Re: [PATCH v3 14/17] vfio/migration: Reset device if setting recover state fails

[Alex Williamson]

On Thu, 3 Nov 2022 18:16:17 +0200
Avihai Horon <avihaih@nvidia.com> wrote:

> If vfio_migration_set_state() fails to set the device in the requested
> state it tries to put it in a recover state. If setting the device in
> the recover state fails as well, hw_error is triggered and the VM is
> aborted.
> 
> To improve user experience and avoid VM data loss, reset the device with
> VFIO_RESET_DEVICE instead of aborting the VM.
> 
> Signed-off-by: Avihai Horon <avihaih@nvidia.com>
> ---
>  hw/vfio/migration.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index f8c3228314..e8068b9147 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -92,8 +92,18 @@ static int vfio_migration_set_state(VFIODevice *vbasedev,
>  
>          mig_state->device_state = recover_state;
>          if (ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature)) {
> -            hw_error("%s: Failed setting device in recover state, err: %s",
> -                     vbasedev->name, strerror(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 -1;
>          }
>  
>          migration->device_state = recover_state;

This addresses one of my comments on 12/ and should probably be rolled
in there.  Thanks,

Alex