[PATCH v2 0/2] accel: Move Xen accelerator code under accel/xen/

[PATCH v2 0/2] accel: Move Xen accelerator code under accel/xen/

[Philippe Mathieu-Daudé]

Supersedes: <20200507155813.16169-1-philmd@redhat.com>

Philippe Mathieu-Daudé (2):
  exec: Check Xen is enabled before calling the Xen API
  accel: Move Xen accelerator code under accel/xen/

 include/exec/ram_addr.h                    | 10 ++++--
 include/hw/xen/xen.h                       | 11 ------
 include/sysemu/xen.h                       | 40 ++++++++++++++++++++++
 hw/xen/xen-common.c => accel/xen/xen-all.c |  3 ++
 hw/acpi/piix4.c                            |  2 +-
 hw/i386/pc.c                               |  1 +
 hw/i386/pc_piix.c                          |  1 +
 hw/i386/pc_q35.c                           |  1 +
 hw/i386/xen/xen-hvm.c                      |  1 +
 hw/i386/xen/xen_platform.c                 |  1 +
 hw/isa/piix3.c                             |  1 +
 hw/pci/msix.c                              |  1 +
 migration/savevm.c                         |  2 +-
 softmmu/vl.c                               |  2 +-
 stubs/xen-hvm.c                            |  9 -----
 target/i386/cpu.c                          |  2 +-
 MAINTAINERS                                |  2 ++
 accel/Makefile.objs                        |  1 +
 accel/xen/Makefile.objs                    |  1 +
 hw/xen/Makefile.objs                       |  2 +-
 20 files changed, 66 insertions(+), 28 deletions(-)
 create mode 100644 include/sysemu/xen.h
 rename hw/xen/xen-common.c => accel/xen/xen-all.c (99%)
 create mode 100644 accel/xen/Makefile.objs

-- 
2.21.3

[PATCH v2 1/2] exec: Check Xen is enabled before calling the Xen API

[Philippe Mathieu-Daudé]

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 include/exec/ram_addr.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index 5e59a3d8d7..dd8713179e 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -330,7 +330,9 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
         }
     }
 
-    xen_hvm_modified_memory(start, length);
+    if (xen_enabled()) {
+        xen_hvm_modified_memory(start, length);
+    }
 }
 
 #if !defined(_WIN32)
@@ -388,7 +390,9 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
             }
         }
 
-        xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
+        if (xen_enabled()) {
+            xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
+        }
     } else {
         uint8_t clients = tcg_enabled() ? DIRTY_CLIENTS_ALL : DIRTY_CLIENTS_NOCODE;
 
-- 
2.21.3

Re: [PATCH v2 1/2] exec: Check Xen is enabled before calling the Xen API

[Juan Quintela]

Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  include/exec/ram_addr.h | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
> index 5e59a3d8d7..dd8713179e 100644
> --- a/include/exec/ram_addr.h
> +++ b/include/exec/ram_addr.h
> @@ -330,7 +330,9 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
>          }
>      }
>  
> -    xen_hvm_modified_memory(start, length);
> +    if (xen_enabled()) {
> +        xen_hvm_modified_memory(start, length);
> +    }
>  }
>  
>  #if !defined(_WIN32)
> @@ -388,7 +390,9 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
>              }
>          }
>  
> -        xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
> +        if (xen_enabled()) {
> +            xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
> +        }
>      } else {
>          uint8_t clients = tcg_enabled() ? DIRTY_CLIENTS_ALL : DIRTY_CLIENTS_NOCODE;

I don't object moving the xen code to accell.  But I think that this
change is bad.

On the following patch:
- You export xen_allowed
  (ok, it was already exported, but I think it shouldn't)

(master)$ find . -type f | xargs grep xen_allowed
./hw/xen/xen-common.c:    ac->allowed = &xen_allowed;
./include/hw/xen/xen.h:extern bool xen_allowed;
./include/hw/xen/xen.h:    return xen_allowed;
./softmmu/vl.c:bool xen_allowed;

This are all the users that I can find.

