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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D379BD19510 for ; Mon, 26 Jan 2026 18:41:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:CC:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/K/o3pEI17vVdEoS4x3GNfBAh3K1FMxWm9mjebWqIVE=; b=KRw4BaJR5rWUrMbUmpwC3sDeOI TmK6tzfjo5+7NKo5fup/QKp/owhyWoc/sL8Xknv6O1q8QewpaEqtaU876HTlw2V32JaqlI1CMrNCu UA5VCTdbMM2GoLdFyGFBjlF67o0WKJhj7Di6T9dDVmOKcARMhYenojceW2nHsBAxMMyn/H2UACOmY rbJAdo5Y+Y5RGPA/6yLc+IWhnkRnIzpUgoYG6jybH8UyyIjDIYxUp0Z98KgBjS7A7HnHw5TZvtlGV 9qi8w6kPY3RgfeIopc3qQXTy78LwBYdTc18OsFzchaIz6WOpMiPXtV5ZUqEkJZwMEDXztu47H+Jpp uZTuipAQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkRWQ-0000000D60Q-28Yh; Mon, 26 Jan 2026 18:41:10 +0000 Received: from mail-westusazon11012023.outbound.protection.outlook.com ([52.101.43.23] helo=SJ2PR03CU001.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vkRWO-0000000D604-0z8X for linux-arm-kernel@lists.infradead.org; Mon, 26 Jan 2026 18:41:09 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=fv17PY9KeZgXFRKw9OaYlZZvay2yf7uxYcb7YgXeOHkrNwPEs3wWuCuAWu6XjusWOFV3Rpo8glO70iDvdAXlINi88yXtF/SJXVnGXftIvuugsx1tgP/7Tfutnkb8PqqhqlRI+E/BVmhP1EdmhEtgccavpf6GMiS+EVKvNXmN5tRF5xCC0LENSD9zUR5VHszXXCjPuhttr0QXOmLEwoeDoQWe42P9kxYsEmJJMCSTkMo2kkKxMpt3Xf/DpBuEBvhhbpr6XgM4ICsce3SfhPP0Y6MpEF4lvRgIS1DPmLtIXlzKRb+TW0VakDPv1U+DLCkUgX/YiGjjdwL5IifflAoKbw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=/K/o3pEI17vVdEoS4x3GNfBAh3K1FMxWm9mjebWqIVE=; b=jF6D7OUiHncJLjU/d7bSUN9CqmSCchcd8ZeTD4nisMKiiaKrGt2V6LayeVdkkgVFbkrJPAVdJE2IK6UnrX1adEh25N4VsdYErI8kADrU/Tda3ieSXC82+cOZPqRpOp01cssAxQ5tpEsyb8FwAvTmDu8+dBkhf5DuF5tAn4Lxfrhfal4vh/E20CdDfPks269zqnKMEooPJoGj5QVYgUqci+tcb4lJeAA3onhFF7MUFB9lkkgVunUtdOfKj2ClH+V9r38zZvUt/KIkUn98YuxpQF+yHnwHyGRauUp6c/SOUzRHjx6cJsEVOPtPLj8PKCudWJCX5rR6LvgyufMxUN2VPg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.117.160) smtp.rcpttodomain=kernel.org smtp.mailfrom=nvidia.com; dmarc=pass (p=reject sp=reject pct=100) action=none header.from=nvidia.com; dkim=none (message not signed); arc=none (0) 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=/K/o3pEI17vVdEoS4x3GNfBAh3K1FMxWm9mjebWqIVE=; b=sVtgFUwLMyQrYoBvdW0p4sbBvZJadNLVeWO2BQOJADO+SJRVmt7WL7ISlBIkSo6zY4OFHz+rQX7uv7c8QZaNeBu3u3vb8OMQWDRni96P+qm4g+wtsrBaS2tiWAKs2NhCKvxDn9QBSZwpvfdrcMnJxxs42EqNsA9n12P6dPCe12JvyjJtqghunB+NADFgPmpjGRU+2xNpj0VC+1LOLGMsIms/ZnAKYujJ4cW8XgTtkIqamgQpktGdaBaEfScbFACMp2i9bVQaOYRSUeKi5lcuyBPb3GSNVbxf4/2M6SwmWf3GxPTZzY12wSbeGGIBEQLT48mVEN9RZP6DiEVNCNENWA== Received: from BN9P220CA0006.NAMP220.PROD.OUTLOOK.COM (2603:10b6:408:13e::11) by MN0PR12MB6318.namprd12.prod.outlook.com (2603:10b6:208:3c1::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9542.15; Mon, 26 Jan 2026 18:41:01 +0000 Received: from BN1PEPF00004685.namprd03.prod.outlook.com (2603:10b6:408:13e:cafe::91) by BN9P220CA0006.outlook.office365.com (2603:10b6:408:13e::11) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9542.16 via Frontend Transport; Mon, 26 Jan 2026 18:41:11 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 216.228.117.160) smtp.mailfrom=nvidia.