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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B554C38145 for ; Tue, 6 Sep 2022 17:59:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229529AbiIFR7Z (ORCPT ); Tue, 6 Sep 2022 13:59:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229495AbiIFR7X (ORCPT ); Tue, 6 Sep 2022 13:59:23 -0400 Received: from NAM02-BN1-obe.outbound.protection.outlook.com (mail-bn1nam07on2068.outbound.protection.outlook.com [40.107.212.68]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B020A7AA3; Tue, 6 Sep 2022 10:59:15 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=KM+Wb6iJtmgNnqLzNR39iGPK4vVeMv9JId05nJ/mse3aHnEJVv4l7XJi5ftFY1HEjmy2G/quMw2GT785f9mNER26XCzpZ3lNp7ZvonsyxjcbXdDfbmf4admpokkCC3cZKkd+EJEhgHP4l9ye2QExiCDqBAiXbtOxOsK9i+L20M0oMVKsZ578vTZZkHtifjOTN1aiEIgwHGwousOFbb0Jxl1ZtKfyzeuPlwEHPwv2W2XRHd3zxrCuUfsp8wGUHrUlYfFBzvsjLVwzbb+voUznSba1zLAifau1AIM9b2iHvC9F8VdEAZlrwb64hL1ISyxS1SdVVYLPSk88WsNdVwiT2g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=XPBe0Mo7BwLdm1Cjdu2xFzCaGIcWRx50sN6KNnVhRgU=; b=kVNYMvPT9Fw4EIMlh9rpn5ZIv2THnmo4Nxe98/lvCMPOJAITXwzVsiJLW24jz3lajDVq0EZaEztsYfzUk17SY/++y3OG04BpBN8vu9bAaQ3oJxCK0xfI4i/voj9W7fwu5EklAAZE0a32JNuPGn2dMtz7X3SW/p9ZxEVPDr2kCA5gmijG3xIATTADemF1NQMSxOdueqMuLRGcI/+TLC86fl/TTF4fy/Af66Skh76mW3zZP5KU5lxovtQ1wfxwq+snGQZwKUoRrcEwzND6MHXneQfbcmsNPLEsN2+N2M0Xk/JJE1amTZ2Wm7uSBLZeL4Vlulya9A4YxZo+gADY30vIgg== 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=XPBe0Mo7BwLdm1Cjdu2xFzCaGIcWRx50sN6KNnVhRgU=; b=Xh9Tjtb5DH8q3mLNrYPT3/bKPajAog6g5zi7e2TnFPPHm9DM5/0968mipC+Quv+3m4Y/Ady/n4/TMwqIWfPpuwd2uF6GAIlw3/8wJQZDpCcAso2ZRGKk1SDunOAI4yJpONbKq9+9Q2FzyhXW9NAOt+4nhI3aGsCvWCLnniQaPps94FerPATVe1Xj3NTVwoPN7jubGPlbzV2CEHYbOjMLTgoj60brHPf5WqlicXPPvGskMEr3bBLODXF9YPTtLK6MyQ24kGxjxu7s9fA9LvzMfVZJexYMjcPFYKId+aMpnbwrOh0XbF7QUOWaqLQiGEAjt2MEK8HNNYfyhnnLyl0KJA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from MN2PR12MB4192.namprd12.prod.outlook.com (2603:10b6:208:1d5::15) by LV2PR12MB5848.namprd12.prod.outlook.com (2603:10b6:408:173::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5588.10; Tue, 6 Sep 2022 17:59:13 +0000 Received: from MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::462:7fe:f04f:d0d5]) by MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::462:7fe:f04f:d0d5%7]) with mapi id 15.20.5588.018; Tue, 6 Sep 2022 17:59:13 +0000 Date: Tue, 6 Sep 2022 14:59:11 -0300 From: Jason Gunthorpe To: Oded Gabbay Cc: Christian =?utf-8?B?S8O2bmln?= , Christoph Hellwig , Alex Williamson , Cornelia Huck , Maling list - DRI developers , KVM list , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Linux Media Mailing List , Sumit Semwal , Daniel Vetter , Leon Romanovsky , linux-rdma , Maor Gottlieb Subject: Re: [PATCH v2 4/4] vfio/pci: Allow MMIO regions to be exported through dma-buf Message-ID: References: <0-v2-472615b3877e+28f7-vfio_dma_buf_jgg@nvidia.com> <4-v2-472615b3877e+28f7-vfio_dma_buf_jgg@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: BL0PR03CA0010.namprd03.prod.outlook.com (2603:10b6:208:2d::23) To MN2PR12MB4192.namprd12.prod.outlook.com (2603:10b6:208:1d5::15) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 0db892cf-56e6-4bbd-dee7-08da903181a3 X-MS-TrafficTypeDiagnostic: LV2PR12MB5848:EE_ X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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:MN2PR12MB4192.