On Fri, 9 Oct 2015 10:36:56 +0300 "Michael S. Tsirkin" <m...@redhat.com> wrote:
> On Fri, Oct 09, 2015 at 09:23:49AM +0200, Greg Kurz wrote: > > On Wed, 07 Oct 2015 14:20:28 +0530 > > "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> wrote: > > > > > Stefan Hajnoczi <stefa...@gmail.com> 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 <gk...@linux.vnet.ibm.com> > > > >> --- > > > >> 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... > > If unplug request fails, that should be enough. > Like setting @hotpluggable to false for the virtio-9p-pci class ? I see no other way for the unplug request to fail... but I will happily accept all suggestions :) -- Greg