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

Paolo Bonzini pbonzini at redhat.com
Wed Dec 13 11:24:13 CET 2017


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.

Thanks!

Paolo


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