Re: [PATCH v1 2/3] virtio-balloon: fix free page hinting check on unrealize

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 5/18/20 10:37 AM, David Hildenbrand wrote:
> Checking against guest features is wrong. We allocated data structures
> based on host features. We can rely on "free_page_bh" as an indicator
> whether to un-do stuff instead.
> 
> Fixes: c13c4153f76d ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
> Cc: Wei Wang <wei.w.wang@intel.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
> Cc: Alexander Duyck <alexander.duyck@gmail.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>   hw/virtio/virtio-balloon.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index dc3b1067ab..a4fcf2d777 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -818,7 +818,7 @@ static void virtio_balloon_device_unrealize(DeviceState *dev)
>       VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>       VirtIOBalloon *s = VIRTIO_BALLOON(dev);
>   
> -    if (virtio_balloon_free_page_support(s)) {
> +    if (s->free_page_bh) {
>           qemu_bh_delete(s->free_page_bh);
>           virtio_balloon_free_page_stop(s);
>           precopy_remove_notifier(&s->free_page_report_notify);
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>