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Date: Sun, 28 Apr 2013 11:31:39 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20130428083138.GC7106@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/3] s390-virtio-bus: sync config only when
 config_len is not zero
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To: Jason Wang <jasowang@redhat.com>
Cc: aliguori@us.ibm.com, Richard Henderson <rth@twiddle.net>, pmatouse@redhat.com, qemu-devel@nongnu.org, Alexander Graf <agraf@suse.de>

On Fri, Apr 26, 2013 at 04:34:04PM +0800, Jason Wang wrote:
> virtio-rng-s390 has zero config length, so no need to sync its config otherwise
> qemu will crash since vdev->config is NULL.
> 
> Cc: Alexander Graf <agraf@suse.de>
> Cc: Richard Henderson <rth@twiddle.net>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Actully, it validates get_config so what's the problem here?

> ---
>  hw/s390x/s390-virtio-bus.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/s390x/s390-virtio-bus.c b/hw/s390x/s390-virtio-bus.c
> index dabbc2e..0f83516 100644
> --- a/hw/s390x/s390-virtio-bus.c
> +++ b/hw/s390x/s390-virtio-bus.c
> @@ -350,6 +350,10 @@ void s390_virtio_device_sync(VirtIOS390Device *dev)
>      dev->feat_offs = cur_offs + dev->feat_len;
>      cur_offs += dev->feat_len * 2;
>  
> +    if (!dev->vdev->config_len) {
> +        return;
> +    }
> +
>      /* Sync config space */
>      if (dev->vdev->get_config) {
>          dev->vdev->get_config(dev->vdev, dev->vdev->config);
> -- 
> 1.7.1