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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8D0A8CCD1AB for ; Wed, 22 Oct 2025 19:51:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E58FC8E0005; Wed, 22 Oct 2025 15:51:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E303C8E0003; Wed, 22 Oct 2025 15:51:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D1F408E0005; Wed, 22 Oct 2025 15:51:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id C01508E0003 for ; Wed, 22 Oct 2025 15:51:02 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 5A97DC094F for ; Wed, 22 Oct 2025 19:51:02 +0000 (UTC) X-FDA: 84026793564.05.090F5B8 Received: from DM1PR04CU001.outbound.protection.outlook.com (mail-centralusazon11010024.outbound.protection.outlook.com [52.101.61.24]) by imf30.hostedemail.com (Postfix) with ESMTP id 64D5A80010 for ; Wed, 22 Oct 2025 19:50:59 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="hHK5M+y/"; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf30.hostedemail.com: domain of jgg@nvidia.com designates 52.101.61.24 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761162659; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=IIzOnANczyqezrt429reqHU52rfSbWVCBV4PAEVXiaU=; b=kkgpGrQEdHUX/Q5V8QauVFB/rN9tyEI0yypUt6nNTKaf7SSm5lyHXzRHaY5sQpgtcvET5O IVh4AQOdadcDaLbjPLrbWwTn3G3YOCiJi0Xpvh7MigW45mtPEw3C9P76u2H2cmnIYgneZp OMpxc0jVjTB4PMZAhOqjbpXbyi/7TuU= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1761162659; a=rsa-sha256; cv=pass; b=tTGWxYaMgdc2KBv3LDGJJvc9s+WRjUlZS/+3Kw3qVY3EkaqwiKtUjey1qVFZy8HVvy4ChE rg8nhXvW5oF11S7Fm1I7kbVzpL83FEiitNOLCXlAgaoGI95J5zLjPX8D5pU2ngdRxuzBQr D92wMgiWdU3WDGUKEk0rdnqI0iirPt0= ARC-Authentication-Results: i=2; imf30.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="hHK5M+y/"; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf30.hostedemail.com: domain of jgg@nvidia.com designates 52.101.61.24 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=GMCit7FX7H41rih19OERjBkjGvh95EweWU6LFEkaM+cKkSnzy3WkpD3OZQD159GPxJ7sBRLhIA/3wd9XvpzAjYbsb2wIkuM5MOHuPU9biQ8yYy6JZXEXVavoQgGgmW1azicNlrkDHpUwm5fcB+b/JK/ADxdSd20cGZi1LJbPCCfz03O+FmoQjAhQzz0819HXm+QD+n84EyTX1IQaf0R+H2nNsqadz9iqCaeJv6bGOPPWk8TWI+5QuiaaeVChaofCN2250VjyVqxgN1S4hMSn9GKXSyJHvxG9Inlem0TAFIGIAxwzPRXRS/yoTUoLVXPM6NeJi8tG4ZhpROTxtntQnA== 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=IIzOnANczyqezrt429reqHU52rfSbWVCBV4PAEVXiaU=; b=wgywd+DTTjj3hZJFG6txySPvGhD2pUXXiqq4oZFeo8d9kCdnOzPr27ehDpFLlaXHhlt2K2NDT6Z1kp8Q9PdhwZACK8lQXVPEaqIKERMXxocez+Lwy6uAB+ZNC9zomLOWchLBpCuEbFprxL52nFAJMxhFFPhZ73wBO3K4u7VcKNbOeMXgfi91gaC3O5iaFNtJSysjZCNNflNHjUFHwlc6kfCRy35EZqTEEY8xHOC8zDFBtaQoYOdCjptnmGnPYgcxAM15I0HAT4N8BOgx+1ISgS6xFVju2GITXMtBMNGohvKneL3YGtmUfjc5XET9BHJw626kmSJvjySd7pNfLSK1ZA== 