From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2041.outbound.protection.outlook.com [40.107.236.41]) (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 E13253D65; Thu, 8 Sep 2022 16:14:46 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=iRFufvCZUeUDOQJRnxng9G3ynBf9d5LmYDnyRj+4X3sbvRGlmFEA/WVx/vOEtUabvovxNpZooT57GrKK/yfD1oGI6Uhh2gSp3fvCMD+vriCHmHAPvre22nmfmFfCgH73sDw5W5ZkFgApnLFMTUgupwLbkzeinleOWsB+LBSjy1fnTNnk6p6nH7sP2XS6tWy8+8aVbPBcFU5LuMWJ54/vBx4W5lBBE/tAx0y3UURhZe08kVWrZy0aE0kaFUxNkq+64m/mBtcF9qwru7K/NtE/EYusxHzHLSRW9wiFmF7kucXrh7YTRpCRT8DKIlxiCcnS50ah1RMUyvgKHOAQLaXo3Q== 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=yJF2EmhiFTi6X5MwBd2ldmxkE6wrBxgYe+fji5XwIS0=; b=FCgjNrN/jdCB6mexx2ALaQzVfwZoFxw0YQjIBc8fzAv0s+rRE7YvszcyQ10EfuUecMr86CWNid3v9zu9blDe8svRZoCVCF6Xy0KnD8LC69inrH7yHgV5+cY7mjPSg/mnLvaramLtTjz78nmQR5K7WWGIElmBe28KoVxB+tsG6nB0/gNu55h+KguY9gU82nx6Ji0SEZfICzifH+g+AJxRkx5jmw5D6s6V4SeF585V536uWESrmkDGGEKFA+pPDcYj9r9VmF+1YsUiZcU5oMevvbar9JT+KS5dD7/MHl+AqNQYefbVhEgmcd1FMAiufFLzBfrIwdTKhemGhtAeGiznKg== 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=yJF2EmhiFTi6X5MwBd2ldmxkE6wrBxgYe+fji5XwIS0=; b=Ssp9+comEwxraWD6+6lCCAOeHQ/xCw+7ezoEkPVzzAEVEHeWLnv/udJ7ebeUpeAmuNeTX3LizuGXnFT8DwR700vWRfB9gxfVmTEk/dUE9ZrIMsJd9LxnD0Lfatntz4Nh8GIP95rghxw+3HRTlnUK112RQWlwXtwZqdIDUZdVz4lL1N5MH45PkrPe4J6ZqTPqY37I5M7ScdqlFl9LthVb1npZQAAUlsL0VjYJZ+cpoodoi+jywsKv8Bk+Dvwpz4vkaMqHmXC4xuoqDxtEXnKUGxd6iYgebS2nn/tBFwWhR3/wXj0W8COYFYjr3W9wVlC+sWQPf9uNhf7m5FurmyP8Nw== 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 LV2PR12MB5943.namprd12.prod.outlook.com (2603:10b6:408:170::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5612.16; Thu, 8 Sep 2022 16:14:43 +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 15.20.5612.019; Thu, 8 Sep 2022 16:14:43 +0000 Date: Thu, 8 Sep 2022 13:14:42 -0300 From: Jason Gunthorpe To: Joerg Roedel Cc: Nicolin Chen , will@kernel.org, robin.murphy@arm.com, alex.williamson@redhat.com, suravee.suthikulpanit@amd.com, marcan@marcan.st, sven@svenpeter.dev, alyssa@rosenzweig.io, robdclark@gmail.com, dwmw2@infradead.org, baolu.lu@linux.intel.com, mjrosato@linux.ibm.com, gerald.schaefer@linux.ibm.com, orsonzhai@gmail.com, baolin.wang@linux.alibaba.com, zhang.lyra@gmail.com, thierry.reding@gmail.com, vdumpa@nvidia.com, jonathanh@nvidia.com, jean-philippe@linaro.org, cohuck@redhat.com, tglx@linutronix.de, shameerali.kolothum.thodi@huawei.com, thunder.leizhen@huawei.com, christophe.jaillet@wanadoo.fr, yangyingliang@huawei.com, jon@solid-run.com, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, kevin.tian@intel.com Subject: Re: [PATCH v6 1/5] iommu: Return -EMEDIUMTYPE for incompatible domain and device/group Message-ID: References: <20220815181437.28127-1-nicolinc@nvidia.com> <20220815181437.28127-2-nicolinc@nvidia.