From mboxrd@z Thu Jan 1 00:00:00 1970 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) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 60F2883F47; Wed, 13 Dec 2017 10:24:21 +0000 (UTC) Received: from [10.36.117.15] (ovpn-117-15.ams2.redhat.com [10.36.117.15]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F338C5D9CC; Wed, 13 Dec 2017 10:24:14 +0000 (UTC) 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" References: <20171213085109.9891-1-maxime.coquelin@redhat.com> From: Paolo Bonzini Message-ID: <5fda0d3d-72e0-6506-29a7-c05e8c916858@redhat.com> Date: Wed, 13 Dec 2017 11:24:13 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 13 Dec 2017 10:24:21 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH v5 0/4] Vhost: fix mq=on but VIRTIO_NET_F_MQ not negotiated X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Dec 2017 10:24:22 -0000 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