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=IIzOnANczyqezrt429reqHU52rfSbWVCBV4PAEVXiaU=; b=hHK5M+y/jRd7hsLHXQiCXPQVUgfv/l96BG26zCMLg0eNL8Snk/yowi6N0d2i9trSOkh7y1E8ko2vkgeFrSdQwtulHKOXdgVqiNgPtdA1vGJU9oZpScbBA9uAmAhceVEHHEKmLvB4GFB1qj0WAXZ281FLj+x/PvjedKWpUW7rKzBC1GiYdZA/AyIF6qAobvhShW6R3Atc+kNLQqgACkT6qqWlisHvR19OW/jKB20prSkyBJOLRHZ6DV914KwcmsGPewY2ogVlr8wpZOXo6J9aRoNxfQidSPqvSx7Y6aNxV/totAMKh6XUeRnAYsXQe6qLUwj8TceatmYgfM6YIq0p5w== Received: from MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) by BL1PR12MB5948.namprd12.prod.outlook.com (2603:10b6:208:39b::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9253.12; Wed, 22 Oct 2025 19:50:54 +0000 Received: from MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b]) by MN2PR12MB3613.namprd12.prod.outlook.com ([fe80::1b3b:64f5:9211:608b%4]) with mapi id 15.20.9253.011; Wed, 22 Oct 2025 19:50:54 +0000 Date: Wed, 22 Oct 2025 16:50:52 -0300 From: Jason Gunthorpe To: Lu Baolu Cc: Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , Jann Horn , Vasant Hegde , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Alistair Popple , Peter Zijlstra , Uladzislau Rezki , Jean-Philippe Brucker , Andy Lutomirski , Yi Lai , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Andrew Morton , Vlastimil Babka , Mike Rapoport , Michal Hocko , Matthew Wilcox , Vinicius Costa Gomes , iommu@lists.linux.dev, security@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v7 1/8] iommu: Disable SVA when CONFIG_X86 is set Message-ID: <20251022195052.GA262900@nvidia.com> References: <20251022082635.2462433-1-baolu.lu@linux.intel.com> <20251022082635.2462433-2-baolu.lu@linux.intel.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251022082635.2462433-2-baolu.lu@linux.intel.com> X-ClientProxiedBy: YT1PR01CA0124.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:2c::33) To MN2PR12MB3613.namprd12.prod.outlook.com (2603:10b6:208:c1::17) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN2PR12MB3613:EE_|BL1PR12MB5948:EE_ X-MS-Office365-Filtering-Correlation-Id: ff747ea2-1cfc-4341-11fe-08de11a44f89 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|366016|1800799024|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?5ekDqMvcDSR5PpLGth5zAFA8s8xcT79sDcX92YzG03VPZvjhqYOUo3eYyLmh?= =?us-ascii?Q?ygUyWpP5qfEBoIgEYol1hRCm0dLt/0oBXK3Xf+vdDlo8Usymd3ako/KkbodY?= =?us-ascii?Q?vhPTMG7dTIpVMxNhUY+3whzaUOzApKGZlKfPOEQJqGrdx5pBMpY0xiIiKprg?= =?us-ascii?Q?K5hFNCLMdUFDGyb9Wga6+HQMJOKX16nJym8jJiXAXtGg5o0MUTNv/WX0mGLm?= =?us-ascii?Q?y22/nnoi5JY7m8gC+P3nxmno+99T3op0T0DWP2oJ9bhkteGKfmWRCQ8yX5VS?= =?us-ascii?Q?kQpx3dbBH/cwtIZ3Gh+D9r4s9mSlFe8oVUUVyCS8AmhG5/FckyYpfjHIYFZO?= =?us-ascii?Q?HJ+/4yZIgkHANa2sp0tR/2KYrPyKIInxEaNxcfZNsUXMF1RCUyw6gSaJU1be?= =?us-ascii?Q?iKiFopgSeA8nIulo5QKT3Tfwe6dCWauj4JdUdGFnHB+rekU93p1URJkU328A?= =?us-ascii?Q?Iv1nxK5ZVesrT60nhsW1cMm30CnfAgANCoIZVxg22kmGkRLAz9ePhJ+HlxmN?= =?us-ascii?Q?VgSLZKd1TlBMEa/5sbIkR8O8rr/sqh0fpDW+PQWV3SKbQ8xCAqr4dgb3Iis5?= =?us-ascii?Q?Samy7LeFdlvDvpmMeZ2VrKKkcHvaS/sUqCeef2Q3ccL94PI1EERROLsPBhNc?= =?us-ascii?Q?WVjkepeGwONXv9TZcVNbwaFKfyrNRW7iLfLj+cV0FgsK452cWHKgS8fG4cAI?