Re: [Qemu-devel] [PULL 09/15] virtio-9p: migrate virtio subsections

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

On Fri, Oct 02, 2015 at 04:45:36PM +0300, Michael S. Tsirkin wrote:
> From: Greg Kurz <gkurz@linux.vnet.ibm.com>
> 
> In a cross-endian setup, the virtio-9p device has state in @device_endian. It
> must be migrated. This patch just adds the minimal support to live migrate
> generic virtio subsections where @device_endian is handled.
> 
> Please note that this is unrelated to the fact that we block migration when
> the 9p share is mounted in the guest. It fixes the case where we want to
> migrate an unactive 9p device (not mounted in the guest) to a QEMU with
> different endianness: the migration currently succeeds but leaves the device
> in an inconsistent state that causes mount to hang until we reboot the guest.
> 
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

I rebased and dropped this at Greg's request.

> ---
>  hw/9pfs/virtio-9p-device.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index 93a407c..e3abcfa 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -43,6 +43,16 @@ static void virtio_9p_get_config(VirtIODevice *vdev, uint8_t *config)
>      g_free(cfg);
>  }
>  
> +static void virtio_9p_save(QEMUFile *f, void *opaque)
> +{
> +    virtio_save(VIRTIO_DEVICE(opaque), f);
> +}
> +
> +static int virtio_9p_load(QEMUFile *f, void *opaque, int version_id)
> +{
> +    return virtio_load(VIRTIO_DEVICE(opaque), f, version_id);
> +}
> +
>  static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
>  {
>      VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> @@ -130,6 +140,7 @@ static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
>      }
>      v9fs_path_free(&path);
>  
> +    register_savevm(dev, "virtio-9p", -1, 1, virtio_9p_save, virtio_9p_load, s);
>      return;
>  out:
>      g_free(s->ctx.fs_root);
> -- 
> MST
>