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[v5,10/14] vfio/migration: Implement VFIO migration protocol v2

Message ID 20221229110345.12480-11-avihaih@nvidia.com
State New
Headers show
Series vfio/migration: Implement VFIO migration protocol v2 | expand

Commit Message

Avihai Horon Dec. 29, 2022, 11:03 a.m. UTC
Implement the basic mandatory part of VFIO migration protocol v2.
This includes all functionality that is necessary to support
VFIO_MIGRATION_STOP_COPY part of the v2 protocol.

The two protocols, v1 and v2, will co-exist and in the following patches
v1 protocol code will be removed.

There are several main differences between v1 and v2 protocols:
- VFIO device state is now represented as a finite state machine instead
  of a bitmap.

- Migration interface with kernel is now done using VFIO_DEVICE_FEATURE
  ioctl and normal read() and write() instead of the migration region.

- Pre-copy is made optional in v2 protocol. Support for pre-copy will be
  added later on.

Detailed information about VFIO migration protocol v2 and its difference
compared to v1 protocol can be found here [1].

[1]
https://lore.kernel.org/all/20220224142024.147653-10-yishaih@nvidia.com/

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
---
 include/hw/vfio/vfio-common.h |   5 +
 hw/vfio/common.c              |  19 +-
 hw/vfio/migration.c           | 450 +++++++++++++++++++++++++++++++---
 hw/vfio/trace-events          |   7 +
 4 files changed, 442 insertions(+), 39 deletions(-)

Comments

Cédric Le Goater Jan. 9, 2023, 10:20 a.m. UTC | #1
Hello Avihai,


On 12/29/22 12:03, Avihai Horon wrote:
>   
> +static int vfio_save_setup(QEMUFile *f, void *opaque)
> +{
> +    VFIODevice *vbasedev = opaque;
> +    VFIOMigration *migration = vbasedev->migration;
> +    uint64_t stop_copy_size;
> +
> +    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
> +
> +    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
> +        stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
> +    }
> +    migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
> +                                      stop_copy_size);
> +    migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
> +    if (!migration->data_buffer) {
> +        error_report("%s: Failed to allocate migration data buffer",
> +                     vbasedev->name);
> +        return -ENOMEM;
> +    }
> +
> +    trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
> +
> +    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
> +
> +    return qemu_file_get_error(f);
> +}
> +

This fails to compile with :

   gcc version 12.2.1 20221121 (Red Hat 12.2.1-4) (GCC) complains with :


   ../include/qemu/osdep.h:315:22: error: ‘stop_copy_size’ may be used uninitialized [-Werror=maybe-uninitialized]
     315 |         _a < _b ? _a : _b;                              \
         |                      ^
   ../hw/vfio/migration.c:262:14: note: ‘stop_copy_size’ was declared here
     262 |     uint64_t stop_copy_size;
         |              ^~~~~~~~~~~~~~
   cc1: all warnings being treated as errors

May be rework the code slightly to avoid the breakage :

+++ qemu.git/hw/vfio/migration.c
@@ -259,13 +259,11 @@ static int vfio_save_setup(QEMUFile *f,
  {
      VFIODevice *vbasedev = opaque;
      VFIOMigration *migration = vbasedev->migration;
-    uint64_t stop_copy_size;
+    uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
  
      qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
  
-    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
-        stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
-    }
+    vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
      migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
                                        stop_copy_size);
      migration->data_buffer = g_try_malloc0(migration->data_buffer_size);


and report the error in vfio_query_stop_copy_size()

Thanks,

C.
Avihai Horon Jan. 9, 2023, 3:12 p.m. UTC | #2
On 09/01/2023 12:20, Cédric Le Goater wrote:
> External email: Use caution opening links or attachments
>
>
> Hello Avihai,
>
>
> On 12/29/22 12:03, Avihai Horon wrote:
>>
>> +static int vfio_save_setup(QEMUFile *f, void *opaque)
>> +{
>> +    VFIODevice *vbasedev = opaque;
>> +    VFIOMigration *migration = vbasedev->migration;
>> +    uint64_t stop_copy_size;
>> +
>> +    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
>> +
>> +    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
>> +        stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
>> +    }
>> +    migration->data_buffer_size = 
>> MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
>> +                                      stop_copy_size);
>> +    migration->data_buffer = 
>> g_try_malloc0(migration->data_buffer_size);
>> +    if (!migration->data_buffer) {
>> +        error_report("%s: Failed to allocate migration data buffer",
>> +                     vbasedev->name);
>> +        return -ENOMEM;
>> +    }
>> +
>> +    trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
>> +
>> +    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
>> +
>> +    return qemu_file_get_error(f);
>> +}
>> +
>
> This fails to compile with :
>
>   gcc version 12.2.1 20221121 (Red Hat 12.2.1-4) (GCC) complains with :
>
>
>   ../include/qemu/osdep.h:315:22: error: ‘stop_copy_size’ may be used 
> uninitialized [-Werror=maybe-uninitialized]
>     315 |         _a < _b ? _a : _b;                              \
>         |                      ^
>   ../hw/vfio/migration.c:262:14: note: ‘stop_copy_size’ was declared here
>     262 |     uint64_t stop_copy_size;
>         |              ^~~~~~~~~~~~~~
>   cc1: all warnings being treated as errors
>
> May be rework the code slightly to avoid the breakage :
>
> +++ qemu.git/hw/vfio/migration.c
> @@ -259,13 +259,11 @@ static int vfio_save_setup(QEMUFile *f,
>  {
>      VFIODevice *vbasedev = opaque;
>      VFIOMigration *migration = vbasedev->migration;
> -    uint64_t stop_copy_size;
> +    uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
>
>      qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
>
> -    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
> -        stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
> -    }
> +    vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
>      migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
>                                        stop_copy_size);
>      migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
>
>
> and report the error in vfio_query_stop_copy_size()
>
Thanks, Cedric.

