From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1BC6C433ED for ; Sat, 8 May 2021 00:31:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB53D6113E for ; Sat, 8 May 2021 00:31:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230468AbhEHAcd (ORCPT ); Fri, 7 May 2021 20:32:33 -0400 Received: from mail-dm6nam12on2083.outbound.protection.outlook.com ([40.107.243.83]:57440 "EHLO NAM12-DM6-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S231396AbhEHAbR (ORCPT ); Fri, 7 May 2021 20:31:17 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Wb4Essvv5JYEN6c9lLQca2AgVOdzwstJ4lzkDqdk9Rsyi1dRtMIAQ8+IhpgLxVtiSfyreOzyNzTlXJQ2/SjPhK8og4hBA7xgnL0u2xlRaW+Pz5Upoj4o53y3THeoYIve3KhOl5s82uomNfIfKqCOSK2/7iP2hw7TZ1Uy7rmG3uhe1caCN/pYuVGRcnXYwK4l+aZ3qqtk5gymkMpB9ZumeVFKn60eo8BEy1mp303BHf4sVyuciQo1Xddc61yGtkUqon1tlHKgLEYi1VV44z/Ur0b9XA+M3LHfjanWQ8XKAssRJIcbLvB0LMsknjyiL3Lb2oTEXsm6Xn0b2jzPiPpZ1A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=dBzeHmEa0rACwzkbn1Pjo4FgmihouGO5M9XYT+VJLlg=; b=IsyGntmDar7e9Pd+G3Yx1WTfWexzToiHjVesUqEENWicpMza66HGP01YLBM2b2D/5zIMT36n/iQ+bD0zPaEaNFMUaNZ6Y4i9C7Q3fwA5Qnt+aCOUbist4ZNhDJMSv+sM+Wr94JZTqxDt5uVJbZkKwXuBjFVyRhQjIummy3SD1gqigfDpSiMWViNKwkeDlH/DnhLv8QIlsB3iuALP4WJ1qQgMGhEyoDJ6RaKqlAXs/ne907OHovvFCuQK5g9eqIIyEbPNhpGilq0vYRYn7onEgl0mhE0QH7vTIX0Sezqm/r4xmukAu78kSYdc6qTxj4GpF4eFZFAmxOk1RAwolxzrOQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.112.32) smtp.rcpttodomain=vger.kernel.org smtp.mailfrom=nvidia.com; dmarc=pass (p=none sp=none pct=100) action=none header.from=nvidia.com; dkim=none (message not signed); arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=dBzeHmEa0rACwzkbn1Pjo4FgmihouGO5M9XYT+VJLlg=; b=BcSZl3UYk/K6kvquAfCygGQWmW8ZoIgcwkcVZqfreOCfYPcsjYcq1woz4OoxC1SEV78TR6FPtHez5Bvh7ATVJAhZcLhuSKC4Ple6+zKEwtDQ4A1yAvnvwl/mQTp74gDz+soh8aaGrBW1VeS0KVGsk3NP7YkOjnvB/cKKmjU4uV+RDIusbKqld+A7FfOUNE3f2/pogXLaceFLLjuYhfKYZt2VNw0g0umcfj36zmOpEtcnm0WMmGMEGQjsDnt6eYR+TPgUR0Hep8SJ6d0IZ0C+Mo55G5czUx/VbN4R2qot84CZ08cVpk+taUA48ErlApMMlNiIYJ/9e/tovk9tIRb2bg== Received: from BN8PR15CA0044.namprd15.prod.outlook.com (2603:10b6:408:80::21) by MN2PR12MB3021.namprd12.prod.outlook.com (2603:10b6:208:c2::30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4108.27; Sat, 8 May 2021 00:30:15 +0000 Received: from BN8NAM11FT030.eop-nam11.prod.protection.outlook.com (2603:10b6:408:80:cafe::f5) by BN8PR15CA0044.outlook.office365.com (2603:10b6:408:80::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4108.25 via Frontend Transport; Sat, 8 May 2021 00:30:15 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 216.228.112.32) smtp.mailfrom=nvidia.com; vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.112.32 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.112.32; helo=mail.nvidia.com; Received: from mail.nvidia.com (216.228.112.32) by BN8NAM11FT030.mail.protection.outlook.com (10.13.177.146) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.4108.25 via Frontend Transport; Sat, 8 May 2021 00:30:15 +0000 Received: from HQMAIL107.nvidia.com (172.20.187.13) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 7 May 2021 17:30:15 -0700 Received: from vdi.nvidia.com (172.20.145.6) by mail.nvidia.com (172.20.187.13) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Sat, 8 May 2021 00:30:14 +0000 From: Liming Sun To: Andy Shevchenko , Darren Hart , Vadim Pasternak CC: Liming Sun , , Subject: [PATCH v2] platform/mellanox: mlxbf-tmfifo: Fix a memory barrier issue Date: Fri, 7 May 2021 20:30:12 -0400 Message-ID: <1620433812-17911-1-git-send-email-limings@nvidia.