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.117.160 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.117.160; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.117.160) by BN1PEPF00004685.mail.protection.outlook.com (10.167.243.86) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9564.3 via Frontend Transport; Mon, 26 Jan 2026 18:41:01 +0000 Received: from rnnvmail204.nvidia.com (10.129.68.6) by mail.nvidia.com (10.129.200.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Mon, 26 Jan 2026 10:40:42 -0800 Received: from rnnvmail203.nvidia.com (10.129.68.9) by rnnvmail204.nvidia.com (10.129.68.6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Mon, 26 Jan 2026 10:40:41 -0800 Received: from Asurada-Nvidia (10.127.8.14) by mail.nvidia.com (10.129.68.9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20 via Frontend Transport; Mon, 26 Jan 2026 10:40:40 -0800 Date: Mon, 26 Jan 2026 10:40:39 -0800 From: Nicolin Chen To: Jason Gunthorpe CC: Will Deacon , , , , , , , , , , , Subject: Re: [PATCH RFCv1 3/3] iommu/arm-smmu-v3: Allow ATS to be always on Message-ID: References: <09cb6be1f8f7472a2f1ccab72154cc6e22cf570b.1768624181.git.nicolinc@nvidia.com> <20260126172020.GP1134360@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260126172020.GP1134360@nvidia.com> X-NV-OnPremToCloud: ExternallySecured X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN1PEPF00004685:EE_|MN0PR12MB6318:EE_ X-MS-Office365-Filtering-Correlation-Id: 8337e1aa-a51a-4bd0-364f-08de5d0a7471 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700013|1800799024|7416014|376014|82310400026; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?VdhNOasmi3T+LZCV+y9reHW9UBEolcVltzg6DeMGe7wh9wj6ViSXEMVytv51?= =?us-ascii?Q?3pKs4qOEFEcI6KQIeCvxsX1919FHruYa9g+Aw0X9uB+2JFu9oZ93q8Ht2xWD?= =?us-ascii?Q?GkxWvm7FGL2LAwKhfxTLL8FzHFEo+X+5KWIaAjwh58KmtYrEGY3I9sTp3au/?= =?us-ascii?Q?Uor1c+mIJx0YI/uz2UwyNKmAlmxskY+EuOeEW/r5en05ttocoXArHLiQN4rk?= =?us-ascii?Q?FeBISElJK8Cm6C1x7OJVxQqbFNZBgWvuWzxb4uWgyND8nFeZcuEIh36AjeBQ?= =?us-ascii?Q?H+JcUoqcKFnXmRX0B9xTch76a1hg0eH5YsIloUXTzrr1nw4Ims0PA3AbC6QV?= =?us-ascii?Q?F4b51Lj4XjojGn6K9MW3PtZWb62UELwqvSTAxfPQCJ3HrV+mA25Z5sh5NIKA?= =?us-ascii?Q?RUmwekrRSddMYWfBoBetKeK8vOc6ZStN7LLhbIbnMQSDmk1JL45wgNVjOAEz?= =?us-ascii?Q?nu0JXZeGDmG8MOpi0+MO8p2GTeBf3VUD1JFHDTZuQBBEVs8575hY3a90DJGr?= =?us-ascii?Q?d25Lxe3JUlL4iPoy+un/rZZ8a1Y6A9iMYj46Kt+Xrf4Y8MRaxrrrrinow2JP?= =?us-ascii?Q?ac9tYuDwTocz6g62R0Ugq1j6EeikJ95nGOdKGztLpQ7HCY7RMBJGw18vm6IS?