There is another similar case in vfio_save_pending().
I will fix both of them.

> Thanks,
>
> C.
Cédric Le Goater Jan. 9, 2023, 5:27 p.m. UTC | #3
On 1/9/23 16:12, Avihai Horon wrote:
> 
> On 09/01/2023 12:20, Cédric Le Goater wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> Hello Avihai,
>>
>>
>> On 12/29/22 12:03, Avihai Horon wrote:
>>>
>>> +static int vfio_save_setup(QEMUFile *f, void *opaque)
>>> +{
>>> +    VFIODevice *vbasedev = opaque;
>>> +    VFIOMigration *migration = vbasedev->migration;
>>> +    uint64_t stop_copy_size;
>>> +
>>> +    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
>>> +
>>> +    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
>>> +        stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
>>> +    }
>>> +    migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
>>> +                                      stop_copy_size);
>>> +    migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
>>> +    if (!migration->data_buffer) {
>>> +        error_report("%s: Failed to allocate migration data buffer",
>>> +                     vbasedev->name);
>>> +        return -ENOMEM;
>>> +    }
>>> +
>>> +    trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
>>> +
>>> +    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
>>> +
>>> +    return qemu_file_get_error(f);
>>> +}
>>> +
>>
>> This fails to compile with :
>>
>>   gcc version 12.2.1 20221121 (Red Hat 12.2.1-4) (GCC) complains with :
>>
>>
>>   ../include/qemu/osdep.h:315:22: error: ‘stop_copy_size’ may be used uninitialized [-Werror=maybe-uninitialized]
>>     315 |         _a < _b ? _a : _b;                              \
>>         |                      ^
>>   ../hw/vfio/migration.c:262:14: note: ‘stop_copy_size’ was declared here
>>     262 |     uint64_t stop_copy_size;
>>         |              ^~~~~~~~~~~~~~
>>   cc1: all warnings being treated as errors
>>
>> May be rework the code slightly to avoid the breakage :
>>
>> +++ qemu.git/hw/vfio/migration.c
>> @@ -259,13 +259,11 @@ static int vfio_save_setup(QEMUFile *f,
>>  {
>>      VFIODevice *vbasedev = opaque;
>>      VFIOMigration *migration = vbasedev->migration;
>> -    uint64_t stop_copy_size;
>> +    uint64_t stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
>>
>>      qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
>>
>> -    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
>> -        stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
>> -    }
>> +    vfio_query_stop_copy_size(vbasedev, &stop_copy_size);
>>      migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
>>                                        stop_copy_size);
>>      migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
>>
>>
>> and report the error in vfio_query_stop_copy_size()
>>
> Thanks, Cedric.
> 
> There is another similar case in vfio_save_pending().
> I will fix both of them.


also, in vfio_migration_query_flags() :

   +static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
   +{
   +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
   +                                  sizeof(struct vfio_device_feature_migration),
   +                              sizeof(uint64_t))] = {};
   +    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
   +    struct vfio_device_feature_migration *mig =
   +        (struct vfio_device_feature_migration *)feature->data;
   +
   +    feature->argsz = sizeof(buf);
   +    feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
   +    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
   +        return -EOPNOTSUPP;
   +    }
   +
   +    *mig_flags = mig->flags;
   +
   +    return 0;
   +}


The code is using any possible error returned by the VFIO_DEVICE_FEATURE
ioctl to distinguish protocol v1 from v2.

Couldn't we use ENOTTY  ? I think a pre-v6.0 kernel would return this errno.
Some error report would be good to have.

Thanks,

C.
Jason Gunthorpe Jan. 9, 2023, 6:36 p.m. UTC | #4
On Mon, Jan 09, 2023 at 06:27:21PM +0100, Cédric Le Goater wrote:
> also, in vfio_migration_query_flags() :
> 
>   +static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
>   +{
>   +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
>   +                                  sizeof(struct vfio_device_feature_migration),
>   +                              sizeof(uint64_t))] = {};
>   +    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
>   +    struct vfio_device_feature_migration *mig =
>   +        (struct vfio_device_feature_migration *)feature->data;
>   +
>   +    feature->argsz = sizeof(buf);
>   +    feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
>   +    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
>   +        return -EOPNOTSUPP;
>   +    }
>   +
>   +    *mig_flags = mig->flags;
>   +
>   +    return 0;
>   +}
> 
> 
> The code is using any possible error returned by the VFIO_DEVICE_FEATURE
> ioctl to distinguish protocol v1 from v2.

I'm comfortable with that from a kernel perspective.

There is no such thing as this API failing in the kernel but userspace
should continue on, no matter what the error code. So always failing
here is correct.

About the only thing you might want to do is convert anything other
than ENOTTY into a hard qemu failure similar to failing to open
/dev/vfio or something - it means something has gone really
wrong.. But that is pretty obscure stuff

Jason
Avihai Horon Jan. 10, 2023, 2:08 p.m. UTC | #5
On 09/01/2023 20:36, Jason Gunthorpe wrote:
> On Mon, Jan 09, 2023 at 06:27:21PM +0100, Cédric Le Goater wrote:
>> also, in vfio_migration_query_flags() :
>>
>>    +static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
>>    +{
>>    +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
>>    +                                  sizeof(struct vfio_device_feature_migration),
>>    +                              sizeof(uint64_t))] = {};
>>    +    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
>>    +    struct vfio_device_feature_migration *mig =
>>    +        (struct vfio_device_feature_migration *)feature->data;
>>    +
>>    +    feature->argsz = sizeof(buf);
>>    +    feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
>>    +    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
>>    +        return -EOPNOTSUPP;
>>    +    }
>>    +
>>    +    *mig_flags = mig->flags;
>>    +
>>    +    return 0;
>>    +}
>>
>>
>> The code is using any possible error returned by the VFIO_DEVICE_FEATURE
>> ioctl to distinguish protocol v1 from v2.
> I'm comfortable with that from a kernel perspective.
>
> There is no such thing as this API failing in the kernel but userspace
> should continue on, no matter what the error code. So always failing
> here is correct.
>
> About the only thing you might want to do is convert anything other
> than ENOTTY into a hard qemu failure similar to failing to open
> /dev/vfio or something - it means something has gone really
> wrong.. But that is pretty obscure stuff

Hi Cedric,

With Jason's input, is it ok by you to leave the code as is?

if not, would this be fine?

