On Tue, Oct 20, 2015 at 08:00:53PM +0200, Greg Kurz wrote: > On Tue, 20 Oct 2015 15:53:08 +0300 > "Michael S. Tsirkin" <m...@redhat.com> wrote: > > > On Tue, Oct 20, 2015 at 11:16:40AM +0200, Greg Kurz wrote: > > > We already have a blocker to prevent migration of an active virtio-9p > > > device. > > > But in fact, there is no migration support at all for 9p, even if the > > > device > > > is considered to be quiescent (when the VirtFS share is not mounted): > > > migration > > > succeeds but the device is lost in the restarted guest. > > > Hotunplug of a virtio-9p device is not supported either (no unrealize > > > handler) > > > and leads to a QEMU crash on the source node, if one unplugs and migrates. > > > > > > This series tries to fix that and brings hotplug and migration support of > > > *quiescent* virtio-9p devices. > > > > > > v2->v3: > > > - renamed QDEV handler @unpluggable to @unplug_is_blocked (patches 2/5 > > > and 3/5) > > > > > > v1->v2: > > > - introduced unplug blocker (patches 2/5 and 3/5) > > > - moved fixes to separate patches (see individual changelogs) > > > > I have some doubts about how hotunplug is handled, but migration > > looks ok. > > Is there a dependency, or can I just pick savevm things meanwhile? > > > > Well... you can drop the unplug blocker patches (2/5 and 3/5) but the > savevm patch (5/5) modifies a function introduced by the unrealize > patch (4/5): > > @@ -146,6 +157,7 @@ static void virtio_9p_device_unrealize(DeviceState *dev, > Error **errp) > v9fs_release_worker_threads(); > g_free(s->ctx.fs_root); > g_free(s->tag); > + unregister_savevm(dev, "virtio-9p", s); > virtio_cleanup(vdev); > } > > and not having an unrealize handler calling unregister_savevm() means > unplug will succeed and leave a dangling pointer in the vm_change_state > list... This causes a systematic crash of the source QEMU when attempting > a migration.
OK ... could you pls re-arrange it so that savevm can be applied first? > > > --- > > > > > > Greg Kurz (5): > > > virtio-9p-coth: fix init function > > > qdev: add the @unplug_is_blocked handler > > > virtio-9p: block hot-unplug when device is active > > > virtio-9p: add unrealize handler > > > virtio-9p: add savem handlers > > > > > > > > > hw/9pfs/virtio-9p-coth.c | 22 ++++++++++++++++++---- > > > hw/9pfs/virtio-9p-coth.h | 2 ++ > > > hw/9pfs/virtio-9p-device.c | 24 ++++++++++++++++++++++++ > > > hw/9pfs/virtio-9p.c | 14 ++++++++++++++ > > > hw/9pfs/virtio-9p.h | 2 ++ > > > hw/core/qdev.c | 4 ++++ > > > hw/s390x/virtio-ccw.c | 8 ++++++++ > > > hw/virtio/virtio-pci.c | 8 ++++++++ > > > include/hw/qdev-core.h | 4 ++++ > > > 9 files changed, 84 insertions(+), 4 deletions(-) > >
