Re: [PATCH v4 11/12] vfio/migration: Don't block migration device dirty tracking is unsupported

[Eric Auger <eric.auger@redhat.com>]

On 7/12/24 13:47, Joao Martins wrote:
> By default VFIO migration is set to auto, which will support live
> migration if the migration capability is set *and* also dirty page
> tracking is supported.
>
> For testing purposes one can force enable without dirty page tracking
> via enable-migration=on, but that option is generally left for testing
> purposes.
>
> So starting with IOMMU dirty tracking it can use to acomodate the lack of
accomodate

Eric
> VF dirty page tracking allowing us to minimize the VF requirements for
> migration and thus enabling migration by default for those too.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  hw/vfio/migration.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index 34d4be2ce1b1..ce3d1b6e9a25 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -1036,7 +1036,8 @@ bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
>          return !vfio_block_migration(vbasedev, err, errp);
>      }
>  
> -    if (!vbasedev->dirty_pages_supported) {
> +    if (!vbasedev->dirty_pages_supported &&
> +        !vbasedev->bcontainer->dirty_pages_supported) {
>          if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
>              error_setg(&err,
>                         "%s: VFIO device doesn't support device dirty tracking",