+static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t 
*mig_flags)
+{
+    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
+                                  sizeof(struct 
vfio_device_feature_migration),
+                              sizeof(uint64_t))] = {};
+    struct vfio_device_feature *feature = (struct vfio_device_feature 
*)buf;
+    struct vfio_device_feature_migration *mig =
+        (struct vfio_device_feature_migration *)feature->data;
+
+    feature->argsz = sizeof(buf);
+    feature->flags = VFIO_DEVICE_FEATURE_GET | 
VFIO_DEVICE_FEATURE_MIGRATION;
+    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
+        if (errno == ENOTTY) {
+            error_report("%s: VFIO migration is not supported in kernel",
+                         vbasedev->name);
+        } else {
+            error_report("%s: Failed to query VFIO migration support, 
err: %s",
+                         vbasedev->name, strerror(errno));
+        }
+
+        return -errno;
+    }
+
+    *mig_flags = mig->flags;
+
+    return 0;
+}
+

and then in vfio_migration_init() prior v1 removal:

+    ret = vfio_migration_query_flags(vbasedev, &mig_flags);
+    if (!ret) {
+        /* Migration v2 */
+    } else if (ret == -ENOTTY) {
+        /* Migration v1 */
+    } else {
+        return ret;
+    }

and after v1 removal vfio_migration_init() will be:

     ret = vfio_migration_query_flags(vbasedev, &mig_flags);
     if (ret) {
         return ret;

     }

Thanks.
Cédric Le Goater Jan. 10, 2023, 4:19 p.m. UTC | #6
Hello Avihai

On 1/10/23 15:08, Avihai Horon wrote:
> 
> On 09/01/2023 20:36, Jason Gunthorpe wrote:
>> On Mon, Jan 09, 2023 at 06:27:21PM +0100, Cédric Le Goater wrote:
>>> also, in vfio_migration_query_flags() :
>>>
>>>    +static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
>>>    +{
>>>    +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
>>>    +                                  sizeof(struct vfio_device_feature_migration),
>>>    +                              sizeof(uint64_t))] = {};
>>>    +    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
>>>    +    struct vfio_device_feature_migration *mig =
>>>    +        (struct vfio_device_feature_migration *)feature->data;
>>>    +
>>>    +    feature->argsz = sizeof(buf);
>>>    +    feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
>>>    +    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
>>>    +        return -EOPNOTSUPP;
>>>    +    }
>>>    +
>>>    +    *mig_flags = mig->flags;
>>>    +
>>>    +    return 0;
>>>    +}
>>>
>>>
>>> The code is using any possible error returned by the VFIO_DEVICE_FEATURE
>>> ioctl to distinguish protocol v1 from v2.
>> I'm comfortable with that from a kernel perspective.
>>
>> There is no such thing as this API failing in the kernel but userspace
>> should continue on, no matter what the error code. So always failing
>> here is correct.
>>
>> About the only thing you might want to do is convert anything other
>> than ENOTTY into a hard qemu failure similar to failing to open
>> /dev/vfio or something - it means something has gone really
>> wrong.. But that is pretty obscure stuff
> 
> Hi Cedric,
> 
> With Jason's input, is it ok by you to leave the code as is?
The patchset removes v1 later on, I think we are fine. I was reading it
sequentially and it felt like a weak spot.

All errors are translated in EOPNOTSUPP. That's always true for pre-v6.0
kernels, returning -ENOTTY, and v6.0+ kernels will do the same unless a
mlx5vf device is passthru. I still wonder if we should report some errors
for the ! -ENOTTY case. So the code below could be a good addition.

Thanks,

C.

