On Wed, Jul 17, 2019 at 12:35:50PM +0200, David Hildenbrand wrote:
> When a guest reboots (ordinary reboots, but also via kexec), it will
> happily reuse any system memory, including previously inflated memory.
>
> We could have tracking data for a pbp (PartiallyBalloonedPage). It could
> happen that a new inflation request from the guest will result in a
> discard of such a pbp, although the guest is (again) reusing some
> memory.
>
> We should reset the pbp on any device resets.
>
> Fixes: ed48c59875b6 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE <
> host page size")
> Cc: qemu-sta...@nongnu.org #v4.0.0
> Cc: Stefan Hajnoczi <stefa...@redhat.com>
> Cc: David Gibson <da...@gibson.dropbear.id.au>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Cc: Igor Mammedov <imamm...@redhat.com>
> Signed-off-by: David Hildenbrand <da...@redhat.com>
Can't something else remove a ramblock besides a reset?
> ---
> hw/virtio/virtio-balloon.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 84d01bceb3..9de3c030bf 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -847,6 +847,7 @@ static void virtio_balloon_device_reset(VirtIODevice
> *vdev)
> if (virtio_balloon_free_page_support(s)) {
> virtio_balloon_free_page_stop(s);
> }
> + virtio_balloon_reset_pbp(s);
>
> if (s->stats_vq_elem != NULL) {
> virtqueue_unpop(s->svq, s->stats_vq_elem, 0);
> --
> 2.21.0
