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Date: Sat, 27 Apr 2013 13:14:25 +0800
From: Jason Wang <jasowang@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: Alexander Graf <agraf@suse.de>
Cc: aliguori@us.ibm.com, Richard Henderson <rth@twiddle.net>, pmatouse@redhat.com, qemu-devel@nongnu.org, mst@redhat.com

On 04/27/2013 01:07 AM, Alexander Graf wrote:
> On 26.04.2013, at 10:34, 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.
> Why is it NULL?

As far as I see, virtio-rng's config_len is zero, so in its vdev->config
were set to NULL in virtio_init().
>
>
> Alex
>
>> Cc: Alexander Graf <agraf@suse.de>
>> Cc: Richard Henderson <rth@twiddle.net>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>> 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
>>
>>