From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yuanhan Liu Subject: Re: [PATCH v2] net/virtio-user: fix cannot get initialized Date: Fri, 14 Apr 2017 13:37:38 +0800 Message-ID: <20170414053738.GL7333@yliu-dev.sh.intel.com> References: <1491551860-15005-1-git-send-email-jianfeng.tan@intel.com> <1492078287-138040-1-git-send-email-jianfeng.tan@intel.com> <20170414042423.GI7333@yliu-dev.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "dev@dpdk.org" , "maxime.coquelin@redhat.com" To: "Tan, Jianfeng" Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id 12A34316B for ; Fri, 14 Apr 2017 07:40:34 +0200 (CEST) Content-Disposition: inline In-Reply-To: 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 Fri, Apr 14, 2017 at 04:35:57AM +0000, Tan, Jianfeng wrote: > > > > -----Original Message----- > > From: Yuanhan Liu [mailto:yuanhan.liu@linux.intel.com] > > Sent: Friday, April 14, 2017 12:24 PM > > To: Tan, Jianfeng > > Cc: dev@dpdk.org; maxime.coquelin@redhat.com > > Subject: Re: [PATCH v2] net/virtio-user: fix cannot get initialized > > > > On Thu, Apr 13, 2017 at 10:11:27AM +0000, Jianfeng Tan wrote: > > > The feature negotiation in virtio-user is proven to be broken, > > > which results in device initialization failure. > > > > > > Originally, we get features from vhost backend, and remove those > > > that are not supported. But when new feature is added, for example, > > > VIRTIO_NET_F_MTU, we fail to remove this new feature. Then, this > > > new feature will be negotiated, as both frontend and backend claim > > > to support this feature. > > > > > > To fix it, we add a macro to record supported featues, as a filter > > > to remove newly added features. > > > > Yes, this is much better! You now don't have to worry that virtio-user > > will be broken every time we add a new feature. > > > > Applied to dpdk-next-virtio, with the title changed to "fix feature > > negotitation". > > > > Thanks. By the way, it's better backporting it to stable branches, however, I forget to CC stable@dpdk.org. As long as we don't backport new features to a stable release, there should be no problem. Besides, the virtio-user features supported in this patch may not match those supported by a stable release (say 16.11 LTS). For example, F_STATUS is just added in this feature. Thus, I don't think it's a good candidate for a stable release (though a backport could fix it). --yliu