Re: [Qemu-devel] [RFC 4/6] virtio/migration: Add VMStateDescription to VirtioDeviceClass

[Cornelia Huck]

On Wed, 24 Aug 2016 14:42:31 +0100
"Dr. David Alan Gilbert (git)" <address@hidden> wrote:

> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> Provide a vmsd pointer for VirtIO devices to use instead of the
> load/save methods.
> 
> We'll eventually kill off the load/save methods.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
>  hw/virtio/virtio.c         | 11 +++++++++++
>  include/hw/virtio/virtio.h |  2 ++
>  2 files changed, 13 insertions(+)
> 

> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index d2490c1..fd386ac 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -124,8 +124,10 @@ typedef struct VirtioDeviceClass {
>       * must mask in frontend instead.
>       */
>      void (*guest_notifier_mask)(VirtIODevice *vdev, int n, bool mask);
> +    /* Saving and loading of a device; use *either* save/load OR vmsd */

Should we try to enforce this in some way? Then virtio_{save,load} can
call either/or instead of fallthrough which may have unintended
consequences...

>      void (*save)(VirtIODevice *vdev, QEMUFile *f);
>      int (*load)(VirtIODevice *vdev, QEMUFile *f, int version_id);
> +    const VMStateDescription *vmsd;
>  } VirtioDeviceClass;
> 
>  void virtio_instance_init_common(Object *proxy_obj, void *data,