On Wed, Jul 26, 2017 at 09:37:30PM -0700, Nick Owens wrote:
> hello tech@,
>
> here is a diff that will follow the virtio spec a little closer, and
> allows 9front's (http://9front.org) virtio-blk driver to correctly find
> the number of queues. i know that virtio-blk only has one queue, but
> the virtio probing code is shared between virtio-blk and virtio-scsi.
>
> without this change, the size of the first queue is used for all
> subsequently probed queues.
>
> for completeness i've changed rng and net to do the same as blk.
>
> some bits from the spec:
>
> 4.1.4.3.1 - "The device MUST present a 0 in queue_size if the virtqueue
> corresponding to the current queue_select is unavailable."
>
> 4.1.5.1.3 - "Write the virtqueue index (first queue is 0) to
> queue_select. Read the virtqueue size from queue_size. This controls
> how big the virtqueue is (see 2.4 Virtqueues). If this field is 0, the
> virtqueue does not exist."
>
vmd diffs are always welcome, thanks. I'll take a look at this later today.
-ml
> Index: virtio.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/vmd/virtio.c,v
> retrieving revision 1.49
> diff -u -p -u -p -r1.49 virtio.c
> --- virtio.c 30 May 2017 17:56:47 -0000 1.49
> +++ virtio.c 27 Jul 2017 04:35:46 -0000
> @@ -150,8 +150,10 @@ void
> viornd_update_qs(void)
> {
> /* Invalid queue? */
> - if (viornd.cfg.queue_select > 0)
> + if (viornd.cfg.queue_select > 0) {
> + viornd.cfg.queue_size = 0;
> return;
> + }
>
> /* Update queue address/size based on queue select */
> viornd.cfg.queue_address =
> viornd.vq[viornd.cfg.queue_select].qa; @@ -324,8 +326,10 @@ void
> vioblk_update_qs(struct vioblk_dev *dev)
> {
> /* Invalid queue? */
> - if (dev->cfg.queue_select > 0)
> + if (dev->cfg.queue_select > 0) {
> + dev->cfg.queue_size = 0;
> return;
> + }
>
> /* Update queue address/size based on queue select */
> dev->cfg.queue_address = dev->vq[dev->cfg.queue_select].qa;
> @@ -1037,8 +1041,10 @@ void
> vionet_update_qs(struct vionet_dev *dev)
> {
> /* Invalid queue? */
> - if (dev->cfg.queue_select > 1)
> + if (dev->cfg.queue_select > 1) {
> + dev->cfg.queue_size = 0;
> return;
> + }
>
> /* Update queue address/size based on queue select */
> dev->cfg.queue_address = dev->vq[dev->cfg.queue_select].qa;
>