= =?us-ascii?Q?i3gX9dy86+G/pEZ73N8ws/LEmNXNF3UTsxlinzIX75cY3ioaduT4ACZsJqEF?= =?us-ascii?Q?VHVaiWMIToRF+Duz9HV8B3X3iL5iHsjLJ2bd7nIvrUelcnR43+bkfPST82F8?= =?us-ascii?Q?opCXXzVDlsPeWiswOhLW2CZos1BaMJ5j63Gc5iGV+jcpyk2cCMdpLY5xijFD?= =?us-ascii?Q?qL10T9DaD2puuW598hY7o9p13DF0zmTVtKfz5OPMrBJ57Il9U7WW9xJxCUjU?= =?us-ascii?Q?YXlpfjygECMP21rFuqIcsgjN9IEjf6tD387VNEzIHrPbccDUBVKT2NGrpEiv?= =?us-ascii?Q?UEYjCEV5m4jKt2uOxwpGPqp7TFykUGkq50T/YGsGbODeT/1Pee+SPW251nlu?= =?us-ascii?Q?B3n8Xf2SeUrci1oG8FA2nBgGReN0hSuwjbEsSj34B5DoOG8+MW2fgWCme4yq?= =?us-ascii?Q?u3KTrobS7Dp39Lu35+3wOaJasHb8qMlTjHGdoi3XM/UDpeyMb3P3Ak37NnR1?= =?us-ascii?Q?bsYMCPCeG2F4030b7h4LS4i+dSMfees61OVDLoBunn40vFP/+tljg4Wq9lyF?= =?us-ascii?Q?6xhnYXOp1if2ByzHSXenlcHJB0kSug1qEjfcBX22BUWNJ6E2xIlfVv0kECCe?= =?us-ascii?Q?vlkGoMe2WDwNVUnCBGwB6Dn/bQKBFPYxoAEYuFqTjeN7VxV66OrAkubah3x0?= =?us-ascii?Q?EUfs80Prh2Dng0wRVyE3O0loY5BC+7qTscMEgcEZdmhmCntS1gXo5v+qc+Ej?= =?us-ascii?Q?iqSAJhjJxqHFZg0craQzD+m2oxXCUvbI?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR12MB3613.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(366016)(1800799024)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?fbugoZ7C3a8d56hP39k/F11E3dfiSBQ2wpIzl9GZQeDbJE6nZ98xzd/5KRrf?= =?us-ascii?Q?RXwoSTKU5J0hLww4xk2japa6Vozn/uY5v+kDh1/ymDs02Om4j9HlBggR04E3?= =?us-ascii?Q?QlwsRGfyHTwEAATxFqn3M/3IZ7sUaOqhZWj52Qna/e+ZxTlKqqqaXCyrL0bJ?= =?us-ascii?Q?IE3E0p5BiAP2tNeHeIDSCWSaxDDZCEgf+1acfChIX1GddiyupEocBRXy+y4T?= =?us-ascii?Q?a1949zQc9AnefikuKSUjLhrSCacegtGeq08OnjcVcN+MhJ3TCbIhPLQw0gMz?= =?us-ascii?Q?JdY+J702SD/E8hGxsVxLVGkl9I2wjFpMvR4ni56ApM2hFEJthBqfLaXkCjQ0?= =?us-ascii?Q?nVNJN9Q5pHSGU0ULRCJ3Qm6Jsxk0ehjwa2cUZpAEu3btCReefTnADlNMnHgc?= =?us-ascii?Q?AwhLqsZAlEjH3pqADpePGy0KjIGbLcMdFBCM+pGIzNdF4rx0yIh4+X6ZwcRD?= =?us-ascii?Q?QevLffJD9JVdA8kYLA1jfKYXtPjjgwOBtAFKmJdGOEf6kQ7YYzBbEpINhkcJ?= =?us-ascii?Q?nIDVvjhQLd2tdaA2wzMPIYQtOCT/TLju2DBMe1DYquBwu39W9cpJmhYtvJzn?= =?us-ascii?Q?J39/JYzoyUYcn8WhmQ/DBRcmYRX7WGZCHKOh2Z5ung+S9mtUwx+sjLhRxlcJ?= =?us-ascii?Q?/KKLky6QrhrAZxKINrNVDTOeIEJT0IoxRx8Lji+0YTpVgqLrnChcWHyvvwvu?= =?us-ascii?Q?eXpy4UpIPr2gbXLxOUBGc17RyzuKvM67UG8A5pLFsoRvQfHB5dj8WHCZWvBN?= =?us-ascii?Q?LC6bUuvSKBFxC5REmT3uyOyQauJaldowBWf4mOAEZL41DUApmwLYEDs67c4D?= =?us-ascii?Q?kSfgO+rhH8RrsX0jHt28xyyjwsqJ9zDPyOxX2z8hzJvAnN5d0TKqDWUMbRhA?= =?us-ascii?Q?094L5zj6QRktL/q89EDQIQx7dGqrFstFn+qsXkd7WWCFLYEgS0unAz9FV+Vv?= =?us-ascii?Q?hzmksly4guga3jW9wWfXOejlImX4MQaNQMbC7KZLSoch7tg1S1SlEovG88j1?= =?us-ascii?Q?tFvDJVONjOdmvyvDR2LqNDfXvyyBUFK9xDjwoSRwWYBf/1dyu/QmggxEpdfs?= =?us-ascii?Q?+sxqui8GPCbmT0GNE9uwjbRAcUKGzzOzKtKziFioxgjd1MOFerOECz1tVA7H?= =?us-ascii?Q?87BEGYHYqzqHoRoHalChapQDYHaMS/REfyBwt5PRCjVrKEmpErHDneOdGI/b?= =?us-ascii?Q?3Czk0u5L3IcaNktSESUU4VjZG0ML81svaRh0NuZZwK8/EuJvIWnti3ow6ieE?= =?us-ascii?Q?COQ6Kn6K5j77wZY1IFCtKb8u6Abt2z6UlUIEwkYJgSVxBXn4EMszq6KAkH5n?= =?us-ascii?Q?VaXYhd9p7AEZgPkqKr2th32nehPcNfTrJ5rdnZcB8TwrMuDION9suAmk7FaG?= =?us-ascii?Q?aU3TmLHSe5yIsagor36p9D5dnwTgxkI4wkzBk+KJ1KJR9DutaGxp8OHlpAfy?