> 
> if not, would this be fine?
> 
> +static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
> +{
> +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
> +                                  sizeof(struct vfio_device_feature_migration),
> +                              sizeof(uint64_t))] = {};
> +    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
> +    struct vfio_device_feature_migration *mig =
> +        (struct vfio_device_feature_migration *)feature->data;
> +
> +    feature->argsz = sizeof(buf);
> +    feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
> +    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
> +        if (errno == ENOTTY) {
> +            error_report("%s: VFIO migration is not supported in kernel",
> +                         vbasedev->name);
> +        } else {
> +            error_report("%s: Failed to query VFIO migration support, err: %s",
> +                         vbasedev->name, strerror(errno));
> +        }
> +
> +        return -errno;
> +    }
> +
> +    *mig_flags = mig->flags;
> +
> +    return 0;
> +}
> +
> 
> and then in vfio_migration_init() prior v1 removal:
> 
> +    ret = vfio_migration_query_flags(vbasedev, &mig_flags);
> +    if (!ret) {
> +        /* Migration v2 */
> +    } else if (ret == -ENOTTY) {
> +        /* Migration v1 */
> +    } else {
> +        return ret;
> +    }
> 
> and after v1 removal vfio_migration_init() will be:
> 
>      ret = vfio_migration_query_flags(vbasedev, &mig_flags);
>      if (ret) {
>          return ret;
> 
>      }
> 
> Thanks.
>
Avihai Horon Jan. 11, 2023, 9:59 a.m. UTC | #7
On 10/01/2023 18:19, Cédric Le Goater wrote:
> External email: Use caution opening links or attachments
>
>
> Hello Avihai
>
> On 1/10/23 15:08, Avihai Horon wrote:
>>
>> On 09/01/2023 20:36, Jason Gunthorpe wrote:
>>> On Mon, Jan 09, 2023 at 06:27:21PM +0100, Cédric Le Goater wrote:
>>>> also, in vfio_migration_query_flags() :
>>>>
>>>>    +static int vfio_migration_query_flags(VFIODevice *vbasedev, 
>>>> uint64_t *mig_flags)
>>>>    +{
>>>>    +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
>>>>    +                                  sizeof(struct 
>>>> vfio_device_feature_migration),
>>>>    +                              sizeof(uint64_t))] = {};
>>>>    +    struct vfio_device_feature *feature = (struct 
>>>> vfio_device_feature *)buf;
>>>>    +    struct vfio_device_feature_migration *mig =
>>>>    +        (struct vfio_device_feature_migration *)feature->data;
>>>>    +
>>>>    +    feature->argsz = sizeof(buf);
>>>>    +    feature->flags = VFIO_DEVICE_FEATURE_GET | 
>>>> VFIO_DEVICE_FEATURE_MIGRATION;
>>>>    +    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
>>>>    +        return -EOPNOTSUPP;
>>>>    +    }
>>>>    +
>>>>    +    *mig_flags = mig->flags;
>>>>    +
>>>>    +    return 0;
>>>>    +}
>>>>
>>>>
>>>> The code is using any possible error returned by the 
>>>> VFIO_DEVICE_FEATURE
>>>> ioctl to distinguish protocol v1 from v2.
>>> I'm comfortable with that from a kernel perspective.
>>>
>>> There is no such thing as this API failing in the kernel but userspace
>>> should continue on, no matter what the error code. So always failing
>>> here is correct.
>>>
>>> About the only thing you might want to do is convert anything other
>>> than ENOTTY into a hard qemu failure similar to failing to open
>>> /dev/vfio or something - it means something has gone really
>>> wrong.. But that is pretty obscure stuff
>>
>> Hi Cedric,
>>
>> With Jason's input, is it ok by you to leave the code as is?
> The patchset removes v1 later on, I think we are fine. I was reading it
> sequentially and it felt like a weak spot.
>
> All errors are translated in EOPNOTSUPP. That's always true for pre-v6.0
> kernels, returning -ENOTTY, and v6.0+ kernels will do the same unless a
> mlx5vf device is passthru. I still wonder if we should report some errors
> for the ! -ENOTTY case. So the code below could be a good addition.
>
Sure, I will add it in next version then.

Thanks.

> Thanks,
>
> C.
>
>>
>> if not, would this be fine?
>>
>> +static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t 
>> *mig_flags)
>> +{
>> +    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
>> +                                  sizeof(struct 
>> vfio_device_feature_migration),
>> +                              sizeof(uint64_t))] = {};
>> +    struct vfio_device_feature *feature = (struct 
>> vfio_device_feature *)buf;
>> +    struct vfio_device_feature_migration *mig =
>> +        (struct vfio_device_feature_migration *)feature->data;
>> +
>> +    feature->argsz = sizeof(buf);
>> +    feature->flags = VFIO_DEVICE_FEATURE_GET | 
>> VFIO_DEVICE_FEATURE_MIGRATION;
>> +    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
>> +        if (errno == ENOTTY) {
>> +            error_report("%s: VFIO migration is not supported in 
>> kernel",
>> +                         vbasedev->name);
>> +        } else {
>> +            error_report("%s: Failed to query VFIO migration 
>> support, err: %s",
>> +                         vbasedev->name, strerror(errno));
>> +        }
>> +
>> +        return -errno;
>> +    }
>> +
>> +    *mig_flags = mig->flags;
>> +
>> +    return 0;
>> +}
>> +
>>
>> and then in vfio_migration_init() prior v1 removal:
>>
>> +    ret = vfio_migration_query_flags(vbasedev, &mig_flags);
>> +    if (!ret) {
>> +        /* Migration v2 */
>> +    } else if (ret == -ENOTTY) {
>> +        /* Migration v1 */
>> +    } else {
>> +        return ret;
>> +    }
>>
>> and after v1 removal vfio_migration_init() will be:
>>
>>      ret = vfio_migration_query_flags(vbasedev, &mig_flags);
>>      if (ret) {
>>          return ret;
>>
>>      }
>>
>> Thanks.
>>
>
diff mbox series

Patch

diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index bbaf72ba00..2ec3346fea 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -66,6 +66,11 @@  typedef struct VFIOMigration {
     int vm_running;
     Notifier migration_state;
     uint64_t pending_bytes;
+    enum vfio_device_mig_state device_state;
+    int data_fd;
+    void *data_buffer;
+    size_t data_buffer_size;
+    bool v2;
 } VFIOMigration;
 
 typedef struct VFIOAddressSpace {
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 6f0157c848..70dff8ea42 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -355,10 +355,18 @@  static bool vfio_devices_all_dirty_tracking(VFIOContainer *container)
                 return false;
             }
 
-            if ((vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
+            if (!migration->v2 &&
+                (vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
                 (migration->device_state_v1 & VFIO_DEVICE_STATE_V1_RUNNING)) {
                 return false;
             }
+
+            if (migration->v2 &&
+                (vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
+                (migration->device_state == VFIO_DEVICE_STATE_RUNNING ||
+                 migration->device_state == VFIO_DEVICE_STATE_RUNNING_P2P)) {
+                return false;
+            }
         }
     }
     return true;
@@ -385,7 +393,14 @@  static bool vfio_devices_all_running_and_mig_active(VFIOContainer *container)
                 return false;
             }
 
-            if (migration->device_state_v1 & VFIO_DEVICE_STATE_V1_RUNNING) {
+            if (!migration->v2 &&
+                migration->device_state_v1 & VFIO_DEVICE_STATE_V1_RUNNING) {
+                continue;
+            }
+
+            if (migration->v2 &&
+                (migration->device_state == VFIO_DEVICE_STATE_RUNNING ||
+                 migration->device_state == VFIO_DEVICE_STATE_RUNNING_P2P)) {
                 continue;
             } else {
                 return false;
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 9df859f4d3..645fa33a46 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -10,6 +10,7 @@ 
 #include "qemu/osdep.h"
 #include "qemu/main-loop.h"
 #include "qemu/cutils.h"
+#include "qemu/units.h"
 #include <linux/vfio.h>
 #include <sys/ioctl.h>
 
