From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: Stefan Hajnoczi <stefanha@redhat.com>,
Michael Roth <michael.roth@amd.com>,
Kevin Wolf <kwolf@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
Hanna Reitz <hreitz@redhat.com>,
qemu-block@nongnu.org,
Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Subject: [PATCH v2 2/5] virtio-blk: clarify that there is at least 1 virtqueue
Date: Tue, 6 Feb 2024 14:06:07 -0500 [thread overview]
Message-ID: <20240206190610.107963-3-stefanha@redhat.com> (raw)
In-Reply-To: <20240206190610.107963-1-stefanha@redhat.com>
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 <hreitz@redhat.com> 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 <hreitz@redhat.com>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
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
next prev parent reply other threads:[~2024-02-06 19:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-06 19:06 [PATCH v2 0/5] virtio-blk: iothread-vq-mapping cleanups Stefan Hajnoczi
2024-02-06 19:06 ` [PATCH v2 1/5] virtio-blk: enforce iothread-vq-mapping validation Stefan Hajnoczi
2024-02-06 19:06 ` Stefan Hajnoczi [this message]
2024-02-06 19:06 ` [PATCH v2 3/5] virtio-blk: add vq_rq[] bounds check in virtio_blk_dma_restart_cb() Stefan Hajnoczi
2024-02-06 19:06 ` [PATCH v2 4/5] virtio-blk: declare VirtIOBlock::rq with a type Stefan Hajnoczi
2024-02-06 19:06 ` [PATCH v2 5/5] monitor: use aio_co_reschedule_self() Stefan Hajnoczi
2024-05-03 17:33 ` Kevin Wolf
2024-05-06 18:09 ` Stefan Hajnoczi
2024-02-06 19:08 ` [PATCH v2 0/5] virtio-blk: iothread-vq-mapping cleanups Michael S. Tsirkin
2024-02-07 13:45 ` Kevin Wolf
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