Re: [PATCH] virtio-pci: fix queue_enable write

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 10, 2020 at 10:03:28AM +0800, Jason Wang wrote:
> 
> On 2020/6/9 下午11:43, Michael S. Tsirkin wrote:
> > On Fri, May 29, 2020 at 11:07:28AM +0800, Jason Wang wrote:
> > > Spec said: The driver uses this to selectively prevent the device from
> > > executing requests from this virtqueue. 1 - enabled; 0 - disabled.
> > > 
> > > Though write 0 to queue_enable is forbidden by the sepc, we should not
> > spec?
> 
> 
> Chapter 4.1.4.3.2 said:
> 
> "
> 
> The driver MUST NOT write a 0 to queue_enable.
> 
> "
> 


I mean you misspelled spec as sepc :)

> > 
> > > assume that the value is 1.
> > > 
> > > Fix this by ignoring the write value other than 1.
> > > 
> > > Cc: Michael S. Tsirkin <mst@redhat.com>
> > > Cc: Stefan Hajnoczi <stefanha@redhat.com>
> > > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > 
> > Do we want to call virtio_error here so we can figure out something's wrong?
> 
> 
> That looks better. Will do.
> 
> Thanks
> 
> 
> > 
> > 
> > 
> > > ---
> > >   hw/virtio/virtio-pci.c | 10 ++++++----
> > >   1 file changed, 6 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > > index d028c17c24..b3558eeaee 100644
> > > --- a/hw/virtio/virtio-pci.c
> > > +++ b/hw/virtio/virtio-pci.c
> > > @@ -1273,16 +1273,18 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr,
> > >           virtio_queue_set_vector(vdev, vdev->queue_sel, val);
> > >           break;
> > >       case VIRTIO_PCI_COMMON_Q_ENABLE:
> > > -        virtio_queue_set_num(vdev, vdev->queue_sel,
> > > -                             proxy->vqs[vdev->queue_sel].num);
> > > -        virtio_queue_set_rings(vdev, vdev->queue_sel,
> > > +        if (val == 1) {
> > > +            virtio_queue_set_num(vdev, vdev->queue_sel,
> > > +                                 proxy->vqs[vdev->queue_sel].num);
> > > +            virtio_queue_set_rings(vdev, vdev->queue_sel,
> > >                          ((uint64_t)proxy->vqs[vdev->queue_sel].desc[1]) << 32 |
> > >                          proxy->vqs[vdev->queue_sel].desc[0],
> > >                          ((uint64_t)proxy->vqs[vdev->queue_sel].avail[1]) << 32 |
> > >                          proxy->vqs[vdev->queue_sel].avail[0],
> > >                          ((uint64_t)proxy->vqs[vdev->queue_sel].used[1]) << 32 |
> > >                          proxy->vqs[vdev->queue_sel].used[0]);
> > > -        proxy->vqs[vdev->queue_sel].enabled = 1;
> > > +            proxy->vqs[vdev->queue_sel].enabled = 1;
> > > +        }
> > >           break;
> > >       case VIRTIO_PCI_COMMON_Q_DESCLO:
> > >           proxy->vqs[vdev->queue_sel].desc[0] = val;
> > > -- 
> > > 2.20.1
> >