+ * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
+ * Copyright (c) 2004, Christian Limpach
+ * Copyright (c) 2004, Andrew Warfield
+ * Copyright (c) 2005, Christopher Clark
+ * Copyright (c) 2005, XenSource Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/version.h>
+#include "block.h"
+#include <linux/cdrom.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <scsi/scsi.h>
+#include <xen/xenbus.h>
+#include <xen/interface/grant_table.h>
+#include <xen/grant_table.h>
+#include <xen/events.h>
+#include <xen/page.h>
+#include <asm/xen/hypervisor.h>
+
+#define BLKIF_STATE_DISCONNECTED 0
+#define BLKIF_STATE_CONNECTED    1
+#define BLKIF_STATE_SUSPENDED    2
+
+#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
+    (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
+#define GRANT_INVALID_REF	0
+
+static void connect(struct blkfront_info *);
+static void blkfront_closing(struct xenbus_device *);
+static int blkfront_remove(struct xenbus_device *);
+static int talk_to_backend(struct xenbus_device *, struct blkfront_info *);
+static int setup_blkring(struct xenbus_device *, struct blkfront_info *);
+
+static void kick_pending_request_queues(struct blkfront_info *);
+
+static irqreturn_t blkif_int(int irq, void *dev_id);
+static void blkif_restart_queue(struct work_struct *work);
+static void blkif_recover(struct blkfront_info *);
+static void blkif_completion(struct blk_shadow *);
+static void blkif_free(struct blkfront_info *, int);
+
+
+/**
+ * Entry point to this code when a new device is created.  Allocate the basic
+ * structures and the ring buffer for communication with the backend, and
+ * inform the backend of the appropriate details for those.  Switch to
+ * Initialised state.
+ */
+static int blkfront_probe(struct xenbus_device *dev,
+			  const struct xenbus_device_id *id)
+{
+	int err, vdevice, i;
+	struct blkfront_info *info;
+
+	/* FIXME: Use dynamic device id if this is not set. */
+	err = xenbus_scanf(XBT_NIL, dev->nodename,
+			   "virtual-device", "%i", &vdevice);
+	if (err != 1) {
+		xenbus_dev_fatal(dev, err, "reading virtual-device");
+		return err;
+	}
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
+		return -ENOMEM;
+	}
+
+	info->xbdev = dev;
+	info->vdevice = vdevice;
+	info->connected = BLKIF_STATE_DISCONNECTED;
+	INIT_WORK(&info->work, blkif_restart_queue);
+
+	for (i = 0; i < BLK_RING_SIZE; i++)
+		info->shadow[i].req.id = i+1;
+	info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
+
+	/* Front end dir is a number, which is used as the id. */
+	info->handle = simple_strtoul(strrchr(dev->nodename,'/')+1, NULL, 0);
+	dev->dev.driver_data = info;
+
+	err = talk_to_backend(dev, info);
+	if (err) {
+		kfree(info);
+		dev->dev.driver_data = NULL;
+		return err;
+	}
+
+	return 0;
+}
+
+
+/**
+ * We are reconnecting to the backend, due to a suspend/resume, or a backend
+ * driver restart.  We tear down our blkif structure and recreate it, but
+ * leave the device-layer structures intact so that this is transparent to the
+ * rest of the kernel.
+ */
+static int blkfront_resume(struct xenbus_device *dev)
+{
+	struct blkfront_info *info = dev->dev.driver_data;
+	int err;
+
+	dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
+
+	blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
+
+	err = talk_to_backend(dev, info);
+	if (info->connected == BLKIF_STATE_SUSPENDED && !err)
+		blkif_recover(info);
+
+	return err;
+}
+
+
+/* Common code used when first setting up, and when resuming. */
+static int talk_to_backend(struct xenbus_device *dev,
+			   struct blkfront_info *info)
+{
+	const char *message = NULL;
+	struct xenbus_transaction xbt;
+	int err;
+
+	/* Create shared ring, alloc event channel. */
+	err = setup_blkring(dev, info);
+	if (err)
+		goto out;
+
+again:
+	err = xenbus_transaction_start(&xbt);
+	if (err) {
+		xenbus_dev_fatal(dev, err, "starting transaction");
+		goto destroy_blkring;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename,
+			    "ring-ref","%u", info->ring_ref);
+	if (err) {
+		message = "writing ring-ref";
+		goto abort_transaction;
+	}
+	err = xenbus_printf(xbt, dev->nodename,
+			    "event-channel", "%u", info->evtchn);
+	if (err) {
+		message = "writing event-channel";
+		goto abort_transaction;
+	}
+
+	err = xenbus_transaction_end(xbt, 0);
+	if (err) {
+		if (err == -EAGAIN)
+			goto again;
+		xenbus_dev_fatal(dev, err, "completing transaction");
+		goto destroy_blkring;
+	}
+
+	xenbus_switch_state(dev, XenbusStateInitialised);
+
+	return 0;
+
+ abort_transaction:
+	xenbus_transaction_end(xbt, 1);
+	if (message)
+		xenbus_dev_fatal(dev, err, "%s", message);
+ destroy_blkring:
+	blkif_free(info, 0);
+ out:
+	return err;
+}
+
+
+static int setup_blkring(struct xenbus_device *dev,
+			 struct blkfront_info *info)
+{
+	struct blkif_sring *sring;
+	int err;
+
+	info->ring_ref = GRANT_INVALID_REF;
+
+	sring = (struct blkif_sring *)__get_free_page(GFP_KERNEL);
+	if (!sring) {
+		xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
+		return -ENOMEM;
+	}
+	SHARED_RING_INIT(sring);
+	FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
+
+	err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
+	if (err < 0) {
+		free_page((unsigned long)sring);
+		info->ring.sring = NULL;
+		goto fail;
+	}
+	info->ring_ref = err;
+
+	err = xenbus_alloc_evtchn(dev, &info->evtchn);
+	if (err)
+		goto fail;
+
+	err = bind_evtchn_to_irqhandler(
+		info->evtchn, blkif_int, IRQF_SAMPLE_RANDOM, "blkif", info);
+	if (err <= 0) {
+		xenbus_dev_fatal(dev, err,
+				 "bind_evtchn_to_irqhandler failed");
+		goto fail;
+	}
+	info->irq = err;
+
+	return 0;
+fail:
+	blkif_free(info, 0);
+	return err;
+}
+
+
+/**
+ * Callback received when the backend's state changes.
+ */
+static void backend_changed(struct xenbus_device *dev,
+			    enum xenbus_state backend_state)
+{
+	struct blkfront_info *info = dev->dev.driver_data;
+	struct block_device *bd;
+
+	dev_dbg(&dev->dev, "blkfront:backend_changed.\n");
+
+	switch (backend_state) {
+	case XenbusStateInitialising:
+	case XenbusStateInitWait:
+	case XenbusStateInitialised:
+	case XenbusStateUnknown:
+	case XenbusStateClosed:
+		break;
+
+	case XenbusStateConnected:
+		connect(info);
+		break;
+
+	case XenbusStateClosing:
+		bd = bdget(info->dev);
+		if (bd == NULL)
+			xenbus_dev_fatal(dev, -ENODEV, "bdget failed");
+
+		mutex_lock(&bd->bd_mutex);
+		if (info->users > 0)
+			xenbus_dev_error(dev, -EBUSY,
+					 "Device in use; refusing to close");
+		else
+			blkfront_closing(dev);
+		mutex_unlock(&bd->bd_mutex);
+		bdput(bd);
+		break;
+	}
+}
+
+
+/* ** Connection ** */
+
+
+/*
+ * Invoked when the backend is finally 'ready' (and has told produced
+ * the details about the physical device - #sectors, size, etc).
+ */
+static void connect(struct blkfront_info *info)
+{
+	unsigned long long sectors;
+	unsigned long sector_size;
+	unsigned int binfo;
+	int err;
+
+	if ((info->connected == BLKIF_STATE_CONNECTED) ||
+	    (info->connected == BLKIF_STATE_SUSPENDED) )
+		return;
+
+	dev_dbg(&info->dev, "blkfront.c:connect:%s.\n", info->xbdev->otherend);
+
+	err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+			    "sectors", "%llu", &sectors,
+			    "info", "%u", &binfo,
+			    "sector-size", "%lu", &sector_size,
+			    NULL);
+	if (err) {
+		xenbus_dev_fatal(info->xbdev, err,
+				 "reading backend fields at %s",
+				 info->xbdev->otherend);
+		return;
+	}
+
+	err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+			    "feature-barrier", "%lu", &info->feature_barrier,
+			    NULL);
+	if (err)
+		info->feature_barrier = 0;
+
+	err = xlvbd_add(sectors, info->vdevice, binfo, sector_size, info);
+	if (err) {
+		xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
+				 info->xbdev->otherend);
+		return;
+	}
+
+	xenbus_switch_state(info->xbdev, XenbusStateConnected);
+
+	/* Kick pending requests. */
+	spin_lock_irq(&blkif_io_lock);
+	info->connected = BLKIF_STATE_CONNECTED;
+	kick_pending_request_queues(info);
+	spin_unlock_irq(&blkif_io_lock);
+
+	add_disk(info->gd);
+}
+
+/**
+ * Handle the change of state of the backend to Closing.  We must delete our
+ * device-layer structures now, to ensure that writes are flushed through to
+ * the backend.  Once is this done, we can switch to Closed in
+ * acknowledgement.
+ */
+static void blkfront_closing(struct xenbus_device *dev)
+{
+	struct blkfront_info *info = dev->dev.driver_data;
+	unsigned long flags;
+
+	dev_dbg(&dev->dev, "blkfront_closing: %s removed\n", dev->nodename);
+
+	if (info->rq == NULL)
+		goto out;
+
+	spin_lock_irqsave(&blkif_io_lock, flags);
+	/* No more blkif_request(). */
+	blk_stop_queue(info->rq);
+	/* No more gnttab callback work. */
+	gnttab_cancel_free_callback(&info->callback);
+	spin_unlock_irqrestore(&blkif_io_lock, flags);
+
+	/* Flush gnttab callback work. Must be done with no locks held. */
+	flush_scheduled_work();
+
+	xlvbd_del(info);
+
+ out:
+	xenbus_frontend_closed(dev);
+}
+
+
+static int blkfront_remove(struct xenbus_device *dev)
+{
+	struct blkfront_info *info = dev->dev.driver_data;
+
+	dev_dbg(&dev->dev, "blkfront_remove: %s removed\n", dev->nodename);
+
+	blkif_free(info, 0);
+
+	kfree(info);
+
+	return 0;
+}
+
+
+static inline int GET_ID_FROM_FREELIST(
+	struct blkfront_info *info)
+{
+	unsigned long free = info->shadow_free;
+	BUG_ON(free > BLK_RING_SIZE);
+	info->shadow_free = info->shadow[free].req.id;
+	info->shadow[free].req.id = 0x0fffffee; /* debug */
+	return free;
+}
+
+static inline void ADD_ID_TO_FREELIST(
+	struct blkfront_info *info, unsigned long id)
+{
+	info->shadow[id].req.id  = info->shadow_free;
+	info->shadow[id].request = 0;
+	info->shadow_free = id;
+}
+
+static inline void flush_requests(struct blkfront_info *info)
+{
+	int notify;
+
+	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
+
+	if (notify)
+		notify_remote_via_irq(info->irq);
+}
+
+static void kick_pending_request_queues(struct blkfront_info *info)
+{
+	if (!RING_FULL(&info->ring)) {
+		/* Re-enable calldowns. */
+		blk_start_queue(info->rq);
+		/* Kick things off immediately. */
+		do_blkif_request(info->rq);
+	}
+}
+
+static void blkif_restart_queue(struct work_struct *work)
+{
+	struct blkfront_info *info = container_of(work, struct blkfront_info, work);
+
+	spin_lock_irq(&blkif_io_lock);
+	if (info->connected == BLKIF_STATE_CONNECTED)
+		kick_pending_request_queues(info);
+	spin_unlock_irq(&blkif_io_lock);
+}
+
+static void blkif_restart_queue_callback(void *arg)
+{
+	struct blkfront_info *info = (struct blkfront_info *)arg;
+	schedule_work(&info->work);
+}
+
+int blkif_open(struct inode *inode, struct file *filep)
+{
+	struct blkfront_info *info = inode->i_bdev->bd_disk->private_data;
+	info->users++;
+	return 0;
+}
+
+
+int blkif_release(struct inode *inode, struct file *filep)
+{
+	struct blkfront_info *info = inode->i_bdev->bd_disk->private_data;
+	info->users--;
+	if (info->users == 0) {
+		/* Check whether we have been instructed to close.  We will
+		   have ignored this request initially, as the device was
+		   still mounted. */
+		struct xenbus_device * dev = info->xbdev;
+		enum xenbus_state state = xenbus_read_driver_state(dev->otherend);
+
+		if (state == XenbusStateClosing)
+			blkfront_closing(dev);
+	}
+	return 0;
+}
+
+
+int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
+{
+	/* We don't have real geometry info, but let's at least return
+	   values consistent with the size of the device */
+	sector_t nsect = get_capacity(bd->bd_disk);
+	sector_t cylinders = nsect;
+
+	hg->heads = 0xff;
+	hg->sectors = 0x3f;
+	sector_div(cylinders, hg->heads * hg->sectors);
+	hg->cylinders = cylinders;
+	if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
+		hg->cylinders = 0xffff;
+	return 0;
+}
+
+/*
+ * blkif_queue_request
+ *
+ * request block io
+ *
+ * id: for guest use only.
+ * operation: BLKIF_OP_{READ,WRITE,PROBE}
+ * buffer: buffer to read/write into. this should be a
+ *   virtual address in the guest os.
+ */
+static int blkif_queue_request(struct request *req)
+{
+	struct blkfront_info *info = req->rq_disk->private_data;
+	unsigned long buffer_mfn;
+	struct blkif_request *ring_req;
+	struct bio *bio;
+	struct bio_vec *bvec;
+	int idx;
+	unsigned long id;
+	unsigned int fsect, lsect;
+	int ref;
+	grant_ref_t gref_head;
+
+	if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
+		return 1;
+
+	if (gnttab_alloc_grant_references(
+		BLKIF_MAX_SEGMENTS_PER_REQUEST, &gref_head) < 0) {
+		gnttab_request_free_callback(
+			&info->callback,
+			blkif_restart_queue_callback,
+			info,
+			BLKIF_MAX_SEGMENTS_PER_REQUEST);
+		return 1;
+	}
+
+	/* Fill out a communications ring structure. */
+	ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
+	id = GET_ID_FROM_FREELIST(info);
+	info->shadow[id].request = (unsigned long)req;
+
+	ring_req->id = id;
+	ring_req->sector_number = (blkif_sector_t)req->sector;
+	ring_req->handle = info->handle;
+
+	ring_req->operation = rq_data_dir(req) ?
+		BLKIF_OP_WRITE : BLKIF_OP_READ;
+	if (blk_barrier_rq(req))
+		ring_req->operation = BLKIF_OP_WRITE_BARRIER;
+
+	ring_req->nr_segments = 0;
+	rq_for_each_bio (bio, req) {
+		bio_for_each_segment (bvec, bio, idx) {
+			BUG_ON(ring_req->nr_segments
+			       == BLKIF_MAX_SEGMENTS_PER_REQUEST);
+			buffer_mfn = pfn_to_mfn(page_to_pfn(bvec->bv_page));
+			fsect = bvec->bv_offset >> 9;
+			lsect = fsect + (bvec->bv_len >> 9) - 1;
+			/* install a grant reference. */
+			ref = gnttab_claim_grant_reference(&gref_head);
+			BUG_ON(ref == -ENOSPC);
+
+			gnttab_grant_foreign_access_ref(
+				ref,
+				info->xbdev->otherend_id,
+				buffer_mfn,
+				rq_data_dir(req) );
+
+			info->shadow[id].frame[ring_req->nr_segments] =
+				mfn_to_pfn(buffer_mfn);
+
+			ring_req->seg[ring_req->nr_segments] =
+				(struct blkif_request_segment) {
+					.gref       = ref,
+					.first_sect = fsect,
+					.last_sect  = lsect };
+
+			ring_req->nr_segments++;
+		}
+	}
+
+	info->ring.req_prod_pvt++;
+
+	/* Keep a private copy so we can reissue requests when recovering. */
+	info->shadow[id].req = *ring_req;
+
+	gnttab_free_grant_references(gref_head);
+
+	return 0;
+}
+
+/*
+ * do_blkif_request
+ *  read a block; request is in a request queue
+ */
+void do_blkif_request(request_queue_t *rq)
+{
+	struct blkfront_info *info = NULL;
+	struct request *req;
+	int queued;
+
+	pr_debug("Entered do_blkif_request\n");
+
+	queued = 0;
+
+	while ((req = elv_next_request(rq)) != NULL) {
+		info = req->rq_disk->private_data;
+		if (!blk_fs_request(req)) {
+			end_request(req, 0);
+			continue;
+		}
+
+		if (RING_FULL(&info->ring))
+			goto wait;
+
+		pr_debug("do_blk_req %p: cmd %p, sec %lx, "
+			 "(%u/%li) buffer:%p [%s]\n",
+			 req, req->cmd, (unsigned long)req->sector,
+			 req->current_nr_sectors,
+			 req->nr_sectors, req->buffer,
+			 rq_data_dir(req) ? "write" : "read");
+
+
+		blkdev_dequeue_request(req);
+		if (blkif_queue_request(req)) {
+			blk_requeue_request(rq, req);
+		wait:
+			/* Avoid pointless unplugs. */
+			blk_stop_queue(rq);
+			break;
+		}
+
+		queued++;
+	}
+
+	if (queued != 0)
+		flush_requests(info);
+}
+
+
+static irqreturn_t blkif_int(int irq, void *dev_id)
+{
+	struct request *req;
+	struct blkif_response *bret;
+	RING_IDX i, rp;
+	unsigned long flags;
+	struct blkfront_info *info = (struct blkfront_info *)dev_id;
+	int uptodate;
+
+	spin_lock_irqsave(&blkif_io_lock, flags);
+
+	if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
+		spin_unlock_irqrestore(&blkif_io_lock, flags);
+		return IRQ_HANDLED;
+	}
+
+ again:
+	rp = info->ring.sring->rsp_prod;
+	rmb(); /* Ensure we see queued responses up to 'rp'. */
+
+	for (i = info->ring.rsp_cons; i != rp; i++) {
+		unsigned long id;
+		int ret;
+
+		bret = RING_GET_RESPONSE(&info->ring, i);
+		id   = bret->id;
+		req  = (struct request *)info->shadow[id].request;
+
+		blkif_completion(&info->shadow[id]);
+
+		ADD_ID_TO_FREELIST(info, id);
+
+		uptodate = (bret->status == BLKIF_RSP_OKAY);
+		switch (bret->operation) {
+		case BLKIF_OP_WRITE_BARRIER:
+			if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
+				printk("blkfront: %s: write barrier op failed\n",
+				       info->gd->disk_name);
+				uptodate = -EOPNOTSUPP;
+				info->feature_barrier = 0;
+			        xlvbd_barrier(info);
+			}
+			/* fall through */
+		case BLKIF_OP_READ:
+		case BLKIF_OP_WRITE:
+			if (unlikely(bret->status != BLKIF_RSP_OKAY))
+				dev_dbg(&info->dev, "Bad return from blkdev data "
+					"request: %x\n", bret->status);
+
+			ret = end_that_request_first(req, uptodate,
+				req->hard_nr_sectors);
+			BUG_ON(ret);
+			end_that_request_last(req, uptodate);
+			break;
+		default:
+			BUG();
+		}
+	}
+
+	info->ring.rsp_cons = i;
+
+	if (i != info->ring.req_prod_pvt) {
+		int more_to_do;
+		RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
+		if (more_to_do)
+			goto again;
+	} else
+		info->ring.sring->rsp_event = i + 1;
+
+	kick_pending_request_queues(info);
+
+	spin_unlock_irqrestore(&blkif_io_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static void blkif_free(struct blkfront_info *info, int suspend)
+{
+	/* Prevent new requests being issued until we fix things up. */
+	spin_lock_irq(&blkif_io_lock);
+	info->connected = suspend ?
+		BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
+	/* No more blkif_request(). */
+	if (info->rq)
+		blk_stop_queue(info->rq);
+	/* No more gnttab callback work. */
+	gnttab_cancel_free_callback(&info->callback);
+	spin_unlock_irq(&blkif_io_lock);
+
+	/* Flush gnttab callback work. Must be done with no locks held. */
+	flush_scheduled_work();
+
+	/* Free resources associated with old device channel. */
+	if (info->ring_ref != GRANT_INVALID_REF) {
+		gnttab_end_foreign_access(info->ring_ref, 0,
+					  (unsigned long)info->ring.sring);
+		info->ring_ref = GRANT_INVALID_REF;
+		info->ring.sring = NULL;
+	}
+	if (info->irq)
+		unbind_from_irqhandler(info->irq, info);
+	info->evtchn = info->irq = 0;
+
+}
+
+static void blkif_completion(struct blk_shadow *s)
+{
+	int i;
+	for (i = 0; i < s->req.nr_segments; i++)
+		gnttab_end_foreign_access(s->req.seg[i].gref, 0, 0UL);
+}
+
+static void blkif_recover(struct blkfront_info *info)
+{
+	int i;
+	struct blkif_request *req;
+	struct blk_shadow *copy;
+	int j;
+
+	/* Stage 1: Make a safe copy of the shadow state. */
+	copy = kmalloc(sizeof(info->shadow), GFP_KERNEL | __GFP_NOFAIL);
+	memcpy(copy, info->shadow, sizeof(info->shadow));
+
+	/* Stage 2: Set up free list. */
+	memset(&info->shadow, 0, sizeof(info->shadow));
+	for (i = 0; i < BLK_RING_SIZE; i++)
+		info->shadow[i].req.id = i+1;
+	info->shadow_free = info->ring.req_prod_pvt;
+	info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;
+
+	/* Stage 3: Find pending requests and requeue them. */
+	for (i = 0; i < BLK_RING_SIZE; i++) {
+		/* Not in use? */
+		if (copy[i].request == 0)
+			continue;
+
+		/* Grab a request slot and copy shadow state into it. */
+		req = RING_GET_REQUEST(
+			&info->ring, info->ring.req_prod_pvt);
+		*req = copy[i].req;
+
+		/* We get a new request id, and must reset the shadow state. */
+		req->id = GET_ID_FROM_FREELIST(info);
+		memcpy(&info->shadow[req->id], &copy[i], sizeof(copy[i]));
+
+		/* Rewrite any grant references invalidated by susp/resume. */
+		for (j = 0; j < req->nr_segments; j++)
+			gnttab_grant_foreign_access_ref(
+				req->seg[j].gref,
+				info->xbdev->otherend_id,
+				pfn_to_mfn(info->shadow[req->id].frame[j]),
+				rq_data_dir(
+					(struct request *)
+					info->shadow[req->id].request));
+		info->shadow[req->id].req = *req;
+
+		info->ring.req_prod_pvt++;
+	}
+
+	kfree(copy);
+
+	xenbus_switch_state(info->xbdev, XenbusStateConnected);
+
+	spin_lock_irq(&blkif_io_lock);
+
+	/* Now safe for us to use the shared ring */
+	info->connected = BLKIF_STATE_CONNECTED;
+
+	/* Send off requeued requests */
+	flush_requests(info);
+
+	/* Kick any other new requests queued since we resumed */
+	kick_pending_request_queues(info);
+
+	spin_unlock_irq(&blkif_io_lock);
+}
+
+
+/* ** Driver Registration ** */
+
+
+static struct xenbus_device_id blkfront_ids[] = {
+	{ "vbd" },
+	{ "" }
+};
+
+
+static struct xenbus_driver blkfront = {
+	.name = "vbd",
+	.owner = THIS_MODULE,
+	.ids = blkfront_ids,
+	.probe = blkfront_probe,
+	.remove = blkfront_remove,
+	.resume = blkfront_resume,
+	.otherend_changed = backend_changed,
+};
+
+
+static int __init xlblk_init(void)
+{
+	if (!is_running_on_xen())
+		return -ENODEV;
+
+	if (xlvbd_alloc_major() < 0)
+		return -ENODEV;
+
+	return xenbus_register_frontend(&blkfront);
+}
+module_init(xlblk_init);
+
+
+static void xlblk_exit(void)
+{
+	return xenbus_unregister_driver(&blkfront);
+}
+module_exit(xlblk_exit);
+
+MODULE_LICENSE("Dual BSD/GPL");
===================================================================
--- /dev/null
+++ b/drivers/block/xen/block.h
@@ -0,0 +1,135 @@
+/******************************************************************************
+ * block.h
+ *
+ * Shared definitions between all levels of XenLinux Virtual block devices.
+ *
+ * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
+ * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
+ * Copyright (c) 2004-2005, Christian Limpach
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __XEN_DRIVERS_BLOCK_H__
+#define __XEN_DRIVERS_BLOCK_H__
+
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/hdreg.h>
+#include <linux/blkdev.h>
+#include <linux/major.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/xenbus.h>
+#include <xen/grant_table.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/io/blkif.h>
+#include <xen/interface/io/ring.h>
+#include <asm/io.h>
+#include <asm/atomic.h>
+#include <asm/uaccess.h>
+
+struct xlbd_type_info
+{
+	int partn_shift;
+	int disks_per_major;
+	char *devname;
+	char *diskname;
+};
+
+struct xlbd_major_info
+{
+	int major;
+	int index;
+	int usage;
+	struct xlbd_type_info *type;
+};
+
+struct blk_shadow {
+	struct blkif_request req;
+	unsigned long request;
+	unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+};
+
+#define BLK_RING_SIZE __RING_SIZE((struct blkif_sring *)0, PAGE_SIZE)
+
+/*
+ * We have one of these per vbd, whether ide, scsi or 'other'.  They
+ * hang in private_data off the gendisk structure. We may end up
+ * putting all kinds of interesting stuff here :-)
+ */
+struct blkfront_info
+{
+	struct xenbus_device *xbdev;
+	dev_t dev;
+ 	struct gendisk *gd;
+	int vdevice;
+	blkif_vdev_t handle;
+	int connected;
+	int ring_ref;
+	struct blkif_front_ring ring;
+	unsigned int evtchn, irq;
+	struct xlbd_major_info *mi;
+	request_queue_t *rq;
+	struct work_struct work;
+	struct gnttab_free_callback callback;
+	struct blk_shadow shadow[BLK_RING_SIZE];
+	unsigned long shadow_free;
+	int feature_barrier;
+
+	/**
+	 * The number of people holding this device open.  We won't allow a
+	 * hot-unplug unless this is 0.
+	 */
+	int users;
+};
+
+extern spinlock_t blkif_io_lock;
+
+extern int blkif_open(struct inode *inode, struct file *filep);
+extern int blkif_release(struct inode *inode, struct file *filep);
+extern int blkif_ioctl(struct inode *inode, struct file *filep,
+		       unsigned command, unsigned long argument);
+extern int blkif_getgeo(struct block_device *, struct hd_geometry *);
+extern int blkif_check(dev_t dev);
+extern int blkif_revalidate(dev_t dev);
+extern void do_blkif_request (request_queue_t *rq);
+
+/* Virtual block device subsystem. */
+int xlvbd_alloc_major(void);
+/* Note that xlvbd_add doesn't call add_disk for you: you're expected
+   to call add_disk on info->gd once the disk is properly connected
+   up. */
+int xlvbd_add(blkif_sector_t capacity, int device,
+	      u16 vdisk_info, u16 sector_size, struct blkfront_info *info);
+void xlvbd_del(struct blkfront_info *info);
+int xlvbd_barrier(struct blkfront_info *info);
+
+#endif /* __XEN_DRIVERS_BLOCK_H__ */
===================================================================
--- /dev/null
+++ b/drivers/block/xen/vbd.c
@@ -0,0 +1,229 @@
+/******************************************************************************
+ * vbd.c
+ *
+ * XenLinux virtual block device driver (xvd).
+ *
+ * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
+ * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
+ * Copyright (c) 2004-2005, Christian Limpach
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "block.h"
+#include <linux/blkdev.h>
+#include <linux/list.h>
+
+#define BLKIF_MAJOR(dev) ((dev)>>8)
+#define BLKIF_MINOR(dev) ((dev) & 0xff)
+
+static struct xlbd_type_info xvd_type_info = {
+	.partn_shift = 4,
+	.disks_per_major = 16,
+	.devname = "xvd",
+	.diskname = "xvd"
+};
+
+static struct xlbd_major_info xvd_major_info = {
+	.major = XENVBD_MAJOR,
+	.type = &xvd_type_info
+};
+
+/* Information about our VBDs. */
+#define MAX_VBDS 64
+static LIST_HEAD(vbds_list);
+
+static struct block_device_operations xlvbd_block_fops =
+{
+	.owner = THIS_MODULE,
+	.open = blkif_open,
+	.release = blkif_release,
+	.getgeo = blkif_getgeo
+};
+
+DEFINE_SPINLOCK(blkif_io_lock);
+
+int
+xlvbd_alloc_major(void)
+{
+	if (register_blkdev(xvd_major_info.major,
+			    xvd_major_info.type->devname)) {
+		printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
+		       xvd_major_info.major, xvd_major_info.type->devname);
+		return -1;
+	}
+	return 0;
+}
+
+static int
+xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
+{
+	request_queue_t *rq;
+
+	rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
+	if (rq == NULL)
+		return -1;
+
+	elevator_init(rq, "noop");
+
+	/* Hard sector size and max sectors impersonate the equiv. hardware. */
+	blk_queue_hardsect_size(rq, sector_size);
+	blk_queue_max_sectors(rq, 512);
+
+	/* Each segment in a request is up to an aligned page in size. */
+	blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
+	blk_queue_max_segment_size(rq, PAGE_SIZE);
+
+	/* Ensure a merged request will fit in a single I/O ring slot. */
+	blk_queue_max_phys_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+	blk_queue_max_hw_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+
+	/* Make sure buffer addresses are sector-aligned. */
+	blk_queue_dma_alignment(rq, 511);
+
+	gd->queue = rq;
+
+	return 0;
+}
+
+static int
+xlvbd_alloc_gendisk(int minor, blkif_sector_t capacity, int vdevice,
+		    u16 vdisk_info, u16 sector_size,
+		    struct blkfront_info *info)
+{
+	struct gendisk *gd;
+	struct xlbd_major_info *mi;
+	int nr_minors = 1;
+	int err = -ENODEV;
+
+	BUG_ON(info->gd != NULL);
+	BUG_ON(info->mi != NULL);
+	BUG_ON(info->rq != NULL);
+
+	mi = &xvd_major_info;
+	info->mi = mi;
+
+	if ((minor & ((1 << mi->type->partn_shift) - 1)) == 0)
+		nr_minors = 1 << mi->type->partn_shift;
+
+	gd = alloc_disk(nr_minors);
+	if (gd == NULL)
+		goto out;
+
+	if (nr_minors > 1)
+		sprintf(gd->disk_name, "%s%c", mi->type->diskname,
+			'a' + mi->index * mi->type->disks_per_major +
+			(minor >> mi->type->partn_shift));
+	else
+		sprintf(gd->disk_name, "%s%c%d", mi->type->diskname,
+			'a' + mi->index * mi->type->disks_per_major +
+			(minor >> mi->type->partn_shift),
+			minor & ((1 << mi->type->partn_shift) - 1));
+
+	gd->major = mi->major;
+	gd->first_minor = minor;
+	gd->fops = &xlvbd_block_fops;
+	gd->private_data = info;
+	gd->driverfs_dev = &(info->xbdev->dev);
+	set_capacity(gd, capacity);
+
+	if (xlvbd_init_blk_queue(gd, sector_size)) {
+		del_gendisk(gd);
+		goto out;
+	}
+
+	info->rq = gd->queue;
+	info->gd = gd;
+
+	if (info->feature_barrier)
+		xlvbd_barrier(info);
+
+	if (vdisk_info & VDISK_READONLY)
+		set_disk_ro(gd, 1);
+
+	if (vdisk_info & VDISK_REMOVABLE)
+		gd->flags |= GENHD_FL_REMOVABLE;
+
+	if (vdisk_info & VDISK_CDROM)
+		gd->flags |= GENHD_FL_CD;
+
+	return 0;
+
+ out:
+	info->mi = NULL;
+	return err;
+}
+
+int
+xlvbd_add(blkif_sector_t capacity, int vdevice, u16 vdisk_info,
+	  u16 sector_size, struct blkfront_info *info)
+{
+	struct block_device *bd;
+	int err = 0;
+
+	info->dev = MKDEV(BLKIF_MAJOR(vdevice), BLKIF_MINOR(vdevice));
+
+	bd = bdget(info->dev);
+	if (bd == NULL)
+		return -ENODEV;
+
+	err = xlvbd_alloc_gendisk(BLKIF_MINOR(vdevice), capacity, vdevice,
+				  vdisk_info, sector_size, info);
+
+	bdput(bd);
+	return err;
+}
+
+void
+xlvbd_del(struct blkfront_info *info)
+{
+	if (info->mi == NULL)
+		return;
+
+	BUG_ON(info->gd == NULL);
+	del_gendisk(info->gd);
+	put_disk(info->gd);
+	info->gd = NULL;
+
+	info->mi = NULL;
+
+	BUG_ON(info->rq == NULL);
+	blk_cleanup_queue(info->rq);
+	info->rq = NULL;
+}
+
+int
+xlvbd_barrier(struct blkfront_info *info)
+{
+	int err;
+
+	err = blk_queue_ordered(info->rq,
+		info->feature_barrier ? QUEUE_ORDERED_DRAIN : QUEUE_ORDERED_NONE, NULL);
+	if (err)
+		return err;
+	printk("blkfront: %s: barriers %s\n",
+	       info->gd->disk_name, info->feature_barrier ? "enabled" : "disabled");
+	return 0;
+}
===================================================================
--- a/include/linux/major.h
+++ b/include/linux/major.h
@@ -156,6 +156,8 @@
 #define VXSPEC_MAJOR		200	/* VERITAS volume config driver */
 #define VXDMP_MAJOR		201	/* VERITAS volume multipath driver */
 
