From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from DM1PR04CU001.outbound.protection.outlook.com (mail-centralusazon11010064.outbound.protection.outlook.com [52.101.61.64]) (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 7758B3C5DA6; Mon, 30 Mar 2026 13:33:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.61.64 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774877624; cv=fail; b=ey/Bqsx7LnLextof73vsxOpno8x6g04dsCd+6wiczBU6iWFS3kN5k/q0obAbzktdB98rOHIHcqtrAziZthzbc+cFX1oJflkaR8Aq+7wdMnBqouba1nxPxQPSLw2MK2/T/jQ7GxOqyFR9SDwbGnc8O2MnYFhyHmbzU6WD3Wv6pgM= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774877624; c=relaxed/simple; bh=9Pujk4dGqlufmzXKIKaeVEa2ZxJqxSMql42An88JObY=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=vE27TNZ8eKzlPRSHE8tnI7KQvpQKrwcjOajkNHM8NiYWQ7p2k+SDvYLAqLNSd3Fg1yXn4omtkvclXQ+9pX4vuO2GB00EL8FSGSAnthvWLJ2D4IXjKUb1wGMWAd2dL5LxvR10o2K04eHPg2qy2/n+0rSTjQetmxNZ2NO0nwCQ000= 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=rRGE3Kn8; arc=fail smtp.client-ip=52.101.61.64 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="rRGE3Kn8" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=TFkhqAcWfnnFDha2DFJFBjBuVOlNVH1AKQDQwAXBZe6UFbTUvKnXMgD0eaaMeJp/Qol5LM7BXAhO4IQAs8zkWhwcqw2R157PSxbjJQK/3V3PLBtEG5IUJQuPGG6705HqbhUrqRRVRvEyNJDnPPram4xD0jJa63sHsjCbG6N63x9cQMY7a0yuVgUZBweorvVa3T3DegGFG1bvbnYPL46cexR8Bi1iiiUj/1wFdrqrqNwePQFNwQvg6fvh5cjAfGPh+wVcRS2/jpbFA9iN8AVlduJ2nOL8WT1dfHoFDC129leduFLgMCm/UzyC6HC4PozGmeq6BQWCwt7B4n9l2kvOEA== 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=9Pujk4dGqlufmzXKIKaeVEa2ZxJqxSMql42An88JObY=; b=S+GNVBYhX2mRkaaexUSfaUScZEGA8MAXPRj43BvfuLTzlEfa2bXYGcw4zwymTN3Kids25pEV2H+f94rSZQZtNCZxLeNGuqBjWKV5afXSqXTxPb5bRuvHKM4h3el265uDXcdgkaOZpbq9PGFx8cK0SSOO75G9Hf+RZj/acpabeyS3xbNA7GAo27bk++xgk/rnQmiJ5nRRWROiS4JZeYARM8M4Uex9REskMKQwfpwrv3PTeqyWSPHWJXkN7QTDRTaLqdQO4lNI9ljIGgvW7gTyo2FluvoYsxqu3Rrb0NYCBfbA003vs2fAs0VNG2PXIOl28XFEX60A9qV6JwAAynPfBw== 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=9Pujk4dGqlufmzXKIKaeVEa2ZxJqxSMql42An88JObY=; b=rRGE3Kn8qe73Z2xFAVeFhhBxXrv0EgFmjZCVSaR16OzuZz+0szs2/l9BZk7fBVRrfiaeIW9U1cYAxTFY/XgL9BozIOj3JGqo0QYMsF8plbJYEbRDeOroJjv3sUU5GvBqNmvQ+n0Nrr9V3ue6w1gOCHzFYZPG6E3tnAZMl+B3fgAnveRd9g80KrAapjkJco36je1BRJjJRHuw7YZq99elOpNQgs6IFi9P1IVCPcI+gi8lHZB/Z2ovcWS8UE2fR5AEEgsMvSvbWBF1lf2jpq/P2eu1BCxRedwMc5YQXS3q+L4CsRJoM/RBo5SpjDCceqK4sZDUh4LSqvHGAO7kcUQ6yQ== 