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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 E9FB2CAC592 for ; Tue, 16 Sep 2025 17:59:56 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AD33A10E3B5; Tue, 16 Sep 2025 17:59:56 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.b="pAOuyEHR"; dkim-atps=neutral Received: from PH0PR06CU001.outbound.protection.outlook.com (mail-westus3azon11011007.outbound.protection.outlook.com [40.107.208.7]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7EF4910E3B3; Tue, 16 Sep 2025 17:59:54 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=I67cICSW5m9nByDMxRxonzblU0Q0dThikgP3cnBstgkjZj69ZSeH9SvR8SWjuOwiusWrpLHOzJPSV1Ww2IVQ9h3o0a89D6cvBQlzYkvQVQbaa9jiOK8v/IsahReOW8s4jp0tT4j/0W+TLj7Wuwi7kEuqNk83a9rWVdJbG5FUA/zy4MYdY2X09rZpPrccQYjaYE57b0kpQBYdefQOSDeb+FhXUQP1QpVIoSRfmuIpqiNPEeaid/SEW4/chIVQstf/ViQwFWx5podiD5qKJuPwU7mGoNIBnS1+VNU3KIjvgqNrlq4mx9tVlPxubOaIs8YACubYis6br6jL6sudP5R9bw== 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=I2crGE4jQ6o+NbKFFZHuH0vUhQpg/XsE3ruMoXZtoBU=; b=Z3R5d51k4fRYVpZG9Ftqz+t5i5sf3tN+epMHtMrqIESPSX5xFs5jqudHeuoPc+vVvDMl01NN1umuJBD6xsz3JkRX7w5cQB/wZCuNtTsvb90FwQqqk5BN6AmCygW/NsK3J7ZF4ne8uGf/C0Hq+dx2ghmKvF0DOmb3Z84/snyoj6a4odalNP4ikpzBCLaFfLuMa29u66HTtfmP20wKMTiVx+Q8m/17xILmwS6vHCbCX7BUo5DNIMuBM+kzMGy+A4ItlHHGbWWTAjgRwB6dNKd5s9JlDtzV3FG2VsFS9GdDzP9LQ2qGk+9ch0yi4vPc2O4znidxp4OoZgtYmTKjRNUzQA== 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=I2crGE4jQ6o+NbKFFZHuH0vUhQpg/XsE3ruMoXZtoBU=; b=pAOuyEHRF8hNe0rfbwZ06cBUwQC3VtaAhe2cbQ2oELc7LKLb2Q0XlRsIxUEswp+yzBa3Dbi6oB6lAN3ze1+U+E2Yo0PbSePxGIip2zMCxZp//MQDBXBQRFBzSH2wH8VK4WVMlrdTTetHC5xrlzGXy/NacscQTqB0NGdp/Vyd+W40n9vAp4aHZOeGGvWubC0iPZHf6iLJm4+tUrQEzphvQgJXSKD/fY7hfGrlNTd4lHmvhYa6ZAlaaLLZqqhv0PEajHtNQWF1iMd04MWlwphymOQLwSTyITZ07cGT4qyBvAVCWL5PBIubp22uS5mkyIdWXvDZKSA475JKabMSMv3Yzg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) by DM6PR12MB4329.namprd12.prod.outlook.com (2603:10b6:5:211::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9115.23; Tue, 16 Sep 2025 17:59:51 +0000 Received: from PH7PR12MB5757.namprd12.prod.outlook.com ([fe80::f012:300c:6bf4:7632]) by PH7PR12MB5757.namprd12.prod.outlook.com ([fe80::f012:300c:6bf4:7632%2]) with mapi id 15.20.9115.022; Tue, 16 Sep 2025 17:59:51 +0000 Date: Tue, 16 Sep 2025 14:59:50 -0300 From: Jason Gunthorpe To: Bjorn Helgaas Cc: Vivek Kasireddy , dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org, Bjorn Helgaas , Logan Gunthorpe , linux-pci@vger.kernel.org Subject: Re: [PATCH v4 1/5] PCI/P2PDMA: Don't enforce ACS check for device functions of Intel GPUs Message-ID: <20250916175950.GU1086830@nvidia.com> References: <20250915072428.1712837-2-vivek.kasireddy@intel.com> <20250916173442.GA1765656@bhelgaas> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250916173442.GA1765656@bhelgaas> X-ClientProxiedBy: SN1PR12CA0045.namprd12.prod.outlook.com (2603:10b6:802:20::16) To PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5757:EE_|DM6PR12MB4329:EE_ X-MS-Office365-Filtering-Correlation-Id: f1c70e98-d826-4b02-57c5-08ddf54ad561 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|366016|1800799024; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?Rv8YWRCR2G7EOXvws9O3vOcYUfcgmxEH9QD4QPg0YrSDW0SDYT2ssNsc04yl?