We must check for new virtqueue buffers after re-enabling notifications.
This prevents the race condition where the guest added buffers just
after we stopped popping the virtqueue but before we re-enabled
notifications.
I think the virtio-crypto code was based on virtio-net but this crucial
detail was missed. virtio-net does not have the race condition because
it processes the virtqueue one more time after re-enabling
notifications.
Cc: Gonglei <arei.gong...@huawei.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
hw/virtio/virtio-crypto.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/hw/virtio/virtio-crypto.c b/hw/virtio/virtio-crypto.c
index 3293843..847dc9d 100644
--- a/hw/virtio/virtio-crypto.c
+++ b/hw/virtio/virtio-crypto.c
@@ -692,8 +692,17 @@ static void virtio_crypto_dataq_bh(void *opaque)
return;
}
- virtio_crypto_handle_dataq(vdev, q->dataq);
- virtio_queue_set_notification(q->dataq, 1);
+ for (;;) {
+ virtio_crypto_handle_dataq(vdev, q->dataq);
+ virtio_queue_set_notification(q->dataq, 1);
+
+ /* Are we done or did the guest add more buffers? */
+ if (virtio_queue_empty(q->dataq)) {
+ break;
+ }
+
+ virtio_queue_set_notification(q->dataq, 0);
+ }
}
static void
--
2.7.4
