From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from BN8PR05CU002.outbound.protection.outlook.com (mail-eastus2azon11011016.outbound.protection.outlook.com [52.101.57.16]) (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 DE1FD4A1E for ; Mon, 22 Sep 2025 12:20:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.57.16 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758543625; cv=fail; b=sWn8MiwAihIqA+0UZ0ACtmlWbCc9gCDd+c27o7aMohwKu497OkhWG07gfvERnlE9ZE6JaX0QSkPR2CrET4QOVNzGP4/zsy+SRQ8rJzL6UgPkrfyW1Jca/st2Nw06sARnJRYVnvPqYyE1IXIIabA+XOkN+gU3yLc/vbSetgapauo= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758543625; c=relaxed/simple; bh=PriCuTcT16uMtpZlSCeO+rYcQXlJ7GF453vdGIHHbRc=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=UHbfyKPSYTx0Gni9CQicyYTP5EnEHST9pcY6w2f72GsraZqJwBcgRr0A+ra4fh9IzRIWliT2BQF5QbJdcTRgAY7XYPMda7TA0sRO+G22nPQcwBCcuRbx5TNM/yxt7AurHHRq93Mj9aroUE3sLVqf9fp4mjrMfpJ634sHmxmuSdc= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=asytvnGL; arc=fail smtp.client-ip=52.101.57.16 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="asytvnGL" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=r1e8L0NhpQAvb6l0621/pUUSgRf6wi2k62KvVkSK6tg1NlKucQwUBHF4c4IVcF9ax3A3k+U+gMZpwwVfO6yE7usFBsXF5fPMd9FFGRRBoBWffE/6Qjqm6HE41DRBcB0C5mxrKH04thFyMf/DaMEc0DiN2QFLf/nXQ8+bB0hN+3zRrC5GXD5/EWdnkdSN2JP3Gr7skD2kNrME8ELqOYOt8ZbByqxS18R/UMhcinCxcotvuaMAAukGC0xIe8jYwzvZ/MLd1l8jW4yY4sK9T9GuoJKp1kQu8tn2qY9kAHNytLqc4KX2MOU9DTtqV42EwwcMm+h7mQZ/buokmmysgkU/wA== 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=PriCuTcT16uMtpZlSCeO+rYcQXlJ7GF453vdGIHHbRc=; b=EgSS1Xiyp7um229V3rMJka1xJQQuEeZu021EabOgjH534Rsqe7hz7bfUb6pfCOEg4IR1289Yw9hDkJGWVOWF7H2DpILz9bDz+sbnFK+W3xRVv1aAAf08LhBM6Kx2uQAVdJy3+mGTXf4TPFX2Lf3a4xWXphaMHkdIW8MGpRysYnbBpuKiC+RG2b6x/TtUxcVj3watyRfJP0JazqiL91kun7CtelRldUb4gmoQsB7HfUGKaJKXTmiHTMb+E/Ee7oz1UMVyuBblEfcBda/LJtcwLhXZVH/A1HVnTLJVH4+VBkLtYB2pAmqNEiqJZqVKvvsXafAkt/hDHiFjVtYKpNBdoQ== 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=PriCuTcT16uMtpZlSCeO+rYcQXlJ7GF453vdGIHHbRc=; b=asytvnGLvjAHsn9MHOoXBJLeDNO4RykD94VOo/st2tKYYvhVAk/JVeDSiyfoCw93KpOXvIM3xy1II4uzDi+cmAeYJUhadYEx7SIBvDlfuP7lMH/qkBmdRDBygMZblWQ94iHeZbkEzYyATmmbhp7ZgrmpkSkjRijpDZBqc3qmpGKTFdBEHqsw1TgwxsLSmAl1pF35FwdeAZVmGkRtV/Tq7Ah5RPxSofjzsrRHxTbdeXP08MKED4PyzxcuteJcM7HFxJ0aU7b2HTbP5+5ZhSTGi1oe2SsGJzQ5qd0IaYQ93K5QsG0pF/MG3ki2sK1dcp3wLCJVbhXUx/d4yu5Jr9J+IQ== 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 SJ2PR12MB7964.namprd12.prod.outlook.com (2603:10b6:a03:4cf::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9137.20; Mon, 22 Sep 2025 12:20:20 +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 15.20.9137.018; Mon, 22 Sep 2025 12:20:19 +0000 Date: Mon, 22 Sep 2025 09:20:18 -0300 From: Jason Gunthorpe To: Christian =?utf-8?B?S8O2bmln?