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 61DDB1B800 for ; Wed, 31 Jan 2018 19:07:56 +0100 (CET) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A65E976547; Wed, 31 Jan 2018 18:07:55 +0000 (UTC) Received: from [10.36.112.31] (ovpn-112-31.ams2.redhat.com [10.36.112.31]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 577E160BE3; Wed, 31 Jan 2018 18:07:52 +0000 (UTC) To: Stefan Hajnoczi , dev@dpdk.org Cc: Yuanhan Liu References: <20180131174651.6386-1-stefanha@redhat.com> <20180131174651.6386-3-stefanha@redhat.com> From: Maxime Coquelin Message-ID: <0032747e-c981-ebd8-357b-b24122c89993@redhat.com> Date: Wed, 31 Jan 2018 19:07:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <20180131174651.6386-3-stefanha@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 31 Jan 2018 18:07:55 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH 2/2] vhost: only drop vqs with built-in virtio_net.c driver 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, 31 Jan 2018 18:07:56 -0000 Hi Stefan, On 01/31/2018 06:46 PM, Stefan Hajnoczi wrote: > Commit e29109323595beb3884da58126ebb3b878cb66f5 ("vhost: destroy unused > virtqueues when multiqueue not negotiated") broke vhost-scsi by removing > virtqueues when the virtio-net-specific VIRTIO_NET_F_MQ feature bit is > missing. > > The vhost_user.c code shouldn't assume all devices are vhost net device > backends. Use the new VIRTIO_DEV_BUILTIN_VIRTIO_NET flag to check > whether virtio_net.c is being used. > > This fixes examples/vhost_scsi. > > Cc: Maxime Coquelin > Signed-off-by: Stefan Hajnoczi > --- > lib/librte_vhost/vhost_user.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c > index 1dd1a61b6..65ee33919 100644 > --- a/lib/librte_vhost/vhost_user.c > +++ b/lib/librte_vhost/vhost_user.c > @@ -187,7 +187,8 @@ vhost_user_set_features(struct virtio_net *dev, uint64_t features) > (dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? "on" : "off", > (dev->features & (1ULL << VIRTIO_F_VERSION_1)) ? "on" : "off"); > > - if (!(dev->features & (1ULL << VIRTIO_NET_F_MQ))) { > + if ((dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET) && > + !(dev->features & (1ULL << VIRTIO_NET_F_MQ))) { If we had an external net backend using the library, we would also need to remove extra queues if it advertised VIRTIO_NET_F_MQ, but the feature isn't negotiated. In this case, the fix I suggested yesterday would work: if ((vhost_features & (1ULL << VIRTIO_NET_F_MQ)) && !(dev->features & (1ULL << VIRTIO_NET_F_MQ)) { ... } For any backend that does not advertise the feature, no queues will be destroyed. Thanks, Maxime > /* > * Remove all but first queue pair if MQ hasn't been > * negotiated. This is safe because the device is not >