| Message ID | 20240205172659.476970-3-stefanha@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | virtio-blk: iothread-vq-mapping cleanups | expand |
On Mon, 05 Feb 2024 19:26, Stefan Hajnoczi <stefanha@redhat.com> wrote: >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> >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 e8b37fd5f4..a0735a9bca 100644 >--- a/hw/block/virtio-blk.c >+++ b/hw/block/virtio-blk.c >@@ -1825,6 +1825,7 @@ 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 > Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
On 05.02.24 18:26, Stefan Hajnoczi wrote: > 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> > Signed-off-by: Stefan Hajnoczi<stefanha@redhat.com> > --- > hw/block/virtio-blk.c | 1 + > 1 file changed, 1 insertion(+) Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index e8b37fd5f4..a0735a9bca 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1825,6 +1825,7 @@ 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) {
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> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- hw/block/virtio-blk.c | 1 + 1 file changed, 1 insertion(+)