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 26D44C433FE for ; Tue, 26 Apr 2022 13:53:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351234AbiDZN47 (ORCPT ); Tue, 26 Apr 2022 09:56:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351232AbiDZN45 (ORCPT ); Tue, 26 Apr 2022 09:56:57 -0400 Received: from NAM02-BN1-obe.outbound.protection.outlook.com (mail-bn1nam07on2045.outbound.protection.outlook.com [40.107.212.45]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29C8C15DD40 for ; Tue, 26 Apr 2022 06:53:49 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=XA03z5uHlSJEgaOYNup0d86chSk2owS9X+J2oSb9jD+xxDXm8OysUZsS9iJ0xINwCb10y8HZ9fMntiP151iVd2+LgFLzaV2ZSQ18hLZYUXatpYZ7yxiIKdPqOgAMgc/eVo22TGHOsdKI93LZ5Spvv39aZJso3LFO3LAajDRJsD7Xgu0zStTRgLzgtQ9AvdOJcw3xTWw8a1bqfqUd6CWVBUXvdnPj5MZgfItAyRK4XJF9asfBfTSn7jrrJKJnNgJO9ga1HL7pUGTxHozuAeIgIKGNO8COOTCTvgAO9P8RicHbugJyMpRPCZldr41LsOl0ruUlMjuO7Vm8ekmlXRLP+A== 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=NsVNCXMff1bsOVQl6xK+qCNXUijD8pmq+eRU2YNH6T8=; b=nyYHdB/W4r59kpe4gtFx/0hJjBLqKDujzzfMWDAkrByomMkLQdSWxWA/O8AF4agdvBTc1Y+3lKn1BGjFCpEZEKxKAL5l7hstYRiyN5h2cIVdVQrX7pqx5a3r7AtTaPA/mFapIk4pkLeSvMYPDoy5J9QaCHS227RNJrWuD94EjAjPlbOXSflt81xlwV+ZSgLOPDammU+kA5ru7s8mDWwJEAXQwpDAlGeg7SerWkb60r0pB+tQqXUsV7VrK5NXIOpDmXc9tqqPg77wATabUBHA1qn59un0MdyuQANCxqJ/OgpgSfIf4LsxmjT4DrnzLI1hCdyGx4o2HpbJ3R/0s2CMtA== 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=NsVNCXMff1bsOVQl6xK+qCNXUijD8pmq+eRU2YNH6T8=; b=TU0djGxaVLfGT7NnIUPptN/Mbx12aGr0eVfdj+xtiYJdv6uJFXRF+jFzYBASMWwI79QrmypXKv5LHI9NZl+LSQ5CL4SS4MwlTfvEh5AkdhXCHE0VtZ1m1k7TUr5qZkB9T5ktK/b7B7g76xNkMR8KM8q+8d8uVyL7tq3YgMg+ApJ7W5YX4D912z6sN9fhhU+osQgYPvQcxsbo+Zp3xXMyvy7DUhBpQZExS7Nibmg2p7xdKtdFqmCE31lwJr8z3CkVQ47wJKI1KI7sOd6NEaG18u/v2+8MYLHYYQFr+v+Pubooz/y4wpl4F8vPp4ilDcNyh+eYsUJJSOgOvALy7XS5ew== 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 CY4PR12MB1414.namprd12.prod.outlook.com (2603:10b6:903:3a::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5186.19; Tue, 26 Apr 2022 13:53:47 +0000 Received: from MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::ec2d:9167:1b47:2db2]) by MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::ec2d:9167:1b47:2db2%6]) with mapi id 15.20.5186.021; Tue, 26 Apr 2022 13:53:47 +0000 Date: Tue, 26 Apr 2022 10:53:45 -0300 From: Jason Gunthorpe To: Yi Liu Cc: "Tian, Kevin" , "Peng, Chao P" , "Sun, Yi