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[Qemu-devel] [PATCH v2 2/6] virtio-balloon: make stats virtqueue length
From: |
Roman Kagan |
Subject: |
[Qemu-devel] [PATCH v2 2/6] virtio-balloon: make stats virtqueue length 1 |
Date: |
Fri, 19 Aug 2016 16:39:21 +0300 |
The protocol for virtio-balloon stats virtqueue doesn't allow more than
one element in the virtqueue.
So, instead of trying to compensate for guest misbehavior if it sends
new data before the slot has been released by the host, just define the
stats virtqueue length to 1 initially and rely on the generic virtio
code to handle overflows.
Signed-off-by: Roman Kagan <address@hidden>
Cc: "Michael S. Tsirkin" <address@hidden>
Cc: Ladi Prosek <address@hidden>
Cc: Stefan Hajnoczi <address@hidden>
---
v1 > v2:
- added assert in virtio_balloon_receive_stats
hw/virtio/virtio-balloon.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 5af429a..fb8784e 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -262,12 +262,8 @@ static void virtio_balloon_receive_stats(VirtIODevice
*vdev, VirtQueue *vq)
goto out;
}
- if (s->stats_vq_elem != NULL) {
- /* This should never happen if the driver follows the spec. */
- virtqueue_push(vq, s->stats_vq_elem, 0);
- virtio_notify(vdev, vq);
- g_free(s->stats_vq_elem);
- }
+ /* enforced by stats virtqueue depth being 1 */
+ assert(!s->stats_vq_elem);
s->stats_vq_elem = elem;
@@ -443,7 +439,7 @@ static void virtio_balloon_device_realize(DeviceState *dev,
Error **errp)
s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output);
- s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats);
+ s->svq = virtio_add_queue(vdev, 1, virtio_balloon_receive_stats);
reset_stats(s);
}
--
2.7.4
- [Qemu-devel] [PATCH v2 0/6] virtio-balloon: assorted fixes, Roman Kagan, 2016/08/19
- [Qemu-devel] [PATCH v2 2/6] virtio-balloon: make stats virtqueue length 1,
Roman Kagan <=
- [Qemu-devel] [PATCH v2 4/6] virtio-balloon: keep collecting stats on save/restore, Roman Kagan, 2016/08/19
- Re: [Qemu-devel] [PATCH v2 0/6] virtio-balloon: assorted fixes, Roman Kagan, 2016/08/19
- [Qemu-devel] [PATCH v2 5/6] virtio-balloon: drop ->stats_vq_offset, Roman Kagan, 2016/08/19
- [Qemu-devel] [PATCH v2 6/6] virtio-balloon: drop reset handler, Roman Kagan, 2016/08/19
- [Qemu-devel] [PATCH v2 6/6] virtio-ballon: drop reset handler, Roman Kagan, 2016/08/19
- [Qemu-devel] [PATCH v2 3/6] virtio-balloon: don't restart stats timer in callback, Roman Kagan, 2016/08/19
- [Qemu-devel] [PATCH v2 1/6] virtio: assert on ->inuse underflow, Roman Kagan, 2016/08/19