= Cc: "Kasireddy, Vivek" , Simona Vetter , "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: <20250922122018.GU1391379@nvidia.com> References: <20250915072428.1712837-1-vivek.kasireddy@intel.com> <20250915072428.1712837-2-vivek.kasireddy@intel.com> <20250916175709.GA1324871@nvidia.com> <20250918120431.GL1391379@nvidia.com> <20250919122931.GR1391379@nvidia.com> <045c6892-9b15-4f31-aa6a-1f45528500f1@amd.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <045c6892-9b15-4f31-aa6a-1f45528500f1@amd.com> X-ClientProxiedBy: BYAPR06CA0054.namprd06.prod.outlook.com (2603:10b6:a03:14b::31) To PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5757:EE_|SJ2PR12MB7964:EE_ X-MS-Office365-Filtering-Correlation-Id: 4d49540c-cefa-4c37-429a-08ddf9d2656e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?cWlQUDZ5Z1lmVWVlemtDTUZPMEg2NDZoQWtHbnZNcGZ4NTk5YnVQT0FwVE9D?= =?utf-8?B?K1BMaUtrNVFTWmYyYXFEYjgwdWFsUFpRSHBTYmdvNHNjTmNuOVdoVmZRVHFW?= =?utf-8?B?TlA0WGljbHROcGFIQ3VEYU1uYTZhKzZaL0U1ZUhidE5LUlJ2SWZENThGZ3NJ?= =?utf-8?B?T3NBZWdiQkpia2txelpoYlJpeFh6VStseTBjL0Y2TllXeHMyM2paTlY2NnFo?= =?utf-8?B?ZFFXZWpVSG1EU0Q5eUtWRkNEdU9IcldsR041bkJoVkxJYjdabnNEcXBHVHdn?= =?utf-8?B?V3FLYmFWNVl3K2ZGTVc1RDd5VUg5cU5XTGljaEVzVTdwbldIVVlVTnFUZjdo?= =?utf-8?B?NW9FcEFhZ2VBdk56M1kwdW5xdE1YRHl6UEEzQmNZVEhDbWlqQ0NVcDZCR0sy?= =?utf-8?B?NFQ4ZGR5anN6OXdBZnZlS3A0Mks2dWxGYmJHKzkzUitIQ25GaWxveDZZZXQr?= =?utf-8?B?Tk04YUdWcElWVU14dng5T2JkcEtCR1pKaW5LbjMzUWVOb3F5VkZ1ZktQY00r?= =?utf-8?B?MWV6RHpWdnZsZElpV1NWajNIZ3puSm01UjVRSlp2eTcxaEEwTmhVclVzeHNR?= =?utf-8?B?RVkrbzIyLzJPSWI1SWM1Wi9xYUthS0RlWmRrUzd5eVVBSHJxbkhvZzFrS3VF?= =?utf-8?B?TmxFUFJ2b1Rxak9odWhDZWQyd1RWM2lkMUtydEtzcmpZOVlzcEswaE5KcFk0?= =?utf-8?B?TGtXUUlHZ3VhWmE0NEkvWVhjR241dmFQK1piY2ZPc3FmcGVNNHFmTXRXcHp4?= =?utf-8?B?ZThCc3kwZVlFZWJ4VG1xakZ6TWVOUGhuRHN3VGJ3RGdGaTl4RkRTcVJZWmpi?= =?utf-8?B?VWJsYk9iQkJ1SnNBNGdXOWErc29PWitleFlIdmlNbjdSdXFmMHNxWnN5Z2NE?= =?utf-8?B?V3FaSXArQ05oQ0dDeVpxRGtJOEF2c0ROU2NGZDUrUFpML2tDeGtYRlU2anB1?= =?utf-8?B?UzBXWGVFMmN5MnRlTmZMVnhGVE41U3pweUdJN2YrbXBsdGQvMHV4ekdGM1pp?= =?utf-8?B?Z1J2MHZaYk84YXh6OFdPdjFDSmlST29hOGtQb1JxZi8wdHN2Z2ZlZFRQcVJy?