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230016)(4636009)(346002)(136003)(396003)(376002)(366004)(39860400002)(66556008)(8676002)(54906003)(478600001)(6916009)(66946007)(6486002)(86362001)(66476007)(186003)(316002)(2616005)(4326008)(38100700002)(41300700001)(26005)(4744005)(6506007)(107886003)(6512007)(8936002)(7416002)(36756003)(2906002)(5660300002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?g26Qw1K9WschwSiUnSc0ZLS0RBYM3MS/2Qa7daI4tsmOS2SyDioHB3faOuWZ?= =?us-ascii?Q?358ZcfLKeqL061vu+6hQSD2S+J22JLQBek+8lLFtDqrmvRPjWGW4wfLwf6d5?= =?us-ascii?Q?3D9Vm3QxsMsdGmNQKwQo6a4KLy4r1ONdML63KrlrBguVrYQfF6W/j7LeFYNX?= =?us-ascii?Q?4XUAoRegrlb9CnmBNGnwGgvCPNOH5Yuvnyzegm2uqUWnSEY8Ro3ZzURNYWMK?= =?us-ascii?Q?2LPAtN1ZSrm6ge6nQS8yrecazHBkMf4RpxU5dZ4YeI+MSmBWxaZCmi2TTo74?= =?us-ascii?Q?mYydomXTdaLsgxXlZfDKbW2sXYlZlFF11fHRQnPhHIjPH1W6uDyERztMe1i6?= =?us-ascii?Q?ZxV+Kc5JyhLEVTe8BBFfXVzv5P6Wh4zP6NKI/IJyQ0GydQm42RUDIv/b/knh?= =?us-ascii?Q?3JoHkFttF3Lmc1qR9+Wtdi1LwQ2I76sTwIpXjYw9XgeznP+ZKOARqHUjJ/Bd?= =?us-ascii?Q?YeTFjxD5pyZ8/fSKytnxXsjvCiyqC9mOcYdXPH+0h5gKEvZ/kuwLpbr+YvK6?= =?us-ascii?Q?dqQdAnfdzpOm0uiNpMAFO4Sg5Aihc7zaYnqlmyodAL6envGEApBfnS9kiicp?= =?us-ascii?Q?oWSYMig1c9QMdNpE3iUppWv38OcM2d/OJdtxD5DDswtALILcgVnNZ1LskeJP?= =?us-ascii?Q?7SiryOyXbIdMtvhdlDdVhEyJQDjxIhqvGOWt3CkJWhT38LFELvMiGDYk4FAP?= =?us-ascii?Q?9rGy36ppm4hWhxYjmf9tQlAETis1n9vbnwPWFWupz5BVxpd7lbuc6iy1KJUH?= =?us-ascii?Q?gwc8zMwrPieb4dpDSEuAlWDG3W/wyXsqGnp0kos+Tn0LXhXXMM0JWb4BLs5V?= =?us-ascii?Q?r5pnwL0CH7C9uKxC4UBsbPpKgp5viRKD4zcIGruF4EzyKPhRPgK4ZZH+cOJ+?= =?us-ascii?Q?gmJnkzkNqwHCnu3xAVrbiGvcn203WgGZLgUbxJ141qMr0JrUuLFRuXTXU6u6?= =?us-ascii?Q?mInOBOOL+0ykPaQQI+xy4zpSTh8+NFIqCGRZ/NTa4XVO2+KAPpYGDnMcTIP3?= =?us-ascii?Q?AjrVzdfAoCMeExwFd9QYBTPjqe3ztg+zpERqgJuJ8GsrBrFLHWDUBlSDjiaO?= =?us-ascii?Q?JeH9O/fiSMKZGXZ0vTCc13xzw0/24ML38k5wYzgJE1k7mopeejO6EkscWbTh?= =?us-ascii?Q?a7tmg0UqdG9UcvCCQdXDpHPzdAyU0VfIHAKWhSvTe2Ko2IcUCSQlxu6yNDgu?= =?us-ascii?Q?GDhRgMi7pisJA0tOFxfk9Twujt9IyVTOCsyGILUKfMpaV+b1v/jC7aSCg9aR?= =?us-ascii?Q?pZlbPdo22P0HJ1twU0QOegRReD9Tv9U5BPlMT8vlKuAUE3TL3pZFngyEZ4G6?= =?us-ascii?Q?/i9r5gFAtEAKQPjn1AXy9F+Fv+drQwniy1+dFpRVc8XjxrGPoed/15HGQX22?= =?us-ascii?Q?y0oJwXLJ+cQuiiSUw46o/DF0CHPwhdq/2hH6RABSMr+hiuy4qjVPWMPv5eiD?= =?us-ascii?Q?g1hBEf5jHnTUpKLboX3I4h9AZqU/PirKoHpK1deHLg90dHWME1bK3EK/PNha?= =?us-ascii?Q?MctbfQh/4Hrll17XdqWtQlwA2Nj+VRFpSIvbO/hNb8B5jIVyjjRnIxS5K5XI?= =?us-ascii?Q?Hd8suYLKAaFuuvSOIRtRf9Yj48czc7o8e8e/ZvKg?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 0db892cf-56e6-4bbd-dee7-08da903181a3 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Sep 2022 17:59:13.0550 (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: ilmAw54G+qxpqD38GpDjJzBkRdlPYI7P5IfTLI7BCQDSaLo33/lia2sDbr/oZQg4 X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV2PR12MB5848 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Sep 06, 2022 at 03:34:02PM +0300, Oded Gabbay wrote: > > > > > + /* > > > > > + * Since the memory being mapped is a device memory it could never be in > > > > > + * CPU caches. > > > > > + */ > > > > DMA_ATTR_SKIP_CPU_SYNC doesn't even apply to dma_map_resource, not sure > > > > where this wisdom comes from. > > > > Habana driver > I hate to throw the ball at someone else, but I actually copied the > code from the amdgpu driver, from amdgpu_vram_mgr_alloc_sgt() iirc. > And if you remember Jason, you asked why we use this specific define > in the original review you did and I replied the following (to which > you agreed and that's why we added the comment): Yes, I remember, but Christophs remark is that DMA_ATTR_SKIP_CPU_SYNC doesn't even do anything when passed to dma_map_resource(). The only attr that seems to be used is DMA_ATTR_PRIVILEGED from what I can see. Jason