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author | Stefan Hajnoczi <stefanha@redhat.com> | 2016-09-07 11:51:25 -0400 |
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committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2016-09-14 20:50:24 -0500 |
commit | 1af2c3fcb89969f0fc5e31d6e50561a770c9fa8a (patch) | |
tree | 34d59c25551ba0e03542f08ff685c439e7dde62e | |
parent | 85d0a53c583656e5e37a8317f9119933c796847f (diff) | |
download | qemu-1af2c3fcb89969f0fc5e31d6e50561a770c9fa8a.zip qemu-1af2c3fcb89969f0fc5e31d6e50561a770c9fa8a.tar.gz qemu-1af2c3fcb89969f0fc5e31d6e50561a770c9fa8a.tar.bz2 |
virtio: zero vq->inuse in virtio_reset()
vq->inuse must be zeroed upon device reset like most other virtqueue
fields.
In theory, virtio_reset() just needs assert(vq->inuse == 0) since
devices must clean up in-flight requests during reset (requests cannot
not be leaked!).
In practice, it is difficult to achieve vq->inuse == 0 across reset
because balloon, blk, 9p, etc implement various different strategies for
cleaning up requests. Most devices call g_free(elem) directly without
telling virtio.c that the VirtQueueElement is cleaned up. Therefore
vq->inuse is not decremented during reset.
This patch zeroes vq->inuse and trusts that devices are not leaking
VirtQueueElements across reset.
I will send a follow-up series that refactors request life-cycle across
all devices and converts vq->inuse = 0 into assert(vq->inuse == 0) but
this more invasive approach is not appropriate for stable trees.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Cc: qemu-stable <qemu-stable@nongnu.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Ladi Prosek <lprosek@redhat.com>
(cherry picked from commit 4b7f91ed0270a371e1933efa21ba600b6da23ab9)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
-rw-r--r-- | hw/virtio/virtio.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 5fbaaaa..519bb03 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -816,6 +816,7 @@ void virtio_reset(void *opaque) vdev->vq[i].signalled_used_valid = false; vdev->vq[i].notification = true; vdev->vq[i].vring.num = vdev->vq[i].vring.num_default; + vdev->vq[i].inuse = 0; } } |