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Re: [PATCH V2] virtio-pci: fix queue_enable write
From: |
Michael S. Tsirkin |
Subject: |
Re: [PATCH V2] virtio-pci: fix queue_enable write |
Date: |
Wed, 10 Jun 2020 05:42:54 -0400 |
On Wed, Jun 10, 2020 at 10:57:26AM +0200, Stefano Garzarella wrote:
> On Wed, Jun 10, 2020 at 01:43:51PM +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 spec, we should not
> > assume that the value is 1.
> >
> > Fix this by ignore the write value other than 1.
> >
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
> > ---
> > Changes from V1:
> > - fix typo
> > - warn wrong value through virtio_error
> > ---
> > hw/virtio/virtio-pci.c | 12 ++++++++----
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> > index d028c17c24..7bc8c1c056 100644
> > --- a/hw/virtio/virtio-pci.c
> > +++ b/hw/virtio/virtio-pci.c
> > @@ -1273,16 +1273,20 @@ 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) {
>
> Does it have to be 1 or can it be any value other than 0?
>
> Thanks,
> Stefano
spec says 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;
> > + } else {
> > + virtio_error(vdev, "wrong value for queue_enable %"PRIx64,
> > val);
> > + }
> > break;
> > case VIRTIO_PCI_COMMON_Q_DESCLO:
> > proxy->vqs[vdev->queue_sel].desc[0] = val;
> > --
> > 2.20.1
> >
> >