From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id E1BCC2C0A for ; Fri, 9 Sep 2016 07:50:18 +0200 (CEST) Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga101.jf.intel.com with ESMTP; 08 Sep 2016 22:50:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,304,1470726000"; d="scan'208";a="6711047" Received: from shwdeisgchi083.ccr.corp.intel.com (HELO [10.239.67.193]) ([10.239.67.193]) by orsmga004.jf.intel.com with ESMTP; 08 Sep 2016 22:50:17 -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> <20160906082011.GA23158@yliu-dev.sh.intel.com> <53e1d78c-e3b0-e16c-992d-e45ed1b31a4f@intel.com> <20160908121818.GO23158@yliu-dev.sh.intel.com> <11291eac-cbbe-7080-3d35-bdacb5341d89@intel.com> <20160909041949.GP23158@yliu-dev.sh.intel.com> Cc: dev@dpdk.org, zhihong.wang@intel.com, lining18@jd.com From: "Tan, Jianfeng" Message-ID: <1537a739-9805-cd51-cf0a-f32d608a97e0@intel.com> Date: Fri, 9 Sep 2016 13:50:16 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20160909041949.GP23158@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: Fri, 09 Sep 2016 05:50:19 -0000 On 9/9/2016 12:19 PM, Yuanhan Liu wrote: >> >> >> Never mind, above fix on the vhost side will not take effect on existing >> vpp-vhost implementations. >> >> Actually, I was talking about the DPDK vhost implementation :) >> >> >> This patch is talking about vpp's native vhost implementation, not dpdk-vhost, >> and not the way vpp uses dpdk-vhost. > Yes, I know. What I meant is there was a "workaround" in DPDK vhost > implementation, and since you bring this issue on the table again, > it's a chance to think about how can we fix it. > > A rough idea come to my mind is we could check all the per-vring message > at the begining of vhost_user_msg_handler() and allocate related vq when > necessary (when it's the first vring message we got). > > Yeah, I know it's a bit ugly, but it at least gets rid of that "not-that-true" > assumption. Sounds workable. So we'd define those vq-specific msgs, like: VHOST_USER_SET_VRING_NUM, VHOST_USER_SET_VRING_ADDR, VHOST_USER_SET_VRING_BASE, VHOST_USER_GET_VRING_BASE(?), VHOST_USER_SET_VRING_KICK, VHOST_USER_SET_VRING_CALL, VHOST_USER_SET_VRING_ENABLE, > >> Still not working. VPP needs SET_VRING_CALL to create vq firstly. >> >> Didn't get it. In the proposal, SET_FEATURES is sent before every other >> messages, thus it should not cause the issue you described in this patch. >> >> >> OK. Let me try to explain. We take three vhost implementations into >> consideration: dpdk-2.2-vhost, dpdk-master-vhost, vpp-native-vhost. >> >> If set_feature before set_vring_call, dpdk-2.2-vhost will fail: inside >> set_feature handler, assigning header length to VQs which will be created in >> set_vring_call handler. > Oh, right. That was an in-correct implementation. > >> So we need to keep set_vring_call firstly. >> Then set_feature needs to be sent >> before any other msgs, this is what vpp-native-vhost requires. In all, the >> sequence is like this: >> 1. set_vring_call, >> 2. set_feature, >> 3. other msgs >> >> >> Besides, haven't we already sent SET_VRING_CALL before other messages >> (well, execept the SET_FEATURES and SET_MEM_TABLE message)? >> >> >> Yes, set_vring_call is already in the first place, but we need to plugin >> set_feature between set_vring_call and other msgs. Previously, set_vring_call >> and other msgs are together. > Okay. Another thing I noticed is that virtio-user lacks some feature > negotiations, like GET_FEATURES and GET_PROTOCOL_FEATURES. I think you > might need add them back somewhen? GET_FEATURES has been done in virtio_user_dev_init(). GET_PROTOCOL_FEATURES is not supported yet. I see those features in PROTOCOL_FEATURES is for live migration (right?). Assuming that, anyone using container/process now enables live migration so far? I don't think so. Thanks, Jianfeng > > --yliu