And xen_havm_modified_memory() is an empty function if xen is not
compiled in.  And in the case that xen is compiled in, the 1st thing
that it checks is:

   if (unlikely(xen_in_migration)) {

That is way more restrictive that xen_enabled().

So, I think that it is better to drop this patch, maintain next one, but
just un-exporting xen_allowed.

What do you think?

Later, Juan.

Re: [PATCH v2 1/2] exec: Check Xen is enabled before calling the Xen API

[Philippe Mathieu-Daudé]

Hi Juan,

On 5/8/20 10:39 AM, Juan Quintela wrote:
> Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>>   include/exec/ram_addr.h | 8 ++++++--
>>   1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
>> index 5e59a3d8d7..dd8713179e 100644
>> --- a/include/exec/ram_addr.h
>> +++ b/include/exec/ram_addr.h
>> @@ -330,7 +330,9 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
>>           }
>>       }
>>   
>> -    xen_hvm_modified_memory(start, length);
>> +    if (xen_enabled()) {
>> +        xen_hvm_modified_memory(start, length);
>> +    }
>>   }
>>   
>>   #if !defined(_WIN32)
>> @@ -388,7 +390,9 @@ static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
>>               }
>>           }
>>   
>> -        xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
>> +        if (xen_enabled()) {
>> +            xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
>> +        }
>>       } else {
>>           uint8_t clients = tcg_enabled() ? DIRTY_CLIENTS_ALL : DIRTY_CLIENTS_NOCODE;
> 
> I don't object moving the xen code to accell.  But I think that this
> change is bad.
> 
> On the following patch:
> - You export xen_allowed
>    (ok, it was already exported, but I think it shouldn't)
> 
> (master)$ find . -type f | xargs grep xen_allowed
> ./hw/xen/xen-common.c:    ac->allowed = &xen_allowed;
> ./include/hw/xen/xen.h:extern bool xen_allowed;
> ./include/hw/xen/xen.h:    return xen_allowed;
> ./softmmu/vl.c:bool xen_allowed;
> 
> This are all the users that I can find.
> 
> And xen_havm_modified_memory() is an empty function if xen is not
> compiled in.  And in the case that xen is compiled in, the 1st thing
> that it checks is:
> 
>     if (unlikely(xen_in_migration)) {
> 
> That is way more restrictive that xen_enabled().
> 
> So, I think that it is better to drop this patch, maintain next one, but
> just un-exporting xen_allowed.
> 
> What do you think?

I blindly trust your judgement on this :) I'd rather not touch this code 
but as it happens to be in "exec/ram_addr.h" I had to modify it.

Thanks for your reviews!

> 
> Later, Juan.
> 
> 

[PATCH v2 2/2] accel: Move Xen accelerator code under accel/xen/

[Philippe Mathieu-Daudé]

This code is not related to hardware emulation.
Move it under accel/ with the other hypervisors.

Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
We could also move the memory management functions from
hw/i386/xen/xen-hvm.c but it is not trivial.

v2: Use g_assert_not_reached() instead of abort()
---
 include/exec/ram_addr.h                    |  2 +-
 include/hw/xen/xen.h                       | 11 ------
 include/sysemu/xen.h                       | 40 ++++++++++++++++++++++
 hw/xen/xen-common.c => accel/xen/xen-all.c |  3 ++
 hw/acpi/piix4.c                            |  2 +-
 hw/i386/pc.c                               |  1 +
 hw/i386/pc_piix.c                          |  1 +
 hw/i386/pc_q35.c                           |  1 +
 hw/i386/xen/xen-hvm.c                      |  1 +
 hw/i386/xen/xen_platform.c                 |  1 +
 hw/isa/piix3.c                             |  1 +
 hw/pci/msix.c                              |  1 +
 migration/savevm.c                         |  2 +-
 softmmu/vl.c                               |  2 +-
 stubs/xen-hvm.c                            |  9 -----
 target/i386/cpu.c                          |  2 +-
 MAINTAINERS                                |  2 ++
 accel/Makefile.objs                        |  1 +
 accel/xen/Makefile.objs                    |  1 +
 hw/xen/Makefile.objs                       |  2 +-
 20 files changed, 60 insertions(+), 26 deletions(-)
 create mode 100644 include/sysemu/xen.h
 rename hw/xen/xen-common.c => accel/xen/xen-all.c (99%)
 create mode 100644 accel/xen/Makefile.objs

diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h
index dd8713179e..a94809f89b 100644
--- a/include/exec/ram_addr.h
+++ b/include/exec/ram_addr.h
@@ -21,7 +21,7 @@
 