+#define XENVBD_MAJOR		202	/* Xen virtual block device */
+
 #define MSR_MAJOR		202
 #define CPUID_MAJOR		203
 

-- 

[PATCH 21/25] xen: Add the Xen virtual network device driver.

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-netfront.patch --]
[-- Type: text/plain, Size: 53909 bytes --]

The network device frontend driver allows the kernel to access network
devices exported exported by a virtual machine containing a physical
network device driver.

Signed-off-by: Ian Pratt <ian.pratt@xensource.com>
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: netdev@vger.kernel.org
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Stephen Hemminger <shemminge@linux-foundation.org>
---
 drivers/net/Kconfig        |   12 
 drivers/net/Makefile       |    2 
 drivers/net/xen-netfront.c | 1957 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1971 insertions(+)

===================================================================
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -2508,6 +2508,18 @@ source "drivers/atm/Kconfig"
 
 source "drivers/s390/net/Kconfig"
 
+config XEN_NETDEV_FRONTEND
+	tristate "Xen network device frontend driver"
+	depends on XEN
+	default y
+	help
+	  The network device frontend driver allows the kernel to
+	  access network devices exported exported by a virtual
+	  machine containing a physical network device driver. The
+	  frontend driver is intended for unprivileged guest domains;
+	  if you are compiling a kernel for a Xen guest, you almost
+	  certainly want to enable this.
+
 config ISERIES_VETH
 	tristate "iSeries Virtual Ethernet driver support"
 	depends on PPC_ISERIES
===================================================================
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -218,3 +218,5 @@ obj-$(CONFIG_FS_ENET) += fs_enet/
 obj-$(CONFIG_FS_ENET) += fs_enet/
 