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <177d12443460bc613aa495fbdbabbbeef43ba7ff.1620400475.git.limings@nvidia.com> References: <177d12443460bc613aa495fbdbabbbeef43ba7ff.1620400475.git.limings@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: e623302f-fb39-4bfa-7f32-08d911b8737a X-MS-TrafficTypeDiagnostic: MN2PR12MB3021: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:556; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:216.228.112.32;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:schybrid01.nvidia.com;CAT:NONE;SFS:(4636009)(39860400002)(396003)(376002)(136003)(346002)(46966006)(36840700001)(70206006)(8676002)(70586007)(26005)(8936002)(4326008)(478600001)(54906003)(186003)(82740400003)(5660300002)(2616005)(47076005)(336012)(110136005)(426003)(7636003)(316002)(86362001)(36756003)(356005)(2906002)(36860700001)(83380400001)(7696005)(82310400003);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 May 2021 00:30:15.6889 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e623302f-fb39-4bfa-7f32-08d911b8737a X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.112.32];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT030.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB3021 Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org The virtio framework uses wmb() when updating avail->idx. It guarantees the write order, but not necessarily loading order for the code accessing the memory. This commit adds a load barrier after reading the avail->idx to make sure all the data in the descriptor is visible. It also adds a barrier when returning the packet to virtio framework to make sure read/writes are visible to the virtio code. Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc") Signed-off-by: Liming Sun --- v1->v2: Updates for Vadim's comments: - Add the 'Fixes' field in the commit message. v1: Initial version --- drivers/platform/mellanox/mlxbf-tmfifo.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c index bbc4e71..38800e8 100644 --- a/drivers/platform/mellanox/mlxbf-tmfifo.c +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c @@ -294,6 +294,9 @@ static irqreturn_t mlxbf_tmfifo_irq_handler(int irq, void *arg) if (vring->next_avail == virtio16_to_cpu(vdev, vr->avail->idx)) return NULL; + /* Make sure 'avail->idx' is visible already. */ + virtio_rmb(false); + idx = vring->next_avail % vr->num; head = virtio16_to_cpu(vdev, vr->avail->ring[idx]); if (WARN_ON(head >= vr->num)) @@ -322,7 +325,7 @@ static void mlxbf_tmfifo_release_desc(struct mlxbf_tmfifo_vring *vring, * done or not. Add a memory barrier here to make sure the update above * completes before updating the idx. */ - mb(); + virtio_mb(false); vr->used->idx = cpu_to_virtio16(vdev, vr_idx + 1); } @@ -733,6 +736,12 @@ static bool mlxbf_tmfifo_rxtx_one_desc(struct mlxbf_tmfifo_vring *vring, desc = NULL; fifo->vring[is_rx] = NULL; + /* + * Make sure the load/store are in order before + * returning back to virtio. + */ + virtio_mb(false); + /* Notify upper layer that packet is done. */ spin_lock_irqsave(&fifo->spin_lock[is_rx], flags); vring_interrupt(0, vring->vq); -- 1.8.3.1