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 0EA9D10AB82A for ; Thu, 26 Mar 2026 21:51:41 +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:MIME-Version:In-Reply-To: Content-Type: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=SSxekb7GZVdb7TEN6uXLZzRnGG5+eFAEFTezW1dkK04=; b=WAZlvaXK4Iar8BD5voS+500yoO quobFhhL1mR4hlmg/wDJWapLIroxsVLzSXrnxmx/OJEt561I5EhAVzsX35sx0iCVcMLHQls1K34Fn Rnty15F527+mjgfFlMVAYdcG7BW5/SS/lTe/Ci5nWdnXl5sd8srPeKFfWicJ6OFPdtXimmm8Ov7km gJmbpAN/4e4OJu+h9Iop2ABfflJWBlextrLUwplBR7MD/SgFp9kJfaUwX3iYwfljqYqSVhV22elfb +iTkLknhWMAPGgjwVMUU5brzzucmJFDb6r1cij1TwIC7+EoWY28ORq9SfUuiOdqeOUSvFlMi065cS GS8lqNXQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w5sc1-00000006Gxg-0dUB; Thu, 26 Mar 2026 21:51:33 +0000 Received: from mail-westus3azon11011032.outbound.protection.outlook.com ([40.107.208.32] helo=PH0PR06CU001.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w5sby-00000006Gx0-3Awe for linux-arm-kernel@lists.infradead.org; Thu, 26 Mar 2026 21:51:32 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=wx5NrXbvE28X+J+eXcwqkrcRusUaJKwKkMS61Pwg9O/pln+3e1xU/4PnWp/XAXm1Uzm2Qt8V0x+kbgH6b0zS5GO99aq7eWnXlfG+jN8M4rBz/cHmHtTcGzyjRXxfGrgMwEv1Bo53DpcpjMrTav0eTRew2HMCsEr2xbdnTNYqzrnXJ5Z3nVMdD7TNQxkNqPkGvkA1dDoLAe/PIqadqmM8vUXociFrcfvxdg1/9ZLmy45dbykgw5lhI1xUlza/1uJ/UpRD9w0oG3d0amjnTm7gusZ5VHkhCpDe6HlkjpOY50L3HRGkAyNdtYoyzRYopxnrmqIaZbgQ8vth5j8FZHIzaQ== 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=SSxekb7GZVdb7TEN6uXLZzRnGG5+eFAEFTezW1dkK04=; b=UX7JRHMn9on1hBsPI98nEQ+R7EA86KQ4NoEUB3JqfpLVPw87ZN5UB/oQeKr2TDx66hUUoUDGSIFEmvGwf2fcEifL7ZDsa9SSVkC7+j81tY9UZ6OzQqda0CBevB2Bx+G+SvNLzcMZCu+NFvKQO3SdOVPDsd+IaeTCI4uTN1gMR1gWBFm/Bv8A7idryqqnxocE/SnVFQMwib0tBaMrPnNdm12MWCagUVr987YUGu659xIa6UM8GrnZQVaAnVLsB8kQ2z1e5A5burRterWzJ8r/rlniLnVjRATfvQ0Ih6i4kw2OL6G1RsYcF7nZdsKCmBjW9SWad4buyrexRLU18UpzPQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; 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=SSxekb7GZVdb7TEN6uXLZzRnGG5+eFAEFTezW1dkK04=; b=t7ekeWA0GAxwXLCPaOO80byVqtkbHzSOoZjxhq5XVIRHPIxszXgoXu/3cUS0X5gRdQzCkcp9dhL0KPQcm6au1pPN1WphuG/NivT4gBkCnId2HCsZsbqAAzRmqAiWLyJxNVPZoEPw3xN2MvBoxOS/kF5OPkBNBXsUJP2yMwKbCoatxguqEE320MkPOeIelAJjSiiU8ulcVFw6pkNTwPZsN/6zRZR+cOtxjEI4OwbAweeicb4Imn7oyVJKBS0ILpCB0oAeobiYwmnHOxLtfT/kN6XOKwp4GRM39XFEwY10EZCoAaXDc7jB5cg6BvIAuKYRDvO6v+NKA7Cr1gjEPZg2kQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from CY1PR12MB9601.namprd12.prod.outlook.com (2603:10b6:930:107::16) by PH7PR12MB7114.namprd12.prod.outlook.com (2603:10b6:510:1ed::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.6; Thu, 26 Mar 2026 21:51:18 +0000 Received: from CY1PR12MB9601.namprd12.prod.outlook.com ([fe80::cd76:b497:475f:4de3]) by CY1PR12MB9601.namprd12.prod.outlook.com ([fe80::cd76:b497:475f:4de3%6]) with mapi id 15.20.9745.019; Thu, 26 Mar 2026 21:51:18 +0000 Date: Thu, 26 Mar 2026 18:51:16 -0300 From: Jason Gunthorpe To: Bjorn Helgaas Cc: Nicolin Chen , will@kernel.org, robin.murphy@arm.com, bhelgaas@google.com, joro@8bytes.org, praan@google.com, baolu.lu@linux.intel.com, kevin.tian@intel.com, miko.lenczewski@arm.com, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, dan.j.williams@intel.com, jonathan.cameron@huawei.com, vsethi@nvidia.com, linux-cxl@vger.kernel.org Subject: Re: [PATCH v3 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices Message-ID: <20260326215116.GK67624@nvidia.com> References: <20260326213854.GA1348488@bhelgaas> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260326213854.GA1348488@bhelgaas> X-ClientProxiedBy: BL1PR13CA0125.namprd13.prod.outlook.com (2603:10b6:208:2bb::10) To CY1PR12MB9601.namprd12.prod.outlook.com (2603:10b6:930:107::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CY1PR12MB9601:EE_|PH7PR12MB7114:EE_ X-MS-Office365-Filtering-Correlation-Id: ff63b225-9d5f-4656-7e59-08de8b81cf56 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|366016|56012099003|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CY1PR12MB9601.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(366016)(56012099003)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?e/UVAIszi5kLwRqIALX22rX20cO3ZdhcVUTwSZm4fp4HJiaTVykE1P9eugA3?= =?us-ascii?Q?pS4fvjCbg3VMrKsWeKjnJjtNJmB0f0W69bgJLtTTa63GIjTfaHj/kgA7Wzmy?= =?us-ascii?Q?f75mcUIONrCYPOnnMjnFLBDn3LyVx9clhjTK7tJFUjj9Pf/A00i1RG5ZpvaV?= =?us-ascii?Q?sHB+lmQs8Ev0xNQMZ9eUCWHsdEdepVVh8EKNeoZFL1dnKyZHUoBHXty8/jcC?= =?us-ascii?Q?rErdFxXGGv8fEqvJLbgCFJGP0jWYhsCiQguA6qyQYrMPInbi/c8fjJSTrwQX?= =?us-ascii?Q?eIcBj1Oy0L57F0RtZw82x0IJpxwCeexaue/rNHaPWee0GMFynD62ND5j/BBv?= =?us-ascii?Q?gbSYU2Yd4lvD/o6ODd5cwXvhmltCFxqVWFVzkME+yOzalASkcOIVMDe5jQh5?= =?us-ascii?Q?65gj8qlNQbZPLIBMz9rR8I96LsabKk+n5QM3N0LKI0wLpFlCBqySNf5ENlWu?= =?us-ascii?Q?q2pNmVgq1CmXROOa9VYOaJXyz8Ixt6pTKKouzgDFMHe8Jbk0/REWJmKJNTEH?= =?us-ascii?Q?mDyHv6szdEfVvMuHMUpN/qGnQitBlkU2NPEHT9sZhAzLGs/LFurIuOmKWheD?= =?us-ascii?Q?+BTMiMyY3HMJc9yynlRYX7BPeKAlR4QDxKqcsYk3q5Gq9NBdemSeF8Lm2Mfp?