 obj-$(CONFIG_NETXEN_NIC) += netxen/
+
+obj-$(CONFIG_XEN_NETDEV_FRONTEND) += xen-netfront.o
===================================================================
--- /dev/null
+++ b/drivers/net/xen-netfront.c
@@ -0,0 +1,1957 @@
+/******************************************************************************
+ * Virtual network driver for conversing with remote driver backends.
+ *
+ * Copyright (c) 2002-2005, K A Fraser
+ * Copyright (c) 2005, XenSource Ltd
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <linux/ethtool.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/moduleparam.h>
+#include <linux/mm.h>
+#include <xen/xenbus.h>
+#include <xen/interface/io/netif.h>
+#include <xen/interface/memory.h>
+#ifdef CONFIG_XEN_BALLOON
+#include <xen/balloon.h>
+#endif
+#include <xen/interface/grant_table.h>
+
+#include <xen/events.h>
+#include <xen/page.h>
+#include <xen/grant_table.h>
+
+/*
+ * Mutually-exclusive module options to select receive data path:
+ *  rx_copy : Packets are copied by network backend into local memory
+ *  rx_flip : Page containing packet data is transferred to our ownership
+ * For fully-virtualised guests there is no option - copying must be used.
+ * For paravirtualised guests, flipping is the default.
+ */
+static int rx_copy;
+module_param(rx_copy, bool, 0);
+MODULE_PARM_DESC(rx_copy, "Copy packets from network card (rather than flip)");
+static int rx_flip;
+module_param(rx_flip, bool, 0);
+MODULE_PARM_DESC(rx_flip, "Flip packets from network card (rather than copy)");
+
+#define RX_COPY_THRESHOLD 256
+
+#define GRANT_INVALID_REF	0
+
+#define NET_TX_RING_SIZE __RING_SIZE((struct netif_tx_sring *)0, PAGE_SIZE)
+#define NET_RX_RING_SIZE __RING_SIZE((struct netif_rx_sring *)0, PAGE_SIZE)
+
+struct netfront_info {
+	struct list_head list;
+	struct net_device *netdev;
+
+	struct net_device_stats stats;
+
+	struct netif_tx_front_ring tx;
+	struct netif_rx_front_ring rx;
+
+	spinlock_t   tx_lock;
+	spinlock_t   rx_lock;
+
+	unsigned int evtchn, irq;
+	unsigned int copying_receiver;
+	unsigned int carrier;
+
+	/* Receive-ring batched refills. */
+#define RX_MIN_TARGET 8
+#define RX_DFL_MIN_TARGET 64
+#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
+	unsigned rx_min_target, rx_max_target, rx_target;
+	struct sk_buff_head rx_batch;
+
+	struct timer_list rx_refill_timer;
+
+	/*
+	 * {tx,rx}_skbs store outstanding skbuffs. The first entry in tx_skbs
+	 * is an index into a chain of free entries.
+	 */
+	struct sk_buff *tx_skbs[NET_TX_RING_SIZE+1];
+	struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
+
+#define TX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
+	grant_ref_t gref_tx_head;
+	grant_ref_t grant_tx_ref[NET_TX_RING_SIZE + 1];
+	grant_ref_t gref_rx_head;
+	grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
+
+	struct xenbus_device *xbdev;
+	int tx_ring_ref;
+	int rx_ring_ref;
+	u8 mac[ETH_ALEN];
+
+	unsigned long rx_pfn_array[NET_RX_RING_SIZE];
+	struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
+	struct mmu_update rx_mmu[NET_RX_RING_SIZE];
+};
+
+struct netfront_rx_info {
+	struct netif_rx_response rx;
+	struct netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
+};
+
+/*
+ * Implement our own carrier flag: the network stack's version causes delays
+ * when the carrier is re-enabled (in particular, dev_activate() may not
+ * immediately be called, which can cause packet loss).
+ */
+#define netfront_carrier_on(netif)	((netif)->carrier = 1)
+#define netfront_carrier_off(netif)	((netif)->carrier = 0)
+#define netfront_carrier_ok(netif)	((netif)->carrier)
+
+/*
+ * Access macros for acquiring freeing slots in tx_skbs[].
+ */
+
+static inline void add_id_to_freelist(struct sk_buff **list, unsigned short id)
+{
+	list[id] = list[0];
+	list[0]  = (void *)(unsigned long)id;
+}
+
+static inline unsigned short get_id_from_freelist(struct sk_buff **list)
+{
+	unsigned int id = (unsigned int)(unsigned long)list[0];
+	list[0] = list[id];
+	return id;
+}
+
+static inline int xennet_rxidx(RING_IDX idx)
+{
+	return idx & (NET_RX_RING_SIZE - 1);
+}
+
+static inline struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
+						RING_IDX ri)
+{
+	int i = xennet_rxidx(ri);
+	struct sk_buff *skb = np->rx_skbs[i];
+	np->rx_skbs[i] = NULL;
+	return skb;
+}
+
+static inline grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
+					    RING_IDX ri)
+{
+	int i = xennet_rxidx(ri);
+	grant_ref_t ref = np->grant_rx_ref[i];
+	np->grant_rx_ref[i] = GRANT_INVALID_REF;
+	return ref;
+}
+
+static int setup_device(struct xenbus_device *, struct netfront_info *);
+static struct net_device *create_netdev(struct xenbus_device *);
+
+static void end_access(int, void *);
+static void netif_disconnect_backend(struct netfront_info *);
+
+static int network_connect(struct net_device *);
+static void network_tx_buf_gc(struct net_device *);
+static void network_alloc_rx_buffers(struct net_device *);
+
+static irqreturn_t netif_int(int irq, void *dev_id);
+
+#ifdef CONFIG_SYSFS
+static int xennet_sysfs_addif(struct net_device *netdev);
+static void xennet_sysfs_delif(struct net_device *netdev);
+#else /* !CONFIG_SYSFS */
+#define xennet_sysfs_addif(dev) (0)
+#define xennet_sysfs_delif(dev) do { } while(0)
+#endif
+
+static inline int xennet_can_sg(struct net_device *dev)
+{
+	return dev->features & NETIF_F_SG;
+}
+
+/**
+ * Entry point to this code when a new device is created.  Allocate the basic
+ * structures and the ring buffers for communication with the backend, and
+ * inform the backend of the appropriate details for those.
+ */
+static int __devinit netfront_probe(struct xenbus_device *dev,
+				    const struct xenbus_device_id *id)
+{
+	int err;
+	struct net_device *netdev;
+	struct netfront_info *info;
+
+	netdev = create_netdev(dev);
+	if (IS_ERR(netdev)) {
+		err = PTR_ERR(netdev);
+		xenbus_dev_fatal(dev, err, "creating netdev");
+		return err;
+	}
+
+	info = netdev_priv(netdev);
+	dev->dev.driver_data = info;
+
+	err = register_netdev(info->netdev);
+	if (err) {
+		printk(KERN_WARNING "%s: register_netdev err=%d\n",
+		       __FUNCTION__, err);
+		goto fail;
+	}
+
+	err = xennet_sysfs_addif(info->netdev);
+	if (err) {
+		unregister_netdev(info->netdev);
+		printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
+		       __FUNCTION__, err);
+		goto fail;
+	}
+
+	return 0;
+
+ fail:
+	free_netdev(netdev);
+	dev->dev.driver_data = NULL;
+	return err;
+}
+
+static int __devexit netfront_remove(struct xenbus_device *dev)
+{
+	struct netfront_info *info = dev->dev.driver_data;
+
+	dev_dbg(&dev->dev, "%s\n", dev->nodename);
+
+	netif_disconnect_backend(info);
+
+	del_timer_sync(&info->rx_refill_timer);
+
+	xennet_sysfs_delif(info->netdev);
+
+	unregister_netdev(info->netdev);
+
+	free_netdev(info->netdev);
+
+	return 0;
+}
+
+/**
+ * We are reconnecting to the backend, due to a suspend/resume, or a backend
+ * driver restart.  We tear down our netif structure and recreate it, but
+ * leave the device-layer structures intact so that this is transparent to the
+ * rest of the kernel.
+ */
+static int netfront_resume(struct xenbus_device *dev)
+{
+	struct netfront_info *info = dev->dev.driver_data;
+
+	dev_dbg(&dev->dev, "%s\n", dev->nodename);
+
+	netif_disconnect_backend(info);
+	return 0;
+}
+
+static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
+{
+	char *s, *e, *macstr;
+	int i;
+
+	macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
+	if (IS_ERR(macstr))
+		return PTR_ERR(macstr);
+
+	for (i = 0; i < ETH_ALEN; i++) {
+		mac[i] = simple_strtoul(s, &e, 16);
+		if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
+			kfree(macstr);
+			return -ENOENT;
+		}
+		s = e+1;
+	}
+
+	kfree(macstr);
+	return 0;
+}
+
+/* Common code used when first setting up, and when resuming. */
+static int talk_to_backend(struct xenbus_device *dev,
+			   struct netfront_info *info)
+{
+	const char *message;
+	struct xenbus_transaction xbt;
+	int err;
+
+	err = xen_net_read_mac(dev, info->mac);
+	if (err) {
+		xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
+		goto out;
+	}
+
+	/* Create shared ring, alloc event channel. */
+	err = setup_device(dev, info);
+	if (err)
+		goto out;
+
+again:
+	err = xenbus_transaction_start(&xbt);
+	if (err) {
+		xenbus_dev_fatal(dev, err, "starting transaction");
+		goto destroy_ring;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref","%u",
+			    info->tx_ring_ref);
+	if (err) {
+		message = "writing tx ring-ref";
+		goto abort_transaction;
+	}
+	err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref","%u",
+			    info->rx_ring_ref);
+	if (err) {
+		message = "writing rx ring-ref";
+		goto abort_transaction;
+	}
+	err = xenbus_printf(xbt, dev->nodename,
+			    "event-channel", "%u", info->evtchn);
+	if (err) {
+		message = "writing event-channel";
+		goto abort_transaction;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
+			    info->copying_receiver);
+	if (err) {
+		message = "writing request-rx-copy";
+		goto abort_transaction;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
+	if (err) {
+		message = "writing feature-rx-notify";
+		goto abort_transaction;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
+	if (err) {
+		message = "writing feature-sg";
+		goto abort_transaction;
+	}
+
+	err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
+	if (err) {
+		message = "writing feature-gso-tcpv4";
+		goto abort_transaction;
+	}
+
+	err = xenbus_transaction_end(xbt, 0);
+	if (err) {
+		if (err == -EAGAIN)
+			goto again;
+		xenbus_dev_fatal(dev, err, "completing transaction");
+		goto destroy_ring;
+	}
+
+	return 0;
+
+ abort_transaction:
+	xenbus_transaction_end(xbt, 1);
+	xenbus_dev_fatal(dev, err, "%s", message);
+ destroy_ring:
+	netif_disconnect_backend(info);
+ out:
+	return err;
+}
+
+static int setup_device(struct xenbus_device *dev, struct netfront_info *info)
+{
+	struct netif_tx_sring *txs;
+	struct netif_rx_sring *rxs;
+	int err;
+	struct net_device *netdev = info->netdev;
+
+	info->tx_ring_ref = GRANT_INVALID_REF;
+	info->rx_ring_ref = GRANT_INVALID_REF;
+	info->rx.sring = NULL;
+	info->tx.sring = NULL;
+	info->irq = 0;
+
+	txs = (struct netif_tx_sring *)get_zeroed_page(GFP_KERNEL);
+	if (!txs) {
+		err = -ENOMEM;
+		xenbus_dev_fatal(dev, err, "allocating tx ring page");
+		goto fail;
+	}
+	SHARED_RING_INIT(txs);
+	FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
+
+	err = xenbus_grant_ring(dev, virt_to_mfn(txs));
+	if (err < 0) {
+		free_page((unsigned long)txs);
+		goto fail;
+	}
+
+	info->tx_ring_ref = err;
+	rxs = (struct netif_rx_sring *)get_zeroed_page(GFP_KERNEL);
+	if (!rxs) {
+		err = -ENOMEM;
+		xenbus_dev_fatal(dev, err, "allocating rx ring page");
+		goto fail;
+	}
+	SHARED_RING_INIT(rxs);
+	FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
+
+	err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
+	if (err < 0) {
+		free_page((unsigned long)rxs);
+		goto fail;
+	}
+	info->rx_ring_ref = err;
+
+	err = xenbus_alloc_evtchn(dev, &info->evtchn);
+	if (err)
+		goto fail;
+
+	memcpy(netdev->dev_addr, info->mac, ETH_ALEN);
+	err = bind_evtchn_to_irqhandler(info->evtchn, netif_int,
+					IRQF_SAMPLE_RANDOM, netdev->name,
+					netdev);
+	if (err < 0)
+		goto fail;
+	info->irq = err;
+	return 0;
+
+ fail:
+	return err;
+}
+
+/**
+ * Callback received when the backend's state changes.
+ */
+static void backend_changed(struct xenbus_device *dev,
+			    enum xenbus_state backend_state)
+{
+	struct netfront_info *np = dev->dev.driver_data;
+	struct net_device *netdev = np->netdev;
+
+	dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
+
+	switch (backend_state) {
+	case XenbusStateInitialising:
+	case XenbusStateInitialised:
+	case XenbusStateConnected:
+	case XenbusStateUnknown:
+	case XenbusStateClosed:
+		break;
+
+	case XenbusStateInitWait:
+		if (dev->state != XenbusStateInitialising)
+			break;
+		if (network_connect(netdev) != 0)
+			break;
+		xenbus_switch_state(dev, XenbusStateConnected);
+		break;
+
+	case XenbusStateClosing:
+		xenbus_frontend_closed(dev);
+		break;
+	}
+}
+
+static inline int netfront_tx_slot_available(struct netfront_info *np)
+{
+	return ((np->tx.req_prod_pvt - np->tx.rsp_cons) <
+		(TX_MAX_TARGET - MAX_SKB_FRAGS - 2));
+}
+
+static inline void network_maybe_wake_tx(struct net_device *dev)
+{
+	struct netfront_info *np = netdev_priv(dev);
+
+	if (unlikely(netif_queue_stopped(dev)) &&
+	    netfront_tx_slot_available(np) &&
+	    likely(netif_running(dev)))
+		netif_wake_queue(dev);
+}
+
+static int network_open(struct net_device *dev)
+{
+	struct netfront_info *np = netdev_priv(dev);
+
+	memset(&np->stats, 0, sizeof(np->stats));
+
+	spin_lock(&np->rx_lock);
+	if (netfront_carrier_ok(np)) {
+		network_alloc_rx_buffers(dev);
+		np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
+		if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
+			netif_rx_schedule(dev);
+	}
+	spin_unlock(&np->rx_lock);
+
+	network_maybe_wake_tx(dev);
+
+	return 0;
+}
+
+static void network_tx_buf_gc(struct net_device *dev)
+{
+	RING_IDX cons, prod;
+	unsigned short id;
+	struct netfront_info *np = netdev_priv(dev);
+	struct sk_buff *skb;
+
+	BUG_ON(!netfront_carrier_ok(np));
+
+	do {
+		prod = np->tx.sring->rsp_prod;
+		rmb(); /* Ensure we see responses up to 'rp'. */
+
+		for (cons = np->tx.rsp_cons; cons != prod; cons++) {
+			struct netif_tx_response *txrsp;
+
+			txrsp = RING_GET_RESPONSE(&np->tx, cons);
+			if (txrsp->status == NETIF_RSP_NULL)
+				continue;
+
+			id  = txrsp->id;
+			skb = np->tx_skbs[id];
+			if (unlikely(gnttab_query_foreign_access(
+				np->grant_tx_ref[id]) != 0)) {
+				printk(KERN_ALERT "network_tx_buf_gc: warning "
+				       "-- grant still in use by backend "
+				       "domain.\n");
+				BUG();
+			}
+			gnttab_end_foreign_access_ref(
+				np->grant_tx_ref[id], GNTMAP_readonly);
+			gnttab_release_grant_reference(
+				&np->gref_tx_head, np->grant_tx_ref[id]);
+			np->grant_tx_ref[id] = GRANT_INVALID_REF;
+			add_id_to_freelist(np->tx_skbs, id);
+			dev_kfree_skb_irq(skb);
+		}
+
+		np->tx.rsp_cons = prod;
+
+		/*
+		 * Set a new event, then check for race with update of tx_cons.
+		 * Note that it is essential to schedule a callback, no matter
+		 * how few buffers are pending. Even if there is space in the
+		 * transmit ring, higher layers may be blocked because too much
+		 * data is outstanding: in such cases notification from Xen is
+		 * likely to be the only kick that we'll get.
+		 */
+		np->tx.sring->rsp_event =
+			prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
+		mb();
+	} while ((cons == prod) && (prod != np->tx.sring->rsp_prod));
+
+	network_maybe_wake_tx(dev);
+}
+
+static void rx_refill_timeout(unsigned long data)
+{
+	struct net_device *dev = (struct net_device *)data;
+	netif_rx_schedule(dev);
+}
+
+static void network_alloc_rx_buffers(struct net_device *dev)
+{
+	unsigned short id;
+	struct netfront_info *np = netdev_priv(dev);
+	struct sk_buff *skb;
+	struct page *page;
+	int i, batch_target, notify;
+	RING_IDX req_prod = np->rx.req_prod_pvt;
+	struct xen_memory_reservation reservation;
+	grant_ref_t ref;
+	unsigned long pfn;
+	void *vaddr;
+	int nr_flips;
+	struct netif_rx_request *req;
+
+	if (unlikely(!netfront_carrier_ok(np)))
+		return;
+
+	/*
+	 * Allocate skbuffs greedily, even though we batch updates to the
+	 * receive ring. This creates a less bursty demand on the memory
+	 * allocator, so should reduce the chance of failed allocation requests
+	 * both for ourself and for other kernel subsystems.
+	 */
+	batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
+	for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
+		/*
+		 * Allocate an skb and a page. Do not use __dev_alloc_skb as
+		 * that will allocate page-sized buffers which is not
+		 * necessary here.
+		 * 16 bytes added as necessary headroom for netif_receive_skb.
+		 */
+		skb = alloc_skb(RX_COPY_THRESHOLD + 16 + NET_IP_ALIGN,
+				GFP_ATOMIC | __GFP_NOWARN);
+		if (unlikely(!skb))
+			goto no_skb;
+
+		page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
+		if (!page) {
+			kfree_skb(skb);
+no_skb:
+			/* Any skbuffs queued for refill? Force them out. */
+			if (i != 0)
+				goto refill;
+			/* Could not allocate any skbuffs. Try again later. */
+			mod_timer(&np->rx_refill_timer,
+				  jiffies + (HZ/10));
+			break;
+		}
+
+		skb_reserve(skb, 16 + NET_IP_ALIGN); /* mimic dev_alloc_skb() */
+		skb_shinfo(skb)->frags[0].page = page;
+		skb_shinfo(skb)->nr_frags = 1;
+		__skb_queue_tail(&np->rx_batch, skb);
+	}
+
+	/* Is the batch large enough to be worthwhile? */
+	if (i < (np->rx_target/2)) {
+		if (req_prod > np->rx.sring->req_prod)
+			goto push;
+		return;
+	}
+
+	/* Adjust our fill target if we risked running out of buffers. */
+	if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
