On Tue, Oct 05, 2010 at 07:15:31PM +0530, Amit Shah wrote:
> > > +
> > > + spin_lock_irqsave(&vp_dev->lock, flags);
> > > + list_for_each_entry(info, &vp_dev->virtqueues, node) {
> > > + /* Select the queue we're interested in */
> > > + iowrite16(info->queue_index,
> > > + vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
> > > +
> > > + /* Update the last idx we sent data in */
> > > + iowrite16(virtqueue_get_avail_idx(info->vq),
> > > + vp_dev->ioaddr + VIRTIO_PCI_AVAIL_IDX);
> >
> > Interesting. Could we just reset the ring instead?
> > I think this would also solve the qemu problem you
> > outline, won't it?
>
> The problem here is qemu doesn't "know" we went into suspend and came
> out of it. When going to suspend, qemu could've received a kick
> notification and would've been just about to process some queue entries.
> Now when we resume and reset the ring, qemu could crash anyway seeing
> invalid index values.
Hmm, I don't completely understand this. When there's a reset I expect
this to discard any previous kicks. No?
> I think that's happening now anyway.
How can one reproduce this?
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