= =?us-ascii?Q?H47PhNOZRXnUbMuvqwvafBZODj6/HfoCqZLEAcB3L8mk2Zh4ydNlXK2zHdjw?= =?us-ascii?Q?lsRG9nc4+Yrqs7ELTgTPd2JYDkBQ48PQVWGh76vCinnhL5t+sh/P0Pbn+fSW?= =?us-ascii?Q?n1SyOJHUVOC134YD6NM3QvjGk2tFfgi55rtd4I7WhQ2TL5uxBWgtME0l+8JW?= =?us-ascii?Q?HgEi4+GIFD8x7lX4S4kGyCm6srMrg+LM0imcX9PrZzL/pVoZFtld3Cz3AWR5?= =?us-ascii?Q?blJkQItzK/Wua2gAcIE4QlEWaf1Rk5VSERS7K/rKRLLuGW9ulhICnJPNUNtd?= =?us-ascii?Q?/F6Ef2oiKt885sqI1MUYgoqvCh5DaRswWrIAHJUsERgLuzuO+OlWN4iVDpod?= =?us-ascii?Q?JLBQlh0EGpCn0jlg8fADawzqMC63m0wjT4V6P9NbLSaFkQKb6DQhpPSWfYqD?= =?us-ascii?Q?3dhMCYdpQf40HSFjx5AwFJmkMYwwo1Rx05mGbpdzOpkKHxu40XSFFPD+LJdK?= =?us-ascii?Q?mUBV85eR68Q+GXVCpU+1QPSQtpxEWg7BWXZcTOffkoPG4fCRfAxSogUBQFk7?= =?us-ascii?Q?lfhNGTIxJApN+w3adwtORGiJXeQqoiJBHemADaOlQKufISxB9qjrMRAvbRwD?= =?us-ascii?Q?rnNbYR+afnWizTiH7Wvl6Dvp1LI3CFOHY25nKzRf8SsqdV0EWeind2jIhlsv?= =?us-ascii?Q?lDXbJ1uvaoYNPjvwzcho4wLlJN1JLPITF9u1DPjU46fJdyFsB6a+vbjLC+R9?= =?us-ascii?Q?BwaP4KQWliW3DIWVmqaqBsevUK9U/yC0lqcWIIi7ECrTqCeEej+q65oFEXn2?= =?us-ascii?Q?pCpm9CxyuUhtDBAT8WDmE6wgyUmj9KmL5Mwq2QGnFReTVSDlFery2ag7Fqgd?= =?us-ascii?Q?aGDUXa4gXcmvfv/u1RULfeZgruiAS8KCsAwpM+qNnzheJjXGOoqN2Dqi+KmE?= =?us-ascii?Q?MPOTg3/xUmGehPopMO87kB0odPFW7keip/wdek/jSfEXAsFyzwoB+duD2n41?= =?us-ascii?Q?W9LA5wEcfH9j4Vq+0VEyBhBSk7LpkAZbaecnpua0rgtqR0mfh7Rg132J11W8?= =?us-ascii?Q?jYyXLZBEezt6gc6juZvHYratWJSRhhyqcDYPMZwblANeWJHX?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: ff63b225-9d5f-4656-7e59-08de8b81cf56 X-MS-Exchange-CrossTenant-AuthSource: CY1PR12MB9601.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Mar 2026 21:51:18.0997 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: HmLK5/SLmuzZ1G+XbnqTZ6P0SzMeYYg9TuS/41Gs82VEj92JbFIw7bp4L1+v+gH7 X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB7114 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260326_145130_809228_A0D47168 X-CRM114-Status: UNSURE ( 8.68 ) X-CRM114-Notice: Please train this message. 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 Thu, Mar 26, 2026 at 04:38:54PM -0500, Bjorn Helgaas wrote: > It's only called from arm-smmu-v3.c. Is there something unique about > SMMU, or will other IOMMUs need something similar? Yeah, every iommu driver will eventually want to use this. IIRC the motivation for using the pci core was to make use of pci quirks. Right now ARM is the only one that turns ATS off for identity, but IMHO those are bugs in the other drivers to not do that. Jason