From: "Michael S. Tsirkin" <mst@redhat.com>
To: David Hildenbrand <david@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>,
qemu-stable@nongnu.org, qemu-devel@nongnu.org,
Stefan Hajnoczi <stefanha@redhat.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [Qemu-devel] [PATCH-for-4.1 v2 3/3] virtio-balloon: reset pbp on device resets
Date: Wed, 17 Jul 2019 06:48:28 -0400 [thread overview]
Message-ID: <20190717063902-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20190717103550.24657-4-david@redhat.com>
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-stable@nongnu.org #v4.0.0
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Signed-off-by: David Hildenbrand <david@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
next prev parent reply other threads:[~2019-07-17 10:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-17 10:35 [Qemu-devel] [PATCH-for-4.1 v2 0/3] virtio-balloon: fixes for PartialBalloonedPage David Hildenbrand
2019-07-17 10:35 ` [Qemu-devel] [PATCH-for-4.1 v2 1/3] virtio-balloon: fix QEMU crashes on pagesize > BALLOON_PAGE_SIZE David Hildenbrand
2019-07-18 3:50 ` David Gibson
2019-07-18 11:50 ` David Hildenbrand
2019-07-17 10:35 ` [Qemu-devel] [PATCH-for-4.1 v2 2/3] virtio-balloon: fix memory leak on unrealize() David Hildenbrand
2019-07-18 3:51 ` David Gibson
2019-07-17 10:35 ` [Qemu-devel] [PATCH-for-4.1 v2 3/3] virtio-balloon: reset pbp on device resets David Hildenbrand
2019-07-17 10:48 ` Michael S. Tsirkin [this message]
2019-07-17 11:06 ` David Hildenbrand
2019-07-17 11:29 ` Michael S. Tsirkin
2019-07-17 11:32 ` David Hildenbrand
2019-07-18 3:52 ` David Gibson
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