Y" , "qemu-devel@nongnu.org" , "david@gibson.dropbear.id.au" , "thuth@redhat.com" , "farman@linux.ibm.com" , "mjrosato@linux.ibm.com" , "akrowiak@linux.ibm.com" , "pasic@linux.ibm.com" , "jjherne@linux.ibm.com" , "jasowang@redhat.com" , "kvm@vger.kernel.org" , "nicolinc@nvidia.com" , "eric.auger@redhat.com" , "eric.auger.pro@gmail.com" , "peterx@redhat.com" Subject: Re: [RFC 15/18] vfio/iommufd: Implement iommufd backend Message-ID: <20220426135345.GN2125828@nvidia.com> References: <20220414104710.28534-1-yi.l.liu@intel.com> <20220414104710.28534-16-yi.l.liu@intel.com> <20220422145815.GK2120790@nvidia.com> <3576770b-e4c2-cf11-da0c-821c55ab9902@intel.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3576770b-e4c2-cf11-da0c-821c55ab9902@intel.com> X-ClientProxiedBy: BL1PR13CA0295.namprd13.prod.outlook.com (2603:10b6:208:2bc::30) 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: e6649dfc-3a9d-49f6-dd3b-08da278c2f50 X-MS-TrafficTypeDiagnostic: CY4PR12MB1414:EE_ X-Microsoft-Antispam-PRVS: 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:(13230001)(4636009)(366004)(186003)(36756003)(6512007)(6486002)(33656002)(6506007)(7416002)(1076003)(2616005)(26005)(508600001)(6916009)(54906003)(2906002)(38100700002)(66946007)(66556008)(66476007)(4744005)(5660300002)(86362001)(8676002)(316002)(8936002)(4326008);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?EYr2iiknfexBNuXw/I0cLd3YIb2xtsTVxfv5pgjiSm0VdmSKQ7IgA/Qi4Whm?= =?us-ascii?Q?1eZKGqd/hP8iYCxtekxwh0EAKaUab/z4ITG0hSGZdkoS5Hc3ZWGezxX2qduB?= =?us-ascii?Q?EE4j2V7iSqS3BxU0WGjJ8wEP3SEj9Xwa+ghZ6RRcaFTw2hwocghoF1th6AeB?= =?us-ascii?Q?7gzw5tGY/LEP648pMb+5GSxUYRknJQOe6Ij5KcCpgv1RluCZhkOY/FoExvxQ?= =?us-ascii?Q?wi2kI2fCjuRoGaHxeDQKL7bbWyazK6Gm/uG1KWkjHLRvulex+veDQ+US+45z?= =?us-ascii?Q?6HY1oZt0NuDELP+ib6idr0bQoH/q24Fy5cb0UZZeCX4wXp2szTJq+A9B/LYW?= =?us-ascii?Q?i8yz7SihJ94PgTBy/Du0bLivu+17eYEKWIsSu055ZUdQCTznvRnVRbprRLa8?= =?us-ascii?Q?JibxVFMFkx0fsy3W/aQWelP0TCuU9YQ9zF6pOD77V3+4OVKA12u342UAAPDm?= =?us-ascii?Q?oQdfNaovLbRLgiLKE6KsgofYDiDg+8Kz4+IgEh7bepqF6HMdwTHuq96InADd?= =?us-ascii?Q?8vL3ymWTalHpXioQN/TyOLzCD86iZn9cy99MqI5CrznO6PoogibRNj+D5V1/?= =?us-ascii?Q?JXnNDso643ircgJ3aOd/rp8akazEVuH0MddtxgmrtIANbuMJgNDBlldcmgEl?= =?us-ascii?Q?LgPAg9ZVWp0SdrBNZHLrVXsFnuCj/zutnt6V+wEH5Gw5zy31oFoIg/j+PaZq?= =?us-ascii?Q?behR9oMLTI2uTV83oeHPH9S4UCXs3AI/R4JGCPNEh/+c5FfjYdT2bbNcEJp9?= =?us-ascii?Q?JjMxvk7nJyS2Vd0N8z3wdF1EcyHgdM1U+XUR6gs5WKeG5ChcwwlVZIX94bkd?