= =?us-ascii?Q?km/fWte4r0UL3BE9B/sDEfNdTKJqDwj3DStK5kmvqitp0BUiggJirIpqZW8L?= =?us-ascii?Q?1QpxMkiOa4Uhpke95aH5nz3DbgkmE3lQe3shxZX2FRGbY3ox1YxiEWoVeYE0?= =?us-ascii?Q?qZWOuG7E8XlN7Q9St/eia6UUgfoCLBHuSkwE/LfiRUfBicoQSbnEDx9PNqM8?= =?us-ascii?Q?iGjioirynkk2EFpy4xGgyKeSZDpXErQbseLhE/bYkOHbxzah/0iCNSRZdIdt?= =?us-ascii?Q?r9mYK5hE/iq7eTL4zViNTDoygBYfQTJqJbbbk6Bdopwelxr5/LomxFB6sIxY?= =?us-ascii?Q?frPqDOSRceAM/37wP90GIobFpXFsBO6xj8a7ub2BmHGUEO8asjleYxAZgGT4?= =?us-ascii?Q?XpN3MA0RHtRgqBNfRvBJqVj3tv6ru73vgd1qd3ZqpTznEjamS9+UBssIAUnI?= =?us-ascii?Q?gFwhpOjjs14GS50TJs9LBWqiL8AMDqi84seVzju7kvHv6rbkd8gKoT8Y5Mun?= =?us-ascii?Q?FnU1ODmg7+WC5AgXuGxu9OK8XuBoGw8uT+LJUSrtzBainsB8Y3lPKlsDTMQi?= =?us-ascii?Q?O0fmnyiLTEyW8i6+2jCbdZxhMbLnx/HqOwASXiXQYhfpmGBIWaTePXU5lddi?= =?us-ascii?Q?BQT8/ynvTBzo872kEeFFYHIs2NykAxaaQ6XmQyYKaBrTkam5sxQiTEnMYdCN?= =?us-ascii?Q?7NcWSzapGZOAJmODkXaLHIS6z8ESc7Da9vdDRLNXtQMT4yLfoVDwVsTvfhUw?= =?us-ascii?Q?zhbpX8QPIsMxayuyNw5yQwBUFMdMq34WAytza0SnfLPx+eC7oPStkw5jlmEE?= =?us-ascii?Q?qiSTi3rDmqrs9JH7CpdceCec57sG7w5m4+anEnQQ8FbWihowuoRUd/I1TKwM?= =?us-ascii?Q?YxYWCIr6TZwkmDig6jIiQHX87w4Iui2zK321MYavlxh/gZjrwHLoMF/VnRqJ?= =?us-ascii?Q?lUgMKly+fe6pR2NpeIxt0aLNJN4jFeEAEIAGDxgVSCSYlec1QQCroYwL9GHS?= =?us-ascii?Q?xvrwsn4o+Tn536EphyZ31aZb5byUfij7BCKxeOUSkRkyDFa4vfG0pebrvDlN?= =?us-ascii?Q?3ONNgQ=3D=3D?= X-Forefront-Antispam-Report: CIP:216.228.117.160;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge1.nvidia.com;CAT:NONE;SFS:(13230040)(36860700013)(1800799024)(7416014)(376014)(82310400026);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2026 18:41:01.5952 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 8337e1aa-a51a-4bd0-364f-08de5d0a7471 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF00004685.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB6318 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260126_104108_278757_FE3284C9 X-CRM114-Status: GOOD ( 14.32 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Jan 26, 2026 at 01:20:20PM -0400, Jason Gunthorpe wrote: > On Mon, Jan 26, 2026 at 12:39:50PM +0000, Will Deacon wrote: > > > + ret = arm_smmu_alloc_cd_tables(master); > > > + if (ret) > > > + return ret; > > > > Were do you allocate the second level entry for ssid 0 if we're using > > 2-level cd tables? > > I don't think we need to. The entire design here has a non-valid CD entry > for SSID 0. Hmm, whether we allocate a 2-level cd table would actually depend on the "1 << cd_table->s1cdmax" v.s. CTXDESC_L2_ENTRIES, right? If the device supports PASID and s1cdmax is large, we should prepare a 2-level cd tables, even if only SSID0 is used at this moment since we have to support !0 pasids via potential SVA domains. In all Other cases, we would prepare a linear one. Nicolin