On 01/30/2017 08:06 PM, Greg Kurz wrote:
>> Currently, under certain circumstances vhost_init_is_le does just a part
>> of the initialization job, and depends on vhost_reset_is_le being called
>> too. For this reason vhost_vq_init_access used to call vhost_reset_is_le
>> when vq->private_data is NULL. This is not only counter intuitive, but
>> also real a problem because it breaks vhost_net. The bug was introduced to
>> vhost_net with commit 2751c9882b94 ("vhost: cross-endian support for
>> legacy devices"). The symptom is corruption of the vq's used.idx field
>> (virtio) after VHOST_NET_SET_BACKEND was issued as a part of the vhost
>> shutdown on a vq with pending descriptors.
>>
>> Let us make sure the outcome of vhost_init_is_le never depend on the state
>> it is actually supposed to initialize, and fix virtio_net by removing the
>> reset from vhost_vq_init_access.
>>
>> With the above, there is no reason for vhost_reset_is_le to do just half
>> of the job. Let us make vhost_reset_is_le reinitialize is_le.
>>
>> Signed-off-by: Halil Pasic <pasic@xxxxxxxxxxxxxxxxxx>
>> Reported-by: Michael A. Tebolt <miket@xxxxxxxxxx>
>> Reported-by: Dr. David Alan Gilbert <dgilbert@xxxxxxxxxx>
>> Fixes: commit 2751c9882b94 ("vhost: cross-endian support for legacy devices")
>> ---
> Reviewed-by: Greg Kurz <groug@xxxxxxxx>
>
Thanks!
We have some tests on s390x (that is BE) running, but I won't be able to
test the change with cross endian and legacy.
What do you think, should I/we RFT or are we fine without?
Regards,
Halil
