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 7C132C433FE for ; Mon, 28 Mar 2022 12:22:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242415AbiC1MY0 (ORCPT ); Mon, 28 Mar 2022 08:24:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242413AbiC1MYZ (ORCPT ); Mon, 28 Mar 2022 08:24:25 -0400 Received: from NAM12-MW2-obe.outbound.protection.outlook.com (mail-mw2nam12on2040.outbound.protection.outlook.com [40.107.244.40]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF3EF46662 for ; Mon, 28 Mar 2022 05:22:44 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Mo3pQuAjw5G9FXmBQSVOTL+rXHlR2d0hOjeEp8JZ4WkYNPEtHMZIQPwQ3F4w12nugOpUMjoHVfDFCr/TclQ20inrjCjMBpBLcY9Fl8prvZlVDTTeIzDLknkj2ErCdFSOiT9YG9OQDPUkC/lImDPDH3kSHZ2sfyGgNA5iItUZxWc3S+NCyX0ZkyuOtEe+YtzxkacXFUrvsFJVlHrgQ7iMnmDox6KaPP2yR33Hd3VG6IYv+tDhVsshKn4AfiAPLsWq/D/tdfkI/l5utVPLXw/LpoGqYgHnUM7kt22np4wpZ256sDK4rfo9Epk6z7ljagRwJQ9wSej55gbEX9g4UaKFtw== 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=leRXqSISEjf+QsN6uXjqGo+pNy63RFr1/INsmU/04c4=; b=RBskU51kJb2iLuf7SgzLkKG2lNSGD/jZjgglBspKEeqd3jvS3pK5So8smiVzfVpvn8wKL6IkQBiBMNJsrLkFEkfDbemQsBqM8DIo6PSTre1KqFfZKDbzawU6LeUwrHTJfRjBC0yjnnvfvCoSis69Iq7kBBnxOjPjz1KhlDAhe5jKwLTZ7lj9CwMARKU8w1kI2aLII+8iJzR5F6B7J8K4AyxMIK9igRkHybA0npDY+gzRNe21edj9PnHDcLQoIanZVAb8La+MD/Ic6wzBLRK3nklrWBfgQGAMVJLEWYX/NsaYOI5zUsQnDcwgcyA9TOtZ6iEeqGmCPdPxAiIx0zLmLA== 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=leRXqSISEjf+QsN6uXjqGo+pNy63RFr1/INsmU/04c4=; b=HE6xKx8PaLWUg0myNj0MZlBcmgD9mMtmkDJBSmLGaw9RIjUzsjDD3HK9VsxfkCyCIi7YjonSMbHpumeD7lULW1ujGZPpIEVVjdM6ykWVa2VE+yhKdAVkPErdlqQU5kAFn9uMxWjIRMfYlX8Mr3T9bJ3Pvcki19KFuGup19KwWGsyySrc+5yzJoftIln6wDvtztmu1P/Z0SH0FMPMX27oI+BK6U5YGaF8heuHmkZ2rjF7pwmxdkYvICFkq0OPv0HgsG/t5CFCNdiRroQpWOCp+p4VzPQMgrz0QBFWXQinXagpqogJr9hcmGAccExmH49TWkYXxMKN4nPFeEXQjJX0xA== 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 DM5PR1201MB0012.namprd12.prod.outlook.com (2603:10b6:3:e7::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5102.22; Mon, 28 Mar 2022 12:22:41 +0000 Received: from MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::11a0:970a:4c24:c70c]) by MN2PR12MB4192.namprd12.prod.outlook.com ([fe80::11a0:970a:4c24:c70c%6]) with mapi id 15.20.5102.023; Mon, 28 Mar 2022 12:22:41 +0000 Date: Mon, 28 Mar 2022 09:22:39 -0300 From: Jason Gunthorpe To: Jason Wang Cc: "Tian, Kevin" , Alex Williamson , Niklas Schnelle , Lu Baolu , Chaitanya Kulkarni , Cornelia Huck , Daniel Jordan , David Gibson , Eric Auger , "iommu@lists.linux-foundation.org" , Jean-Philippe Brucker , "Martins, Joao" , "kvm@vger.kernel.org" , Matthew Rosato , "Michael S. Tsirkin" , Nicolin Chen , Shameerali Kolothum Thodi , "Liu, Yi L" , Keqian Zhu , Sean Mooney Subject: Re: [PATCH RFC 04/12] kernel/user: Allow user::locked_vm to be usable for iommufd Message-ID: <20220328122239.GL1342626@nvidia.com> References: <20220322092923.5bc79861.alex.williamson@redhat.com> <20220322161521.GJ11336@nvidia.com> <20220324114605.GX11336@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: BL1P223CA0013.NAMP223.PROD.OUTLOOK.COM (2603:10b6:208:2c4::18) 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: c18c30c6-ba1a-433c-c2de-08da10b5a759 X-MS-TrafficTypeDiagnostic: DM5PR1201MB0012: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)(5660300002)(36756003)(7416002)(6486002)(6916009)(316002)(54906003)(2616005)(66556008)(66476007)(8676002)(4744005)(66946007)(4326008)(508600001)(86362001)(8936002)(38100700002)(2906002)(6506007)(6512007)(1076003)(33656002)(26005)(186003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?u9Yef1VZbu0Lv4NsKquELRfI4MzieG/0YnriZ3wq8Aa5wC60WZE/NSWN/Fk1?