= =?us-ascii?Q?PW1rAMO6CKToeNDAB88uGGwlzlspFKkvz0WIeuFzm1mNfzpI5OjmdO49lUNH?= =?us-ascii?Q?2ZKso0oiSQmV+szgblZEiYiKjs03vZTHAUfdBYX/9knZOBB4evpppqa5sooP?= =?us-ascii?Q?SEIvKkToEfjDMBbDPWs=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: ff747ea2-1cfc-4341-11fe-08de11a44f89 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB3613.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Oct 2025 19:50:54.1485 (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: kBFr1oET4FYUqCUgKUUA6/ID+6hiIxDzfrNNnqtbxhsHQ6O7oJhd0Bub5Rep7ZW+ X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5948 X-Rspamd-Server: rspam05 X-Stat-Signature: m494i9xakyfejw7xmipmnu4k5dqkcioa X-Rspam-User: X-Rspamd-Queue-Id: 64D5A80010 X-HE-Tag: 1761162659-653558 X-HE-Meta: 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 zgHBZcFb 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Oct 22, 2025 at 04:26:27PM +0800, Lu Baolu wrote: > In the IOMMU Shared Virtual Addressing (SVA) context, the IOMMU hardware > shares and walks the CPU's page tables. The x86 architecture maps the > kernel's virtual address space into the upper portion of every process's > page table. Consequently, in an SVA context, the IOMMU hardware can walk > and cache kernel page table entries. > > The Linux kernel currently lacks a notification mechanism for kernel page > table changes, specifically when page table pages are freed and reused. > The IOMMU driver is only notified of changes to user virtual address > mappings. This can cause the IOMMU's internal caches to retain stale > entries for kernel VA. > > Use-After-Free (UAF) and Write-After-Free (WAF) conditions arise when > kernel page table pages are freed and later reallocated. The IOMMU could > misinterpret the new data as valid page table entries. The IOMMU might > then walk into attacker-controlled memory, leading to arbitrary physical > memory DMA access or privilege escalation. This is also a Write-After-Free > issue, as the IOMMU will potentially continue to write Accessed and Dirty > bits to the freed memory while attempting to walk the stale page tables. > > Currently, SVA contexts are unprivileged and cannot access kernel > mappings. However, the IOMMU will still walk kernel-only page tables > all the way down to the leaf entries, where it realizes the mapping > is for the kernel and errors out. This means the IOMMU still caches > these intermediate page table entries, making the described vulnerability > a real concern. > > Disable SVA on x86 architecture until the IOMMU can receive notification > to flush the paging cache before freeing the CPU kernel page table pages. > > Fixes: 26b25a2b98e4 ("iommu: Bind process address spaces to devices") > Cc: stable@vger.kernel.org > Suggested-by: Jason Gunthorpe > Signed-off-by: Lu Baolu > --- > drivers/iommu/iommu-sva.c | 3 +++ > 1 file changed, 3 insertions(+) Reviewed-by: Jason Gunthorpe Jason