+	    ((np->rx_target *= 2) > np->rx_max_target))
+		np->rx_target = np->rx_max_target;
+
+ refill:
+	for (nr_flips = i = 0; ; i++) {
+		if ((skb = __skb_dequeue(&np->rx_batch)) == NULL)
+			break;
+
+		skb->dev = dev;
+
+		id = xennet_rxidx(req_prod + i);
+
+		BUG_ON(np->rx_skbs[id]);
+		np->rx_skbs[id] = skb;
+
+		ref = gnttab_claim_grant_reference(&np->gref_rx_head);
+		BUG_ON((signed short)ref < 0);
+		np->grant_rx_ref[id] = ref;
+
+		pfn = page_to_pfn(skb_shinfo(skb)->frags[0].page);
+		vaddr = page_address(skb_shinfo(skb)->frags[0].page);
+
+		req = RING_GET_REQUEST(&np->rx, req_prod + i);
+		if (!np->copying_receiver) {
+			gnttab_grant_foreign_transfer_ref(ref,
+							  np->xbdev->otherend_id,
+							  pfn);
+			np->rx_pfn_array[nr_flips] = pfn_to_mfn(pfn);
+			if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+				/* Remove this page before passing
+				 * back to Xen. */
+				set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
+				MULTI_update_va_mapping(np->rx_mcl+i,
+							(unsigned long)vaddr,
+							__pte(0), 0);
+			}
+			nr_flips++;
+		} else {
+			gnttab_grant_foreign_access_ref(ref,
+							np->xbdev->otherend_id,
+							pfn_to_mfn(pfn),
+							0);
+		}
+
+		req->id = id;
+		req->gref = ref;
+	}
+
+	if ( nr_flips != 0 ) {
+#ifdef CONFIG_XEN_BALLOON
+		/* Tell the ballon driver what is going on. */
+		balloon_update_driver_allowance(i);
+#endif
+
+		reservation.extent_start = np->rx_pfn_array;
+		reservation.nr_extents   = nr_flips;
+		reservation.extent_order = 0;
+		reservation.address_bits = 0;
+		reservation.domid        = DOMID_SELF;
+
+		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+			/* After all PTEs have been zapped, flush the TLB. */
+			np->rx_mcl[i-1].args[MULTI_UVMFLAGS_INDEX] =
+				UVMF_TLB_FLUSH|UVMF_ALL;
+
+			/* Give away a batch of pages. */
+			np->rx_mcl[i].op = __HYPERVISOR_memory_op;
+			np->rx_mcl[i].args[0] = XENMEM_decrease_reservation;
+			np->rx_mcl[i].args[1] = (unsigned long)&reservation;
+
+			/* Zap PTEs and give away pages in one big
+			 * multicall. */
+			(void)HYPERVISOR_multicall(np->rx_mcl, i+1);
+
+			/* Check return status of HYPERVISOR_memory_op(). */
+			if (unlikely(np->rx_mcl[i].result != i))
+				panic("Unable to reduce memory reservation\n");
+		} else {
+			if (HYPERVISOR_memory_op(XENMEM_decrease_reservation,
+						 &reservation) != i)
+				panic("Unable to reduce memory reservation\n");
+		}
+	} else {
+		wmb();
+	}
+
+	/* Above is a suitable barrier to ensure backend will see requests. */
+	np->rx.req_prod_pvt = req_prod + i;
+ push:
+	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
+	if (notify)
+		notify_remote_via_irq(np->irq);
+}
+
+static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
+				grant_ref_t ref)
+{
+	int new = xennet_rxidx(np->rx.req_prod_pvt);
+
+	BUG_ON(np->rx_skbs[new]);
+	np->rx_skbs[new] = skb;
+	np->grant_rx_ref[new] = ref;
+	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
+	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
+	np->rx.req_prod_pvt++;
+}
+
+static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
+			      struct netif_tx_request *tx)
+{
+	struct netfront_info *np = netdev_priv(dev);
+	char *data = skb->data;
+	unsigned long mfn;
+	RING_IDX prod = np->tx.req_prod_pvt;
+	int frags = skb_shinfo(skb)->nr_frags;
+	unsigned int offset = offset_in_page(data);
+	unsigned int len = skb_headlen(skb);
+	unsigned int id;
+	grant_ref_t ref;
+	int i;
+
+	while (len > PAGE_SIZE - offset) {
+		tx->size = PAGE_SIZE - offset;
+		tx->flags |= NETTXF_more_data;
+		len -= tx->size;
+		data += tx->size;
+		offset = 0;
+
+		id = get_id_from_freelist(np->tx_skbs);
+		np->tx_skbs[id] = skb_get(skb);
+		tx = RING_GET_REQUEST(&np->tx, prod++);
+		tx->id = id;
+		ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+		BUG_ON((signed short)ref < 0);
+
+		mfn = virt_to_mfn(data);
+		gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
+						mfn, GNTMAP_readonly);
+
+		tx->gref = np->grant_tx_ref[id] = ref;
+		tx->offset = offset;
+		tx->size = len;
+		tx->flags = 0;
+	}
+
+	for (i = 0; i < frags; i++) {
+		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+
+		tx->flags |= NETTXF_more_data;
+
+		id = get_id_from_freelist(np->tx_skbs);
+		np->tx_skbs[id] = skb_get(skb);
+		tx = RING_GET_REQUEST(&np->tx, prod++);
+		tx->id = id;
+		ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+		BUG_ON((signed short)ref < 0);
+
+		mfn = pfn_to_mfn(page_to_pfn(frag->page));
+		gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
+						mfn, GNTMAP_readonly);
+
+		tx->gref = np->grant_tx_ref[id] = ref;
+		tx->offset = frag->page_offset;
+		tx->size = frag->size;
+		tx->flags = 0;
+	}
+
+	np->tx.req_prod_pvt = prod;
+}
+
+static int network_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	unsigned short id;
+	struct netfront_info *np = netdev_priv(dev);
+	struct netif_tx_request *tx;
+	struct netif_extra_info *extra;
+	char *data = skb->data;
+	RING_IDX i;
+	grant_ref_t ref;
+	unsigned long mfn;
+	int notify;
+	int frags = skb_shinfo(skb)->nr_frags;
+	unsigned int offset = offset_in_page(data);
+	unsigned int len = skb_headlen(skb);
+
+	frags += (offset + len + PAGE_SIZE - 1) / PAGE_SIZE;
+	if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
+		printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
+		       frags);
+		dump_stack();
+		goto drop;
+	}
+
+	spin_lock_irq(&np->tx_lock);
+
+	if (unlikely(!netfront_carrier_ok(np) ||
+		     (frags > 1 && !xennet_can_sg(dev)) ||
+		     netif_needs_gso(dev, skb))) {
+		spin_unlock_irq(&np->tx_lock);
+		goto drop;
+	}
+
+	i = np->tx.req_prod_pvt;
+
+	id = get_id_from_freelist(np->tx_skbs);
+	np->tx_skbs[id] = skb;
+
+	tx = RING_GET_REQUEST(&np->tx, i);
+
+	tx->id   = id;
+	ref = gnttab_claim_grant_reference(&np->gref_tx_head);
+	BUG_ON((signed short)ref < 0);
+	mfn = virt_to_mfn(data);
+	gnttab_grant_foreign_access_ref(
+		ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
+	tx->gref = np->grant_tx_ref[id] = ref;
+	tx->offset = offset;
+	tx->size = len;
+	extra = NULL;
+
+ 	tx->flags = 0;
+ 	if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
+ 		tx->flags |= NETTXF_csum_blank | NETTXF_data_validated;
+
+	if (skb_shinfo(skb)->gso_size) {
+		struct netif_extra_info *gso = (struct netif_extra_info *)
+			RING_GET_REQUEST(&np->tx, ++i);
+
+		if (extra)
+			extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
+		else
+			tx->flags |= NETTXF_extra_info;
+
+		gso->u.gso.size = skb_shinfo(skb)->gso_size;
+		gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
+		gso->u.gso.pad = 0;
+		gso->u.gso.features = 0;
+
+		gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
+		gso->flags = 0;
+		extra = gso;
+	}
+
+	np->tx.req_prod_pvt = i + 1;
+
+	xennet_make_frags(skb, dev, tx);
+	tx->size = skb->len;
+
+	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
+	if (notify)
+		notify_remote_via_irq(np->irq);
+
+	network_tx_buf_gc(dev);
+
+	if (!netfront_tx_slot_available(np))
+		netif_stop_queue(dev);
+
+	spin_unlock_irq(&np->tx_lock);
+
+	np->stats.tx_bytes += skb->len;
+	np->stats.tx_packets++;
+
+	return 0;
+
+ drop:
+	np->stats.tx_dropped++;
+	dev_kfree_skb(skb);
+	return 0;
+}
+
+static irqreturn_t netif_int(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct netfront_info *np = netdev_priv(dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&np->tx_lock, flags);
+
+	if (likely(netfront_carrier_ok(np))) {
+		network_tx_buf_gc(dev);
+		/* Under tx_lock: protects access to rx shared-ring indexes. */
+		if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
+			netif_rx_schedule(dev);
+	}
+
+	spin_unlock_irqrestore(&np->tx_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static void handle_incoming_queue(struct net_device *dev, struct sk_buff_head *rxq)
+{
+	struct sk_buff *skb;
+
+	while ((skb = __skb_dequeue(rxq)) != NULL) {
+		struct page *page = (struct page *)skb->nh.raw;
+		void *vaddr = page_address(page);
+
+		memcpy(skb->data, vaddr + (skb->h.raw - skb->nh.raw),
+		       skb_headlen(skb));
+
+		if (page != skb_shinfo(skb)->frags[0].page)
+			__free_page(page);
+
+		/* Ethernet work: Delayed to here as it peeks the header. */
+		skb->protocol = eth_type_trans(skb, dev);
+
+		/* Pass it up. */
+		netif_receive_skb(skb);
+		dev->last_rx = jiffies;
+	}
+}
+
+int xennet_get_extras(struct netfront_info *np,
+		      struct netif_extra_info *extras, RING_IDX rp)
+
+{
+	struct netif_extra_info *extra;
+	struct device *dev = &np->netdev->dev;
+	RING_IDX cons = np->rx.rsp_cons;
+	int err = 0;
+
+	do {
+		struct sk_buff *skb;
+		grant_ref_t ref;
+
+		if (unlikely(cons + 1 == rp)) {
+			if (net_ratelimit())
+				dev_warn(dev, "Missing extra info\n");
+			err = -EBADR;
+			break;
+		}
+
+		extra = (struct netif_extra_info *)
+			RING_GET_RESPONSE(&np->rx, ++cons);
+
+		if (unlikely(!extra->type ||
+			     extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
+			if (net_ratelimit())
+				dev_warn(dev, "Invalid extra type: %d\n",
+					extra->type);
+			err = -EINVAL;
+		} else {
+			memcpy(&extras[extra->type - 1], extra,
+			       sizeof(*extra));
+		}
+
+		skb = xennet_get_rx_skb(np, cons);
+		ref = xennet_get_rx_ref(np, cons);
+		xennet_move_rx_slot(np, skb, ref);
+	} while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
+
+	np->rx.rsp_cons = cons;
+	return err;
+}
+
+static int xennet_get_responses(struct netfront_info *np,
+				struct netfront_rx_info *rinfo, RING_IDX rp,
+				struct sk_buff_head *list,
+				int *pages_flipped_p)
+{
+	int pages_flipped = *pages_flipped_p;
+	struct mmu_update *mmu;
+	struct multicall_entry *mcl;
+	struct netif_rx_response *rx = &rinfo->rx;
+	struct netif_extra_info *extras = rinfo->extras;
+	struct device *dev = &np->netdev->dev;
+	RING_IDX cons = np->rx.rsp_cons;
+	struct sk_buff *skb = xennet_get_rx_skb(np, cons);
+	grant_ref_t ref = xennet_get_rx_ref(np, cons);
+	int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
+	int frags = 1;
+	int err = 0;
+	unsigned long ret;
+
+	if (rx->flags & NETRXF_extra_info) {
+		err = xennet_get_extras(np, extras, rp);
+		cons = np->rx.rsp_cons;
+	}
+
+	for (;;) {
+		unsigned long mfn;
+
+		if (unlikely(rx->status < 0 ||
+			     rx->offset + rx->status > PAGE_SIZE)) {
+			if (net_ratelimit())
+				dev_warn(dev, "rx->offset: %x, size: %u\n",
+					 rx->offset, rx->status);
+			xennet_move_rx_slot(np, skb, ref);
+			err = -EINVAL;
+			goto next;
+		}
+
+		/*
+		 * This definitely indicates a bug, either in this driver or in
+		 * the backend driver. In future this should flag the bad
+		 * situation to the system controller to reboot the backed.
+		 */
+		if (ref == GRANT_INVALID_REF) {
+			if (net_ratelimit())
+				dev_warn(dev, "Bad rx response id %d.\n",
+					 rx->id);
+			err = -EINVAL;
+			goto next;
+		}
+
+		if (!np->copying_receiver) {
+			/* Memory pressure, insufficient buffer
+			 * headroom, ... */
+			mfn = gnttab_end_foreign_transfer_ref(ref);
+			if (!mfn) {
+				if (net_ratelimit())
+					dev_warn(dev, "Unfulfilled rx req "
+						 "(id=%d, st=%d).\n",
+						 rx->id, rx->status);
+				xennet_move_rx_slot(np, skb, ref);
+				err = -ENOMEM;
+				goto next;
+			}
+
+			if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+				/* Remap the page. */
+				struct page *page =
+					skb_shinfo(skb)->frags[0].page;
+				unsigned long pfn = page_to_pfn(page);
+				void *vaddr = page_address(page);
+
+				mcl = np->rx_mcl + pages_flipped;
+				mmu = np->rx_mmu + pages_flipped;
+
+				MULTI_update_va_mapping(mcl,
+							(unsigned long)vaddr,
+							mfn_pte(mfn, PAGE_KERNEL),
+							0);
+				mmu->ptr = ((u64)mfn << PAGE_SHIFT)
+					| MMU_MACHPHYS_UPDATE;
+				mmu->val = pfn;
+
+				set_phys_to_machine(pfn, mfn);
+			}
+			pages_flipped++;
+		} else {
+			ret = gnttab_end_foreign_access_ref(ref, 0);
+			BUG_ON(!ret);
+		}
+
+		gnttab_release_grant_reference(&np->gref_rx_head, ref);
+
+		__skb_queue_tail(list, skb);
+
+next:
+		if (!(rx->flags & NETRXF_more_data))
+			break;
+
+		if (cons + frags == rp) {
+			if (net_ratelimit())
+				dev_warn(dev, "Need more frags\n");
+			err = -ENOENT;
+			break;
+		}
+
+		rx = RING_GET_RESPONSE(&np->rx, cons + frags);
+		skb = xennet_get_rx_skb(np, cons + frags);
+		ref = xennet_get_rx_ref(np, cons + frags);
+		frags++;
+	}
+
+	if (unlikely(frags > max)) {
+		if (net_ratelimit())
+			dev_warn(dev, "Too many frags\n");
+		err = -E2BIG;
+	}
+
+	if (unlikely(err))
+		np->rx.rsp_cons = cons + frags;
+
+	*pages_flipped_p = pages_flipped;
+
+	return err;
+}
+
+static RING_IDX xennet_fill_frags(struct netfront_info *np,
+				  struct sk_buff *skb,
+				  struct sk_buff_head *list)
+{
+	struct skb_shared_info *shinfo = skb_shinfo(skb);
+	int nr_frags = shinfo->nr_frags;
+	RING_IDX cons = np->rx.rsp_cons;
+	skb_frag_t *frag = shinfo->frags + nr_frags;
+	struct sk_buff *nskb;
+
+	while ((nskb = __skb_dequeue(list))) {
+		struct netif_rx_response *rx =
+			RING_GET_RESPONSE(&np->rx, ++cons);
+
+		frag->page = skb_shinfo(nskb)->frags[0].page;
+		frag->page_offset = rx->offset;
+		frag->size = rx->status;
+
+		skb->data_len += rx->status;
+
+		skb_shinfo(nskb)->nr_frags = 0;
+		kfree_skb(nskb);
+
+		frag++;
+		nr_frags++;
+	}
+
+	shinfo->nr_frags = nr_frags;
+	return cons;
+}
+
+static int xennet_set_skb_gso(struct sk_buff *skb, struct netif_extra_info *gso)
+{
+	if (!gso->u.gso.size) {
+		if (net_ratelimit())
+			printk(KERN_WARNING "GSO size must not be zero.\n");
+		return -EINVAL;
+	}
+
+	/* Currently only TCPv4 S.O. is supported. */
+	if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
+		if (net_ratelimit())
+			printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type);
+		return -EINVAL;
+	}
+
+	skb_shinfo(skb)->gso_size = gso->u.gso.size;
+	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+
+	/* Header must be checked, and gso_segs computed. */
+	skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+	skb_shinfo(skb)->gso_segs = 0;
+
+	return 0;
+}
+
+static int netif_poll(struct net_device *dev, int *pbudget)
+{
+	struct netfront_info *np = netdev_priv(dev);
+	struct sk_buff *skb;
+	struct netfront_rx_info rinfo;
+	struct netif_rx_response *rx = &rinfo.rx;
+	struct netif_extra_info *extras = rinfo.extras;
+	RING_IDX i, rp;
+	struct multicall_entry *mcl;
+	int work_done, budget, more_to_do = 1;
+	struct sk_buff_head rxq;
+	struct sk_buff_head errq;
+	struct sk_buff_head tmpq;
+	unsigned long flags;
+	unsigned int len;
+	int pages_flipped = 0;
+	int err;
+
+	spin_lock(&np->rx_lock);
+
+	if (unlikely(!netfront_carrier_ok(np))) {
+		spin_unlock(&np->rx_lock);
+		return 0;
+	}
+
+	skb_queue_head_init(&rxq);
+	skb_queue_head_init(&errq);
+	skb_queue_head_init(&tmpq);
+
+	if ((budget = *pbudget) > dev->quota)
+		budget = dev->quota;
+	rp = np->rx.sring->rsp_prod;
+	rmb(); /* Ensure we see queued responses up to 'rp'. */
+
+	i = np->rx.rsp_cons;
+	work_done = 0;
+	while ((i != rp) && (work_done < budget)) {
+		memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
+		memset(extras, 0, sizeof(rinfo.extras));
+
+		err = xennet_get_responses(np, &rinfo, rp, &tmpq,
+					   &pages_flipped);
+
+		if (unlikely(err)) {
+err:
+			while ((skb = __skb_dequeue(&tmpq)))
+				__skb_queue_tail(&errq, skb);
+			np->stats.rx_errors++;
+			i = np->rx.rsp_cons;
+			continue;
+		}
+
+		skb = __skb_dequeue(&tmpq);
+
+		if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
+			struct netif_extra_info *gso;
+			gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
+
+			if (unlikely(xennet_set_skb_gso(skb, gso))) {
+				__skb_queue_head(&tmpq, skb);
+				np->rx.rsp_cons += skb_queue_len(&tmpq);
+				goto err;
+			}
+		}
+
+		skb->nh.raw = (void *)skb_shinfo(skb)->frags[0].page;
+		skb->h.raw = skb->nh.raw + rx->offset;
+
+		len = rx->status;
+		if (len > RX_COPY_THRESHOLD)
+			len = RX_COPY_THRESHOLD;
+		skb_put(skb, len);
+
+		if (rx->status > len) {
+			skb_shinfo(skb)->frags[0].page_offset =
+				rx->offset + len;
+			skb_shinfo(skb)->frags[0].size = rx->status - len;
+			skb->data_len = rx->status - len;
+		} else {
+			skb_shinfo(skb)->frags[0].page = NULL;
+			skb_shinfo(skb)->nr_frags = 0;
+		}
+
+		i = xennet_fill_frags(np, skb, &tmpq);
+
+		/*
+		 * Truesize must approximates the size of true data plus
+		 * any supervisor overheads. Adding hypervisor overheads
+		 * has been shown to significantly reduce achievable
+		 * bandwidth with the default receive buffer size. It is
+		 * therefore not wise to account for it here.
+		 *
+		 * After alloc_skb(RX_COPY_THRESHOLD), truesize is set to
+		 * RX_COPY_THRESHOLD + the supervisor overheads. Here, we
+		 * add the size of the data pulled in xennet_fill_frags().
+		 *
+		 * We also adjust for any unused space in the main data
+		 * area by subtracting (RX_COPY_THRESHOLD - len). This is
+		 * especially important with drivers which split incoming
