[Qemu-devel] [PULL 0/3] VFIO fixes 2017-05-03

[Qemu-devel] [PULL 0/3] VFIO fixes 2017-05-03

[Alex Williamson]

The following changes since commit e619b14746e5d8c0e53061661fd0e1da01fd4d60:

  Merge remote-tracking branch 'sthibault/tags/samuel-thibault' into staging (2017-05-02 15:16:29 +0100)

are available in the git repository at:


  git://github.com/awilliam/qemu-vfio.git tags/vfio-updates-20170503.0

for you to fetch changes up to 6e4e6f0d403b1fb25f9dfdbe17754c643997753d:

  vfio/pci: Fix incorrect error message (2017-05-03 14:52:35 -0600)

----------------------------------------------------------------
VFIO fixes 2017-05-03

 - Enable 8-byte memory region accesses (Jose Ricardo Ziviani)
 - Fix vfio-pci error message (Dong Jia Shi)

----------------------------------------------------------------
Dong Jia Shi (1):
      vfio/pci: Fix incorrect error message

Jose Ricardo Ziviani (2):
      vfio: Set MemoryRegionOps:max_access_size and min_access_size
      vfio: enable 8-byte reads/writes to vfio

 hw/vfio/common.c | 14 ++++++++++++++
 hw/vfio/pci.c    |  4 ++--
 2 files changed, 16 insertions(+), 2 deletions(-)

[Qemu-devel] [PULL 1/3] vfio: Set MemoryRegionOps:max_access_size and min_access_size

[Alex Williamson]

From: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>

Sets valid.max_access_size and valid.min_access_size to ensure safe
8-byte accesses to vfio. Today, 8-byte accesses are broken into pairs
of 4-byte calls that goes unprotected:

qemu_mutex_lock locked mutex 0x10905ad8
  vfio_region_write  (0001:03:00.0:region1+0xc0, 0x2020c, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8
qemu_mutex_lock locked mutex 0x10905ad8
  vfio_region_write  (0001:03:00.0:region1+0xc4, 0xa0000, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8

which occasionally leads to:

qemu_mutex_lock locked mutex 0x10905ad8
  vfio_region_write  (0001:03:00.0:region1+0xc0, 0x2030c, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8
qemu_mutex_lock locked mutex 0x10905ad8
  vfio_region_write  (0001:03:00.0:region1+0xc0, 0x1000c, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8
qemu_mutex_lock locked mutex 0x10905ad8
  vfio_region_write  (0001:03:00.0:region1+0xc4, 0xb0000, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8
qemu_mutex_lock locked mutex 0x10905ad8
  vfio_region_write  (0001:03:00.0:region1+0xc4, 0xa0000, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8

causing strange errors in guest OS. With this patch, such accesses
are protected by the same lock guard:

qemu_mutex_lock locked mutex 0x10905ad8
vfio_region_write  (0001:03:00.0:region1+0xc0, 0x2000c, 4)
vfio_region_write  (0001:03:00.0:region1+0xc4, 0xb0000, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8

This happens because the 8-byte write should be broken into 4-byte
writes by memory.c:access_with_adjusted_size() in order to be under
the same lock. Today, it's done in exec.c:address_space_write_continue()
which was able to handle only 4 bytes due to a zero'ed
valid.max_access_size (see exec.c:memory_access_size()).

Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/common.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 6b33b9f55df1..6572c0744cb5 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -190,6 +190,10 @@ const MemoryRegionOps vfio_region_ops = {
     .read = vfio_region_read,
     .write = vfio_region_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+    },
 };
 
 /*

[Qemu-devel] [PULL 2/3] vfio: enable 8-byte reads/writes to vfio

[Alex Williamson]

From: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>

This patch enables 8-byte writes and reads to VFIO. Such implemention
is already done but it's missing the 'case' to handle such accesses in
both vfio_region_write and vfio_region_read and the MemoryRegionOps:
impl.max_access_size and impl.min_access_size.

