Re: [PATCH V3 18/19] virtio_vdpa: don't warn when fail to disable vq

[Jason Wang]

On 2021/2/5 下午11:24, Michael S. Tsirkin wrote:
> On Mon, Jan 04, 2021 at 02:55:02PM +0800, Jason Wang wrote:
> > There's no guarantee that the device can disable a specific virtqueue
> > through set_vq_ready(). One example is the modern virtio-pci
> > device. So this patch removes the warning.
> >
> > Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
>
> Do we need the read as a kind of flush though?


The problem is that PCI forbids write 0 to queue_enable. So I'm not sure 
what kind of flush do we need here?

Thanks


> > ---
> >   drivers/virtio/virtio_vdpa.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
> > index 4a9ddb44b2a7..e28acf482e0c 100644
> > --- a/drivers/virtio/virtio_vdpa.c
> > +++ b/drivers/virtio/virtio_vdpa.c
> > @@ -225,9 +225,8 @@ static void virtio_vdpa_del_vq(struct virtqueue *vq)
> >   	list_del(&info->node);
> >   	spin_unlock_irqrestore(&vd_dev->lock, flags);
> >   
> > -	/* Select and deactivate the queue */
> > +	/* Select and deactivate the queue (best effort) */
> >   	ops->set_vq_ready(vdpa, index, 0);
> > -	WARN_ON(ops->get_vq_ready(vdpa, index));
> >   
> >   	vring_del_virtqueue(vq);
> >   
> > --
> > 2.25.1