Re: [Qemu-devel] [PATCH 3/3] virtio-balloon: fix stats vq migration

[Stefan Hajnoczi]

On Wed, Sep 07, 2016 at 05:20:49PM +0200, Ladi Prosek wrote:
> The statistics virtqueue is not migrated properly because virtio-balloon
> does not include s->stats_vq_elem in the migration stream.
> 
> After migration the statistics virtqueue hangs because the host never
> completes the last element (s->stats_vq_elem is NULL on the destination
> QEMU).  Therefore the guest never submits new elements and the virtqueue
> is hung.
> 
> Instead of changing the migration stream format in an incompatible way,
> detect the migration case and rewind the virtqueue so the last element
> can be completed.
> 
> Cc: Michael S. Tsirkin <address@hidden>
> Cc: Roman Kagan <address@hidden>
> Cc: Stefan Hajnoczi <address@hidden>
> Suggested-by: Roman Kagan <address@hidden>
> Signed-off-by: Ladi Prosek <address@hidden>
> ---
>  hw/virtio/virtio-balloon.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)

Reviewed-by: Stefan Hajnoczi <address@hidden>

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