@@ -44,8 +45,103 @@ 
 #define VFIO_MIG_FLAG_DEV_SETUP_STATE   (0xffffffffef100003ULL)
 #define VFIO_MIG_FLAG_DEV_DATA_STATE    (0xffffffffef100004ULL)
 
+/*
+ * This is an arbitrary size based on migration of mlx5 devices, where typically
+ * total device migration size is on the order of 100s of MB. Testing with
+ * larger values, e.g. 128MB and 1GB, did not show a performance improvement.
+ */
+#define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB)
+
 static int64_t bytes_transferred;
 
+static const char *mig_state_to_str(enum vfio_device_mig_state state)
+{
+    switch (state) {
+    case VFIO_DEVICE_STATE_ERROR:
+        return "ERROR";
+    case VFIO_DEVICE_STATE_STOP:
+        return "STOP";
+    case VFIO_DEVICE_STATE_RUNNING:
+        return "RUNNING";
+    case VFIO_DEVICE_STATE_STOP_COPY:
+        return "STOP_COPY";
+    case VFIO_DEVICE_STATE_RESUMING:
+        return "RESUMING";
+    case VFIO_DEVICE_STATE_RUNNING_P2P:
+        return "RUNNING_P2P";
+    default:
+        return "UNKNOWN STATE";
+    }
+}
+
+static int vfio_migration_set_state(VFIODevice *vbasedev,
+                                    enum vfio_device_mig_state new_state,
+                                    enum vfio_device_mig_state recover_state)
+{
+    VFIOMigration *migration = vbasedev->migration;
+    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
+                              sizeof(struct vfio_device_feature_mig_state),
+                              sizeof(uint64_t))] = {};
+    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
+    struct vfio_device_feature_mig_state *mig_state =
+        (struct vfio_device_feature_mig_state *)feature->data;
+
+    feature->argsz = sizeof(buf);
+    feature->flags =
+        VFIO_DEVICE_FEATURE_SET | VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE;
+    mig_state->device_state = new_state;
+    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
+        /* Try to set the device in some good state */
+        int err = -errno;
+
+        error_report(
+            "%s: Failed setting device state to %s, err: %s. Setting device in recover state %s",
+                     vbasedev->name, mig_state_to_str(new_state),
+                     strerror(errno), mig_state_to_str(recover_state));
+
+        mig_state->device_state = recover_state;
+        if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
+            err = -errno;
+            error_report(
+                "%s: Failed setting device in recover state, err: %s. Resetting device",
+                         vbasedev->name, strerror(errno));
+
+            if (ioctl(vbasedev->fd, VFIO_DEVICE_RESET)) {
+                hw_error("%s: Failed resetting device, err: %s", vbasedev->name,
+                         strerror(errno));
+            }
+
+            migration->device_state = VFIO_DEVICE_STATE_RUNNING;
+
+            return err;
+        }
+
+        migration->device_state = recover_state;
+
+        return err;
+    }
+
+    migration->device_state = new_state;
+    if (mig_state->data_fd != -1) {
+        if (migration->data_fd != -1) {
+            /*
+             * This can happen if the device is asynchronously reset and
+             * terminates a data transfer.
+             */
+            error_report("%s: data_fd out of sync", vbasedev->name);
+            close(mig_state->data_fd);
+
+            return -EBADF;
+        }
+
+        migration->data_fd = mig_state->data_fd;
+    }
+
+    trace_vfio_migration_set_state(vbasedev->name, mig_state_to_str(new_state));
+
+    return 0;
+}
+
 static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count,
                                   off_t off, bool iswrite)
 {
@@ -260,6 +356,18 @@  static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev, uint64_t *size)
     return ret;
 }
 
+static int vfio_load_buffer(QEMUFile *f, VFIODevice *vbasedev,
+                            uint64_t data_size)
+{
+    VFIOMigration *migration = vbasedev->migration;
+    int ret;
+
+    ret = qemu_file_get_to_fd(f, migration->data_fd, data_size);
+    trace_vfio_load_state_device_data(vbasedev->name, data_size, ret);
+
+    return ret;
+}
+
 static int vfio_v1_load_buffer(QEMUFile *f, VFIODevice *vbasedev,
                                uint64_t data_size)
 {
@@ -394,6 +502,14 @@  static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
     return qemu_file_get_error(f);
 }
 
+static void vfio_migration_cleanup(VFIODevice *vbasedev)
+{
+    VFIOMigration *migration = vbasedev->migration;
+
+    close(migration->data_fd);
+    migration->data_fd = -1;
+}
+
 static void vfio_migration_v1_cleanup(VFIODevice *vbasedev)
 {
     VFIOMigration *migration = vbasedev->migration;
@@ -403,8 +519,82 @@  static void vfio_migration_v1_cleanup(VFIODevice *vbasedev)
     }
 }
 
+static int vfio_query_stop_copy_size(VFIODevice *vbasedev,
+                                     uint64_t *stop_copy_size)
+{
+    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
+                              sizeof(struct vfio_device_feature_mig_data_size),
+                              sizeof(uint64_t))] = {};
+    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
+    struct vfio_device_feature_mig_data_size *mig_data_size =
+        (struct vfio_device_feature_mig_data_size *)feature->data;
+
+    feature->argsz = sizeof(buf);
+    feature->flags =
+        VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIG_DATA_SIZE;
+
+    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
+        return -errno;
+    }
+
+    *stop_copy_size = mig_data_size->stop_copy_length;
+
+    return 0;
+}
+
+/* Returns 1 if end-of-stream is reached, 0 if more data and -1 if error */
+static int vfio_save_block(QEMUFile *f, VFIOMigration *migration)
+{
+    ssize_t data_size;
+
+    data_size = read(migration->data_fd, migration->data_buffer,
+                     migration->data_buffer_size);
+    if (data_size < 0) {
+        return -errno;
+    }
+    if (data_size == 0) {
+        return 1;
+    }
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
+    qemu_put_be64(f, data_size);
+    qemu_put_buffer(f, migration->data_buffer, data_size);
+    bytes_transferred += data_size;
+
+    trace_vfio_save_block(migration->vbasedev->name, data_size);
+
+    return qemu_file_get_error(f);
+}
+
 /* ---------------------------------------------------------------------- */
 