+		 * packets into header and data, using only 66 bytes of
+		 * the main data area (see the e1000 driver for example.)
+		 * On such systems, without this last adjustement, our
+		 * achievable receive throughout using the standard receive
+		 * buffer size was cut by 25%(!!!).
+		 */
+		skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len);
+		skb->len += skb->data_len;
+
+		if (rx->flags & NETRXF_data_validated)
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+		np->stats.rx_packets++;
+		np->stats.rx_bytes += skb->len;
+
+		__skb_queue_tail(&rxq, skb);
+
+		np->rx.rsp_cons = ++i;
+		work_done++;
+	}
+
+	if (pages_flipped) {
+#ifdef CONFIG_XEN_BALLOON
+		/* Some pages are no longer absent... */
+		balloon_update_driver_allowance(-pages_flipped);
+#endif
+		/* Do all the remapping work, and M2P updates. */
+		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+			mcl = np->rx_mcl + pages_flipped;
+			MULTI_mmu_update(mcl, np->rx_mmu,
+					 pages_flipped, 0, DOMID_SELF);
+			(void)HYPERVISOR_multicall(np->rx_mcl,
+						   pages_flipped + 1);
+		}
+	}
+
+	while ((skb = __skb_dequeue(&errq)))
+		kfree_skb(skb);
+
+	handle_incoming_queue(dev, &rxq);
+
+	/* If we get a callback with very few responses, reduce fill target. */
+	/* NB. Note exponential increase, linear decrease. */
+	if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
+	     ((3*np->rx_target) / 4)) &&
+	    (--np->rx_target < np->rx_min_target))
+		np->rx_target = np->rx_min_target;
+
+	network_alloc_rx_buffers(dev);
+
+	*pbudget   -= work_done;
+	dev->quota -= work_done;
+
+	if (work_done < budget) {
+		local_irq_save(flags);
+
+		RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
+		if (!more_to_do)
+			__netif_rx_complete(dev);
+
+		local_irq_restore(flags);
+	}
+
+	spin_unlock(&np->rx_lock);
+
+	return more_to_do;
+}
+
+static void netif_release_tx_bufs(struct netfront_info *np)
+{
+	struct sk_buff *skb;
+	int i;
+
+	for (i = 1; i <= NET_TX_RING_SIZE; i++) {
+		if ((unsigned long)np->tx_skbs[i] < PAGE_OFFSET)
+			continue;
+
+		skb = np->tx_skbs[i];
+		gnttab_end_foreign_access_ref(
+			np->grant_tx_ref[i], GNTMAP_readonly);
+		gnttab_release_grant_reference(
+			&np->gref_tx_head, np->grant_tx_ref[i]);
+		np->grant_tx_ref[i] = GRANT_INVALID_REF;
+		add_id_to_freelist(np->tx_skbs, i);
+		dev_kfree_skb_irq(skb);
+	}
+}
+
+static void netif_release_rx_bufs(struct netfront_info *np)
+{
+	struct mmu_update      *mmu = np->rx_mmu;
+	struct multicall_entry *mcl = np->rx_mcl;
+	struct sk_buff_head free_list;
+	struct sk_buff *skb;
+	unsigned long mfn;
+	int xfer = 0, noxfer = 0, unused = 0;
+	int id, ref;
+
+	if (np->copying_receiver) {
+		dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
+			 __FUNCTION__);
+		return;
+	}
+
+	skb_queue_head_init(&free_list);
+
+	spin_lock(&np->rx_lock);
+
+	for (id = 0; id < NET_RX_RING_SIZE; id++) {
+		if ((ref = np->grant_rx_ref[id]) == GRANT_INVALID_REF) {
+			unused++;
+			continue;
+		}
+
+		skb = np->rx_skbs[id];
+		mfn = gnttab_end_foreign_transfer_ref(ref);
+		gnttab_release_grant_reference(&np->gref_rx_head, ref);
+		np->grant_rx_ref[id] = GRANT_INVALID_REF;
+		add_id_to_freelist(np->rx_skbs, id);
+
+		if (0 == mfn) {
+#ifdef CONFIG_XEN_BALLOON
+			struct page *page = skb_shinfo(skb)->frags[0].page;
+			balloon_release_driver_page(page);
+#endif
+			skb_shinfo(skb)->nr_frags = 0;
+			dev_kfree_skb(skb);
+			noxfer++;
+			continue;
+		}
+
+		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+			/* Remap the page. */
+			struct page *page = skb_shinfo(skb)->frags[0].page;
+			unsigned long pfn = page_to_pfn(page);
+			void *vaddr = page_address(page);
+
+			MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
+						mfn_pte(mfn, PAGE_KERNEL),
+						0);
+			mcl++;
+			mmu->ptr = ((u64)mfn << PAGE_SHIFT)
+				| MMU_MACHPHYS_UPDATE;
+			mmu->val = pfn;
+			mmu++;
+
+			set_phys_to_machine(pfn, mfn);
+		}
+		__skb_queue_tail(&free_list, skb);
+		xfer++;
+	}
+
+	dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
+		 __FUNCTION__, xfer, noxfer, unused);
+
+	if (xfer) {
+#ifdef CONFIG_XEN_BALLOON
+		/* Some pages are no longer absent... */
+		balloon_update_driver_allowance(-xfer);
+#endif
+
+		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+			/* Do all the remapping work and M2P updates. */
+			mcl->op = __HYPERVISOR_mmu_update;
+			mcl->args[0] = (unsigned long)np->rx_mmu;
+			mcl->args[1] = mmu - np->rx_mmu;
+			mcl->args[2] = 0;
+			mcl->args[3] = DOMID_SELF;
+			mcl++;
+			HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
+		}
+	}
+
+	while ((skb = __skb_dequeue(&free_list)) != NULL)
+		dev_kfree_skb(skb);
+
+	spin_unlock(&np->rx_lock);
+}
+
+static int network_close(struct net_device *dev)
+{
+	struct netfront_info *np = netdev_priv(dev);
+	netif_stop_queue(np->netdev);
+	return 0;
+}
+
+
+static struct net_device_stats *network_get_stats(struct net_device *dev)
+{
+	struct netfront_info *np = netdev_priv(dev);
+	return &np->stats;
+}
+
+static int xennet_change_mtu(struct net_device *dev, int mtu)
+{
+	int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;
+
+	if (mtu > max)
+		return -EINVAL;
+	dev->mtu = mtu;
+	return 0;
+}
+
+static int xennet_set_sg(struct net_device *dev, u32 data)
+{
+	if (data) {
+		struct netfront_info *np = netdev_priv(dev);
+		int val;
+
+		if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
+				 "%d", &val) < 0)
+			val = 0;
+		if (!val)
+			return -ENOSYS;
+	} else if (dev->mtu > ETH_DATA_LEN)
+		dev->mtu = ETH_DATA_LEN;
+
+	return ethtool_op_set_sg(dev, data);
+}
+
+static int xennet_set_tso(struct net_device *dev, u32 data)
+{
+	if (data) {
+		struct netfront_info *np = netdev_priv(dev);
+		int val;
+
+		if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
+				 "feature-gso-tcpv4", "%d", &val) < 0)
+			val = 0;
+		if (!val)
+			return -ENOSYS;
+	}
+
+	return ethtool_op_set_tso(dev, data);
+}
+
+static void xennet_set_features(struct net_device *dev)
+{
+	/* Turn off all GSO bits except ROBUST. */
+	dev->features &= (1 << NETIF_F_GSO_SHIFT) - 1;
+	dev->features |= NETIF_F_GSO_ROBUST;
+	xennet_set_sg(dev, 0);
+
+	/* We need checksum offload to enable scatter/gather and TSO. */
+	if (!(dev->features & NETIF_F_IP_CSUM))
+		return;
+
+	if (!xennet_set_sg(dev, 1))
+		xennet_set_tso(dev, 1);
+}
+
+static int network_connect(struct net_device *dev)
+{
+	struct netfront_info *np = netdev_priv(dev);
+	int i, requeue_idx, err;
+	struct sk_buff *skb;
+	grant_ref_t ref;
+	struct netif_rx_request *req;
+	unsigned int feature_rx_copy, feature_rx_flip;
+
+	err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
+			   "feature-rx-copy", "%u", &feature_rx_copy);
+	if (err != 1)
+		feature_rx_copy = 0;
+	err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
+			   "feature-rx-flip", "%u", &feature_rx_flip);
+	if (err != 1)
+		feature_rx_flip = 1;
+
+	/*
+	 * Copy packets on receive path if:
+	 *  (a) This was requested by user, and the backend supports it; or
+	 *  (b) Flipping was requested, but this is unsupported by the backend.
+	 */
+	np->copying_receiver = ((rx_copy && feature_rx_copy) ||
+				(rx_flip && !feature_rx_flip));
+
+	err = talk_to_backend(np->xbdev, np);
+	if (err)
+		return err;
+
+	xennet_set_features(dev);
+
+	dev_info(&dev->dev, "has %sing receive path.\n",
+		 np->copying_receiver ? "copy" : "flipp");
+
+	spin_lock_irq(&np->tx_lock);
+	spin_lock(&np->rx_lock);
+
+	/*
+	 * Recovery procedure:
+	 *  NB. Freelist index entries are always going to be less than
+	 *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
+	 *  greater than PAGE_OFFSET: we use this property to distinguish
+	 *  them.
+	 */
+
+	/* Step 1: Discard all pending TX packet fragments. */
+	netif_release_tx_bufs(np);
+
+	/* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
+	for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
+		if (!np->rx_skbs[i])
+			continue;
+
+		skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
+		ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
+		req = RING_GET_REQUEST(&np->rx, requeue_idx);
+
+		if (!np->copying_receiver) {
+			gnttab_grant_foreign_transfer_ref(
+				ref, np->xbdev->otherend_id,
+				page_to_pfn(skb_shinfo(skb)->frags->page));
+		} else {
+			gnttab_grant_foreign_access_ref(
+				ref, np->xbdev->otherend_id,
+				pfn_to_mfn(page_to_pfn(skb_shinfo(skb)->
+						       frags->page)),
+				0);
+		}
+		req->gref = ref;
+		req->id   = requeue_idx;
+
+		requeue_idx++;
+	}
+
+	np->rx.req_prod_pvt = requeue_idx;
+
+	/*
+	 * Step 3: All public and private state should now be sane.  Get
+	 * ready to start sending and receiving packets and give the driver
+	 * domain a kick because we've probably just requeued some
+	 * packets.
+	 */
+	netfront_carrier_on(np);
+	notify_remote_via_irq(np->irq);
+	network_tx_buf_gc(dev);
+	network_alloc_rx_buffers(dev);
+
+	spin_unlock(&np->rx_lock);
+	spin_unlock_irq(&np->tx_lock);
+
+	return 0;
+}
+
+static void netif_uninit(struct net_device *dev)
+{
+	struct netfront_info *np = netdev_priv(dev);
+	netif_release_tx_bufs(np);
+	netif_release_rx_bufs(np);
+	gnttab_free_grant_references(np->gref_tx_head);
+	gnttab_free_grant_references(np->gref_rx_head);
+}
+
+static struct ethtool_ops network_ethtool_ops =
+{
+	.get_tx_csum = ethtool_op_get_tx_csum,
+	.set_tx_csum = ethtool_op_set_tx_csum,
+	.get_sg = ethtool_op_get_sg,
+	.set_sg = xennet_set_sg,
+	.get_tso = ethtool_op_get_tso,
+	.set_tso = xennet_set_tso,
+	.get_link = ethtool_op_get_link,
+};
+
+#ifdef CONFIG_SYSFS
+static ssize_t show_rxbuf_min(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	struct netfront_info *info = netdev_priv(netdev);
+
+	return sprintf(buf, "%u\n", info->rx_min_target);
+}
+
+static ssize_t store_rxbuf_min(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t len)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	struct netfront_info *np = netdev_priv(netdev);
+	char *endp;
+	unsigned long target;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	target = simple_strtoul(buf, &endp, 0);
+	if (endp == buf)
+		return -EBADMSG;
+
+	if (target < RX_MIN_TARGET)
+		target = RX_MIN_TARGET;
+	if (target > RX_MAX_TARGET)
+		target = RX_MAX_TARGET;
+
+	spin_lock(&np->rx_lock);
+	if (target > np->rx_max_target)
+		np->rx_max_target = target;
+	np->rx_min_target = target;
+	if (target > np->rx_target)
+		np->rx_target = target;
+
+	network_alloc_rx_buffers(netdev);
+
+	spin_unlock(&np->rx_lock);
+	return len;
+}
+
+static ssize_t show_rxbuf_max(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	struct netfront_info *info = netdev_priv(netdev);
+
+	return sprintf(buf, "%u\n", info->rx_max_target);
+}
+
+static ssize_t store_rxbuf_max(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t len)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	struct netfront_info *np = netdev_priv(netdev);
+	char *endp;
+	unsigned long target;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	target = simple_strtoul(buf, &endp, 0);
+	if (endp == buf)
+		return -EBADMSG;
+
+	if (target < RX_MIN_TARGET)
+		target = RX_MIN_TARGET;
+	if (target > RX_MAX_TARGET)
+		target = RX_MAX_TARGET;
+
+	spin_lock(&np->rx_lock);
+	if (target < np->rx_min_target)
+		np->rx_min_target = target;
+	np->rx_max_target = target;
+	if (target < np->rx_target)
+		np->rx_target = target;
+
+	network_alloc_rx_buffers(netdev);
+
+	spin_unlock(&np->rx_lock);
+	return len;
+}
+
+static ssize_t show_rxbuf_cur(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	struct netfront_info *info = netdev_priv(netdev);
+
+	return sprintf(buf, "%u\n", info->rx_target);
+}
+
+static struct device_attribute xennet_attrs[] = {
+	__ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
+	__ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
+	__ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
+};
+
+static int xennet_sysfs_addif(struct net_device *netdev)
+{
+	int i;
+	int error = 0;
+
+	for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
+		error = device_create_file(&netdev->dev,
+					   &xennet_attrs[i]);
+		if (error)
+			goto fail;
+	}
+	return 0;
+
+ fail:
+	while (--i >= 0)
+		device_remove_file(&netdev->dev, &xennet_attrs[i]);
+	return error;
+}
+
+static void xennet_sysfs_delif(struct net_device *netdev)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
+		device_remove_file(&netdev->dev, &xennet_attrs[i]);
+	}
+}
+
+#endif /* CONFIG_SYSFS */
+
+
+/*
+ * Nothing to do here. Virtual interface is point-to-point and the
+ * physical interface is probably promiscuous anyway.
+ */
+static void network_set_multicast_list(struct net_device *dev)
+{
+}
+
+static struct net_device * __devinit create_netdev(struct xenbus_device *dev)
+{
+	int i, err = 0;
+	struct net_device *netdev = NULL;
+	struct netfront_info *np = NULL;
+
+	netdev = alloc_etherdev(sizeof(struct netfront_info));
+	if (!netdev) {
+		printk(KERN_WARNING "%s> alloc_etherdev failed.\n",
+		       __FUNCTION__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	np                   = netdev_priv(netdev);
+	np->xbdev            = dev;
+
+	spin_lock_init(&np->tx_lock);
+	spin_lock_init(&np->rx_lock);
+
+	skb_queue_head_init(&np->rx_batch);
+	np->rx_target     = RX_DFL_MIN_TARGET;
+	np->rx_min_target = RX_DFL_MIN_TARGET;
+	np->rx_max_target = RX_MAX_TARGET;
+
+	init_timer(&np->rx_refill_timer);
+	np->rx_refill_timer.data = (unsigned long)netdev;
+	np->rx_refill_timer.function = rx_refill_timeout;
+
+	/* Initialise {tx,rx}_skbs as a free chain containing every entry. */
+	for (i = 0; i <= NET_TX_RING_SIZE; i++) {
+		np->tx_skbs[i] = (void *)((unsigned long) i+1);
+		np->grant_tx_ref[i] = GRANT_INVALID_REF;
+	}
+
+	for (i = 0; i < NET_RX_RING_SIZE; i++) {
+		np->rx_skbs[i] = NULL;
+		np->grant_rx_ref[i] = GRANT_INVALID_REF;
+	}
+
+	/* A grant for every tx ring slot */
+	if (gnttab_alloc_grant_references(TX_MAX_TARGET,
+					  &np->gref_tx_head) < 0) {
+		printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
+		err = -ENOMEM;
+		goto exit;
+	}
+	/* A grant for every rx ring slot */
+	if (gnttab_alloc_grant_references(RX_MAX_TARGET,
+					  &np->gref_rx_head) < 0) {
+		printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n");
+		err = -ENOMEM;
+		goto exit_free_tx;
+	}
+
+	netdev->open            = network_open;
+	netdev->hard_start_xmit = network_start_xmit;
+	netdev->stop            = network_close;
+	netdev->get_stats       = network_get_stats;
+	netdev->poll            = netif_poll;
+	netdev->set_multicast_list = network_set_multicast_list;
+	netdev->uninit          = netif_uninit;
+	netdev->change_mtu	= xennet_change_mtu;
+	netdev->weight          = 64;
+	netdev->features        = NETIF_F_IP_CSUM;
+
+	SET_ETHTOOL_OPS(netdev, &network_ethtool_ops);
+	SET_MODULE_OWNER(netdev);
+	SET_NETDEV_DEV(netdev, &dev->dev);
+
+	np->netdev = netdev;
+
+	netfront_carrier_off(np);
+
+	return netdev;
+
+ exit_free_tx:
+	gnttab_free_grant_references(np->gref_tx_head);
+ exit:
+	free_netdev(netdev);
+	return ERR_PTR(err);
+}
+
+
+static void netif_disconnect_backend(struct netfront_info *info)
+{
+	/* Stop old i/f to prevent errors whilst we rebuild the state. */
+	spin_lock_irq(&info->tx_lock);
+	spin_lock(&info->rx_lock);
+	netfront_carrier_off(info);
+	spin_unlock(&info->rx_lock);
+	spin_unlock_irq(&info->tx_lock);
+
+	if (info->irq)
+		unbind_from_irqhandler(info->irq, info->netdev);
+	info->evtchn = info->irq = 0;
+
+	end_access(info->tx_ring_ref, info->tx.sring);
+	end_access(info->rx_ring_ref, info->rx.sring);
+	info->tx_ring_ref = GRANT_INVALID_REF;
+	info->rx_ring_ref = GRANT_INVALID_REF;
+	info->tx.sring = NULL;
+	info->rx.sring = NULL;
+}
+
+
+static void end_access(int ref, void *page)
+{
+	if (ref != GRANT_INVALID_REF)
+		gnttab_end_foreign_access(ref, 0, (unsigned long)page);
+}
+
+
+/* ** Driver registration ** */
+
+
+static struct xenbus_device_id netfront_ids[] = {
+	{ "vif" },
+	{ "" }
+};
+
+
+static struct xenbus_driver netfront = {
+	.name = "vif",
+	.owner = THIS_MODULE,
+	.ids = netfront_ids,
+	.probe = netfront_probe,
+	.remove = __devexit_p(netfront_remove),
+	.resume = netfront_resume,
+	.otherend_changed = backend_changed,
+};
+
+static int __init netif_init(void)
+{
+	if (!is_running_on_xen())
+		return -ENODEV;
+
+	if (rx_flip && rx_copy) {
+		printk(KERN_WARNING "netfront: Cannot specify both rx_copy and rx_flip.\n");
+		return -EINVAL;
+	}
+
+	if (!rx_flip && !rx_copy)
+		rx_flip = 1; /* Default is to flip. */
+
+	if (is_initial_xendomain())
+		return 0;
+
+	printk(KERN_INFO "Initialising virtual ethernet driver.\n");
+
+	return xenbus_register_frontend(&netfront);
+}
+module_init(netif_init);
+
+
+static void __exit netif_exit(void)
+{
+	if (is_initial_xendomain())
+		return;
+
+	return xenbus_unregister_driver(&netfront);
+}
+module_exit(netif_exit);
+
+MODULE_LICENSE("Dual BSD/GPL");