 #ifndef CONFIG_USER_ONLY
 #include "cpu.h"
-#include "hw/xen/xen.h"
+#include "sysemu/xen.h"
 #include "sysemu/tcg.h"
 #include "exec/ramlist.h"
 #include "exec/ramblock.h"
diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
index 5ac1c6dc55..771dd447f2 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -20,13 +20,6 @@ extern uint32_t xen_domid;
 extern enum xen_mode xen_mode;
 extern bool xen_domid_restrict;
 
-extern bool xen_allowed;
-
-static inline bool xen_enabled(void)
-{
-    return xen_allowed;
-}
-
 int xen_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num);
 void xen_piix3_set_irq(void *opaque, int irq_num, int level);
 void xen_piix_pci_write_config_client(uint32_t address, uint32_t val, int len);
@@ -39,10 +32,6 @@ void xenstore_store_pv_console_info(int i, struct Chardev *chr);
 
 void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory);
 
-void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
-                   struct MemoryRegion *mr, Error **errp);
-void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length);
-
 void xen_register_framebuffer(struct MemoryRegion *mr);
 
 #endif /* QEMU_HW_XEN_H */
diff --git a/include/sysemu/xen.h b/include/sysemu/xen.h
new file mode 100644
index 0000000000..e3d30e327f
--- /dev/null
+++ b/include/sysemu/xen.h
@@ -0,0 +1,40 @@
+/*
+ * QEMU Xen support
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef SYSEMU_XEN_H
+#define SYSEMU_XEN_H
+
+#ifdef CONFIG_XEN
+
+extern bool xen_allowed;
+
+#define xen_enabled() (xen_allowed)
+
+#ifndef CONFIG_USER_ONLY
+void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length);
+void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
+                   struct MemoryRegion *mr, Error **errp);
+#endif
+
+#else /* !CONFIG_XEN */
+
+#define xen_enabled() 0
+#ifndef CONFIG_USER_ONLY
+static inline void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length)
+{
+    g_assert_not_reached();
+}
+static inline void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
+                                 MemoryRegion *mr, Error **errp)
+{
+    g_assert_not_reached();
+}
+#endif
+
+#endif /* CONFIG_XEN */
+
+#endif
diff --git a/hw/xen/xen-common.c b/accel/xen/xen-all.c
similarity index 99%
rename from hw/xen/xen-common.c
rename to accel/xen/xen-all.c
index a15070f7f6..5c64571cb8 100644
--- a/hw/xen/xen-common.c
+++ b/accel/xen/xen-all.c
@@ -16,6 +16,7 @@
 #include "hw/xen/xen_pt.h"
 #include "chardev/char.h"
 #include "sysemu/accel.h"
+#include "sysemu/xen.h"
 #include "sysemu/runstate.h"
 #include "migration/misc.h"
 #include "migration/global_state.h"
@@ -31,6 +32,8 @@
     do { } while (0)
 #endif
 
