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 BAE6CFCC065 for ; Fri, 6 Mar 2026 19:43:30 +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=9u0y00V5NYgbi7YNW2P5Ejl5FaRFp4YF5J/OeWyeldM=; b=UBV3VoH8/n+WQHmkL9jRrCIE6/ a120OPe+X2Uo66aDRRhUJmow3IKpGIlV56TUBAswDpKpZABegQfCNMx8ldWxWGqHWTGa1fuhT5V8X T03azkBpX/iTQvysA+cS++BI8gpamGxCdpkHSDwtc0U8g9Hyi2OTbNSftKvhkPRSGkKd5yZ1A3d8S 9bWipZwvYWDN2mMwfuDrLKseY6tsATlK69iAR/lsphxENDZeRvGESWEj3tXHX8eZVYeKZuywPMBa/ G302CFFM/ODRiT2dgMo32QC+l9KIJp3bWTFMKEOVf9N7x3OcIGyer1isQPyGcUu8yML5QgMg1dQ2I OUS8R2vw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vyb4z-00000004Pp4-1iEY; Fri, 06 Mar 2026 19:43:21 +0000 Received: from mail-eastusazon11011000.outbound.protection.outlook.com ([52.101.52.0] helo=BL2PR02CU003.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vyb4x-00000004Poi-0Ssd for linux-arm-kernel@lists.infradead.org; Fri, 06 Mar 2026 19:43:20 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=C9Iatxa5AgSlYWS3ckQTSsW9eO2vaaOtLuPISxBfCLVoyryS5MgyL8cvaO53PTDmVXt0IkOBdNScigwFbAHBX8swDTS4zdyzlrGxbY+2todcXnm698xYIXc+CJhw2FpVIiueCPXt1VXVznX113AOJ1rMG9ZZXwhEEIJefERgM7CjcZMFEiA0IXNtp0zmhvUQvsAg36nRRr0x4HxYFvkhsfOR4dwqSlUbexrvTu9//CameKcegbPEv8OtM+R0QTr0QSyIEvaIwCzgA47VSQ1oThxPD74WWRFR+pRV/bQXDK3OHu9O76+Q77HwwZO2bdt/cMv76hnsWlfGTnkCvdMfww== 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=9u0y00V5NYgbi7YNW2P5Ejl5FaRFp4YF5J/OeWyeldM=; b=WeX8uWbFNCYmxfmShEeG8Bch9cm0r6/qr3xiwBWMvDAYOcAAT0wLb+X6J7Gsbvnb7rkAD1pSzdL6/d2D/DEf1AQJ9j66NBQPyW5bXodp8Rr4l0/8V13FOntPJG7+iZaXLq1yOBeK8c1GNxA9BAqjParN8uNBWgfZlwG5kC/nYs/eHkC4MgnZTglcooIOtoZ4BI4N9Bfl7Mpul4t7kKoh+p92C8z1ADZLrU2l0VX7lYYimkdhaBnbqlN9Dh3clrNBZi8JgJn74zEXPGMJb1PzMKdI+wuTMupFlvqboDdwk0cfC3zdAWVcjj3cBhuM3RjQNAdkBxCj7FiuBkd2pJ+ClQ== 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=9u0y00V5NYgbi7YNW2P5Ejl5FaRFp4YF5J/OeWyeldM=; b=tjlqkv4QpnVM+V6pdBPqyR33Qyw2jWwAcxxNXbzmve8eL+lo+LYD6Q9nFofT+60PLYEBKzxbcVGkvrOPyPwXFJMPr+vlGYCdZLYo8jgS9O3b45LTSLzoOIIq8dYfiSOH7cFqJ4WmtGBLJSQw0WzMbmCLuCmqWzfx9K6ezFMfu4PgomlGR9KbrZcEpfkz7Y4jmuSi/h5lqfA2Cmz2mghWSZzj2NfCseizSDcDDQaH5jrC+OeUJ9cz3jvO69t8yFdLBcTL8wdgWH+zjGC3fpSkX2iPPg0ce5z/t4qfPonNs9+jUYkWs49SQwpdUs5Z1L1r2g3Mqix2QGwzO+jfVxVxpQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) by BY5PR12MB4179.namprd12.prod.outlook.com (2603:10b6:a03:211::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9700.5; Fri, 6 Mar 2026 19:43:13 +0000 Received: from LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528]) by LV8PR12MB9620.namprd12.prod.outlook.com ([fe80::299d:f5e0:3550:1528%5]) with mapi id 15.20.9654.022; Fri, 6 Mar 2026 19:43:13 +0000 Date: Fri, 6 Mar 2026 15:43:12 -0400 From: Jason Gunthorpe To: Samiullah Khawaja Cc: Baolu Lu , Nicolin Chen , will@kernel.org, robin.murphy@arm.com, joro@8bytes.org, bhelgaas@google.com, rafael@kernel.org, lenb@kernel.org, praan@google.com, kees@kernel.org, smostafa@google.com, Alexander.Grest@microsoft.