= =?us-ascii?Q?4BrkPrO8jLtS3WLquVRvV3kq+15oDbvkWKUwmlGvVzhd41sU3VB4B+m7tPwh?= =?us-ascii?Q?OEEaUIc21qaTT0NNgj8sueC88HDq2zVBLIZWgP7WIA7Sr24dE9o2OpZdj6Hp?= =?us-ascii?Q?Usiddm9p9BD9aOCSc98s2btNcvr9Gw/ry4zCe6YrYdrQ3AQbywnZhzvgsNu/?= =?us-ascii?Q?W0v/5jPGV5V6MSViZj/7ot68lz1kkymCdOptpVSi5gCr/N+s6n6t8YlcwtL6?= =?us-ascii?Q?NqKHG7UaKQWZyeBZyQfBIsjPyUyencFjMlspr62r8vFKgFk3sU6aQLN0qUlE?= =?us-ascii?Q?M4yAetAEPmFIhOGrwdZTuQvztBh1ZdJ5ukQ/xGrb5YIgFO6RME131JnFS9Zy?= =?us-ascii?Q?R0ua/ID7u5905OuxzEajw5H23848qowk0/UQ54K7NydvVGjwQkIyJa7yu+/v?= =?us-ascii?Q?vHNSPUlOdd4KWajTWA18gAxB2w/uNCOk4VgKV4+5E+kgouAwiq+LJ4hzri47?= =?us-ascii?Q?2KVZgnwmLeUXm5bD0IPM5JfnoRNb/wQjIibt8TutQdVvZzUI7IkoBQpNdCi0?= =?us-ascii?Q?WdqHZp1q3CeQoOEG1emDAkoH/S3nOJMF+Aa58Qk8U6KARdCVg6Hp2TjyU616?= =?us-ascii?Q?4YlfM2EflebLH3yistGG6H6CWezzpVQKFWAqfKAt3Y31b6l6QPSwVaRi0O/a?= =?us-ascii?Q?HunqhV07xcIB6RVQNqyTpU1YD1vkSV1ivaFGfKSqcE8P1SQHCaA7GX5zKD3E?= =?us-ascii?Q?5WIlXwGUKpKebF1C7rN//+0081vG51gkRzxjRZ3CrxwitLBFSU5jU2jMPxcn?= =?us-ascii?Q?6vm8UsGUVlhqEan0S7nJvvqVea/lF+zX2lUER3fVoqefD6yFbBjI4EuBzIvr?= =?us-ascii?Q?oUOAypnIkhD2wtjOgPz+hoqhkQkQUCH62p6HpDd1nKDsxuvfpCxFx9MPoC4N?= =?us-ascii?Q?MfRr8u9F4jwsCsac2zJxgWaJEUgPEoFip15gtHS+ghAaKtLsf8nhgYX+NyS0?= =?us-ascii?Q?0Bo9DOP9RnG2CtzDpyNtO9UoA9xW2nHM88jeKaSRGjsu00e/r9NBqHmJ8BBG?= =?us-ascii?Q?HheUo30RzLOA1vONUwqDy92PLfNgrUmUKazYEOj8p2YQyOzxyYMPHynUb2Jl?= =?us-ascii?Q?8575TUfz/OBpCO53wROvFuVI1tIzRq6gUiJo09dCXiP93XrVMI8+Gun2FagW?= =?us-ascii?Q?WidP4B1+q1BTAhiv+DUm3MT5c37o81TYSW9VWVPrDMp65ehAQG/7Lm19UsyG?= =?us-ascii?Q?jbUBG0zCpGJBTwgRNXFEUsgzhvC9T8QYm88ilvtxXUU9/gBCMu+j6eEl2yF6?= =?us-ascii?Q?z3N9ruMIR6GcDxK3zHvY+ZW4+0UoCtOLUKN7mzzNe4KTeSC0TLYUfW5dSS2X?= =?us-ascii?Q?K8d6h+M+XdjhhwyfxNLcO9iHf5vj8l4J0TJGjZVO1S3hq460zOc+JqBTgOKK?= =?us-ascii?Q?OPkBBNve5aEGTYst+gXSppQdn2lftQxwHaeRf0esITFN7RGM1ehFHD+c9ER3?= =?us-ascii?Q?J1oy3OBp3arIfz5klAZo6mpC2Pvz+mnewGFaYsQ7RN5n8FLVqygbfaiScLWp?= =?us-ascii?Q?o8NDEPrFBRqathSQDFYSyAUoYemEnQvUFMbVwSkoR8gKwpKlXh+P+VBozDhL?= =?us-ascii?Q?mTMwJgTjl9g0J9Ifmka/1r7clZygCI1fUfy4ADV6qQIepdlsVyw5SPf+kYU1?= =?us-ascii?Q?J10efGTP6Vqv84S2/+2lJFaNRDOcJlwCO0WdwA9llJ8l6pGJXST4CJY7kvrm?= =?us-ascii?Q?PksVikuuFg=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: c18c30c6-ba1a-433c-c2de-08da10b5a759 X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Mar 2022 12:22:41.2117 (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: cBCWE12KV/5WZKOdR5QZgP1EGQdU+XZTMNGHhLzWp2X7UuBIcdyiGoMD75zVPIMG X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR1201MB0012 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Mar 28, 2022 at 09:53:27AM +0800, Jason Wang wrote: > To me, it looks more easier to not answer this question by letting > userspace know about the change, That is not backwards compatbile, so I don't think it helps unless we say if you open /dev/vfio/vfio you get old behavior and if you open /dev/iommu you get new... Nor does it answer if I can fix RDMA or not :\ So we really do need to know what exactly is the situation here. Jason