From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2040.outbound.protection.outlook.com [40.107.236.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 62F7B33CEE; Wed, 15 Nov 2023 15:36:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="tg/7Jvcr" ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=V+jyNXs2KVEbhrO+ad8UyOLn0iGJzwU+3MIoJumvP+SeoFpspd+CKWx01POprbKNkW2lW+iZwH8vy5ZMWNg5qK0qHb8OmHbkWvjrMARa6LkV81tpj16RJpQ+MbxEvUCp1lpdpVCHjacdeOMhZ0qu8MmCMblAWrGHbGQF0Xa6INkQdatIw5OeNkC9mlWqALx9CalqAJq4tHTsqgEgv4euO26UqVOgBRMg+aFtnXCZ/XAJ+zywr+/tbAEcD2iHvNlH9Ovcq0VLfdgY6mlfyLHLiblsoCqwzvr6bWuXQmio1G+lO2sw0Ynoqft8DMT1mNYolaqnJW4CZzXMHLPH3l1RVg== 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-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=BNdEynjYlj699bnc292naIDTMR9TOq3rH4L/DuV5nF0=; b=K3imG2kkXEw8k5GHM6WOIZdFw/gU2DSFBbR96k/EndEY4+wWZZ6FWHndcf74I1SXFqM/yHm+EpPCWkEJuauZZNLFvkuITFvjjLkY0nMtgmp1zcYuHCxFn/KYednM6v0+8Zjvu9MbNstzFqtWFHE6M0CL742T3EbYxoUbrg2Np+veMjNdMhFzbnPdiFrAcwNZRFun4Vjn3+U6TITs+mFLTuasS1m+hHnwRcfCjBw0u8ta7jMcL1HpJDXBnomEIuJ0teJc/74xi/Vss41xTheCsdEaqAeP53WOms2Y1UbFJ5ObhT4WEdyeePNlXiEXmA6SewkmW6Ifn9P1Q+LSButmNQ== 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=BNdEynjYlj699bnc292naIDTMR9TOq3rH4L/DuV5nF0=; b=tg/7JvcrCdLadHSq4Qn6LFEUP9nSWlscqWB2IBbSu0EmRLMPstI9O9nR2plS5FcOpA8BEo+bypaRMspxqhETAllxZFdl8qAdX+2efG4aZiXjcqWePAvChDxFSkOkGPv4r4etULzUXnLJau+KQAUeYsb+dNTa305gQ5/pAHscFDh1RavEvL4hs8ZYVXjHpO0iNa4a0C4gQqkAUwiu2Yfisc7zCmCK6filnMozpeJ/b4f0oiB7VApwMlAWv8tC0ByLirpyFoxP1b5QpbPPzYv7dRmZR/2/3NZ4L8Gbk4CP0Hgm63o/3mcHJKMrErNqZPA0bYjcObmafT0lIUobDXgUiQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) by IA1PR12MB6185.namprd12.prod.outlook.com (2603:10b6:208:3e7::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7002.17; Wed, 15 Nov 2023 15:36:05 +0000 Received: from LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::60d4:c1e3:e1aa:8f93]) by LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::60d4:c1e3:e1aa:8f93%4]) with mapi id 15.20.6977.029; Wed, 15 Nov 2023 15:36:05 +0000 Date: Wed, 15 Nov 2023 11:36:02 -0400 From: Jason Gunthorpe To: Robin Murphy Cc: acpica-devel@lists.linux.dev, Alyssa Rosenzweig , Albert Ou , asahi@lists.linux.dev, Catalin Marinas , Dexuan Cui , devicetree@vger.kernel.org, David Woodhouse , Frank Rowand , Hanjun Guo , Haiyang Zhang , iommu@lists.linux.dev, Jean-Philippe Brucker , Jonathan Hunter , Joerg Roedel , "K. Y. Srinivasan" , Len Brown , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, linux-snps-arc@lists.infradead.org, linux-tegra@vger.kernel.org, Russell King , Lorenzo Pieralisi , Marek Szyprowski , Hector Martin , Palmer Dabbelt , patches@lists.linux.dev, Paul Walmsley , "Rafael J. Wysocki" , Robert Moore , Rob Herring , Sudeep Holla , Suravee Suthikulpanit , Sven Peter , Thierry Reding , Thomas Bogendoerfer , Krishna Reddy , Vineet Gupta , virtualization@lists.linux.dev, Wei Liu , Will Deacon , =?utf-8?B?QW5kcsOp?