[PATCH V2 1/7]: PVH: basic and header changes, elfnote changes, ...

[PATCH V2 1/7]: PVH: basic and header changes, elfnote changes, ...

[Mukesh Rathor]

PVH: is a PV linux guest that has extended capabilities. This patch allows it to be configured and enabled. Also, basic header file changes to add new subcalls to physmap hypercall. Lastly, mfn_to_local_pfn must return mfn for paging mode translate

Signed-off-by: Mukesh R <mukesh.rathor@oracle.com>
---
 arch/x86/include/asm/xen/page.h |    3 +++
 arch/x86/xen/Kconfig            |   10 ++++++++++
 arch/x86/xen/xen-head.S         |   11 ++++++++++-
 include/xen/interface/memory.h  |   30 +++++++++++++++++++++++++++---
 include/xen/interface/physdev.h |   10 ++++++++++
 5 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 472b9b7..6af440d 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -159,6 +159,9 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine)
 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
 {
 	unsigned long pfn = mfn_to_pfn(mfn);
+
+	if (xen_feature(XENFEAT_auto_translated_physmap))
+		return mfn;
 	if (get_phys_to_machine(pfn) != mfn)
 		return -1; /* force !pfn_valid() */
 	return pfn;
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index fdce49c..9323b8c 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -50,3 +50,13 @@ config XEN_DEBUG_FS
 	  Enable statistics output and various tuning options in debugfs.
 	  Enabling this option may incur a significant performance overhead.
 
+config XEN_X86_PVH
+	bool "Support for running as a PVH guest (EXPERIMENTAL)"
+	depends on X86_64 && XEN && INTEL_IOMMU && EXPERIMENTAL
+	default n
+	help
+	   This option enables support for running as a PVH guest (PV guest
+	   using hardware extensions) under a suitably capable hypervisor.
+	   This option is EXPERIMETNAL because the hypervisor interfaces
+	   which it uses are not yet considered stable therefore backwards and
+	   forwards compatibility is not yet guaranteed.  If unsure, say N.
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index 7faed58..3e65ece 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -13,6 +13,15 @@
 #include <xen/interface/elfnote.h>
 #include <asm/xen/interface.h>
 
+#ifdef CONFIG_XEN_X86_PVH
+#define FEATURES_PVH "| writable_descriptor_tables" \
+		     "| auto_translated_physmap" \
+		     "| supervisor_mode_kernel" \
+		     "| hvm_callback_vector"
+#else
+#define FEATURES_PVH /* Not supported */
+#endif
+
 	__INIT
 ENTRY(startup_xen)
 	cld
@@ -95,7 +104,7 @@ NEXT_HYPERCALL(arch_6)
 #endif
 	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR startup_xen)
 	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
-	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz "!writable_page_tables|pae_pgdir_above_4gb")
+	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz "!writable_page_tables|pae_pgdir_above_4gb"FEATURES_PVH)
 	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz "yes")
 	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz "generic")
 	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,
diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index d8e33a9..dbf4c6b 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -163,14 +163,22 @@ struct xen_add_to_physmap {
     /* Which domain to change the mapping for. */
     domid_t domid;
 
-    /* Number of pages to go through for gmfn_range */
-    uint16_t    size;
-
+    union {
+	/* Number of pages to go through for gmfn_range */
+	uint16_t    size;
+	/* IFF XENMAPSPACE_gmfn_foreign */
+	domid_t foreign_domid;
+    } u;
     /* Source mapping space. */
 #define XENMAPSPACE_shared_info 0 /* shared info page */
 #define XENMAPSPACE_grant_table 1 /* grant table page */
+#define XENMAPSPACE_gmfn        2 /* GMFN */
+#define XENMAPSPACE_gmfn_range  3 /* GMFN range */
+#define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another guest */
     unsigned int space;
 
+#define XENMAPIDX_grant_table_status 0x80000000
+
     /* Index into source mapping space. */
     unsigned long idx;
 
@@ -237,4 +245,20 @@ DEFINE_GUEST_HANDLE_STRUCT(xen_memory_map);
  * during a driver critical region.
  */
 extern spinlock_t xen_reservation_lock;
+
+/*
+ * Unmaps the page appearing at a particular GPFN from the specified guest's
+ * pseudophysical address space.
+ * arg == addr of xen_remove_from_physmap_t.
+ */
+#define XENMEM_remove_from_physmap      15
+struct xen_remove_from_physmap {
+    /* Which domain to change the mapping for. */
+    domid_t domid;
+
+    /* GPFN of the current mapping of the page. */
+    xen_pfn_t gpfn;
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_remove_from_physmap);
+
 #endif /* __XEN_PUBLIC_MEMORY_H__ */
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 9ce788d..3b9d5b6 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -258,6 +258,16 @@ struct physdev_pci_device {
     uint8_t devfn;
 };
 
+#define PHYSDEVOP_pvh_map_iomem        30
+struct physdev_map_iomem {
+    /* IN */
+    uint64_t first_gfn;
+    uint64_t first_mfn;
+    uint32_t nr_mfns;
+    uint32_t add_mapping;        /* 1 == add mapping;  0 == unmap */
+
+};
+
 /*
  * Notify that some PIRQ-bound event channels have been unmasked.
  * ** This command is obsolete since interface version 0x00030202 and is **
-- 
1.7.2.3

Re: [Xen-devel] [PATCH V2 1/7]: PVH: basic and header changes, elfnote changes, ...

