Re: [PATCH v6 9/9] vfio/common: Allow disabling device dirty page tracking

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

On 7/22/24 23:13, Joao Martins wrote:
> The property 'x-pre-copy-dirty-page-tracking' allows disabling the whole
> tracking of VF pre-copy phase of dirty page tracking, though it means
> that it will only be used at the start of the switchover phase.
>
> Add an option that disables the VF dirty page tracking, and fall
> back into container-based dirty page tracking. This also allows to
> use IOMMU dirty tracking even on VFs with their own dirty
> tracker scheme.

Forced ON value isn't really meaningful though. I mean only valid values
are AUTO and OFF, correct?

Eric
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  include/hw/vfio/vfio-common.h | 1 +
>  hw/vfio/common.c              | 3 +++
>  hw/vfio/migration.c           | 4 +++-
>  hw/vfio/pci.c                 | 3 +++
>  4 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 1e02c98b09ba..fed499b199f0 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -138,6 +138,7 @@ typedef struct VFIODevice {
>      VFIOMigration *migration;
>      Error *migration_blocker;
>      OnOffAuto pre_copy_dirty_page_tracking;
> +    OnOffAuto device_dirty_page_tracking;
>      bool dirty_pages_supported;
>      bool dirty_tracking;
>      bool iommu_dirty_tracking;
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index da12cbd56408..36d0cf6585b2 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -199,6 +199,9 @@ bool vfio_devices_all_device_dirty_tracking(const VFIOContainerBase *bcontainer)
>      VFIODevice *vbasedev;
>  
>      QLIST_FOREACH(vbasedev, &bcontainer->device_list, container_next) {
> +        if (vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) {
> +            return false;
> +        }
>          if (!vbasedev->dirty_pages_supported) {
>              return false;
>          }
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index cbfaef7afffe..262d42a46e58 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -1036,7 +1036,9 @@ bool vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
>          return !vfio_block_migration(vbasedev, err, errp);
>      }
>  
> -    if (!vbasedev->dirty_pages_supported && !vbasedev->iommu_dirty_tracking) {
> +    if ((!vbasedev->dirty_pages_supported ||
> +         vbasedev->device_dirty_page_tracking == ON_OFF_AUTO_OFF) &&
> +        !vbasedev->iommu_dirty_tracking) {
>          if (vbasedev->enable_migration == ON_OFF_AUTO_AUTO) {
>              error_setg(&err,
>                         "%s: VFIO device doesn't support device and "
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 8c0f212a163e..a0767de54b8d 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -3364,6 +3364,9 @@ static Property vfio_pci_dev_properties[] = {
>      DEFINE_PROP_ON_OFF_AUTO("x-pre-copy-dirty-page-tracking", VFIOPCIDevice,
>                              vbasedev.pre_copy_dirty_page_tracking,
>                              ON_OFF_AUTO_ON),
> +    DEFINE_PROP_ON_OFF_AUTO("x-device-dirty-page-tracking", VFIOPCIDevice,
> +                            vbasedev.device_dirty_page_tracking,
> +                            ON_OFF_AUTO_ON),
>      DEFINE_PROP_ON_OFF_AUTO("display", VFIOPCIDevice,
>                              display, ON_OFF_AUTO_OFF),
>      DEFINE_PROP_UINT32("xres", VFIOPCIDevice, display_xres, 0),