= Draszik , Lu Baolu , Christoph Hellwig , Jerry Snitselaar , Moritz Fischer , Zhenhua Huang , "Rafael J. Wysocki" , Rob Herring Subject: Re: [PATCH v2 00/17] Solve iommu probe races around iommu_fwspec Message-ID: References: <0-v2-36a0088ecaa7+22c6e-iommu_fwspec_jgg@nvidia.com> <1316b55e-8074-4b2f-99df-585df2f3dd06@arm.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1316b55e-8074-4b2f-99df-585df2f3dd06@arm.com> X-ClientProxiedBy: BL6PEPF00013E0A.NAMP222.PROD.OUTLOOK.COM (2603:10b6:22e:400:0:1001:0:12) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|IA1PR12MB6185:EE_ X-MS-Office365-Filtering-Correlation-Id: 3957cc99-c86c-4656-7282-08dbe5f0946e X-LD-Processed: 43083d15-7273-40c1-b7db-39efd9ccc17a,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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:LV2PR12MB5869.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(39860400002)(366004)(376002)(396003)(136003)(346002)(230922051799003)(1800799009)(451199024)(186009)(64100799003)(8676002)(8936002)(4001150100001)(26005)(6512007)(2906002)(4326008)(6666004)(53546011)(6506007)(83380400001)(38100700002)(41300700001)(7416002)(7366002)(5660300002)(7406005)(2616005)(6486002)(54906003)(316002)(66946007)(66556008)(66476007)(86362001)(478600001)(6916009)(36756003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?xQ7WcmH+2JjyjAQy5Dd/SaszgKmm2ydPZS+UYOt/lWAa5N1TXS6+BXuafCfa?= =?us-ascii?Q?W0NGhI9r2trDzzpU1CBjYD0VBn/nMNMyw3MsSPw+nRGOZSEYTKEtWwtVv1YQ?= =?us-ascii?Q?/427KQsdyEDwi8NWGoABGqp6WiS1P0G2mmRgYuyys+TIbODuKeUC4nSlyJAQ?= =?us-ascii?Q?EpO7MCj2bPhdT00ZE5o0e9nvqPpU0JXYVF1idGMO1ICegmy78a0yRPNvt82Q?= =?us-ascii?Q?9EvHW49tpNlhZDZiIgGbDxXiWjk5RhM6vzVFuuqn6O2OjP2/pSr4Ycw9ienC?= =?us-ascii?Q?pg8QgmJI1+Sqs5LfN3g24d+25HgTaTOWtNX4Mp/Ml8ft6QlVvEfsX+F08R2L?= =?us-ascii?Q?COjuSMC7ZE5h9KUBVgeTiExkUdPXhI6ZKff8eVKd0w5i0P/xyUqs0j32WNE+?= =?us-ascii?Q?wfQIJ5qa/xROHonMP1f/do7ApdeST7rSygdVH6X3oJGJ8XcLHaLYz+JGpH0V?= =?us-ascii?Q?a3wow588VtP1+TlYyRkKPr8efPIKaTypvA/g0ZReinoq0KxPpJpPwklyCwuk?= =?us-ascii?Q?vcvT5rG5vT16PBr69WgHhgrbMTaDXamBl+MuTBFzRo0lqxEhjikgkqloCOP8?= =?us-ascii?Q?WUqNiwHVELFSQ0SCSB28abssTVsNCsqp2XP4DHOdNiI5N4vuhRmo4fjl9zu7?= =?us-ascii?Q?MXxDNUv9npe8cP/hzRLmyunDP8ZDh7X9W/GhEquoFtWox4YqZTYAHMPXR8y5?= =?us-ascii?Q?qmw8kJwVCFc/iKFjYkB0lLhl++3x0oHizRYKB64u3Wfsfh/D0W32sa9Y93T7?