= =?us-ascii?Q?nC/ZrUd9QaQuAbn6K5pY1yAf3CX/IC0PQs/w1oMTmaUHbxQwU6AwSzqghync?= =?us-ascii?Q?mUPsQDlAol8Sk1mpxgq92VGYi2vP+TfJ8W/oBrpHfyXbvWEdakYUlrXXxAjM?= =?us-ascii?Q?r3JPaMdWVLER1H6LPdWH+qnhX1hu3xqbtJR0Lk7JuPB4JHuVzlgePa6kND0I?= =?us-ascii?Q?gGJD9wtwJy9/+VwrIHZiDsD39jFT1cNmhupcXFzG5yGNQZdBCSeyL4Qq+g6r?= =?us-ascii?Q?Tuc/sT4c2STxV+hFltcKOm9qTM5ul02IvMHyGD4bkdHqvsE51CyiKW7yU+Mf?= =?us-ascii?Q?nbiz6QXLYivHBNIFWDOt9wXOBNKSbZD1g3Dx/B88xlZeyAreMJb7rMEfrT9/?= =?us-ascii?Q?ol4EuYpB5+WrnXaX8wCE4RqjNhVLoeKqgnCL0zysq2f1hPdgFHLyCH77IYLJ?= =?us-ascii?Q?/1g9RKUrR1dMcvho3hd9fE3E8Iw9XRD3Z6Zk3JJxJbGQm2p0incWLLvdhQiY?= =?us-ascii?Q?rnVDgP0fCwLtHeJIxiVk8yaoNcaDfO6ZrdNSL7Yl/e+ok329qqIMuQiSHgy3?= =?us-ascii?Q?XXpXqdcmTNMDrOgoacbpyoIhOSsSvYOjRJgVxxwv9rIqgHUAMFF6mTu4RT1L?= =?us-ascii?Q?Hd2ZHdPklsNI+/7gV8Yyl0hxdNqzB6X8sK9CInORAbwIrxZj8j8noRjt+wJd?= =?us-ascii?Q?rkugr27CBN/2uwKXIXnK7FI6FUG6Pd8IaoTaFhncW76N4EKe5qhh95xAc0Un?= =?us-ascii?Q?S+ddp9jDBS8noMnsKc++Swai8qXaGJmWPb9clup+6/LQotN+XAR7jkJRhsxa?= =?us-ascii?Q?7WV5Go30JLouUcBNel8s73kdU0/Y27JhN8kfMUvANQWig3ijjGZmCb8Ghfj1?= =?us-ascii?Q?yPc8rpobih9BZlm78+RN/N27P0SixCNjKr6zbg/GQ6i9Jo9U6UZidfQM0kFj?= =?us-ascii?Q?wLUfA8pvXg=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: e6649dfc-3a9d-49f6-dd3b-08da278c2f50 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Apr 2022 13:53:47.1110 (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: jf3A3TM4auHoV07PqwPfCKy+waBPE10opulL1/mvS61FTXjqg85P/kC0H+RY2ji/ X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR12MB1414 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Apr 26, 2022 at 05:55:29PM +0800, Yi Liu wrote: > > I also suggest falling back to using "/dev/char/%u:%u" if the above > > does not exist which prevents "vfio/devices/vfio" from turning into > > ABI. > > do you mean there is no matched file under /dev/vfio/devices/? Is this > possible? The layout of /dev/ depens on udev rules, so it is possible. I only suggested it to avoid creating ABI here. > > It would be a good idea to make a general open_cdev function that does > > all this work once the sysfs is found and cdev read out of it, all the > > other vfio places can use it too. > > hmmm, it's good to have a general open_cdev() function. But I guess this > is the only place in VFIO to open the device cdev. Do you mean the vdpa > stuffes? Any place that starts from a sysfs name would be interested - I don't know what vdpa does Jason