= =?us-ascii?Q?nItAHQFV8Rx2Cdj+70SQPhPA1Hmg0ST3EX4yghgbqY13yDi3PcxixunY6v38?= =?us-ascii?Q?E1qkGF9LnQ7X+o3N1T/hWKuFsqCvqvHyAyezdcqsrY0eiZJi07hLEB5bhlh+?= =?us-ascii?Q?jV/tpLadHjlFNPs8IfTrNFX8Df/4g6skERFWuoZ1CA4dLCIL0rMUh6j8ltGY?= =?us-ascii?Q?3P12U0SvlAF2l5K5HpxB9PpqVbMsw+6oO5bGX2q3Rpwz0rIm+iJ1bfzzxSlv?= =?us-ascii?Q?Q7WDaGlxD+rlSmiuSXwm2VLlNPYct5GBvafnRbc1Tb1GJPHIVS66Nq5bHk9H?= =?us-ascii?Q?LUCQYD8nQb4sDQBcQ4fAdI92gJSzpQ3oCwuk9lU5RBYU9pCiklglhpMp241O?= =?us-ascii?Q?iIAMqYgVJ13Y2NmUhTXGW+VLgYwq43kn6GDqgBCcQwzTR14cnQbj47Sy0gcJ?= =?us-ascii?Q?Su+D0HKxZVg6J6f1J+LtBiYwe2bZuatxic9RwWh6zLvuLqioBhjxqDZtixc+?= =?us-ascii?Q?6eelpvLnqeKchGXYTtZv0DhKBFB5KluhKfeJxvWK1ASXD1Uf0UCmXIxVdFG1?= =?us-ascii?Q?wfJkLquUNLejSugkrst7jUa0huJzfU8bRJ1+5d4Rtc4pCfo1Yyiqrv9yyAWN?= =?us-ascii?Q?Hu938sxjKxx3PXnkQwGe+Td1soM5pPXMgr53ghl2MZjhNov7ZtMcS/AIXRke?= =?us-ascii?Q?xx7z/4rnvp/kcW1BdDOkw2LiEd0ZcP+RkBRiswGTjSuLMgeIdNnY2+orIFmG?= =?us-ascii?Q?0WgBsaCh5YZ6W/XzPLZB8fCHGCABftbF4g/8ov5+KKuavrKkLEUcO35xr0c4?= =?us-ascii?Q?lPRh2SD+E//CP0SVGi1YT8LT6kbeuqwaOcJ0fZkarlHRzMsU+7qsxu3RNmqh?= =?us-ascii?Q?fIjqsgkVUpTZQdv+YulodunPR6PQUMmWS3twcgU1kynCOkIvzOEskuuqbWA0?= =?us-ascii?Q?rDx1fOhQLGwvvB485lHi06H3t2zJYm1mFuhV+jdmTClfBgL4my6NAaFu20aZ?= =?us-ascii?Q?LFQr3IYvWzLLfiynQQOJAtCpGyDuen9nKuHaVzEz86EjeWGokw8mkYHCbICs?= =?us-ascii?Q?f5aF3dDFBYxWUN/8Fu9Hxr7cHVzlxEx/zvbQok/JgPhy5cVYVW7YwThAG267?= =?us-ascii?Q?Xf7dIKNRoS6ELw9noTvfjDYZcGYQrB/gVRebRBhSsSHLkB7RqJdz0F8pe+K7?= =?us-ascii?Q?rmuY+zCOGCVjAAT3j6N+KzjIvV4pxFoOlYoyuBfRWsPgTHpYOOgsoWfB6cet?= =?us-ascii?Q?n4QzQh82HkHxeYp1Om+j+2czJlhq4AtEyBztw9R50F1vbwzY0MZHBKrtrS7C?= =?us-ascii?Q?B0iZevfw8e/MRjD552ZTPCylCmkOeBlEP6jkwk97nn+Jz2apFyWo/ETO+WC3?= =?us-ascii?Q?qDRGVj0TD6ymKn9FBn00c0XuHcvhwLMxurIEtkEd+uZuVLwB2P/NmLRIAY5p?= =?us-ascii?Q?hHLm6rdStOg=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:PH7PR12MB5757.namprd12.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230040)(376014)(366016)(1800799024); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?e5XxclYhQI6ZvrTT+aFGRoFLoI0b0zOB5cplEWUCbA1x33uqUoA2Mc3a25ls?= =?us-ascii?Q?Se/TECz3nG/tHevQ9b4YFZlZ1ZHzD22IJlwFIm/3qRvHviOb/eNi38lcjWRn?= =?us-ascii?Q?lt1xQh1SE/2Fchutnta2UyPxcgIjIDqJhpSjeujt4C1aUaRqu2W06UCmmXTa?= =?us-ascii?Q?UGXJw+49kCzCs3z8hPOzHxNa5ZuDRdDnGx8upSkFd1lNjCpKSEeVFRO9XDea?= =?us-ascii?Q?WxMT3mtmCrzwwuGTY48WGgqp6KYd9+cnkjyv1+T/ckcJ2C+x1+B/rjWHeWVs?= =?us-ascii?Q?fPMkCqgwRmSe3dExaLzcna2sPpG7naX3bvGsXDeyVAWQI0wAh5ebqvJSYJgO?