On Sun, Jan 5, 2020 at 1:39 PM Michael S. Tsirkin <
address@hidden> wrote:
On Thu, Jan 02, 2020 at 09:09:04AM +0200, Yuri Benditovich wrote:
>
>
> On Thu, Jan 2, 2020 at 1:50 AM Michael S. Tsirkin <address@hidden> wrote:
>
> On Thu, Dec 26, 2019 at 11:29:50AM +0200, Yuri Benditovich wrote:
> > On Thu, Dec 26, 2019 at 10:58 AM Jason Wang <address@hidden> wrote:
> > >
> > >
> > > On 2019/12/26 下午12:36, Yuri Benditovich wrote:
> > > > https://bugzilla.redhat.com/show_bug.cgi?id=1708480
> > > > Fix leak of region reference that prevents complete
> > > > device deletion on hot unplug.
> > >
> > >
> > > More information is needed here, the bug said only q35 can meet this
> > > issue. What makes q35 different here?
> > >
> >
> > I do not have any ready answer, I did not dig into it too much.
> > Probably Michael Tsirkin or Paolo Bonzini can answer without digging.
>
>
>
> > >
> > > >
> > > > Signed-off-by: Yuri Benditovich <address@hidden>
> > > > ---
> > > > hw/virtio/virtio.c | 5 +++++
> > > > 1 file changed, 5 insertions(+)
> > > >
> > > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> > > > index 04716b5f6c..baadec8abc 100644
> > > > --- a/hw/virtio/virtio.c
> > > > +++ b/hw/virtio/virtio.c
> > > > @@ -2340,6 +2340,11 @@ void virtio_del_queue(VirtIODevice *vdev, int
> n)
> > > > vdev->vq[n].vring.num_default = 0;
> > > > vdev->vq[n].handle_output = NULL;
> > > > vdev->vq[n].handle_aio_output = NULL;
> > > > + /*
> > > > + * with vring.num = 0 the queue will be ignored
> > > > + * in later loops of region cache reset
> > > > + */
> > >
> > >
> > > I can't get the meaning of this comment.
> > >
> > > Thanks
> > >
> > >
> > > > + virtio_virtqueue_reset_region_cache(&vdev->vq[n]);
>
>
> Do we need to drop this from virtio_device_free_virtqueues then?
>
>
>
> Not mandatory. Repetitive virtio_virtqueue_reset_region_cache does not do
> anything bad.
> Some of virtio devices do not do 'virtio_del_queue' at all. Currently
> virtio_device_free_virtqueues resets region cache for them.
> IMO, not calling 'virtio_del_queue' is a bug, but not in the scope of current
> series, I'll take care of that later.
Maybe we should just del all queues in virtio_device_unrealize?
Will allow us to drop some logic tracking which vqs were created.
Yes, this is also possible with some rework of virtio_device_free_virtqueues.
virtio-net has some additional operations around queue deletion, it deletes queues when switches from single queue to multiple.
>
> > > > g_free(vdev->vq[n].used_elems);
> > > > }
> > > >
> > >
>
>