-- 

[PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-netfront-use-cb.patch --]
[-- Type: text/plain, Size: 1873 bytes --]

Netfront's use of nh.raw and h.raw for storing page+offset is a bit
hinky, and it breaks with upcoming network stack updates which reduce
these fields to sub-pointer sizes.  Fortunately, skb offers the "cb"
field specifically for stashing this kind of info, so use it.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>

---
 drivers/net/xen-netfront.c |   18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

===================================================================
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -52,6 +52,13 @@
 #include <xen/page.h>
 #include <xen/grant_table.h>
 
+struct netfront_cb {
+	struct page *page;
+	unsigned offset;
+};
+
+#define NETFRONT_SKB_CB(skb)	((struct netfront_cb *)((skb)->cb))
+
 /*
  * Mutually-exclusive module options to select receive data path:
  *  rx_copy : Packets are copied by network backend into local memory
@@ -944,10 +951,11 @@ static void handle_incoming_queue(struct
 	struct sk_buff *skb;
 
 	while ((skb = __skb_dequeue(rxq)) != NULL) {
-		struct page *page = (struct page *)skb->nh.raw;
+		struct page *page = NETFRONT_SKB_CB(skb)->page;
 		void *vaddr = page_address(page);
-
-		memcpy(skb->data, vaddr + (skb->h.raw - skb->nh.raw),
+		unsigned offset = NETFRONT_SKB_CB(skb)->offset;
+
+		memcpy(skb->data, vaddr + offset,
 		       skb_headlen(skb));
 
 		if (page != skb_shinfo(skb)->frags[0].page)
@@ -1251,8 +1259,8 @@ err:
 			}
 		}
 
-		skb->nh.raw = (void *)skb_shinfo(skb)->frags[0].page;
-		skb->h.raw = skb->nh.raw + rx->offset;
+		NETFRONT_SKB_CB(skb)->page = skb_shinfo(skb)->frags[0].page;
+		NETFRONT_SKB_CB(skb)->offset = rx->offset;
 
 		len = rx->status;
 		if (len > RX_COPY_THRESHOLD)

-- 

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Herbert Xu]

On Mon, Apr 23, 2007 at 02:57:00PM -0700, Jeremy Fitzhardinge wrote:
> Netfront's use of nh.raw and h.raw for storing page+offset is a bit
> hinky, and it breaks with upcoming network stack updates which reduce
> these fields to sub-pointer sizes.  Fortunately, skb offers the "cb"
> field specifically for stashing this kind of info, so use it.
> 
> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Chris Wright <chrisw@sous-sol.org>
> Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>

Thanks Jeremy.  The patch looks good.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Jeremy Fitzhardinge]

Herbert Xu wrote:
> Thanks Jeremy.  The patch looks good.

Could you give netfront an overall review as well?  I know you're
already pretty familiar with it, but if you could cast a fresh eye over
it, that would be helpful.

Thanks,
    J

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Herbert Xu]

On Mon, Apr 23, 2007 at 09:34:55PM -0700, Jeremy Fitzhardinge wrote:
> 
> Could you give netfront an overall review as well?  I know you're
> already pretty familiar with it, but if you could cast a fresh eye over
> it, that would be helpful.

Sure thing.  I'll look over it soon.

Actually there is one thing I'd like to see changed first up: I noticed
that you've stripped out the checksum hack which is in the main Xen tree.
We actually have the code in net-2.6.22 (which is also in mm) that lets
you use CHECKSUM_PARTIAL on received packets without having to do that
hack.

Here's the patch that I've been testing so far.  It's against the Xen
source, but should be easy to adapt to your version as well.

I just thought about this again, and in fact we need this change for
correctness as well as performance.  Because not setting ip_summed
to CHECKSUM_PARTIAL in netfront is not going to stop netback from
sending CHECKSUM_PARTIAL packets to us.  If these packets are then
routed/bridged back to netback, they'll have the wrong checksum.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
diff -ur linux-2.6.20.noarch/drivers/xen/core/skbuff.c linux-2.6.20.i686/drivers/xen/core/skbuff.c
--- linux-2.6.20.noarch/drivers/xen/core/skbuff.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/drivers/xen/core/skbuff.c	2007-03-30 21:06:20.000000000 +1000
@@ -9,6 +9,10 @@
 #include <linux/etherdevice.h>
 #include <linux/skbuff.h>
 #include <linux/init.h>
+#include <linux/if_ether.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <net/ip.h>
 #include <asm/io.h>
 #include <asm/page.h>
 #include <asm/hypervisor.h>
@@ -78,6 +82,37 @@
 	return skb;
 }
 
+int skb_checksum_setup(struct sk_buff *skb)
+{
+	if (skb->protocol != htons(ETH_P_IP))
+		goto out;
+	skb->h.raw = (unsigned char *)skb->nh.iph + 4*skb->nh.iph->ihl;
+	if (skb->h.raw >= skb->tail)
+		goto out;
+	switch (skb->nh.iph->protocol) {
+	case IPPROTO_TCP:
+		skb->csum_offset = offsetof(struct tcphdr, check);
+		break;
+	case IPPROTO_UDP:
+		skb->csum_offset = offsetof(struct udphdr, check);
+		break;
+	default:
+		if (net_ratelimit())
+			printk(KERN_ERR "Attempting to checksum a non-"
+			       "TCP/UDP packet, dropping a protocol"
+			       " %d packet", skb->nh.iph->protocol);
+		goto out;
+	}
+	if ((skb->h.raw + skb->csum_offset + 2) > skb->tail)
+		goto out;
+	skb->ip_summed = CHECKSUM_PARTIAL;
+
+	return 0;
+out:
+	return -EPROTO;
+}
+EXPORT_SYMBOL(skb_checksum_setup);
+
 static void skbuff_ctor(void *buf, struct kmem_cache *cachep, unsigned long unused)
 {
 	int order = 0;
diff -ur linux-2.6.20.noarch/drivers/xen/netback/loopback.c linux-2.6.20.i686/drivers/xen/netback/loopback.c
--- linux-2.6.20.noarch/drivers/xen/netback/loopback.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/drivers/xen/netback/loopback.c	2007-03-30 21:01:02.000000000 +1000
@@ -149,16 +149,6 @@
 	np->stats.rx_bytes += skb->len;
 	np->stats.rx_packets++;
 
-	if (skb->ip_summed == CHECKSUM_PARTIAL) {
-		/* Defer checksum calculation. */
-		skb->proto_csum_blank = 1;
-		/* Must be a local packet: assert its integrity. */
-		skb->proto_data_valid = 1;
-	}
-
-	skb->ip_summed = skb->proto_data_valid ?
-		CHECKSUM_UNNECESSARY : CHECKSUM_NONE;
-
 	skb->pkt_type = PACKET_HOST; /* overridden by eth_type_trans() */
 	skb->protocol = eth_type_trans(skb, dev);
 	skb->dev      = dev;
diff -ur linux-2.6.20.noarch/drivers/xen/netback/netback.c linux-2.6.20.i686/drivers/xen/netback/netback.c
--- linux-2.6.20.noarch/drivers/xen/netback/netback.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/drivers/xen/netback/netback.c	2007-03-31 21:07:48.000000000 +1000
@@ -293,7 +293,6 @@
 		/* Copy only the header fields we use in this driver. */
 		nskb->dev = skb->dev;
 		nskb->ip_summed = skb->ip_summed;
-		nskb->proto_data_valid = skb->proto_data_valid;
 		dev_kfree_skb(skb);
 		skb = nskb;
 	}
@@ -666,9 +665,11 @@
 		id = meta[npo.meta_cons].id;
 		flags = nr_frags ? NETRXF_more_data : 0;
 
