Re: [PATCH QEMU v25 16/17] vfio: Make vfio-pci device migration capable

[Cornelia Huck]

On Sun, 21 Jun 2020 01:51:25 +0530
Kirti Wankhede <kwankhede@nvidia.com> wrote:

> If device is not failover primary device call vfio_migration_probe()
> and vfio_migration_finalize() functions for vfio-pci device to enable
> migration for vfio PCI device which support migration.

"If the device is not a failover primary device, call
vfio_migration_probe() and vfio_migration_finalize() to enable
migration support for those devices that support it respectively to
tear it down again."

?

> Removed vfio_pci_vmstate structure.
> Removed migration blocker from VFIO PCI device specific structure and use
> migration blocker from generic structure of  VFIO device.
> 
> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> Reviewed-by: Neo Jia <cjia@nvidia.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  hw/vfio/pci.c | 32 +++++++++++---------------------
>  hw/vfio/pci.h |  1 -
>  2 files changed, 11 insertions(+), 22 deletions(-)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 5ba340aee1d4..9dc2868993fb 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2841,22 +2841,11 @@ static void vfio_realize(PCIDevice *pdev, Error 
> **errp)
>          return;
>      }
>  
> -    if (!pdev->failover_pair_id) {
> -        error_setg(&vdev->migration_blocker,
> -                "VFIO device doesn't support migration");
> -        ret = migrate_add_blocker(vdev->migration_blocker, &err);
> -        if (ret) {
> -            error_propagate(errp, err);
> -            error_free(vdev->migration_blocker);
> -            vdev->migration_blocker = NULL;
> -            return;
> -        }
> -    }
> -
>      vdev->vbasedev.name = g_path_get_basename(vdev->vbasedev.sysfsdev);
>      vdev->vbasedev.ops = &vfio_pci_ops;
>      vdev->vbasedev.type = VFIO_DEVICE_TYPE_PCI;
>      vdev->vbasedev.dev = DEVICE(vdev);
> +    vdev->vbasedev.device_state = 0;
>  
>      tmp = g_strdup_printf("%s/iommu_group", vdev->vbasedev.sysfsdev);
>      len = readlink(tmp, group_path, sizeof(group_path));
> @@ -3120,6 +3109,14 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>          }
>      }
>  
> +    if (!pdev->failover_pair_id) {
> +        ret = vfio_migration_probe(&vdev->vbasedev, errp);
> +        if (ret) {
> +            error_report("%s: Failed to setup for migration",

"%s: migration not enabled" ?

(Although I wonder how often we need to moan here, given that the
called function already prints error reports.)

> +                         vdev->vbasedev.name);
> +        }
> +    }
> +
>      vfio_register_err_notifier(vdev);
>      vfio_register_req_notifier(vdev);
>      vfio_setup_resetfn_quirk(vdev);

LGTM.