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 SA1PR12MB8162.namprd12.prod.outlook.com (2603:10b6:806:33a::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.15; Mon, 30 Mar 2026 13:33:38 +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 15.20.9769.014; Mon, 30 Mar 2026 13:33:38 +0000 Date: Mon, 30 Mar 2026 10:33:36 -0300 From: Jason Gunthorpe To: Matt Evans Cc: Alex Williamson , Leon Romanovsky , Alex Mastro , Mahmoud Adam , David Matlack , =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , Sumit Semwal , Christian =?utf-8?B?S8O2bmln?= , Kevin Tian , Ankit Agrawal , Pranjal Shrivastava , Alistair Popple , Vivek Kasireddy , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, kvm@vger.kernel.org Subject: Re: [RFC v2 PATCH 09/10] vfio/pci: Add mmap() attributes to DMABUF feature Message-ID: <20260330133336.GT310919@nvidia.com> References: <20260312184613.3710705-1-mattev@meta.com> <20260312184613.3710705-10-mattev@meta.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260312184613.3710705-10-mattev@meta.com> X-ClientProxiedBy: BLAPR03CA0180.namprd03.prod.outlook.com (2603:10b6:208:32f::10) To LV8PR12MB9620.namprd12.prod.outlook.com (2603:10b6:408:2a1::19) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV8PR12MB9620:EE_|SA1PR12MB8162:EE_ X-MS-Office365-Filtering-Correlation-Id: d65c013a-1b1e-47d5-9b76-08de8e60f2f2 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|7416014|1800799024|18002099003|22082099003|56012099003; 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)(366016)(376014)(7416014)(1800799024)(18002099003)(22082099003)(56012099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?Cep76aewBNsCGFY5xmYcGu8FL9LNfZWdDJnBVCZsy1v0WRJdbZF3wGwRzhPe?= =?us-ascii?Q?vTZRR1n5FARtqFhg3T83oveQ1a/Cq3CX3i7R3BjsTNICssUZ+rTLPrPKwEPa?= =?us-ascii?Q?PAQrH7mkggoWY1Y4VXGWOxAxEjZ3EIPCIfI9HQpjEguuoE1Mpll4AguNECj8?= =?us-ascii?Q?/KCiLWsXBK2+8HLrQQ1bic4J6Q09eoLeKDEAlS0RNfYc1FlCHI/voqE0pnUt?= =?us-ascii?Q?+vJKtanZlvnhDI8L4fyYCdKsiyiS8lHjmGWpyPNDzM4AI3rohJpqd1c3Q7Vn?= =?us-ascii?Q?tHYG4d7MGARa8xEC/LXoOkdCgr8GXI7v74DhToU4SvGUdqRIV/YKJbZhH5Fj?= =?us-ascii?Q?XWJnykD+EdugJEkgcUiqg44NA4G/s88skV1B5tTNmu97Au8bIFBHxA0pJ3Sk?= =?us-ascii?Q?yeOScJdgID1iPiN2t5RiIVxkdBIUCCvYHlNOaQBKRIuczmuL7DQIX/YuSkPL?= =?us-ascii?Q?KCYcCEEnxjYzbCx9WAnc1CfkFp/STWIVDi8RqeMNExJoyDhh8Vsr8puWlYCN?