Re: [Qemu-devel] [PATCH v8 01/20] virtio-serial: don't migrate the config space

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

On Fri, Jun 13, 2014 at 01:18:42PM +0200, Greg Kurz wrote:
> The device configuration is set at realize time and never changes. It
> should not be migrated as it is done today. For the sake of compatibility,
> let's just skip them at load time.
> 
> Signed-off-by: Alexander Graf <agraf@suse.de>
> [ added missing casts to uint16_t *,
>   added SoB and commit message,
>   Greg Kurz <gkurz@linux.vnet.ibm.com> ]
> Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>

This one is definitely a good thing to have, regardless.
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  hw/char/virtio-serial-bus.c |   16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
> index 2b647b6..ee1ba16 100644
> --- a/hw/char/virtio-serial-bus.c
> +++ b/hw/char/virtio-serial-bus.c
> @@ -670,6 +670,7 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
>      uint32_t max_nr_ports, nr_active_ports, ports_map;
>      unsigned int i;
>      int ret;
> +    uint32_t tmp;
>  
>      if (version_id > 3) {
>          return -EINVAL;
> @@ -685,17 +686,12 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
>          return 0;
>      }
>  
> -    /* The config space */
> -    qemu_get_be16s(f, &s->config.cols);
> -    qemu_get_be16s(f, &s->config.rows);
> -
> -    qemu_get_be32s(f, &max_nr_ports);
> -    tswap32s(&max_nr_ports);
> -    if (max_nr_ports > tswap32(s->config.max_nr_ports)) {
> -        /* Source could have had more ports than us. Fail migration. */
> -        return -EINVAL;
> -    }
> +    /* Unused */
> +    qemu_get_be16s(f, (uint16_t *) &tmp);
> +    qemu_get_be16s(f, (uint16_t *) &tmp);
> +    qemu_get_be32s(f, &tmp);
>  
> +    max_nr_ports = tswap32(s->config.max_nr_ports);
>      for (i = 0; i < (max_nr_ports + 31) / 32; i++) {
>          qemu_get_be32s(f, &ports_map);
>