[dpdk-dev] [PATCH v5 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ not negotiated

Laszlo Ersek lersek at redhat.com
Wed Dec 13 12:23:32 CET 2017


On 12/13/17 11:24, Paolo Bonzini wrote:
> On 13/12/2017 11:11, Maxime Coquelin wrote:
>>> Hi Maxime,
>>>
>>> I think this series is wrong from the virtio spec's point of view.  If
>>> the driver requests VIRTIO_NET_F_MQ, that does not mean "the driver
>>> knows about multiqueue", it only means that "the driver wants to read
>>> max_virtqueue_pairs" from configuration space.
>>
>> Actually, my series fixes half of the problem, the case where driver
>> does not know about multiqueue.
>>
>> In this case, there is no point in the backend to wait for the
>> initialization of queues that does not exist.
>>
>> So I think my series is not enough, but not wrong.
> 
> You're right; what I meant by "wrong" is that it becomes unnecessary if
> you do VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET.  But since this requires a
> vhost-user update, doing both makes sense.

Based on this, plus reviewing patch #4 for:

+			vq = dev->virtqueue[--dev->nr_vring];
+			if (!vq)
+				continue;
+
+			dev->virtqueue[dev->nr_vring] = NULL;

Acked-by: Laszlo Ersek <lersek at redhat.com>

Thanks
Laszlo


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