From: Stefan Hajnoczi <[email protected]>
It is not possible to instantiate a virtio-blk device with 0 virtqueues.
The following check is located in ->realize():
if (!conf->num_queues) {
error_setg(errp, "num-queues property must be larger than 0");
return;
}
Later on we access s->vq_aio_context[0] under the assumption that there
is as least one virtqueue. Hanna Czenczek <[email protected]> noted that
it would help to show that the array index is already valid.
Add an assertion to document that s->vq_aio_context[0] is always
safe...and catch future code changes that break this assumption.
Suggested-by: Hanna Czenczek <[email protected]>
Reviewed-by: Manos Pitsidianakis <[email protected]>
Reviewed-by: Hanna Czenczek <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
Message-ID: <[email protected]>
Reviewed-by: Kevin Wolf <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>
---
hw/block/virtio-blk.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 6e3e3a23ee..e430ba583c 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -1824,6 +1824,7 @@ static int virtio_blk_start_ioeventfd(VirtIODevice *vdev)
* Try to change the AioContext so that block jobs and other operations can
* co-locate their activity in the same AioContext. If it fails, nevermind.
*/
+ assert(nvqs > 0); /* enforced during ->realize() */
r = blk_set_aio_context(s->conf.conf.blk, s->vq_aio_context[0],
&local_err);
if (r < 0) {
--
2.43.0