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-acpi@vger.kernel.org, linux-pci@vger.kernel.org, vsethi@nvidia.com Subject: Re: [PATCH v1 2/2] iommu/arm-smmu-v3: Recover ATC invalidate timeouts Message-ID: <20260306194312.GL1651202@nvidia.com> References: <20260305153911.GT972761@nvidia.com> <6416b7fe-0190-4c7b-9a62-5da7d5eea794@linux.intel.com> <20260306130006.GF1651202@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MN2PR13CA0025.namprd13.prod.outlook.com (2603:10b6:208:160::38) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|BY5PR12MB4179:EE_ X-MS-Office365-Filtering-Correlation-Id: c5e104af-a449-45a1-9273-08de7bb89a6f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014; 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:LV8PR12MB9620.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(7416014)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?rgprLKSOygY/bkiZfsb5+w3STGeXMsjSx221BcPUwNQmD/Z+up8h4prfgNeK?= =?us-ascii?Q?LbX1vmna/guLZ1e7yK74UrQ93ht0b+uNGzpRqXPtB42fCf+DPQlEidNIrbGg?= =?us-ascii?Q?6HgL0BljUj3286l/MoUSm9GHWVkhJ8nxYF2wvrrBRtOp9rw9NsvXHvdrFFtF?= =?us-ascii?Q?j3LNNeKMS/CyH28wXPmnCYe6KOs4UqLqDftxMcIeN3u9Zq8OJshpvNxD8c7t?= =?us-ascii?Q?o/MgSLnCiySUgs0SQ2lfQtxOtNUnxcINNysmytEvpUwARXlbvUufBYyNwWvf?= =?us-ascii?Q?CtB7l7JYktHsvtikPf8jmFhVBcUZoMTAwvhjnvOz8Ghw0V/Y9BZbmTfTm9rN?= =?us-ascii?Q?VfHg98Jbwr8pv0FkXj8+ArtsdRjlUEyuiKHSw/XQ6nb2idWUJTZbMLvljY1d?= =?us-ascii?Q?xjotTTmcAYG8LmJIYlARic8aXgNUu4fJs1aJ1GsSx/K5deyAmX7VERLewKuc?= =?us-ascii?Q?p7mAyZmqWadokGKc26sH4vXRf6xKtsOi5a0VyK/CBOP66asxU0Kw0wm8KTfT?= =?us-ascii?Q?F0uoeuEjyerx3fXjVKncp88mFGGbcDIDcd4rh/rBnd2Uvm2fPx7idjW5rjp7?= =?us-ascii?Q?TDNJ4EEVr0I2jtuIH45fZQ8XQfLzElYc1G26YQczNN1K2xPAzy39a3win/jp?= =?us-ascii?Q?TFH07HVHmJ1F52Qxav4MQ/64tPAZO0XGVA4wPyov3GnVIE3uvNYNGSftSaTw?= =?us-ascii?Q?2WI49MHLsfPS0L1nH6fxax8gXhXSyyfWI4Yw26+f8skfv1qqxNKKfYnYWnel?= =?us-ascii?Q?9bVuNPk+4+TPM5ytDP4GjqexbnUCkjDRt6pdIVOe0rQSzDKxg9hZjpqYO+oV?= =?us-ascii?Q?3zdrPihdHLqkfNQgXks1fLEcJ+Hx615xj1Fqh32+Dksqnj5zUzVbXDBv7kmB?= =?us-ascii?Q?INiG/eO0UCTcbOo9Gs/7zy9KpDBNu9HgMLNjmeNY4OsWjha+5hf9/E0/8pks?= =?us-ascii?Q?oGJP5b7biWZCrLTRXzIcKWLLu6205mBls0T89lNRfec6IhVJhkaonksNoMti?= =?us-ascii?Q?T1GgCJZsP3KjdOLpanW1HciUmqVH056rZrkrG8idI+of9t96sMYIALeySsA9?= =?us-ascii?Q?SwRUi0zDy2eau5lp+pxNhImjyt+RkCMjhYmURLlMQAOI9IHYpcgii6fqgynZ?= =?us-ascii?Q?dnXurLFEUqNBGVPk9pifQrpO+1s4lTzTlfOANZmbjP5qet/4CgxHReaus4Lz?= =?us-ascii?Q?7z9e9p2UVGENUd5uWh1OfY9JDPO2SZqsmb1Snh/rqOUUlAOu+iKzU/njuF8W?