+static int vfio_save_setup(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+    uint64_t stop_copy_size;
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
+
+    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
+        stop_copy_size = VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE;
+    }
+    migration->data_buffer_size = MIN(VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE,
+                                      stop_copy_size);
+    migration->data_buffer = g_try_malloc0(migration->data_buffer_size);
+    if (!migration->data_buffer) {
+        error_report("%s: Failed to allocate migration data buffer",
+                     vbasedev->name);
+        return -ENOMEM;
+    }
+
+    trace_vfio_save_setup(vbasedev->name, migration->data_buffer_size);
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+
+    return qemu_file_get_error(f);
+}
+
 static int vfio_v1_save_setup(QEMUFile *f, void *opaque)
 {
     VFIODevice *vbasedev = opaque;
@@ -448,6 +638,17 @@  static int vfio_v1_save_setup(QEMUFile *f, void *opaque)
     return 0;
 }
 
+static void vfio_save_cleanup(void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    VFIOMigration *migration = vbasedev->migration;
+
+    g_free(migration->data_buffer);
+    migration->data_buffer = NULL;
+    vfio_migration_cleanup(vbasedev);
+    trace_vfio_save_cleanup(vbasedev->name);
+}
+
 static void vfio_v1_save_cleanup(void *opaque)
 {
     VFIODevice *vbasedev = opaque;
@@ -456,6 +657,34 @@  static void vfio_v1_save_cleanup(void *opaque)
     trace_vfio_save_cleanup(vbasedev->name);
 }
 
+/*
+ * Migration size of VFIO devices can be as little as a few KBs or as big as
+ * many GBs. This value should be big enough to cover the worst case.
+ */
+#define VFIO_MIG_STOP_COPY_SIZE (100 * GiB)
+static void vfio_save_pending(void *opaque, uint64_t threshold_size,
+                              uint64_t *res_precopy_only,
+                              uint64_t *res_compatible,
+                              uint64_t *res_postcopy_only)
+{
+    VFIODevice *vbasedev = opaque;
+    uint64_t stop_copy_size;
+
+    if (vfio_query_stop_copy_size(vbasedev, &stop_copy_size)) {
+        /*
+         * Failed to get pending migration size. Report big pending size so
+         * downtime limit won't be violated.
+         */
+        stop_copy_size = VFIO_MIG_STOP_COPY_SIZE;
+    }
+
+    *res_precopy_only += stop_copy_size;
+
+    trace_vfio_save_pending(vbasedev->name, *res_precopy_only,
+                            *res_postcopy_only, *res_compatible,
+                            stop_copy_size);
+}
+
 static void vfio_v1_save_pending(void *opaque, uint64_t threshold_size,
                                  uint64_t *res_precopy_only,
                                  uint64_t *res_compatible,
@@ -523,6 +752,41 @@  static int vfio_save_iterate(QEMUFile *f, void *opaque)
     return 0;
 }
 
+static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+    enum vfio_device_mig_state recover_state;
+    int ret;
+
+    /* We reach here with device state STOP only */
+    recover_state = VFIO_DEVICE_STATE_STOP;
+    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP_COPY,
+                                   recover_state);
+    if (ret) {
+        return ret;
+    }
+
+    do {
+        ret = vfio_save_block(f, vbasedev->migration);
+        if (ret < 0) {
+            return ret;
+        }
+    } while (!ret);
+
+    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
+    ret = qemu_file_get_error(f);
+    if (ret) {
+        return ret;
+    }
+
+    recover_state = VFIO_DEVICE_STATE_ERROR;
+    ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_STOP,
+                                   recover_state);
+    trace_vfio_save_complete_precopy(vbasedev->name, ret);
+
+    return ret;
+}
+
 static int vfio_v1_save_complete_precopy(QEMUFile *f, void *opaque)
 {
     VFIODevice *vbasedev = opaque;
@@ -592,6 +856,14 @@  static void vfio_save_state(QEMUFile *f, void *opaque)
     }
 }
 
+static int vfio_load_setup(QEMUFile *f, void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+
+    return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
+                                   vbasedev->migration->device_state);
+}
+
 static int vfio_v1_load_setup(QEMUFile *f, void *opaque)
 {
     VFIODevice *vbasedev = opaque;
@@ -619,6 +891,16 @@  static int vfio_v1_load_setup(QEMUFile *f, void *opaque)
     return ret;
 }
 
+static int vfio_load_cleanup(void *opaque)
+{
+    VFIODevice *vbasedev = opaque;
+
+    vfio_migration_cleanup(vbasedev);
+    trace_vfio_load_cleanup(vbasedev->name);
+
+    return 0;
+}
+
 static int vfio_v1_load_cleanup(void *opaque)
 {
     VFIODevice *vbasedev = opaque;
@@ -661,7 +943,11 @@  static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
             uint64_t data_size = qemu_get_be64(f);
 
             if (data_size) {
-                ret = vfio_v1_load_buffer(f, vbasedev, data_size);
+                if (vbasedev->migration->v2) {
+                    ret = vfio_load_buffer(f, vbasedev, data_size);
+                } else {
+                    ret = vfio_v1_load_buffer(f, vbasedev, data_size);
+                }
                 if (ret < 0) {
                     return ret;
                 }
@@ -682,6 +968,17 @@  static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
     return ret;
 }
 
