From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <olivier.matz@6wind.com> Received: from mail.droids-corp.org (zoll.droids-corp.org [94.23.50.67]) by dpdk.org (Postfix) with ESMTP id C35F52B9A for <dev@dpdk.org>; Tue, 19 Jul 2016 15:11:34 +0200 (CEST) Received: from alille-653-1-293-182.w90-1.abo.wanadoo.fr ([90.1.53.182] helo=[192.168.1.13]) by mail.droids-corp.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from <olivier.matz@6wind.com>) id 1bPUqc-0004i4-Gm; Tue, 19 Jul 2016 15:14:09 +0200 To: "Tan, Jianfeng" <jianfeng.tan@intel.com>, "dev@dpdk.org" <dev@dpdk.org>, "Xie, Huawei" <huawei.xie@intel.com>, "yuanhan.liu@linux.intel.com" <yuanhan.liu@linux.intel.com> References: <1468931519-7381-1-git-send-email-olivier.matz@6wind.com> <ED26CBA2FAD1BF48A8719AEF02201E361062162F@SHSMSX103.ccr.corp.intel.com> From: Olivier Matz <olivier.matz@6wind.com> Message-ID: <d9d58218-1b2a-1991-898d-ddda26f641f0@6wind.com> Date: Tue, 19 Jul 2016 15:11:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.1.0 MIME-Version: 1.0 In-Reply-To: <ED26CBA2FAD1BF48A8719AEF02201E361062162F@SHSMSX103.ccr.corp.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH] virtio: fix packet corruption X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Tue, 19 Jul 2016 13:11:34 -0000 Hi Jianfeng, On 07/19/2016 03:03 PM, Tan, Jianfeng wrote: > Hi Oliver, > >> -----Original Message----- >> From: Olivier Matz [mailto:olivier.matz@6wind.com] >> Sent: Tuesday, July 19, 2016 8:32 PM >> To: dev@dpdk.org; Tan, Jianfeng; Xie, Huawei; yuanhan.liu@linux.intel.com >> Subject: [PATCH] virtio: fix packet corruption >> >> The support of virtio-user changed the way the mbuf dma address is >> retrieved, using a physical address in case of virtio-pci and a virtual >> address in case of virtio-user. >> >> This change introduced some possible memory corruption in packets, >> replacing: >> m->buf_physaddr + RTE_PKTMBUF_HEADROOM >> by: >> m->buf_physaddr + m->data_off (through a macro) >> >> This patch fixes this issue, restoring the original behavior. > > Could you be more specific on why we cannot use m->data_off here? There is no guarantee that m->data_off == RTE_PKTMBUF_HEADROOM here as virtqueue_enqueue_recv_refill() is called on a mbuf that is just allocated with rte_mbuf_raw_alloc(). An alternative would be to set data_off to RTE_PKTMBUF_HEADROOM, but as it's a fix and we are close to the release, I prefered to restore the initial behavior. I did not include the test plan because it relies on patch that are not submitted yet (offload patches, they will be upstreamed very soon). It is a quite simple test case with testpmd. Regards, Olivier