From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH v5 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ not negotiated Date: Wed, 13 Dec 2017 11:24:13 +0100 Message-ID: <5fda0d3d-72e0-6506-29a7-c05e8c916858@redhat.com> References: <20171213085109.9891-1-maxime.coquelin@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit To: Maxime Coquelin , dev@dpdk.org, yliu@fridaylinux.org, tiwei.bie@intel.com, jianfeng.tan@intel.com, lprosek@redhat.com, lersek@redhat.com, "Michael S. Tsirkin" Return-path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 11D8914E8 for ; Wed, 13 Dec 2017 11:24:21 +0100 (CET) In-Reply-To: Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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