Re: [PATCH v2 3/4] virtio-gpu: add x-vmstate-version

[Peter Xu <peterx@redhat.com>]

Hey, Marc-Andre,

On Mon, May 13, 2024 at 11:19:04AM +0400, marcandre.lureau@redhat.com wrote:
> diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
> index ae831b6b3e..7f9fb5eacc 100644
> --- a/hw/display/virtio-gpu.c
> +++ b/hw/display/virtio-gpu.c
> @@ -1234,7 +1234,8 @@ static int virtio_gpu_save(QEMUFile *f, void *opaque, size_t size,
>      }
>      qemu_put_be32(f, 0); /* end of list */
>  
> -    return vmstate_save_state(f, &vmstate_virtio_gpu_scanouts, g, NULL);
> +    return vmstate_save_state_v(f, &vmstate_virtio_gpu_scanouts, g,
> +                                NULL, g->vmstate_version, NULL);
>  }
>  
>  static bool virtio_gpu_load_restore_mapping(VirtIOGPU *g,
> @@ -1339,7 +1340,7 @@ static int virtio_gpu_load(QEMUFile *f, void *opaque, size_t size,
>      }
>  
>      /* load & apply scanout state */
> -    vmstate_load_state(f, &vmstate_virtio_gpu_scanouts, g, 1);
> +    vmstate_load_state(f, &vmstate_virtio_gpu_scanouts, g, g->vmstate_version);

[sorry for a late response; attending a conf, and will reply to the v1
 thread later for the other discussions..]

These two changes shouldn't be needed if we go with the .field_exists()
approach, am I right?  IIUC in that case we can keep the version 1 here and
don't boost anything, because we relied on the machine versions.

IIUC this might be the reason why we found 9.0 mahines are broken on
migration.  E.g, IIUC my original patch should work for 9.0<->9.0 too.

Thanks,

>  
>      return 0;
>  }
> @@ -1659,6 +1660,7 @@ static Property virtio_gpu_properties[] = {
>      DEFINE_PROP_BIT("blob", VirtIOGPU, parent_obj.conf.flags,
>                      VIRTIO_GPU_FLAG_BLOB_ENABLED, false),
>      DEFINE_PROP_SIZE("hostmem", VirtIOGPU, parent_obj.conf.hostmem, 0),
> +    DEFINE_PROP_UINT8("x-vmstate-version", VirtIOGPU, vmstate_version, 1),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>  
> -- 
> 2.41.0.28.gd7d8841f67
> 

-- 
Peter Xu