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

[Christian Borntraeger <borntraeger@de.ibm.com>]

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.

> ---
>  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) {
>