After this patch, 8-byte writes such as:

qemu_mutex_lock locked mutex 0x10905ad8
vfio_region_write  (0001:03:00.0:region1+0xc0, 0x4140c, 4)
vfio_region_write  (0001:03:00.0:region1+0xc4, 0xa0000, 4)
qemu_mutex_unlock unlocked mutex 0x10905ad8

goes like this:

qemu_mutex_lock locked mutex 0x10905ad8
vfio_region_write  (0001:03:00.0:region1+0xc0, 0xbfd0008, 8)
qemu_mutex_unlock unlocked mutex 0x10905ad8

Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/common.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 6572c0744cb5..a8f12eeb3589 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -119,6 +119,9 @@ void vfio_region_write(void *opaque, hwaddr addr,
     case 4:
         buf.dword = cpu_to_le32(data);
         break;
+    case 8:
+        buf.qword = cpu_to_le64(data);
+        break;
     default:
         hw_error("vfio: unsupported write size, %d bytes", size);
         break;
@@ -173,6 +176,9 @@ uint64_t vfio_region_read(void *opaque,
     case 4:
         data = le32_to_cpu(buf.dword);
         break;
+    case 8:
+        data = le64_to_cpu(buf.qword);
+        break;
     default:
         hw_error("vfio: unsupported read size, %d bytes", size);
         break;
@@ -194,6 +200,10 @@ const MemoryRegionOps vfio_region_ops = {
         .min_access_size = 1,
         .max_access_size = 8,
     },
+    .impl = {
+        .min_access_size = 1,
+        .max_access_size = 8,
+    },
 };
 
 /*

[Qemu-devel] [PULL 3/3] vfio/pci: Fix incorrect error message

[Alex Williamson]

From: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>

When the "No host device provided" error occurs, the hint message
that starts with "Use -vfio-pci," makes no sense, since "-vfio-pci"
is not a valid command line parameter.

Correct this by replacing "-vfio-pci" with "-device vfio-pci".

Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/pci.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 03a3d0154976..32aca7770177 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2625,8 +2625,8 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
         if (!(~vdev->host.domain || ~vdev->host.bus ||
               ~vdev->host.slot || ~vdev->host.function)) {
             error_setg(errp, "No provided host device");
-            error_append_hint(errp, "Use -vfio-pci,host=DDDD:BB:DD.F "
-                              "or -vfio-pci,sysfsdev=PATH_TO_DEVICE\n");
+            error_append_hint(errp, "Use -device vfio-pci,host=DDDD:BB:DD.F "
+                              "or -device vfio-pci,sysfsdev=PATH_TO_DEVICE\n");
             return;
         }
         vdev->vbasedev.sysfsdev =

Re: [Qemu-devel] [PULL 0/3] VFIO fixes 2017-05-03

[Stefan Hajnoczi]

[-- Attachment #1: Type: text/plain, Size: 1284 bytes --]

On Wed, May 03, 2017 at 03:38:39PM -0600, Alex Williamson wrote:
> The following changes since commit e619b14746e5d8c0e53061661fd0e1da01fd4d60:
> 
>   Merge remote-tracking branch 'sthibault/tags/samuel-thibault' into staging (2017-05-02 15:16:29 +0100)
> 
> are available in the git repository at:
> 
> 
>   git://github.com/awilliam/qemu-vfio.git tags/vfio-updates-20170503.0
> 
> for you to fetch changes up to 6e4e6f0d403b1fb25f9dfdbe17754c643997753d:
> 
>   vfio/pci: Fix incorrect error message (2017-05-03 14:52:35 -0600)
> 
> ----------------------------------------------------------------
> VFIO fixes 2017-05-03
> 
>  - Enable 8-byte memory region accesses (Jose Ricardo Ziviani)
>  - Fix vfio-pci error message (Dong Jia Shi)
> 
> ----------------------------------------------------------------
> Dong Jia Shi (1):
>       vfio/pci: Fix incorrect error message
> 
> Jose Ricardo Ziviani (2):
>       vfio: Set MemoryRegionOps:max_access_size and min_access_size
>       vfio: enable 8-byte reads/writes to vfio
> 
>  hw/vfio/common.c | 14 ++++++++++++++
>  hw/vfio/pci.c    |  4 ++--
>  2 files changed, 16 insertions(+), 2 deletions(-)
> 

Thanks, applied to my staging tree:
https://github.com/stefanha/qemu/commits/staging

Stefan

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