+static const SaveVMHandlers savevm_vfio_handlers = {
+    .save_setup = vfio_save_setup,
+    .save_cleanup = vfio_save_cleanup,
+    .save_live_pending = vfio_save_pending,
+    .save_live_complete_precopy = vfio_save_complete_precopy,
+    .save_state = vfio_save_state,
+    .load_setup = vfio_load_setup,
+    .load_cleanup = vfio_load_cleanup,
+    .load_state = vfio_load_state,
+};
+
 static SaveVMHandlers savevm_vfio_v1_handlers = {
     .save_setup = vfio_v1_save_setup,
     .save_cleanup = vfio_v1_save_cleanup,
@@ -696,6 +993,34 @@  static SaveVMHandlers savevm_vfio_v1_handlers = {
 
 /* ---------------------------------------------------------------------- */
 
+static void vfio_vmstate_change(void *opaque, bool running, RunState state)
+{
+    VFIODevice *vbasedev = opaque;
+    enum vfio_device_mig_state new_state;
+    int ret;
+
+    if (running) {
+        new_state = VFIO_DEVICE_STATE_RUNNING;
+    } else {
+        new_state = VFIO_DEVICE_STATE_STOP;
+    }
+
+    ret = vfio_migration_set_state(vbasedev, new_state,
+                                   VFIO_DEVICE_STATE_ERROR);
+    if (ret) {
+        /*
+         * Migration should be aborted in this case, but vm_state_notify()
+         * currently does not support reporting failures.
+         */
+        if (migrate_get_current()->to_dst_file) {
+            qemu_file_set_error(migrate_get_current()->to_dst_file, ret);
+        }
+    }
+
+    trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state),
+                              mig_state_to_str(new_state));
+}
+
 static void vfio_v1_vmstate_change(void *opaque, bool running, RunState state)
 {
     VFIODevice *vbasedev = opaque;
@@ -769,12 +1094,17 @@  static void vfio_migration_state_notifier(Notifier *notifier, void *data)
     case MIGRATION_STATUS_CANCELLED:
     case MIGRATION_STATUS_FAILED:
         bytes_transferred = 0;
-        ret = vfio_migration_v1_set_state(vbasedev,
-                                          ~(VFIO_DEVICE_STATE_V1_SAVING |
-                                            VFIO_DEVICE_STATE_V1_RESUMING),
-                                          VFIO_DEVICE_STATE_V1_RUNNING);
-        if (ret) {
-            error_report("%s: Failed to set state RUNNING", vbasedev->name);
+        if (migration->v2) {
+            vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RUNNING,
+                                     VFIO_DEVICE_STATE_ERROR);
+        } else {
+            ret = vfio_migration_v1_set_state(vbasedev,
+                                              ~(VFIO_DEVICE_STATE_V1_SAVING |
+                                                VFIO_DEVICE_STATE_V1_RESUMING),
+                                              VFIO_DEVICE_STATE_V1_RUNNING);
+            if (ret) {
+                error_report("%s: Failed to set state RUNNING", vbasedev->name);
+            }
         }
     }
 }
@@ -783,12 +1113,34 @@  static void vfio_migration_exit(VFIODevice *vbasedev)
 {
     VFIOMigration *migration = vbasedev->migration;
 
-    vfio_region_exit(&migration->region);
-    vfio_region_finalize(&migration->region);
+    if (!migration->v2) {
+        vfio_region_exit(&migration->region);
+        vfio_region_finalize(&migration->region);
+    }
     g_free(vbasedev->migration);
     vbasedev->migration = NULL;
 }
 
+static int vfio_migration_query_flags(VFIODevice *vbasedev, uint64_t *mig_flags)
+{
+    uint64_t buf[DIV_ROUND_UP(sizeof(struct vfio_device_feature) +
+                                  sizeof(struct vfio_device_feature_migration),
+                              sizeof(uint64_t))] = {};
+    struct vfio_device_feature *feature = (struct vfio_device_feature *)buf;
+    struct vfio_device_feature_migration *mig =
+        (struct vfio_device_feature_migration *)feature->data;
+
+    feature->argsz = sizeof(buf);
+    feature->flags = VFIO_DEVICE_FEATURE_GET | VFIO_DEVICE_FEATURE_MIGRATION;
+    if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
+        return -EOPNOTSUPP;
+    }
+
+    *mig_flags = mig->flags;
+
+    return 0;
+}
+
 static int vfio_migration_init(VFIODevice *vbasedev)
 {
     int ret;
@@ -797,6 +1149,7 @@  static int vfio_migration_init(VFIODevice *vbasedev)
     char id[256] = "";
     g_autofree char *path = NULL, *oid = NULL;
     struct vfio_region_info *info;
+    uint64_t mig_flags;
 
     if (!vbasedev->ops->vfio_get_object) {
         return -EINVAL;
@@ -807,34 +1160,48 @@  static int vfio_migration_init(VFIODevice *vbasedev)
         return -EINVAL;
     }
 
-    ret = vfio_get_dev_region_info(vbasedev,
-                                   VFIO_REGION_TYPE_MIGRATION_DEPRECATED,
-                                   VFIO_REGION_SUBTYPE_MIGRATION_DEPRECATED,
-                                   &info);
-    if (ret) {
-        return ret;
-    }
+    ret = vfio_migration_query_flags(vbasedev, &mig_flags);
+    if (!ret) {
+        /* Migration v2 */
+        /* Basic migration functionality must be supported */
+        if (!(mig_flags & VFIO_MIGRATION_STOP_COPY)) {
+            return -EOPNOTSUPP;
+        }
+        vbasedev->migration = g_new0(VFIOMigration, 1);
+        vbasedev->migration->device_state = VFIO_DEVICE_STATE_RUNNING;
+        vbasedev->migration->data_fd = -1;
+        vbasedev->migration->v2 = true;
+    } else {
+        /* Migration v1 */
+        ret = vfio_get_dev_region_info(vbasedev,
+                                       VFIO_REGION_TYPE_MIGRATION_DEPRECATED,
+                                       VFIO_REGION_SUBTYPE_MIGRATION_DEPRECATED,
+                                       &info);
+        if (ret) {
+            return ret;
+        }
 