-		if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
+		if (skb->ip_summed == CHECKSUM_PARTIAL)
+			/* local packet? */
 			flags |= NETRXF_csum_blank | NETRXF_data_validated;
-		else if (skb->proto_data_valid) /* remote but checksummed? */
+		else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
+			/* remote but checksummed? */
 			flags |= NETRXF_data_validated;
 
 		if (meta[npo.meta_cons].copy)
@@ -1303,23 +1304,19 @@
 			netif_idx_release(pending_idx);
 		}
 
-		/*
-		 * Old frontends do not assert data_validated but we
-		 * can infer it from csum_blank so test both flags.
-		 */
-		if (txp->flags & (NETTXF_data_validated|NETTXF_csum_blank)) {
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
-			skb->proto_data_valid = 1;
-		} else {
-			skb->ip_summed = CHECKSUM_NONE;
-			skb->proto_data_valid = 0;
-		}
-		skb->proto_csum_blank = !!(txp->flags & NETTXF_csum_blank);
-
 		netbk_fill_frags(skb);
 
 		skb->dev      = netif->dev;
 		skb->protocol = eth_type_trans(skb, skb->dev);
+		skb->nh.raw   = skb->data;
+
+		if (txp->flags & NETTXF_csum_blank) {
+			if (skb_checksum_setup(skb)) {
+				kfree_skb(skb);
+				continue;
+			}
+		} else if (txp->flags & NETTXF_data_validated)
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 		netif->stats.rx_bytes += skb->len;
 		netif->stats.rx_packets++;
diff -ur linux-2.6.20.noarch/drivers/xen/netfront/netfront.c linux-2.6.20.i686/drivers/xen/netfront/netfront.c
--- linux-2.6.20.noarch/drivers/xen/netfront/netfront.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/drivers/xen/netfront/netfront.c	2007-03-31 21:07:43.000000000 +1000
@@ -925,12 +925,12 @@
 	tx->flags = 0;
 	extra = NULL;
 
-	if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
+	if (skb->ip_summed == CHECKSUM_PARTIAL)
+		/* local packet? */
 		tx->flags |= NETTXF_csum_blank | NETTXF_data_validated;
-#ifdef CONFIG_XEN
-	if (skb->proto_data_valid) /* remote but checksummed? */
+	else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
+		/* remote but checksummed? */
 		tx->flags |= NETTXF_data_validated;
-#endif
 
 #ifdef HAVE_TSO
 	if (skb_is_gso(skb)) {
@@ -1351,20 +1351,10 @@
 		skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len);
 		skb->len += skb->data_len;
 
-		/*
-		 * Old backends do not assert data_validated but we
-		 * can infer it from csum_blank so test both flags.
-		 */
-		if (rx->flags & (NETRXF_data_validated|NETRXF_csum_blank))
+		if (rx->flags & NETRXF_csum_blank)
+			skb->ip_summed = CHECKSUM_PARTIAL;
+		else if (rx->flags & NETRXF_data_validated)
 			skb->ip_summed = CHECKSUM_UNNECESSARY;
-		else
-			skb->ip_summed = CHECKSUM_NONE;
-#ifdef CONFIG_XEN
-		skb->proto_data_valid = (skb->ip_summed != CHECKSUM_NONE);
-		skb->proto_csum_blank = !!(rx->flags & NETRXF_csum_blank);
-#endif
-		np->stats.rx_packets++;
-		np->stats.rx_bytes += skb->len;
 
 		__skb_queue_tail(&rxq, skb);
 
@@ -1404,6 +1394,19 @@
 
 		/* Ethernet work: Delayed to here as it peeks the header. */
 		skb->protocol = eth_type_trans(skb, dev);
+		skb->nh.raw = skb->data;
+
+		if (skb->ip_summed == CHECKSUM_PARTIAL) {
+			if (skb_checksum_setup(skb)) {
+				work_done--;
+				kfree_skb(skb);
+				np->stats.rx_errors++;
+				continue;
+			}
+		}
+
+		np->stats.rx_packets++;
+		np->stats.rx_bytes += skb->len;
 
 		/* Pass it up. */
 		netif_receive_skb(skb);
diff -ur linux-2.6.20.noarch/include/linux/skbuff.h linux-2.6.20.i686/include/linux/skbuff.h
--- linux-2.6.20.noarch/include/linux/skbuff.h	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/include/linux/skbuff.h	2007-03-30 21:01:02.000000000 +1000
@@ -202,8 +202,6 @@
  *	@local_df: allow local fragmentation
  *	@cloned: Head may be cloned (check refcnt to be sure)
  *	@nohdr: Payload reference only, must not modify header
- *	@proto_data_valid: Protocol data validated since arriving at localhost
- *	@proto_csum_blank: Protocol csum must be added before leaving localhost
  *	@pkt_type: Packet class
  *	@fclone: skbuff clone status
  *	@ip_summed: Driver fed us an IP checksum
@@ -286,13 +284,7 @@
 				nfctinfo:3;
 	__u8			pkt_type:3,
 				fclone:2,
-#ifndef CONFIG_XEN
 				ipvs_property:1;
-#else
-				ipvs_property:1,
-				proto_data_valid:1,
-				proto_csum_blank:1;
-#endif
 	__be16			protocol;
 
 	void			(*destructor)(struct sk_buff *skb);
@@ -1345,6 +1337,8 @@
 
 extern struct sk_buff *skb_segment(struct sk_buff *skb, int features);
 
+extern int skb_checksum_setup(struct sk_buff *skb);
+
 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
 				       int len, void *buffer)
 {
diff -ur linux-2.6.20.noarch/net/core/dev.c linux-2.6.20.i686/net/core/dev.c
--- linux-2.6.20.noarch/net/core/dev.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/net/core/dev.c	2007-04-03 15:26:04.000000000 +1000
@@ -117,12 +117,6 @@
 #include <linux/err.h>
 #include <linux/ctype.h>
 
-#ifdef CONFIG_XEN
-#include <net/ip.h>
-#include <linux/tcp.h>
-#include <linux/udp.h>
-#endif
-
 /*
  *	The list of packet types we will receive (as opposed to discard)
  *	and the routines to invoke.
@@ -1398,43 +1392,6 @@
 	}						\
 }
 
-#ifdef CONFIG_XEN
-inline int skb_checksum_setup(struct sk_buff *skb)
-{
-	if (skb->proto_csum_blank) {
-		if (skb->protocol != htons(ETH_P_IP))
-			goto out;
-		skb->h.raw = (unsigned char *)skb->nh.iph + 4*skb->nh.iph->ihl;
-		if (skb->h.raw >= skb->tail)
-			goto out;
-		switch (skb->nh.iph->protocol) {
-		case IPPROTO_TCP:
-			skb->csum = offsetof(struct tcphdr, check);
-			break;
-		case IPPROTO_UDP:
-			skb->csum = offsetof(struct udphdr, check);
-			break;
-		default:
-			if (net_ratelimit())
-				printk(KERN_ERR "Attempting to checksum a non-"
-				       "TCP/UDP packet, dropping a protocol"
-				       " %d packet", skb->nh.iph->protocol);
-			goto out;
-		}
-		if ((skb->h.raw + skb->csum + 2) > skb->tail)
-			goto out;
-		skb->ip_summed = CHECKSUM_PARTIAL;
-		skb->proto_csum_blank = 0;
-	}
-	return 0;
-out:
-	return -EPROTO;
-}
-#else
-inline int skb_checksum_setup(struct sk_buff *skb) { return 0; }
-#endif
-
-
 /**
  *	dev_queue_xmit - transmit a buffer
  *	@skb: buffer to transmit
@@ -1467,12 +1424,6 @@
 	struct Qdisc *q;
 	int rc = -ENOMEM;
 
- 	/* If a checksum-deferred packet is forwarded to a device that needs a
- 	 * checksum, correct the pointers and force checksumming.
- 	 */
- 	if (skb_checksum_setup(skb))
- 		goto out_kfree_skb;
-
 	/* GSO will handle the following emulations directly. */
 	if (netif_needs_gso(dev, skb))
 		goto gso;
@@ -1848,19 +1799,6 @@
 	}
 #endif
 
-#ifdef CONFIG_XEN
-	switch (skb->ip_summed) {
-	case CHECKSUM_UNNECESSARY:
-		skb->proto_data_valid = 1;
-		break;
-	case CHECKSUM_PARTIAL:
-		/* XXX Implement me. */
-	default:
-		skb->proto_data_valid = 0;
-		break;
-	}
-#endif
-
 	list_for_each_entry_rcu(ptype, &ptype_all, list) {
 		if (!ptype->dev || ptype->dev == skb->dev) {
 			if (pt_prev) 
@@ -3625,7 +3563,6 @@
 EXPORT_SYMBOL(net_enable_timestamp);
 EXPORT_SYMBOL(net_disable_timestamp);
 EXPORT_SYMBOL(dev_get_flags);
-EXPORT_SYMBOL(skb_checksum_setup);
 
 #if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
 EXPORT_SYMBOL(br_handle_frame_hook);
diff -ur linux-2.6.20.noarch/net/core/skbuff.c linux-2.6.20.i686/net/core/skbuff.c
--- linux-2.6.20.noarch/net/core/skbuff.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/net/core/skbuff.c	2007-03-30 21:01:02.000000000 +1000
@@ -484,10 +484,6 @@
 	C(local_df);
 	n->cloned = 1;
 	n->nohdr = 0;
-#ifdef CONFIG_XEN
-	C(proto_data_valid);
-	C(proto_csum_blank);
-#endif
 	C(pkt_type);
 	C(ip_summed);
 	C(priority);
diff -ur linux-2.6.20.noarch/net/ipv4/netfilter/ip_nat_proto_tcp.c linux-2.6.20.i686/net/ipv4/netfilter/ip_nat_proto_tcp.c
--- linux-2.6.20.noarch/net/ipv4/netfilter/ip_nat_proto_tcp.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/net/ipv4/netfilter/ip_nat_proto_tcp.c	2007-03-30 21:01:02.000000000 +1000
@@ -129,15 +129,8 @@
 	if (hdrsize < sizeof(*hdr))
 		return 1;
 
-#ifdef CONFIG_XEN
-	if ((*pskb)->proto_csum_blank)
-		nf_csum_replace4(&hdr->check, oldip, newip);
-	else
-#endif
-	{
 	nf_proto_csum_replace4(&hdr->check, *pskb, oldip, newip, 1);
 	nf_proto_csum_replace2(&hdr->check, *pskb, oldport, newport, 0);
-	}
 	return 1;
 }
 
diff -ur linux-2.6.20.noarch/net/ipv4/netfilter/ip_nat_proto_udp.c linux-2.6.20.i686/net/ipv4/netfilter/ip_nat_proto_udp.c
--- linux-2.6.20.noarch/net/ipv4/netfilter/ip_nat_proto_udp.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/net/ipv4/netfilter/ip_nat_proto_udp.c	2007-03-30 21:01:02.000000000 +1000
@@ -115,16 +115,8 @@
 	}
 
 	if (hdr->check || (*pskb)->ip_summed == CHECKSUM_PARTIAL) {
-#ifdef CONFIG_XEN
-		if ((*pskb)->proto_csum_blank)
-			nf_csum_replace4(&hdr->check, oldip, newip);
-		else
-#endif
-		{
 		nf_proto_csum_replace4(&hdr->check, *pskb, oldip, newip, 1);
 		nf_proto_csum_replace2(&hdr->check, *pskb, *portptr, newport, 0);
-		}
-
 		if (!hdr->check)
 			hdr->check = CSUM_MANGLED_0;
 	}
diff -ur linux-2.6.20.noarch/net/ipv4/xfrm4_output.c linux-2.6.20.i686/net/ipv4/xfrm4_output.c
--- linux-2.6.20.noarch/net/ipv4/xfrm4_output.c	2007-04-03 15:26:15.000000000 +1000
+++ linux-2.6.20.i686/net/ipv4/xfrm4_output.c	2007-03-30 21:01:02.000000000 +1000
@@ -18,8 +18,6 @@
 #include <net/xfrm.h>
 #include <net/icmp.h>
 
-extern int skb_checksum_setup(struct sk_buff *skb);
-
 static int xfrm4_tunnel_check_size(struct sk_buff *skb)
 {
 	int mtu, ret = 0;
@@ -49,10 +47,6 @@
 	struct dst_entry *dst = skb->dst;
 	struct xfrm_state *x = dst->xfrm;
 	int err;
-	
-	err = skb_checksum_setup(skb);
-	if (err)
-		goto error_nolock;
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
 		err = skb_checksum_help(skb);

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Jeremy Fitzhardinge]

Herbert Xu wrote:
> Sure thing.  I'll look over it soon.
>
> Actually there is one thing I'd like to see changed first up: I noticed
> that you've stripped out the checksum hack which is in the main Xen tree.
> We actually have the code in net-2.6.22 (which is also in mm) that lets
> you use CHECKSUM_PARTIAL on received packets without having to do that
> hack.
>
> Here's the patch that I've been testing so far.  It's against the Xen
> source, but should be easy to adapt to your version as well.
>
> I just thought about this again, and in fact we need this change for
> correctness as well as performance.  Because not setting ip_summed
> to CHECKSUM_PARTIAL in netfront is not going to stop netback from
> sending CHECKSUM_PARTIAL packets to us.  If these packets are then
> routed/bridged back to netback, they'll have the wrong checksum.
>   

OK, I've been sitting on this in the hope that I'll suddenly see the
light and work out what you're talking about - but apparently that's not
going to happen.  So, some questions:

   1. Does this patch change the dom0 <-> domU interface?  or does it
      fix something that's currently broken?
   2. Can just apply the netfront part to the pv_ops kernel, or does it
      require the corresponding dom0 patch to be applied as well?

Thanks,
    J

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Herbert Xu]

On Fri, Apr 27, 2007 at 03:19:50PM -0700, Jeremy Fitzhardinge wrote:
> 
> OK, I've been sitting on this in the hope that I'll suddenly see the
> light and work out what you're talking about - but apparently that's not
> going to happen.  So, some questions:
> 
>    1. Does this patch change the dom0 <-> domU interface?  or does it
>       fix something that's currently broken?

No it doesn't change the interface at all.

>    2. Can just apply the netfront part to the pv_ops kernel, or does it
>       require the corresponding dom0 patch to be applied as well?

They can be applied separately so you don't need the dom0 part for your
tree.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Jeremy Fitzhardinge]

Herbert Xu wrote:
> They can be applied separately so you don't need the dom0 part for your
> tree.

Great, thanks.

    J

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Herbert Xu]

On Fri, Apr 27, 2007 at 04:27:21PM -0700, Jeremy Fitzhardinge wrote:
> Herbert Xu wrote:
> > They can be applied separately so you don't need the dom0 part for your
> > tree.
> 
> Great, thanks.

BTW, the version I posted to you is missing the following line.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
--- linux-2.6.20.i386/drivers/xen/core/skbuff.c	2007-04-28 15:30:16.000000000 +1000
+++ build-2.6.20.i386/drivers/xen/core/skbuff.c	2007-04-28 15:30:52.000000000 +1000
@@ -89,6 +89,7 @@
 	skb->h.raw = (unsigned char *)skb->nh.iph + 4*skb->nh.iph->ihl;
 	if (skb->h.raw >= skb->tail)
 		goto out;
+	skb->csum_start = skb->h.raw - skb->head;
 	switch (skb->nh.iph->protocol) {
 	case IPPROTO_TCP:
 		skb->csum_offset = offsetof(struct tcphdr, check);

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Jeremy Fitzhardinge]

Herbert Xu wrote:
> BTW, the version I posted to you is missing the following line.
>   
> --- linux-2.6.20.i386/drivers/xen/core/skbuff.c	2007-04-28 15:30:16.000000000 +1000
> +++ build-2.6.20.i386/drivers/xen/core/skbuff.c	2007-04-28 15:30:52.000000000 +1000
> @@ -89,6 +89,7 @@
>  	skb->h.raw = (unsigned char *)skb->nh.iph + 4*skb->nh.iph->ihl;
>  	if (skb->h.raw >= skb->tail)
>  		goto out;
> +	skb->csum_start = skb->h.raw - skb->head;
>  	switch (skb->nh.iph->protocol) {
>  	case IPPROTO_TCP:
>  		skb->csum_offset = offsetof(struct tcphdr, check);
>   

drivers/xen/core/skbuff.c?  What's that?