= =?utf-8?B?aGFkVFRGc01sZ2ZNN3BvK05CYmxHbjhUb0RLYmxLZnR1Y2ZEcjNsTk51RlNs?= =?utf-8?B?NUFpb1gwSXovaDl4dXl5b1lObXFtazFWNkFnalVPTVVZc3lSTmJYblk5Wldh?= =?utf-8?B?TUJuczkwZ0NYa05aTlZQN01BQmwraEVVcWtMVFo0dW5WaXhXZVNiVlNuamJq?= =?utf-8?B?V2FEbHhjdHg0OWYyWjdIcDVQZFQ5UHczOUVvWFZseWhNMUFBWm82MkdOeGFv?= =?utf-8?B?eU50dGxkYUFYU2tjSEZOSVNGY1ZkWnRFY0JiWWRHR0RtQmtERFEvRy92c21p?= =?utf-8?B?R0FoVElSVjJ6UDNPUHVteDdPYlFTTXJlRWdyMU40MU85c3hBSVZUM2dPalBR?= =?utf-8?B?T2lkeXNDNDJ5aHZuenluOWhWWGF5K2UrNnBuN1pXbmtkQjA1QU9IZGxJSDVW?= =?utf-8?B?ZUc5eW1iVFcveCtnZ29tQjFhZTZJMzVnZzZjcElXNExSQm1Zdzd2ckRSdTM4?= =?utf-8?B?M29UbUtmTExmMUZORllSSFBIbXc2eUlBbzU3SEtydk5jSVFhcElVZStkOFdX?= =?utf-8?B?Y3hLWlBSSGZkdTdTbDkycElVcDVTZjZMQ0d6cnBIdTg4SXBGUU5RYmZtbjNx?= =?utf-8?B?ejRITUhxZStYVzU3NDhibVlvWk90bVBFWi9HaHBycXVBQVdDc25YUkllN0Zk?= =?utf-8?B?VHJ6c2F4SXBzM3U1MHlwK0tQMEg0YzNOZVVnMGR0bnlPb2wzVHp3WnVCQ2pH?= =?utf-8?B?bUI3UGx1MWNWMlFYeXRHK3hBczVZOVVXQ1lwTnNkdlh5eHdPaXNUK2IzWUwx?= =?utf-8?B?WFRIcytPT1JRZFNUblBiNmtlcUQ1TG9wekpONnpCWGFWMUpnRm85aHB5K3ZX?= =?utf-8?Q?deqaT+0fLgI=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)(1800799024)(376014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?VDZDUjhxUUVRSlpYVlhNT2E4UXBYd1lxeThEVHF5bEYzdkFKcDZzaHNWYmxR?= =?utf-8?B?a1l1SkUxUnBWaDk2SWlyWmJFRlBraEV3N3J1VHBmamJueEFwOU5ieHFLZCsz?= =?utf-8?B?VkUxdmxPaktpR3dOcEF3NTg3bkhEQ21JQUJrUTBXL3M2THdySi9lNTNVTGhY?= =?utf-8?B?c1VtMGVHeVdGaWNWRlJsdkVUYU5wM2tjcVNiSlM2OVBBY1h1MWhLaEJtL1VV?= =?utf-8?B?QXRMano5RUJlcC94VThzZG9pc2pzVTJKR0tkQytNMjVCMzMyZE9OMFozUzZB?= =?utf-8?B?N3BDYnpzTXF1bDFCU3hSdmgwaVBBbzFydUZyYnhwY0xKaU5oN0FOelA2UG9J?= =?utf-8?B?TVdXNjdyQTdaOHdrNUZXWmZGWU5tZHhVWGNRY2NmdnM4RGNWcFJGdWJlQTUv?= =?utf-8?B?WEkrZVFBL2dsUExnTnIvdEZuMFVSZlp2Y0UybmJLdklJN1NtR0orL3JrbERn?= =?utf-8?B?RXBiZkF0ZmE0U0hrbGh0WC8xdGxYb0NqUkI2Ulh3M3VwU1hhU2l4bnZNNkVG?= =?utf-8?B?Sk5yZjFRTkg1NEVVZGJCdlcwenl2anV1aCtNaWQyZVNyVHMxZlZFOEtXM3dj?= =?utf-8?B?Sml1a2htTnZ5T01UUjVRNnVheFp2enowTTd4VWJyZ0lSdlFZNk5FWG5hcTU5?= =?utf-8?B?Q0RWQzhGZkZJNVdPT2pLQUNiRzRZWkJGcUhuSm1zYVBiZkYza1hpK25ldWo0?= =?utf-8?B?NlNkZHRjYjBrcGh0US8zVEc0aEs2NGNwbTl6UmgxV2lNdWFCOURuc0N4dWhZ?= =?utf-8?B?WCt4RU16cG55SXRpTDVkRDc2NG1ZVkI2MEFLOXFNdnRvU3ZlLzFCOXFuMUxF?= =?utf-8?B?SFMwR3dTcUV3aU5jUVFkOVltem8zallKd0RoODFlME02MDA4RGIrbVIxZHVL?= =?utf-8?B?V2hiSTNCeXJlb1laL05lMEtlQW5DVXIrWmgyUEtBTlZVVUx4VWNrZnFxL001?= =?utf-8?B?RTZ3TFFMaE00VmswZ015cFA0WkwwaERSb1AvYnp6VktuQVlXQmZxTEFxL3Q5?= =?utf-8?B?Vlhpem0wQno3OXZzbDJ5TlR4OGZKZnN0VDVOS2VOQnpJUzd1bVN1VWFBZ3Nu?