From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id C78DBDE0; Mon, 5 Sep 2016 07:28:57 +0200 (CEST) Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP; 04 Sep 2016 22:28:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,285,1470726000"; d="scan'208";a="4762020" Received: from yliu-dev.sh.intel.com (HELO yliu-dev) ([10.239.67.162]) by orsmga005.jf.intel.com with ESMTP; 04 Sep 2016 22:28:54 -0700 Date: Mon, 5 Sep 2016 13:40:51 +0800 From: Yuanhan Liu To: "Wang, Zhihong" Cc: Yuanhan Liu , "dev@dpdk.org" , "maxime.coquelin@redhat.com" , "thomas.monjalon@6wind.com" , "stable@dpdk.org" Message-ID: <20160905054051.GQ7328@yliu-dev.sh.intel.com> References: <1471319402-112998-1-git-send-email-zhihong.wang@intel.com> <1472528164-54296-1-git-send-email-zhihong.wang@intel.com> <1472528164-54296-2-git-send-email-zhihong.wang@intel.com> <20160905052446.GP7328@yliu-dev.sh.intel.com> <8F6C2BD409508844A0EFC19955BE09414E70B93E@SHSMSX103.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8F6C2BD409508844A0EFC19955BE09414E70B93E@SHSMSX103.ccr.corp.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Subject: Re: [dpdk-dev] [dpdk-stable] [PATCH v4 1/6] vhost: fix windows vm hang 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: Mon, 05 Sep 2016 05:28:58 -0000 On Mon, Sep 05, 2016 at 05:25:31AM +0000, Wang, Zhihong wrote: > > > > -----Original Message----- > > From: Yuanhan Liu [mailto:yuanhan.liu@linux.intel.com] > > Sent: Monday, September 5, 2016 1:25 PM > > To: Wang, Zhihong > > Cc: dev@dpdk.org; maxime.coquelin@redhat.com; > > yuanhan.liu@linux.intel.com; thomas.monjalon@6wind.com; > > stable@dpdk.org > > Subject: Re: [dpdk-stable] [PATCH v4 1/6] vhost: fix windows vm hang > > > > On Mon, Aug 29, 2016 at 11:35:59PM -0400, Zhihong Wang wrote: > > > This patch fixes a Windows VM compatibility issue in DPDK 16.07 vhost > > code, > > > which causes the guest to hang once any packets are enqueued when > > mrg_rxbuf > > > is turned on. > > > > This commit log lacks two important pieces: why does the hang happen and > > how does your patch fix it. > > Okay, I'll add it in v5. > > > > > > How to test? > > > > > > 1. Start testpmd in the host with a vhost port. > > > > > > 2. Start a Windows VM image with qemu and connect to the vhost port. > > > > > > 3. Start io forwarding with tx_first in host testpmd. > > > > > > For 16.07 code, the Windows VM will hang once any packets are enqueued. > > > > > > Cc: > > > Signed-off-by: Zhihong Wang > > > --- > > > lib/librte_vhost/vhost_rxtx.c | 17 ++++++++++++----- > > > 1 file changed, 12 insertions(+), 5 deletions(-) > > > > > > diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c > > > index 08a73fd..5806f99 100644 > > > --- a/lib/librte_vhost/vhost_rxtx.c > > > +++ b/lib/librte_vhost/vhost_rxtx.c > > > @@ -384,6 +384,8 @@ copy_mbuf_to_desc_mergeable(struct virtio_net > > *dev, struct vhost_virtqueue *vq, > > > uint16_t start_idx = vq->last_used_idx; > > > uint16_t cur_idx = start_idx; > > > uint64_t desc_addr; > > > + uint32_t desc_chain_head; > > > + uint32_t desc_chain_len; > > > > What's the point of introducing "desc_chain_len"? It has the same value > > of desc_offset. > > No it's not, desc_offset is the offset of the current desc only. > That's where the old code goes wrong. Oh, right. --yliu