= =?us-ascii?Q?advCjcZob1AzKYugaOeoUKNorEKkST+GJqr1o+AlPfZ4rYfS7n4tE0h4+i9z?= =?us-ascii?Q?XKNMnLANN4iqxNMF6HBAqksnHB/nnFgVeRxiSmNTVOMd0eNqMmTkEEScv+2o?= =?us-ascii?Q?p+ehcTkWPNkqkKEh3W3HAzbzLDFBwVXS8z6aFUPGBC80jCVtUk4x+agmyGpt?= =?us-ascii?Q?DK8OtCdUY+t8hdzPY4I0E+e7s8C9QMG+ZlvzfZIyj6/pWhc26A1Vfpq243zI?= =?us-ascii?Q?pDnYqgT25qAt0YYwVIdl5rwT/vGClDkDvp/HpVOquz0FXMslHHeJ5wduO1k5?= =?us-ascii?Q?zl8kbRN/plfUc3V9n4bsSNRNgBKk1MtSWRGXF+VJKPrW3mKu/YiIjQb79b8p?= =?us-ascii?Q?ad1lrPuvqThm4OoMFmTODBFgcWVJf4s23hFivDcbNHp0GbIQpurk5YiQQjhA?= =?us-ascii?Q?UOVN4vh7sw3bN4JQZ5+eIBfxclSpsYw5PDNxUuSRHcKb+0TfcqIWZgBJ1fDD?= =?us-ascii?Q?XkWxwwqOunKPrUP11ukUDKA50MSpvPKj/nhjnYJyVPUcTiPEywQdt+ISIbHZ?= =?us-ascii?Q?eWMRC3Lm08WGMjPQt+C+3KpoOwQ3b7hTjD26m9xbSebz9lSGg9le6WiZLBY6?= =?us-ascii?Q?c8UDoxgSvD6M4M7Wi3wdCSQ/D5V2y5UVtrajW2+aAiOrxj6bMIB65Z7c6bcT?= =?us-ascii?Q?9h3iGc/cak399ZqOU3ZgxjtP5wfKRETNUzpPohCutynIB9iPuwKTpSQTaSGl?= =?us-ascii?Q?hTfYQzSR6FxLsHJqQF743cOkoffz+mOPC1a9cb9oQnHhurWLDZLw+PoSFIZM?= =?us-ascii?Q?XvqnixYWmS+aRQQwj37fHf6RiGkVOr+ycXwmBNy40c083FE8b/C0dE5T8T9P?= =?us-ascii?Q?Y5vP0m1lIXGVXiFrjkiDryvb+ZkgcGNeP0kh2dhIytAY1Pps//lY7+4dxmGS?= =?us-ascii?Q?9GCPWKXKZYLCn6dssU6+KXYZS7GFFgaN1pcP3X7hrVqjAPM/H/+GIagBnvy2?= =?us-ascii?Q?gcOip2al4GlJXl20/rC7kDUF5TsQIqyPllK3GhWjnkdP6/KcepJaagF05sR/?= =?us-ascii?Q?T1zByActozywFSSSh90V3kM+rSlZ3bR1Er5j4vPa6TJ/9Qmuj2WDVSI/zTiC?= =?us-ascii?Q?ZTLfgMOsAKujfhVqIxL7htIAnKAbAqf5hWVScNsx17nrAiMPI+0vmB6RMRl1?= =?us-ascii?Q?r2TyWxnomm/IaIi+JSiG/ZxKRaMbGPKN3uB8HTN+R3DVAlRyZFsaCTYTUR63?= =?us-ascii?Q?M7/OTv8tMd0DhMv2yoT8uhiohyObjPEgEKh/wyjk?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: f1c70e98-d826-4b02-57c5-08ddf54ad561 X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5757.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Sep 2025 17:59:51.4496 (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: J0FTT6PvO4idjugQRARmaZaaUkm5WukF9/WmGOlIegn2RGLgIeonCYRhdlK+R12s X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4329 X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, Sep 16, 2025 at 12:34:42PM -0500, Bjorn Helgaas wrote: > I know I've asked this before, but I'm still confused about how this > is related to PCIe r7.0, sec 7.7.12, which says that if an SR-IOV > device implements internal peer-to-peer transactions, ACS is required, > and ACS P2P Egress Control must be supported. Right, certainly for SRIOV Linux has always taken the view that VFs and PFs have NO internal loopback if there are no ACS caps. The entire industry has aligned to this because having an hidden uncontrolled internal loopback where the VF can reach the PF's BAR would be catastrophically security broken for virtualization. Virtualization is the main use case for having SRIOV in the first place, so nobody would build an insecure internal loopback.. Jason