    J

Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Herbert Xu]

On Sun, Apr 29, 2007 at 12:43:33AM -0700, Jeremy Fitzhardinge wrote:
> Herbert Xu wrote:
> > BTW, the version I posted to you is missing the following line.
> >   
> > --- linux-2.6.20.i386/drivers/xen/core/skbuff.c	2007-04-28 15:30:16.000000000 +1000
> > +++ build-2.6.20.i386/drivers/xen/core/skbuff.c	2007-04-28 15:30:52.000000000 +1000
> > @@ -89,6 +89,7 @@
> >  	skb->h.raw = (unsigned char *)skb->nh.iph + 4*skb->nh.iph->ihl;
> >  	if (skb->h.raw >= skb->tail)
> >  		goto out;
> > +	skb->csum_start = skb->h.raw - skb->head;
> >  	switch (skb->nh.iph->protocol) {
> >  	case IPPROTO_TCP:
> >  		skb->csum_offset = offsetof(struct tcphdr, check);
> >   
> 
> drivers/xen/core/skbuff.c?  What's that?

It's part of the skb_checksum_setup function which we still need
for this because the current netback protocol doesn't pass the
csum_start and csum_offset values along.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH 23/25] xen: Lockdep fixes for xen-netfront

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-netfront-lockdep-fix.patch --]
[-- Type: text/plain, Size: 4226 bytes --]

netfront contains two locking problems found by lockdep:

1. rx_lock is a normal spinlock, and tx_lock is an irq spinlock.  This
   means that in normal use, tx_lock may be taken by an interrupt routine
   while rx_lock is held.  However, netif_disconnect_backend takes them
   in the order tx_lock->rx_lock, which could lead to a deadlock.  Reverse
   them
2. rx_lock can also be taken in softirq context, so it should be taken/released
   with spin_(un)lock_bh.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>

---
 drivers/net/xen-netfront.c |   30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

===================================================================
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -515,14 +515,14 @@ static int network_open(struct net_devic
 
 	memset(&np->stats, 0, sizeof(np->stats));
 
-	spin_lock(&np->rx_lock);
+	spin_lock_bh(&np->rx_lock);
 	if (netfront_carrier_ok(np)) {
 		network_alloc_rx_buffers(dev);
 		np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
 		if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
 			netif_rx_schedule(dev);
 	}
-	spin_unlock(&np->rx_lock);
+	spin_unlock_bh(&np->rx_lock);
 
 	network_maybe_wake_tx(dev);
 
@@ -1212,10 +1212,10 @@ static int netif_poll(struct net_device 
 	int pages_flipped = 0;
 	int err;
 
-	spin_lock(&np->rx_lock);
+	spin_lock_bh(&np->rx_lock);
 
 	if (unlikely(!netfront_carrier_ok(np))) {
-		spin_unlock(&np->rx_lock);
+		spin_unlock_bh(&np->rx_lock);
 		return 0;
 	}
 
@@ -1356,7 +1356,7 @@ err:
 		local_irq_restore(flags);
 	}
 
-	spin_unlock(&np->rx_lock);
+	spin_unlock_bh(&np->rx_lock);
 
 	return more_to_do;
 }
@@ -1399,7 +1399,7 @@ static void netif_release_rx_bufs(struct
 
 	skb_queue_head_init(&free_list);
 
-	spin_lock(&np->rx_lock);
+	spin_lock_bh(&np->rx_lock);
 
 	for (id = 0; id < NET_RX_RING_SIZE; id++) {
 		if ((ref = np->grant_rx_ref[id]) == GRANT_INVALID_REF) {
@@ -1469,7 +1469,7 @@ static void netif_release_rx_bufs(struct
 	while ((skb = __skb_dequeue(&free_list)) != NULL)
 		dev_kfree_skb(skb);
 
-	spin_unlock(&np->rx_lock);
+	spin_unlock_bh(&np->rx_lock);
 }
 
 static int network_close(struct net_device *dev)
@@ -1579,8 +1579,8 @@ static int network_connect(struct net_de
 	dev_info(&dev->dev, "has %sing receive path.\n",
 		 np->copying_receiver ? "copy" : "flipp");
 
+	spin_lock_bh(&np->rx_lock);
 	spin_lock_irq(&np->tx_lock);
-	spin_lock(&np->rx_lock);
 
 	/*
 	 * Recovery procedure:
@@ -1632,8 +1632,8 @@ static int network_connect(struct net_de
 	network_tx_buf_gc(dev);
 	network_alloc_rx_buffers(dev);
 
-	spin_unlock(&np->rx_lock);
 	spin_unlock_irq(&np->tx_lock);
+	spin_unlock_bh(&np->rx_lock);
 
 	return 0;
 }
@@ -1689,7 +1689,7 @@ static ssize_t store_rxbuf_min(struct de
 	if (target > RX_MAX_TARGET)
 		target = RX_MAX_TARGET;
 
-	spin_lock(&np->rx_lock);
+	spin_lock_bh(&np->rx_lock);
 	if (target > np->rx_max_target)
 		np->rx_max_target = target;
 	np->rx_min_target = target;
@@ -1698,7 +1698,7 @@ static ssize_t store_rxbuf_min(struct de
 
 	network_alloc_rx_buffers(netdev);
 
-	spin_unlock(&np->rx_lock);
+	spin_unlock_bh(&np->rx_lock);
 	return len;
 }
 
@@ -1732,7 +1732,7 @@ static ssize_t store_rxbuf_max(struct de
 	if (target > RX_MAX_TARGET)
 		target = RX_MAX_TARGET;
 
-	spin_lock(&np->rx_lock);
+	spin_lock_bh(&np->rx_lock);
 	if (target < np->rx_min_target)
 		np->rx_min_target = target;
 	np->rx_max_target = target;
@@ -1741,7 +1741,7 @@ static ssize_t store_rxbuf_max(struct de
 
 	network_alloc_rx_buffers(netdev);
 
-	spin_unlock(&np->rx_lock);
+	spin_unlock_bh(&np->rx_lock);
 	return len;
 }
 
@@ -1885,11 +1885,11 @@ static void netif_disconnect_backend(str
 static void netif_disconnect_backend(struct netfront_info *info)
 {
 	/* Stop old i/f to prevent errors whilst we rebuild the state. */
+	spin_lock_bh(&info->rx_lock);
 	spin_lock_irq(&info->tx_lock);
-	spin_lock(&info->rx_lock);
 	netfront_carrier_off(info);
-	spin_unlock(&info->rx_lock);
 	spin_unlock_irq(&info->tx_lock);
+	spin_unlock_bh(&info->rx_lock);
 
 	if (info->irq)
 		unbind_from_irqhandler(info->irq, info->netdev);

-- 

Re: [PATCH 23/25] xen: Lockdep fixes for xen-netfront

[Herbert Xu]

Jeremy Fitzhardinge <jeremy@goop.org> wrote:
>
> @@ -1212,10 +1212,10 @@ static int netif_poll(struct net_device 
>        int pages_flipped = 0;
>        int err;
> 
> -       spin_lock(&np->rx_lock);
> +       spin_lock_bh(&np->rx_lock);
> 
>        if (unlikely(!netfront_carrier_ok(np))) {
> -               spin_unlock(&np->rx_lock);
> +               spin_unlock_bh(&np->rx_lock);

You don't need to disable BH in netif_poll since it's always called
with BH disabled.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 23/25] xen: Lockdep fixes for xen-netfront

[Jeremy Fitzhardinge]

Herbert Xu wrote:
> You don't need to disable BH in netif_poll since it's always called
> with BH disabled.
>   

Ah, yes, you mentioned that before.  I'll fix it up.

    J

[PATCH 24/25] xen: xen: diddle netfront

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-netfront-diddle.patch --]
[-- Type: text/plain, Size: 2387 bytes --]

Move things around a bit to match xen-unstable netfront.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 drivers/net/xen-netfront.c |   36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

===================================================================
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -750,19 +750,6 @@ no_skb:
 		notify_remote_via_irq(np->irq);
 }
 
-static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
-				grant_ref_t ref)
-{
-	int new = xennet_rxidx(np->rx.req_prod_pvt);
-
-	BUG_ON(np->rx_skbs[new]);
-	np->rx_skbs[new] = skb;
-	np->grant_rx_ref[new] = ref;
-	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
-	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
-	np->rx.req_prod_pvt++;
-}
-
 static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
 			      struct netif_tx_request *tx)
 {
@@ -944,6 +931,19 @@ static irqreturn_t netif_int(int irq, vo
 	spin_unlock_irqrestore(&np->tx_lock, flags);
 
 	return IRQ_HANDLED;
+}
+
+static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
+				grant_ref_t ref)
+{
+	int new = xennet_rxidx(np->rx.req_prod_pvt);
+
+	BUG_ON(np->rx_skbs[new]);
+	np->rx_skbs[new] = skb;
+	np->grant_rx_ref[new] = ref;
+	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
+	RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
+	np->rx.req_prod_pvt++;
 }
 
 static void handle_incoming_queue(struct net_device *dev, struct sk_buff_head *rxq)
@@ -1169,7 +1169,8 @@ static RING_IDX xennet_fill_frags(struct
 	return cons;
 }
 
-static int xennet_set_skb_gso(struct sk_buff *skb, struct netif_extra_info *gso)
+static int xennet_set_skb_gso(struct sk_buff *skb,
+			      struct netif_extra_info *gso)
 {
 	if (!gso->u.gso.size) {
 		if (net_ratelimit())
@@ -1456,11 +1457,8 @@ static void netif_release_rx_bufs(struct
 
 		if (!xen_feature(XENFEAT_auto_translated_physmap)) {
 			/* Do all the remapping work and M2P updates. */
-			mcl->op = __HYPERVISOR_mmu_update;
-			mcl->args[0] = (unsigned long)np->rx_mmu;
-			mcl->args[1] = mmu - np->rx_mmu;
-			mcl->args[2] = 0;
-			mcl->args[3] = DOMID_SELF;
+			MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
+					 0, DOMID_SELF);
 			mcl++;
 			HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
 		}

-- 

[PATCH 25/25] xen: Xen machine operations

[Jeremy Fitzhardinge]

[-- Attachment #1: xen-machine-ops.patch --]
[-- Type: text/plain, Size: 2368 bytes --]

Make the appropriate hypercalls to halt and reboot the virtual machine.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/xen/enlighten.c |   43 +++++++++++++++++++++++++++++++++++++++++++
 arch/i386/xen/smp.c       |    4 +---
 2 files changed, 44 insertions(+), 3 deletions(-)

===================================================================
--- a/arch/i386/xen/enlighten.c
+++ b/arch/i386/xen/enlighten.c
@@ -14,6 +14,7 @@
 
 #include <xen/interface/xen.h>
 #include <xen/interface/vcpu.h>
+#include <xen/interface/sched.h>
 #include <xen/features.h>
 #include <xen/page.h>
 
@@ -28,6 +29,7 @@
 #include <asm/pgtable.h>
 #include <asm/smp.h>
 #include <asm/tlbflush.h>
+#include <asm/reboot.h>
 
 #include "xen-ops.h"
 #include "mmu.h"
@@ -787,6 +789,45 @@ static const struct smp_ops xen_smp_ops 
 };
 #endif	/* CONFIG_SMP */
 
+static void xen_reboot(int reason)
+{
+#ifdef CONFIG_SMP
+	smp_send_stop();
+#endif
+
+	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, reason))
+		BUG();
+}
+
+static void xen_restart(char *msg)
+{
+	xen_reboot(SHUTDOWN_reboot);
+}
+
+static void xen_emergency_restart(void)
+{
+	xen_reboot(SHUTDOWN_reboot);
+}
+
+static void xen_machine_halt(void)
+{
+	xen_reboot(SHUTDOWN_poweroff);
+}
+
+static void xen_crash_shutdown(struct pt_regs *regs)
+{
+	xen_reboot(SHUTDOWN_crash);
+}
+
+static const struct machine_ops __initdata xen_machine_ops = {
+	.restart = xen_restart,
+	.halt = xen_machine_halt,
+	.power_off = xen_machine_halt,
+	.shutdown = xen_machine_halt,
+	.crash_shutdown = xen_crash_shutdown,
+	.emergency_restart = xen_emergency_restart,
+};
+
 /* First C function to be called on Xen boot */
 static asmlinkage void __init xen_start_kernel(void)
 {
@@ -800,6 +841,8 @@ static asmlinkage void __init xen_start_
 
 	/* Install Xen paravirt ops */
 	paravirt_ops = xen_paravirt_ops;
+	machine_ops = xen_machine_ops;
+
 #ifdef CONFIG_SMP
 	smp_ops = xen_smp_ops;
 #endif
===================================================================
--- a/arch/i386/xen/smp.c
+++ b/arch/i386/xen/smp.c
@@ -303,9 +303,7 @@ static void stop_self(void *v)
 
 void xen_smp_send_stop(void)
 {
-	cpumask_t mask = cpu_online_map;
-	cpu_clear(smp_processor_id(), mask);
-	xen_smp_call_function_mask(mask, stop_self, NULL, 0);
+	smp_call_function(stop_self, NULL, 0, 0);
 }
 
 void xen_smp_send_reschedule(int cpu)

-- 

Re: [PATCH 00/25] xen: Xen implementation for paravirt_ops

[Andi Kleen]

On Monday 23 April 2007 23:56:38 Jeremy Fitzhardinge wrote:
> Hi Andi,
> 
> It applies to 2.6.21-rc7 + your patches + the last batch of pv_ops
> patches 

I got most of those except for the broken sched_clock change.

> I posted. 

How much testing outside Jeremylabs has it gotten? Some beta
testing before merging would be good, otherwise we'll just have
a flood of fixes shortly when it is exposed to users.

> This patch generally restricts itself to Xen-specific parts of the tree,
> though it does make a few small changes elsewhere.

The general problem is that it is much more than just an architecture update.

> These patches include:
>  - some helper routines for allocating address space and walking pagetables

Needs review from mm people.

>  - Xen interface header files
>  - Core Xen implementation
>  - Efficient late-pinning/early-unpinning pagetable handling 

The number of new paravirt hooks makes me thing of renaming it to
everything_ops @|

>  - Virtualized time, including stolen time

Can you let it be reviewed by the time people? (Thomas, Ingo, John, Roman etc.)

>  - SMP support
>  - Preemption support
>  - Batched pagetable updates

>  - Xen console, based on hvc console
>  - Xenbus

That one would need to be reviewed first. It's so much code that I can't
do it all myself.

>  - Netfront, the paravirtualized network device

That one should go through the network device maintainer/netdev.

>  - Blockfront, the paravirtualized block device

And that needs a block device review and whoever maintains that (Jens?) 

-Andi

Re: [PATCH 00/25] xen: Xen implementation for paravirt_ops

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> On Monday 23 April 2007 23:56:38 Jeremy Fitzhardinge wrote:
>   
>> Hi Andi,
>>
>> It applies to 2.6.21-rc7 + your patches + the last batch of pv_ops
>> patches 
>>     
>
> I got most of those except for the broken sched_clock change.
>   

Er, we had a bit of back-and-forward with that.  How did that end up?

>> I posted. 
>>     
>
> How much testing outside Jeremylabs has it gotten? Some beta
> testing before merging would be good, otherwise we'll just have
> a flood of fixes shortly when it is exposed to users.
>   

Yes.  I'm just prepping a tree for xen-devel, and I primed people at the
Xen Summit last week.

>> This patch generally restricts itself to Xen-specific parts of the tree,
>> though it does make a few small changes elsewhere.
>>     
>
> The general problem is that it is much more than just an architecture update.
>
>   
>> These patches include:
>>  - some helper routines for allocating address space and walking pagetables
>>     
>
> Needs review from mm people.
>   

These have been pretty well looked at already.  They have been posted
repeatedly, and I think all the comments have been sorted out. 
alloc_vm_area() will be a bit affected by Andrew's -mm patch to make
vmalloc_sync_all a globally-visible arch export, but they merge nicely.

>>  - Xen interface header files
>>  - Core Xen implementation
>>  - Efficient late-pinning/early-unpinning pagetable handling 
>>     
>
> The number of new paravirt hooks makes me thing of renaming it to
> everything_ops @|
>   

There's only one new op in this series, and I couldn't work out a way to
avoid it, other than putting a #ifdef CONFIG_XEN in kernel/setup.c.  The
last patch posting didn't add any new hooks.  Which ones are you
referring to?

>>  - Virtualized time, including stolen time
>>     
>
> Can you let it be reviewed by the time people? (Thomas, Ingo, John, Roman etc.)
>   

Thomas has looked at and generally approves of the Xen clocksource/event
code.  The stolen time code is really only used to generate a few
numbers in /proc, and so has very little direct impact on the rest of
the kernel, and hasn't really attracted much interest as a result.  I've
posted the patch to implement sched_clock in terms of unstolen time to
the various time people repeatedly, and nobody has responded, so I guess
it doesn't irritate anyone too much; it would be nice to have some
definite feedback though.

>>  - Xen console, based on hvc console
>>  - Xenbus
>>     
>
> That one would need to be reviewed first. It's so much code that I can't
> do it all myself.
>   

I put a specific plea for GregKH to look at this.

>>  - Netfront, the paravirtualized network device
>>     
>
> That one should go through the network device maintainer/netdev.
>   

Stephen Hemminger has looked at this in the past and we've addressed all
his comments so far.  But it would be nice to get some more net
developers to review this; it was cc:d to netdev.

>>  - Blockfront, the paravirtualized block device
>>     
>
> And that needs a block device review and whoever maintains that (Jens?) 
>   

He was cc:d.  I'll ask him specifically.

    J