From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by dpdk.org (Postfix) with ESMTP id 4AA195901 for ; Tue, 6 Sep 2016 09:54:34 +0200 (CEST) Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP; 06 Sep 2016 00:54:33 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,291,1470726000"; d="scan'208";a="1051913523" Received: from shwdeisgchi083.ccr.corp.intel.com (HELO [10.239.67.193]) ([10.239.67.193]) by fmsmga002.fm.intel.com with ESMTP; 06 Sep 2016 00:54:32 -0700 To: Yuanhan Liu References: <1470397003-5782-1-git-send-email-jianfeng.tan@intel.com> <1470397003-5782-3-git-send-email-jianfeng.tan@intel.com> <20160906064246.GQ30752@yliu-dev.sh.intel.com> Cc: dev@dpdk.org, zhihong.wang@intel.com, lining18@jd.com From: "Tan, Jianfeng" Message-ID: Date: Tue, 6 Sep 2016 15:54:30 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160906064246.GQ30752@yliu-dev.sh.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH 2/3] net/virtio_user: fix wrong sequence of messages X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Sep 2016 07:54:34 -0000 Hi Yuanhan, On 9/6/2016 2:42 PM, Yuanhan Liu wrote: > On Fri, Aug 05, 2016 at 11:36:42AM +0000, Jianfeng Tan wrote: >> When virtio_user is used with VPP's native vhost user, it cannot >> send/receive any packets. >> >> The root cause is that vpp-vhost-user translates the message >> VHOST_USER_SET_FEATURES as puting this device into init state, >> aka, zero all related structures. However, previous code >> puts this message at last in the whole initialization process, >> which leads to all previous information are zeroed. >> >> To fix this issue, we rearrange the sequence of those messages. >> - step 0, send VHOST_USER_SET_VRING_CALL so that vhost allocates >> virtqueue structures; > Yes, it is. However, it's not that right to do that (you see there is > a FIXME in vhost_user_set_vring_call()). I suppose you are specifying vhost_set_vring_call(). > > That means it need be fixed: we should not rely on fact that it's the > first per-vring message we will get in the current QEMU implementation > as the truth. > > That also means, naming a function like virtio_user_create_queue() based > on above behaviour is wrong. It's actually a good catch. After a light thought, I think in DPDK vhost, we may need to create those virtqueues once unix socket gets connected, just like in vhost-net, virtqueues are created on char file open. Right? > >> - step 1, send VHOST_USER_SET_FEATURES to confirm the features; >> - step 2, send VHOST_USER_SET_MEM_TABLE to share mem regions; >> - step 3, send VHOST_USER_SET_VRING_NUM, VHOST_USER_SET_VRING_BASE, >> VHOST_USER_SET_VRING_ADDR, VHOST_USER_SET_VRING_KICK for each >> queue; >> - ... >> >> Fixes: 37a7eb2ae816 ("net/virtio-user: add device emulation layer") >> >> Reported-by: Zhihong Wang >> Signed-off-by: Jianfeng Tan >> --- >> drivers/net/virtio/virtio_user/virtio_user_dev.c | 120 ++++++++++++++--------- >> 1 file changed, 72 insertions(+), 48 deletions(-) > That's too much of code for a bug fix. I'm wondering how about just > moving VHOST_USER_GET_PROTOCOL_FEATURES ahead, to the begining of > virtio_user_start_device()? It should fix this issue. Why does VHOST_USER_GET_PROTOCOL_FEATURES care? Do you mean shifting VHOST_USER_SET_FEATURES earlier? Thanks, Jianfeng > > --yliu