From patchwork Mon Sep 6 03:32:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ruifeng Wang X-Patchwork-Id: 98020 X-Patchwork-Delegate: qi.z.zhang@intel.com Return-Path: X-Original-To: patchwork@inbox.dpdk.org Delivered-To: patchwork@inbox.dpdk.org Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 2B211A0C4D; Mon, 6 Sep 2021 05:32:25 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 16498410F0; Mon, 6 Sep 2021 05:32:25 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mails.dpdk.org (Postfix) with ESMTP id 38654410ED; Mon, 6 Sep 2021 05:32:24 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B472BD6E; Sun, 5 Sep 2021 20:32:23 -0700 (PDT) Received: from net-arm-n1amp-02.shanghai.arm.com (net-arm-n1amp-02.shanghai.arm.com [10.169.210.110]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5BD783F5A1; Sun, 5 Sep 2021 20:32:20 -0700 (PDT) From: Ruifeng Wang To: dev@dpdk.org Cc: beilei.xing@intel.com, qi.z.zhang@intel.com, bruce.richardson@intel.com, jerinj@marvell.com, hemant.agrawal@nxp.com, drc@linux.vnet.ibm.com, honnappa.nagarahalli@arm.com, stable@dpdk.org, nd@arm.com, Ruifeng Wang Date: Mon, 6 Sep 2021 11:32:00 +0800 Message-Id: <20210906033201.1789796-2-ruifeng.wang@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210906033201.1789796-1-ruifeng.wang@arm.com> References: <20210906033201.1789796-1-ruifeng.wang@arm.com> MIME-Version: 1.0 Subject: [dpdk-dev] [PATCH 1/2] net/i40e: fix risk in Rx descriptor read in NEON vector path X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Rx descriptor is 16B/32B in size and consists of multiple words. The word that includes DD field should be read first. Read result with DD bit set indicates the rest part in a descriptor is valid. In NEON vector PMD, vector load loads two contiguous 8B of descriptor data into vector register. Given vector load ensures no 16B atomicity, read of the word that includes DD field could be reordered after read of other words. In this case, some words could be invalid data. Read barrier is added after read of qword1 that includes DD field. And qword0 is reloaded to update vector register. This ensures what fetched is correct descriptor data. Fixes: ae0eb310f253 ("net/i40e: implement vector PMD for ARM") Cc: stable@dpdk.org Signed-off-by: Ruifeng Wang Reviewed-by: Honnappa Nagarahalli --- drivers/net/i40e/i40e_rxtx_vec_neon.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/net/i40e/i40e_rxtx_vec_neon.c b/drivers/net/i40e/i40e_rxtx_vec_neon.c index b2683fda60..71191c7cc8 100644 --- a/drivers/net/i40e/i40e_rxtx_vec_neon.c +++ b/drivers/net/i40e/i40e_rxtx_vec_neon.c @@ -286,6 +286,14 @@ _recv_raw_pkts_vec(struct i40e_rx_queue *__rte_restrict rxq, descs[1] = vld1q_u64((uint64_t *)(rxdp + 1)); descs[0] = vld1q_u64((uint64_t *)(rxdp)); + /* Use acquire fence to order loads of descriptor qwords */ + rte_atomic_thread_fence(__ATOMIC_ACQUIRE); + /* A.2 reload qword0 to make it ordered after qword1 load */ + descs[3] = vld1q_lane_u64((uint64_t *)(rxdp + 3), descs[3], 0); + descs[2] = vld1q_lane_u64((uint64_t *)(rxdp + 2), descs[2], 0); + descs[1] = vld1q_lane_u64((uint64_t *)(rxdp + 1), descs[1], 0); + descs[0] = vld1q_lane_u64((uint64_t *)(rxdp), descs[0], 0); + /* B.1 load 4 mbuf point */ mbp1 = vld1q_u64((uint64_t *)&sw_ring[pos]); mbp2 = vld1q_u64((uint64_t *)&sw_ring[pos + 2]);