[Qemu-devel] Re: [PATCH] virtio-net migration fix

[Anthony Liguori <anthony@codemonkey.ws>]

Mark McLoughlin wrote:
> We are failing to save whether the guest will supply us rx
> buffers using the new mergeable format; this can cause a
> migrated guest to crash with:
>
>    virtio-net header not in first element
>   

We should bump the version number so that we can gracefully fail 
migrations where the dest or source end is broken.  I would make the 
virtio_net_load not accept version 1 saves too just to be on the safe side.

Regards,

Anthony Liguori

> Signed-off-by: Mark McLoughlin <markmc@redhat.com>
> ---
>  hw/virtio-net.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index 1f45b2d..66d43d9 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -275,6 +275,7 @@ static void virtio_net_save(QEMUFile *f, void *opaque)
>  
>      qemu_put_buffer(f, n->mac, 6);
>      qemu_put_be32(f, n->tx_timer_active);
> +    qemu_put_be32(f, n->mergeable_rx_bufs);
>  }
>  
>  static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
> @@ -288,6 +289,7 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
>  
>      qemu_get_buffer(f, n->mac, 6);
>      n->tx_timer_active = qemu_get_be32(f);
> +    n->mergeable_rx_bufs = qemu_get_be32(f);
>  
>      if (n->tx_timer_active) {
>          qemu_mod_timer(n->tx_timer,
>