Re: [Qemu-devel] [PATCH 2/3] virtio-9p: add unrealize handler

[Greg Kurz]

On Wed, 07 Oct 2015 14:20:28 +0530
"Aneesh Kumar K.V" <address@hidden> wrote:

> Stefan Hajnoczi <address@hidden> writes:
> 
> > On Mon, Oct 05, 2015 at 11:07:23AM +0200, Greg Kurz wrote:
> >> If the user tries to hot unplug a virtio-9p device, it seems to succeed but
> >> in fact:
> >> - virtio-9p coroutines thread pool and async queue are leaked
> >> - QEMU crashes in virtio_vmstate_change() if the user tries to live migrate
> >> 
> >> This patch brings hot unplug support to virtio-9p-device. It fixes both
> >> above issues.
> >> 
> >> Signed-off-by: Greg Kurz <address@hidden>
> >> ---
> >>  hw/9pfs/virtio-9p-device.c |   12 ++++++++++++
> >>  1 file changed, 12 insertions(+)
> >
> > What happens to in-flight I/O requests?  We cannot assume that the guest
> > driver quiesces the device.
> 
> We enable migration blocker when we have an active mount. So if we get
> here, that should indicate no active 9p mounts.
> 
> -aneesh

Oops.. Stefan is talking about hot-unplug versus in-flight requests... not
about migration. And there is no such thing as a hot-unplug blocker...

--
Greg