= =?utf-8?B?R1ZoL1RyVUtzTG4xbWRqRDFNaFFHZy9MZlJSbWhodHpvbDRQWDZVbHIzNzFW?= =?utf-8?B?eDlnTDNNWVh6dUt0TlptOEZ5RXhOWlFkblV2MnhOY0hVb3lZUGJCTmxVQUp1?= =?utf-8?B?Y21NcDlPejIrZE1RWUp3d0pFYmN5WnEyVmZaODVtVUtrZkZWcTRmWGl1R29r?= =?utf-8?B?UnRSS3pIbWN3SGpNbEdkVUphRmpoaWY5MHFDejZ0a1pLdUFFdHBLRGlBcVls?= =?utf-8?B?eVd3MnFxOFgxeExhQXJmNWpLanlRaEN2bUUwUDFwK1JPWUk3VmNnYjBGOXFD?= =?utf-8?B?MGVCSVVLVVc4bjJIMjRCc0QyNGFPYnF0NFpMQmdVQ1o4NjNETHpoSUpDRHlo?= =?utf-8?B?RDJVeXFnSWh1d2xIK1Q4K0MvL0w1QnE5MXQ4VDMxbEU2ZFBaeWJTRDBjRWJT?= =?utf-8?B?dDZoNzBJdDJlRjlMSktCWWRGYnovRXBqelo4aGU3WFdMNHlBc3M3dXdTd3RJ?= =?utf-8?B?eklmR3d3eTUxVGdxYWcyVmRnZFpDd1NIYjRGQTlpSWlNbFYrQTNMUlhnOEtu?= =?utf-8?B?ZmhGajhUZHgvVmc1UWx2RVVOZ1lJdEorTE0xYitCdkhab1Z6c1hWd0FNeS91?= =?utf-8?B?NER3NXUyeHcyYmhBTU9GSkdvNHlXRmFjc0t5RHYrc2Nib2FYd080a2pNYklh?= =?utf-8?B?V1BoWVhMNlBCbkZldG9VUEp3aGtxNE1GWnk3TkdBR29LVVlnTjlIbnBmV2l4?= =?utf-8?B?RHRvUi9aU1pWVXFZSm9hc2x1bTNPWnNraW14cVFlWEFCSENOUnBzQlR3ZlpS?= =?utf-8?B?TW1zWml5MGFuamR5SmZRVFJHd1M3Q2NqaWk0aTJybWhzaElsRm1wSHZPdnI3?= =?utf-8?B?T0ZRYjJlNlV1MVRSNlpEeXFWdUxac2x1eVNlQmV0Kyt0S1JEQUNlNU5GbGdX?= =?utf-8?B?NXhIbkgxTEFCcjZ2b051Z3RTanBDTGM4TkRVZ1VQVnk1WUFxeHBOQWhGaGdm?= =?utf-8?B?c1VvMldtSnRNVkY2aS9oN0lrdFI2TEQvQWZlUDgycEZQdHpldHUwSUplZkk5?= =?utf-8?Q?/Jdw=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 4d49540c-cefa-4c37-429a-08ddf9d2656e X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5757.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Sep 2025 12:20:19.8178 (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: 9fpVC45fKB2githgHTMP69LSiSRYpLMEw3oJS8laip4ayCW9OUUU1YsKYSTC+GXi X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB7964 On Mon, Sep 22, 2025 at 01:22:49PM +0200, Christian König wrote: > Well what exactly is happening here? You have a PF assigned to the > host and a VF passed through to a guest, correct? > > And now the PF (from the host side) wants to access a BAR of the VF? Not quite. It is a GPU so it has a pool of VRAM. The PF can access all VRAM and the VF can access some VRAM. They want to get a DMABUF handle for a bit of the VF's reachable VRAM that the PF can import and use through it's own funciton. The use of the VF's BAR in this series is an ugly hack. The PF never actually uses the VF BAR, it just hackily converts the dma_addr_t back to CPU physical and figures out where it is in the VRAM pool and then uses a PF centric address for it. All they want is either the actual VRAM address or the CPU physical. Jason