Re: [Qemu-devel] [PATCH] virtio-migration: Migrate config vector for virtio devices

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 03, 2015 at 05:42:17PM +0200, Christian Borntraeger wrote:
> Am 03.06.2015 um 17:04 schrieb Jason J. Herne:
> > virtio_ccw_{save|load}_config are missing code to save and restore a vdev's
> > config_vector value. This causes some virtio devices to become disabled
> > following a migration.
> > 
> > This patch fixes a bug whereby the qmp/hmp balloon command (virsh setmem)
> > silently fails to update the guest's available memory because the device was not
> > properly migrated.
> > 
> > Signed-off-by: Jason J. Herne <jjherne@linux.vnet.ibm.com>
> 
> Will apply to my s390 branch with a slightly modified subject (virtio-ccw/migration:)
> and will add some explanation about how the machine cpu state version change between
> v2.3 and v2.4 will protect us.
> 
> Thanks.

OK I queued this but I can back it out. Sent a review tag.

> > ---
> >  hw/s390x/virtio-ccw.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
> > index ef90fed..05eaee2 100644
> > --- a/hw/s390x/virtio-ccw.c
> > +++ b/hw/s390x/virtio-ccw.c
> > @@ -1310,6 +1310,7 @@ static void virtio_ccw_save_config(DeviceState *d, QEMUFile *f)
> >  {
> >      VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
> >      SubchDev *s = dev->sch;
> > +    VirtIODevice *vdev = virtio_ccw_get_vdev(s);
> > 
> >      subch_device_save(s, f);
> >      if (dev->indicators != NULL) {
> > @@ -1333,6 +1334,7 @@ static void virtio_ccw_save_config(DeviceState *d, QEMUFile *f)
> >          qemu_put_be32(f, 0);
> >          qemu_put_be64(f, 0UL);
> >      }
> > +    qemu_put_be16(f, vdev->config_vector);
> >      qemu_put_be64(f, dev->routes.adapter.ind_offset);
> >      qemu_put_byte(f, dev->thinint_isc);
> >  }
> > @@ -1341,6 +1343,7 @@ static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
> >  {
> >      VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
> >      SubchDev *s = dev->sch;
> > +    VirtIODevice *vdev = virtio_ccw_get_vdev(s);
> >      int len;
> > 
> >      s->driver_data = dev;
> > @@ -1366,6 +1369,7 @@ static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
> >          qemu_get_be64(f);
> >          dev->summary_indicator = NULL;
> >      }
> > +    qemu_get_be16s(f, &vdev->config_vector);
> >      dev->routes.adapter.ind_offset = qemu_get_be64(f);
> >      dev->thinint_isc = qemu_get_byte(f);
> >      if (s->thinint_active) {
> >