[Ian Campbell]

On Thu, 2012-10-11 at 22:53 +0100, Mukesh Rathor wrote:
> PVH: is a PV linux guest that has extended capabilities. This patch allows it to be configured and enabled. Also, basic header file changes to add new subcalls to physmap hypercall. Lastly, mfn_to_local_pfn must return mfn for paging mode translate
> 
> Signed-off-by: Mukesh R <mukesh.rathor@oracle.com>

Since a S-o-b is a quasi-legal statement you probably ought to put your
full name here (I know it's obvious from the email address, but...)

> diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
> index fdce49c..9323b8c 100644
> --- a/arch/x86/xen/Kconfig
> +++ b/arch/x86/xen/Kconfig
> @@ -50,3 +50,13 @@ config XEN_DEBUG_FS
>  	  Enable statistics output and various tuning options in debugfs.
>  	  Enabling this option may incur a significant performance overhead.
>  
> +config XEN_X86_PVH
> +	bool "Support for running as a PVH guest (EXPERIMENTAL)"
> +	depends on X86_64 && XEN && INTEL_IOMMU && EXPERIMENTAL

OOI why does the kernel side require an INTEL_IOMMU? I can see why the
hypervisor would need it but the guests (including dom0) can't actually
see the underlying IOMMU, can they?

> +	default n
> +	help
> +	   This option enables support for running as a PVH guest (PV guest
> +	   using hardware extensions) under a suitably capable hypervisor.
> +	   This option is EXPERIMETNAL because the hypervisor interfaces

You've carried over my original "EXPERIMETNAL" typo.

> +	   which it uses are not yet considered stable therefore backwards and
> +	   forwards compatibility is not yet guaranteed.  If unsure, say N.
> diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
> index 7faed58..3e65ece 100644
> --- a/arch/x86/xen/xen-head.S
> +++ b/arch/x86/xen/xen-head.S
> @@ -13,6 +13,15 @@
>  #include <xen/interface/elfnote.h>
>  #include <asm/xen/interface.h>
>  
> +#ifdef CONFIG_XEN_X86_PVH
> +#define FEATURES_PVH "| writable_descriptor_tables" \
> +		     "| auto_translated_physmap" \
> +		     "| supervisor_mode_kernel" \
> +		     "| hvm_callback_vector"

It's pretty lame but it looks like elf_xen_parse_features doesn't
support stripping whitespace.

Since we need these features to be parsable by older hypervisors and
tools I think we're stuck with that snafu.

> diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
> index 9ce788d..3b9d5b6 100644
> --- a/include/xen/interface/physdev.h
> +++ b/include/xen/interface/physdev.h
> @@ -258,6 +258,16 @@ struct physdev_pci_device {
>      uint8_t devfn;
>  };
>  
> +#define PHYSDEVOP_pvh_map_iomem        30
> +struct physdev_map_iomem {
> +    /* IN */
> +    uint64_t first_gfn;
> +    uint64_t first_mfn;
> +    uint32_t nr_mfns;
> +    uint32_t add_mapping;        /* 1 == add mapping;  0 == unmap */
> +
> +};
> +
>  /*
>   * Notify that some PIRQ-bound event channels have been unmasked.
>   * ** This command is obsolete since interface version 0x00030202 and is **

Re: [Xen-devel] [PATCH V2 1/7]: PVH: basic and header changes, elfnote changes, ...

[Mukesh Rathor]

On Fri, 12 Oct 2012 09:48:48 +0100
Ian Campbell <Ian.Campbell@citrix.com> wrote:

> > index fdce49c..9323b8c 100644
> > --- a/arch/x86/xen/Kconfig
> > +++ b/arch/x86/xen/Kconfig
> > @@ -50,3 +50,13 @@ config XEN_DEBUG_FS
> >  	  Enable statistics output and various tuning options in
> > debugfs. Enabling this option may incur a significant performance
> > overhead. 
> > +config XEN_X86_PVH
> > +	bool "Support for running as a PVH guest (EXPERIMENTAL)"
> > +	depends on X86_64 && XEN && INTEL_IOMMU && EXPERIMENTAL
> 
> OOI why does the kernel side require an INTEL_IOMMU? I can see why the
> hypervisor would need it but the guests (including dom0) can't
> actually see the underlying IOMMU, can they?

Well, the kernel requires the hypervisor to have it, but I guess
thats not what this is referring to. The tools can decide that.
I'll take it out.