= =?us-ascii?Q?pcvLQfefbyJh6WVwxejGL+xCOrS48B2fKjjiOyfBi3dwG4LFJM+I+scdbQcJ?= =?us-ascii?Q?bU8DOrZgozSnMe24AVWQ5HkIPaei9jSLtHL+SLdugcteC+W2in5TKhVfZLAp?= =?us-ascii?Q?sTi8lW+/tzjYVNkYIfN0X2OajOeYKagv4NDrLNTaQIGvxnqmx7s+oRXWoRT4?= =?us-ascii?Q?XCz/7QySWsloWOFq82ct7mxXvcIE2G8ETJvboECchzwJRNCjRXrSDcHG9jKc?= =?us-ascii?Q?Hw0kDn6htfTBzbDdwa4Ctuw4oh2+vBp31h1SHTII7YKbjsyfuKQkxfeumXvR?= =?us-ascii?Q?eh5NJ83eIA7JX3qog88Kx+rADMe8pHxMQqhO5j+yNoRKtwRnXGl86Vfg9n6A?= =?us-ascii?Q?UdwtE2h5Rg8nIkvC4iDTzCHdLwvlplPw2orxywefC/7YZqpXM3p5wrEH45RS?= =?us-ascii?Q?Wjz/5cuunoTR9NLfgmN601QL7LxttODSyw5YFgp+aJdHF/advmvx7R3uXc28?= =?us-ascii?Q?f4IyBEHfpy0XJgDv0CYZifhZ6AES+Vn5nbonjA7S6A9laUdnhGMAonl2ChFO?= =?us-ascii?Q?m+2kbJCiHfZgsuIeBoziqjsVghYtAZJ9oQFMauAYob6IgLNJHJmdsRykhGI1?= =?us-ascii?Q?V/xK/hjEL6WpogHivoaOg4/q9ZjVnL/N760eoQAu4rKIn3Xv7j5U3uRDTtG0?= =?us-ascii?Q?+VIcGi9lzuGs1HRBbt4xughNIiiAnroAaUVc6iIfIU61+oft2e3CemGG7JAx?= =?us-ascii?Q?lnbnRLF26WTFuTMYVQ3M2I/xol2//cva+lNJ+V8FDaqYlG1IItLZNtpsuEzK?= =?us-ascii?Q?kr8BYVdtQcJc/KCeKMc=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 3957cc99-c86c-4656-7282-08dbe5f0946e X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Nov 2023 15:36:04.9421 (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: unWruElbHsCpXAlLTcHSHUBRjm0fbejZjo3lk/WLM+HLtY2J8roqGxQxVEwFhZM+ X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB6185 On Wed, Nov 15, 2023 at 03:22:09PM +0000, Robin Murphy wrote: > On 2023-11-15 2:05 pm, Jason Gunthorpe wrote: > > [Several people have tested this now, so it is something that should sit in > > linux-next for a while] > > What's the aim here? This is obviously far, far too much for a > stable fix, To fix the locking bug and ugly abuse of dev->iommu? I wouldn't say that, it is up to the people who care about this to decide. It seems alot of people are hitting it so maybe it should be backported in some situations. Regardless, we should not continue to have this locking bug in v6.8. > but then it's also not the refactoring we want for the future either, since > it's moving in the wrong direction of cementing the fundamental brokenness > further in place rather than getting any closer to removing it. I haven't seen patches or an outline on what you have in mind though? In my view I would like to get rid of of_xlate(), at a minimum. It is a micro-optimization I don't think we need. I see a pretty straightforward path to get there from here. Do you also want to get rid of iommu_fwspec, or at least thin it out? That seems reasonable too, I think that becomes within reach once of_xlate is gone. What do you see as "cemeting"? Jason