+bool xen_allowed;
+
 xc_interface *xen_xc;
 xenforeignmemory_handle *xen_fmem;
 xendevicemodel_handle *xen_dmod;
diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 964d6f5990..daed273687 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -30,6 +30,7 @@
 #include "hw/acpi/acpi.h"
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
+#include "sysemu/xen.h"
 #include "qapi/error.h"
 #include "qemu/range.h"
 #include "exec/address-spaces.h"
@@ -41,7 +42,6 @@
 #include "hw/mem/nvdimm.h"
 #include "hw/acpi/memory_hotplug.h"
 #include "hw/acpi/acpi_dev_interface.h"
-#include "hw/xen/xen.h"
 #include "migration/vmstate.h"
 #include "hw/core/cpu.h"
 #include "trace.h"
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 97e345faea..1a599e1de9 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -56,6 +56,7 @@
 #include "sysemu/tcg.h"
 #include "sysemu/numa.h"
 #include "sysemu/kvm.h"
+#include "sysemu/xen.h"
 #include "sysemu/qtest.h"
 #include "sysemu/reset.h"
 #include "sysemu/runstate.h"
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 3862e5120e..c00472b4c5 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -53,6 +53,7 @@
 #include "cpu.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
+#include "sysemu/xen.h"
 #ifdef CONFIG_XEN
 #include <xen/hvm/hvm_info_table.h>
 #include "hw/xen/xen_pt.h"
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 3349e38a4c..e929749d8e 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -36,6 +36,7 @@
 #include "hw/rtc/mc146818rtc.h"
 #include "hw/xen/xen.h"
 #include "sysemu/kvm.h"
+#include "sysemu/xen.h"
 #include "hw/kvm/clock.h"
 #include "hw/pci-host/q35.h"
 #include "hw/qdev-properties.h"
diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
index 82ece6b9e7..041303a2fa 100644
--- a/hw/i386/xen/xen-hvm.c
+++ b/hw/i386/xen/xen-hvm.c
@@ -28,6 +28,7 @@
 #include "qemu/range.h"
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
+#include "sysemu/xen.h"
 #include "sysemu/xen-mapcache.h"
 #include "trace.h"
 #include "exec/address-spaces.h"
diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index 0f7b05e5e1..a1492fdecd 100644
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -33,6 +33,7 @@
 #include "hw/xen/xen-legacy-backend.h"
 #include "trace.h"
 #include "exec/address-spaces.h"
+#include "sysemu/xen.h"
 #include "sysemu/block-backend.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
diff --git a/hw/isa/piix3.c b/hw/isa/piix3.c
index fd1c78879f..1a5267e19f 100644
--- a/hw/isa/piix3.c
+++ b/hw/isa/piix3.c
@@ -28,6 +28,7 @@
 #include "hw/irq.h"
 #include "hw/isa/isa.h"
 #include "hw/xen/xen.h"
+#include "sysemu/xen.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/reset.h"
 #include "sysemu/runstate.h"
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index 29187898f2..2c7ead7667 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -19,6 +19,7 @@
 #include "hw/pci/msix.h"
 #include "hw/pci/pci.h"
 #include "hw/xen/xen.h"
+#include "sysemu/xen.h"
 #include "migration/qemu-file-types.h"
 #include "migration/vmstate.h"
 #include "qemu/range.h"
diff --git a/migration/savevm.c b/migration/savevm.c
index c00a6807d9..b979ea6e7f 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -28,7 +28,6 @@
 
 #include "qemu/osdep.h"
 #include "hw/boards.h"
-#include "hw/xen/xen.h"
 #include "net/net.h"
 #include "migration.h"
 #include "migration/snapshot.h"
@@ -59,6 +58,7 @@
 #include "sysemu/replay.h"
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
+#include "sysemu/xen.h"
 #include "qjson.h"
 #include "migration/colo.h"
 #include "qemu/bitmap.h"
diff --git a/softmmu/vl.c b/softmmu/vl.c
index afd2615fb3..0344e5fd2e 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -36,6 +36,7 @@
 #include "sysemu/runstate.h"
 #include "sysemu/seccomp.h"
 #include "sysemu/tcg.h"
+#include "sysemu/xen.h"
 
 #include "qemu/error-report.h"
 #include "qemu/sockets.h"
@@ -178,7 +179,6 @@ static NotifierList exit_notifiers =
 static NotifierList machine_init_done_notifiers =
     NOTIFIER_LIST_INITIALIZER(machine_init_done_notifiers);
 