= =?us-ascii?Q?DfLHcxwQn9dwRoDaQU79M4+Fs4Uga9Z+EVDiXIyhv3LpqD1t5kZZjR4RDEez?= =?us-ascii?Q?ZtBDwn5YzrQyUAYypteK/1uFjcwLX3et44GjVIFATtLVjXgQW95r7W/DRtgk?= =?us-ascii?Q?rjhAEsNAZSirhRN9Tl0fZeMzMeaQdoq+Jf/owNOqQgvLyXspfMHO2NxqOhzI?= =?us-ascii?Q?1zYXTsjcFvrQMZDlrTsNbxBJViFx67HvXpcLzKfk4byBx/W6Txrv0gpd/6Cn?= =?us-ascii?Q?Sa/EEmaRB0Cka1IBhO4LFt9zfbvqnp5i5WQt1od74YCe/IpsfCmHgwK5r7iN?= =?us-ascii?Q?DOfa5QEFRAHCdlVv/elpDGQCxnwwSYlSPOQR4J5yzOcH6YZhBWLXfF2M1Fog?= =?us-ascii?Q?QIEGh/8emLX92kQYEjF56VaKwqydZB2HSA/s6mVoeg9Q4HHlcCExGTZaty/l?= =?us-ascii?Q?9GQKaKlcqAGtanaIlbZQqNm7MFcK8kfO+qlo7FUaKcL1J5AGX+DjjjiFaVTy?= =?us-ascii?Q?UZdlw+9irA=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: c5e104af-a449-45a1-9273-08de7bb89a6f X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Mar 2026 19:43:13.1453 (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: jkx5uAh+20mkyr1nh1DUhDeLH1T8rMGrIvzw6A7s6Nd8371TbHXB22kCWvTOMb0c X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR12MB4179 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260306_114319_154895_39156D3F X-CRM114-Status: GOOD ( 18.42 ) 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 Fri, Mar 06, 2026 at 07:35:19PM +0000, Samiullah Khawaja wrote: > On Fri, Mar 06, 2026 at 09:00:06AM -0400, Jason Gunthorpe wrote: > > On Fri, Mar 06, 2026 at 11:22:52AM +0800, Baolu Lu wrote: > > > I believe this issue is not unique to the arm-smmu-v3 driver. Device ATC > > > invalidation timeout is a generic challenge across all IOMMU > > > architectures that support PCI ATS. Would it be feasible to implement a > > > common 'fencing and recovery' mechanism in the IOMMU core so that all > > > IOMMU drivers could benefit? > > > > I think yes, for parts, but the driver itself has to do something deep > > inside it's invalidation to allow the flush to complete without > > exposing the system to memory corruption - meaning it has to block > > translated requests before completing the flush > > Yes and currently the underlying drivers have software timeouts > (AMD=100millisecond, arm-smmu-v3=1second) defined which could timeout > before the actual ATC invalidation timeout occurs. Do you think maybe > the timeout needs to be propagated to the caller (flush callback) so the > memory/IOVA is not allocated to something else? No, definitely not, that's basically impossible, so many callers just can't handle such an idea, and you can't ever fully recover from such a thing. > Or blocking translated requests for such devices should be enough? Yes, we have to fence the hardware and then allow the existing SW stack to continue without any fear of UAF from the broken HW. Fencing the HW means using the IOMMU to block translated requests. Jason