-    vbasedev->migration = g_new0(VFIOMigration, 1);
-    vbasedev->migration->device_state_v1 = VFIO_DEVICE_STATE_V1_RUNNING;
-    vbasedev->migration->vm_running = runstate_is_running();
+        vbasedev->migration = g_new0(VFIOMigration, 1);
+        vbasedev->migration->device_state_v1 = VFIO_DEVICE_STATE_V1_RUNNING;
+        vbasedev->migration->vm_running = runstate_is_running();
 
-    ret = vfio_region_setup(obj, vbasedev, &vbasedev->migration->region,
-                            info->index, "migration");
-    if (ret) {
-        error_report("%s: Failed to setup VFIO migration region %d: %s",
-                     vbasedev->name, info->index, strerror(-ret));
-        goto err;
-    }
+        ret = vfio_region_setup(obj, vbasedev, &vbasedev->migration->region,
+                                info->index, "migration");
+        if (ret) {
+            error_report("%s: Failed to setup VFIO migration region %d: %s",
+                         vbasedev->name, info->index, strerror(-ret));
+            goto err;
+        }
 
-    if (!vbasedev->migration->region.size) {
-        error_report("%s: Invalid zero-sized VFIO migration region %d",
-                     vbasedev->name, info->index);
-        ret = -EINVAL;
-        goto err;
-    }
+        if (!vbasedev->migration->region.size) {
+            error_report("%s: Invalid zero-sized VFIO migration region %d",
+                         vbasedev->name, info->index);
+            ret = -EINVAL;
+            goto err;
+        }
 
-    g_free(info);
+        g_free(info);
+    }
 
     migration = vbasedev->migration;
     migration->vbasedev = vbasedev;
@@ -847,11 +1214,20 @@  static int vfio_migration_init(VFIODevice *vbasedev)
     }
     strpadcpy(id, sizeof(id), path, '\0');
 
-    register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1,
-                         &savevm_vfio_v1_handlers, vbasedev);
+    if (migration->v2) {
+        register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1,
+                             &savevm_vfio_handlers, vbasedev);
+
+        migration->vm_state = qdev_add_vm_change_state_handler(
+            vbasedev->dev, vfio_vmstate_change, vbasedev);
+    } else {
+        register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1,
+                             &savevm_vfio_v1_handlers, vbasedev);
+
+        migration->vm_state = qdev_add_vm_change_state_handler(
+            vbasedev->dev, vfio_v1_vmstate_change, vbasedev);
+    }
 
-    migration->vm_state = qdev_add_vm_change_state_handler(
-        vbasedev->dev, vfio_v1_vmstate_change, vbasedev);
     migration->migration_state.notify = vfio_migration_state_notifier;
     add_migration_state_change_notifier(&migration->migration_state);
     return 0;
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index 9eb9aff295..e7b3b4658c 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -149,20 +149,27 @@  vfio_display_edid_write_error(void) ""
 
 # migration.c
 vfio_migration_probe(const char *name) " (%s)"
+vfio_migration_set_state(const char *name, const char *state) " (%s) state %s"
 vfio_migration_v1_set_state(const char *name, uint32_t state) " (%s) state %d"
+vfio_vmstate_change(const char *name, int running, const char *reason, const char *dev_state) " (%s) running %d reason %s device state %s"
 vfio_v1_vmstate_change(const char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d"
 vfio_migration_state_notifier(const char *name, const char *state) " (%s) state %s"
+vfio_save_setup(const char *name, uint64_t data_buffer_size) " (%s) data buffer size 0x%"PRIx64
 vfio_v1_save_setup(const char *name) " (%s)"
 vfio_save_cleanup(const char *name) " (%s)"
 vfio_save_buffer(const char *name, uint64_t data_offset, uint64_t data_size, uint64_t pending) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64" pending 0x%"PRIx64
 vfio_update_pending(const char *name, uint64_t pending) " (%s) pending 0x%"PRIx64
 vfio_save_device_config_state(const char *name) " (%s)"
+vfio_save_pending(const char *name, uint64_t precopy, uint64_t postcopy, uint64_t compatible, uint64_t stopcopy_size) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64" compatible 0x%"PRIx64" stopcopy size 0x%"PRIx64
 vfio_v1_save_pending(const char *name, uint64_t precopy, uint64_t postcopy, uint64_t compatible) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64" compatible 0x%"PRIx64
 vfio_save_iterate(const char *name, int data_size) " (%s) data_size %d"
+vfio_save_complete_precopy(const char *name, int ret) " (%s) ret %d"
 vfio_v1_save_complete_precopy(const char *name) " (%s)"
 vfio_load_device_config_state(const char *name) " (%s)"
 vfio_load_state(const char *name, uint64_t data) " (%s) data 0x%"PRIx64
 vfio_v1_load_state_device_data(const char *name, uint64_t data_offset, uint64_t data_size) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64
+vfio_load_state_device_data(const char *name, uint64_t data_size, int ret) " (%s) size 0x%"PRIx64" ret %d"
 vfio_load_cleanup(const char *name) " (%s)"
 vfio_get_dirty_bitmap(int fd, uint64_t iova, uint64_t size, uint64_t bitmap_size, uint64_t start) "container fd=%d, iova=0x%"PRIx64" size= 0x%"PRIx64" bitmap_size=0x%"PRIx64" start=0x%"PRIx64
 vfio_iommu_map_dirty_notify(uint64_t iova_start, uint64_t iova_end) "iommu dirty @ 0x%"PRIx64" - 0x%"PRIx64
+vfio_save_block(const char *name, int data_size) " (%s) data_size %d"