= =?us-ascii?Q?4khvvEgrX4l2DhCWADyY03ZiHew8RTyy64/vD1GbmtipmVVUNOposTyhkffz?= =?us-ascii?Q?Ok5UAvr4HALPSc6zRe0CPr3ZfEJqt6T8X+bWrgUl2pmskzSDFCET46x/Wdju?= =?us-ascii?Q?lXUCtex6fugJh/xI5UkHG/31A2Z3q15oiiWge6M6K10+FamVbcEVzkSdU0/p?= =?us-ascii?Q?uQTDmPBMWJ+A/IXb2WR8oLfQX4SIPi4QHUrV48iieYOR9rFkq6Z1PlL3+6vy?= =?us-ascii?Q?JAIa8XErdIlSUBEtfC5hTr3KtXvmmK4YY1JnTsTc1Q9d64W+YSba2Ambt7Tg?= =?us-ascii?Q?c/wnUmux5CdQs1jLnCQ7GHYC26o4UsZMP8UDh9/8nWN27NUZ8zVWzeEIqfcL?= =?us-ascii?Q?NtMky89NAa2sHoa9aEH9kFub/Ff3dxbHVZnbEgo8Bdt7IkN/3Xqgam86hb5/?= =?us-ascii?Q?e1kExIhSwbvuYEEV+kQPTa6k5hzq2725l6dJg9XE6w1wATn3bqVeSIpOayXG?= =?us-ascii?Q?P6psBimVltaxzUHmtuDpVX38SAJuKVZhJ+O4Ao4Np42I+MeO6dIIUw83sMmI?= =?us-ascii?Q?YhEo2Z/wiMjzo/0dungT8PrWygW17vAnnBR59CxKGYFzz7W7IzEkDAcN9M+1?= =?us-ascii?Q?nVxm1XLmUnHh+fSzs9eThiWdJp4D+ouQl0glnpHgrrXRWu3+TSNKKHdqturk?= =?us-ascii?Q?ReUN003Cek4pkaGha9iXjwT4pLl1RTyy7Le/C64FdETemdkx9EX4FjEvA+bF?= =?us-ascii?Q?hgycsoJE/JdpzLDg/rLlOBUsDFujkp+77XFcZj2UpYx86FmpDDJVu4L2xvE6?= =?us-ascii?Q?cIzJxxDJlY1Ea7XCgxUkv3fu/whTP011KuYBAEH/8k6ih6K00Z27ZLp2NSP2?= =?us-ascii?Q?Os+gRVI+6blZz72ZDrEml5J+MwtOKwvwYK2HJKnB+Vuu+q+u+21bbGINiebC?= =?us-ascii?Q?w7AwGQW6z6yoNUZSYAkzoNp3Xvda15jkyMMBFzqPqPGMNUFIRcekFG0WNl8a?= =?us-ascii?Q?1Elj4Nfqyi9IyHjwf7H177vfi6bojk30Xioiuk/e15bEkZe+uHJxqoJTmD7a?= =?us-ascii?Q?aiR6ude0gJYo285MYdiEeU5rPrBMKETWrbVbG9enTYSKSi/b+isbUjAXYJ1i?= =?us-ascii?Q?Jq3ECUoDETSltq//rjwSqhzlxwl6HkIlyi/HE5cvWaGYlQvrlZM7LPAQrlqj?= =?us-ascii?Q?gQ7vNWS2nilZY8B9GgtHh+5mg4G+7/xTwekX02F53ys5Cj5G?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: d65c013a-1b1e-47d5-9b76-08de8e60f2f2 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Mar 2026 13:33:38.0534 (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: p3MYCT7qiID55Jcg8RSvibbewI/Asvb/fjEkLiMAOkyH9qVHWouDI8ZDzKj6hp8b X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR12MB8162 On Thu, Mar 12, 2026 at 11:46:07AM -0700, Matt Evans wrote: > A new field is reserved in vfio_device_feature_dma_buf.flags to > request CPU-facing memory type attributes for mmap()s of the buffer. > Add a flag VFIO_DEVICE_FEATURE_DMA_BUF_ATTR_WC, which results in WC > PTEs for the DMABUF's BAR region. This seems very straightforward, I like it Did I get it right that the idea is the user would request a dmabuf with these flags and then mmap the dmabuf? Jason