Re: [PATCH v18 QEMU 07/18] vfio: Add migration state change notifier

[Cornelia Huck <cohuck@redhat.com>]

On Tue, 5 May 2020 04:14:42 +0530
Kirti Wankhede <kwankhede@nvidia.com> wrote:

> Added migration state change notifier to get notification on migration state
> change. These states are translated to VFIO device state and conveyed to vendor
> driver.
> 
> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> Reviewed-by: Neo Jia <cjia@nvidia.com>
> ---
>  hw/vfio/migration.c           | 30 ++++++++++++++++++++++++++++++
>  hw/vfio/trace-events          |  5 +++--
>  include/hw/vfio/vfio-common.h |  1 +
>  3 files changed, 34 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index e79b34003079..c2f5564b51c3 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -154,6 +154,28 @@ static void vfio_vmstate_change(void *opaque, int running, RunState state)
>      }
>  }
>  
> +static void vfio_migration_state_notifier(Notifier *notifier, void *data)
> +{
> +    MigrationState *s = data;
> +    VFIODevice *vbasedev = container_of(notifier, VFIODevice, migration_state);
> +    int ret;
> +
> +    trace_vfio_migration_state_notifier(vbasedev->name,
> +                                        MigrationStatus_str(s->state));
> +
> +    switch (s->state) {
> +    case MIGRATION_STATUS_CANCELLING:
> +    case MIGRATION_STATUS_CANCELLED:
> +    case MIGRATION_STATUS_FAILED:
> +        ret = vfio_migration_set_state(vbasedev,
> +                      ~(VFIO_DEVICE_STATE_SAVING | VFIO_DEVICE_STATE_RESUMING),
> +                      VFIO_DEVICE_STATE_RUNNING);
> +        if (ret) {
> +            error_report("%s: Failed to set state RUNNING", vbasedev->name);
> +        }

What is the actually desired state transition here? Again, I find the
interface hard to read... and my comments regarding state propagation
and error states from the previous patch apply here as well.


> +    }
> +}
> +