On Thu, 18 Aug 2022 16:10:45 +0800, Jason Wang <jasowang@xxxxxxxxxx> wrote:
> On Thu, Aug 18, 2022 at 11:04 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
> >
> > Legacy virtio pci has no way to communicate a change in vq size to
> > the hypervisor. If ring sizes don't match hypervisor will happily
> > corrupt memory.
> >
> > We add a check to vring size before calling
> > vp_legacy_set_queue_address(). Checking the memory range directly is a
> > bit cumbersome.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > ---
> >
> > v2: replace BUG_ON with WARN_ON_ONCE. @Linus
> >
> > drivers/virtio/virtio_pci_legacy.c | 9 +++++++++
> > 1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c
> > index 2257f1b3d8ae..091e73d74e94 100644
> > --- a/drivers/virtio/virtio_pci_legacy.c
> > +++ b/drivers/virtio/virtio_pci_legacy.c
> > @@ -146,6 +146,15 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > goto out_del_vq;
> > }
> >
> > + /* Legacy virtio pci has no way to communicate a change in vq size to
> > + * the hypervisor. If ring sizes don't match hypervisor will happily
> > + * corrupt memory.
> > + */
> > + if (WARN_ON_ONCE(num != virtqueue_get_vring_size(vq))) {
> > + err = -EPERM;
> > + goto out_del_vq;
> > + }
>
> I wonder if it's better to have a num_min instead.
num_min?
What is that?
Thanks.
>
> Thanks
>
> > +
> > /* activate the queue */
> > vp_legacy_set_queue_address(&vp_dev->ldev, index, q_pfn);
> >
> > --
> > 2.31.0
> >
>
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