-bool xen_allowed;
 uint32_t xen_domid;
 enum xen_mode xen_mode = XEN_EMULATE;
 bool xen_domid_restrict;
diff --git a/stubs/xen-hvm.c b/stubs/xen-hvm.c
index b7d53b5e2f..6954a5b696 100644
--- a/stubs/xen-hvm.c
+++ b/stubs/xen-hvm.c
@@ -35,11 +35,6 @@ int xen_is_pirq_msi(uint32_t msi_data)
     return 0;
 }
 
-void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size, MemoryRegion *mr,
-                   Error **errp)
-{
-}
-
 qemu_irq *xen_interrupt_controller_init(void)
 {
     return NULL;
@@ -49,10 +44,6 @@ void xen_register_framebuffer(MemoryRegion *mr)
 {
 }
 
-void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length)
-{
-}
-
 void xen_hvm_init(PCMachineState *pcms, MemoryRegion **ram_memory)
 {
 }
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 9c256ab159..f9b3ef1ef2 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -29,6 +29,7 @@
 #include "sysemu/reset.h"
 #include "sysemu/hvf.h"
 #include "sysemu/cpus.h"
+#include "sysemu/xen.h"
 #include "kvm_i386.h"
 #include "sev_i386.h"
 
@@ -54,7 +55,6 @@
 #include "hw/i386/topology.h"
 #ifndef CONFIG_USER_ONLY
 #include "exec/address-spaces.h"
-#include "hw/xen/xen.h"
 #include "hw/i386/apic_internal.h"
 #include "hw/boards.h"
 #endif
diff --git a/MAINTAINERS b/MAINTAINERS
index 1f84e3ae2c..95ddddfb1d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -438,6 +438,7 @@ M: Paul Durrant <paul@xen.org>
 L: xen-devel@lists.xenproject.org
 S: Supported
 F: */xen*
+F: accel/xen/*
 F: hw/9pfs/xen-9p*
 F: hw/char/xen_console.c
 F: hw/display/xenfb.c
@@ -451,6 +452,7 @@ F: hw/i386/xen/
 F: hw/pci-host/xen_igd_pt.c
 F: include/hw/block/dataplane/xen*
 F: include/hw/xen/
+F: include/sysemu/xen.h
 F: include/sysemu/xen-mapcache.h
 
 Guest CPU Cores (HAXM)
diff --git a/accel/Makefile.objs b/accel/Makefile.objs
index 17e5ac6061..ff72f0d030 100644
--- a/accel/Makefile.objs
+++ b/accel/Makefile.objs
@@ -2,4 +2,5 @@ common-obj-$(CONFIG_SOFTMMU) += accel.o
 obj-$(call land,$(CONFIG_SOFTMMU),$(CONFIG_POSIX)) += qtest.o
 obj-$(CONFIG_KVM) += kvm/
 obj-$(CONFIG_TCG) += tcg/
+obj-$(CONFIG_XEN) += xen/
 obj-y += stubs/
diff --git a/accel/xen/Makefile.objs b/accel/xen/Makefile.objs
new file mode 100644
index 0000000000..7482cfb436
--- /dev/null
+++ b/accel/xen/Makefile.objs
@@ -0,0 +1 @@
+obj-y += xen-all.o
diff --git a/hw/xen/Makefile.objs b/hw/xen/Makefile.objs
index 84df60a928..340b2c5096 100644
--- a/hw/xen/Makefile.objs
+++ b/hw/xen/Makefile.objs
@@ -1,5 +1,5 @@
 # xen backend driver support
-common-obj-$(CONFIG_XEN) += xen-legacy-backend.o xen_devconfig.o xen_pvdev.o xen-common.o xen-bus.o xen-bus-helper.o xen-backend.o
+common-obj-$(CONFIG_XEN) += xen-legacy-backend.o xen_devconfig.o xen_pvdev.o xen-bus.o xen-bus-helper.o xen-backend.o
 
 obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen-host-pci-device.o
 obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pt.o xen_pt_config_init.o xen_pt_graphics.o xen_pt_msi.o
-- 
2.21.3