Re: [Qemu-devel] [PATCH v2 for-1.6 0/2] virtio-mmio: fixes to QueueNum, QueueNumMax

[Michael S. Tsirkin]

On Fri, Aug 09, 2013 at 04:47:40PM +0100, Peter Maydell wrote:
> On 26 July 2013 16:41, Peter Maydell <address@hidden> wrote:
> > These patches fix a couple of bugs in virtio-mmio's
> > handling of the registers that deal with the queue size:
> >
> >  * as mst points out, letting the guest flip a queue between
> >    "exists" and "doesn't exist" is a bad idea
> >  * QueueNumMax wasn't reading the correct value for nonexistent
> >    queues
> >
> > This doesn't include any change to the behaviour of queuesize
> > on reset (discussed in other thread); the current behaviour is
> > not a problem for well-behaved guests, and safe in the face
> > of badly-behaved guests, and currently improving the reset
> > behaviour is blocked by an unrelated bug.
> >
> > v1->v2: changes as per mst review:
> >  * avoid explicit "== 0" comparisons
> >  * avoid unnecessary parens round comparison ops
> >  * do the "don't flip between existent and nonexistent" check
> >    with "!!num != !!oldnum" (and add a comment noting why we're
> >    doing this check)
> >
> > Peter Maydell (2):
> >   hw/virtio/virtio: Don't allow guests to add/remove queues
> >   hw/virtio/virtio-mmio: Make QueueNumMax read 0 for unavailable queues
> 
> These didn't make it into 1.6, but in the absence of any
> review comments I'm putting them into arm-devs for post-1.6.
> 
> thanks
> -- PMM

I'd say these are important bugfixes, should be OK for 1.6 still.