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MN2PR04CA0014.namprd04.prod.outlook.com (2603:10b6:208:d4::27) To MN2PR12MB4192.namprd12.prod.outlook.com (2603:10b6:208:1d5::15) Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN2PR12MB4192:EE_|LV2PR12MB5943:EE_ X-MS-Office365-Filtering-Correlation-Id: f4d7caab-751a-4bb2-77c3-08da91b53d6f 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)(376002)(136003)(39860400002)(346002)(366004)(396003)(86362001)(83380400001)(6506007)(6916009)(8676002)(316002)(478600001)(41300700001)(6486002)(186003)(2616005)(6512007)(26005)(7406005)(4326008)(7416002)(36756003)(5660300002)(2906002)(38100700002)(66476007)(66556008)(66946007)(8936002)(67856001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?rgHdQNvKytT8KAjagVLrkQzSXmc557KiaR+7oeg/yK6pqghbhQxw2c2txssU?= =?us-ascii?Q?3+VLiAnjLtudsMQGahypFfA2gzFqNL5wvfknWF7g+oNS5SSgOQ+oGC2b0IFp?= =?us-ascii?Q?JtKFhJVkDdNnlMG9ECrO036HYhtakKrHDx2Z/L86Doc8imhGv4ZXUFCZF1hd?= =?us-ascii?Q?oZwmuLmivheuSjx1QFW3wb03Ns0KLUmLcpAHj/UXMyGON4ZwDarBdCBQjrB4?= =?us-ascii?Q?OXHjbfub6x+KvTyaNymyVSU2HZF/Vw5tGV1s8s8CktIhDaufzCUl13aR9xnh?= =?us-ascii?Q?1rFxO8zHaPlhKf6ZslxoVUoapVV8EGJAolCTTrVL+f0xzhAzXGgloiaFLz7U?= =?us-ascii?Q?V+CbTfdEk3XIWecvhALALdA707ptW2aXgnJVvJZPU1dZ/JGA/QU67FhTgpY4?= =?us-ascii?Q?Uy35aSaCbDDhLNaVASGPWdjV1dRCEiRSkHKcpievWmisHzF05mIbrAwZ9sGm?= =?us-ascii?Q?bu30UTsMwdvMqFGUYO35hwPcpPRGqPRP6HUJqe6aE6gw7HQ2HhreroU49tjL?= =?us-ascii?Q?HEssdJzeunJXRDRkOvM7UJ86WUELcu53T6XlCKyvj3ihNpD4lhFwzVktakSv?= =?us-ascii?Q?i0uxjrw8nj0OAxe0bFiNDEMLEApw60FwWnXIa2of5t1gMHt1ik3uN4gJBIKj?= =?us-ascii?Q?4mEaQa79VTlNqtapv3zM6374VdkvwDSptlai3txGLZB17DSBOoeYMT21zHr/?= =?us-ascii?Q?fU/tAOLunEOzcV9crso6vbiVz/HVy5bnA7lnos15xRTqEaaXe6cMPK34vqrs?= =?us-ascii?Q?tqPBBrQNwhwlMcA6LrRzIL1Tzgyg5mg8FbTU7uxCi1Xsi2/QwEz8ciVln3CK?= =?us-ascii?Q?xwX4E1HpkovP73Wb7QqKBSC+ZVx0igzK9gkvIYI5CNy3ikt/DP5p5NTefwz9?= =?us-ascii?Q?LmEy7MouknWYjkZ+jJCwxvzfUxpfTmr7zZNwXoydWwiGFOtqKJVHGX88I5Az?= =?us-ascii?Q?VJX2Mlstn4GMALkVU7wpMwIG9CQTUc3iU0/IqN8ZCn+//Wn+OkTxgcwAzIen?= =?us-ascii?Q?bQ6kk7L7CG815H80d0lz3yRn124PxVaVTGF22dM1qzIikO/IqlR7amJ6tWTf?= =?us-ascii?Q?jahu7FKa2mJ1sULvdZHESpEvQQQcLjVwN/lI0ILfWdsagv7p79j+fzt+l6EF?= =?us-ascii?Q?KkjjHffys/FGPjj3VY6/ypEpKh2HyHjVKbqnXW4CIuuZIuAeLnRP4sLOHlDr?= =?us-ascii?Q?hUpIy/8LcFmaA4IC0kcRCu6IYBDJ0IDidtlyJMDu35dXUSdbCwdYyPbkdJ14?= =?us-ascii?Q?bdFkXiYIm3/AMrzkHFOLrojoPkoSa4zOKdT7qPzKmtD+QHJk5XOTHpB0XPML?= =?us-ascii?Q?+UHzUKhXS9bJjdusSti1GlY1JmF+S9Rg5MCDTowo6+TzQarcSmZO/+RCBadh?= =?us-ascii?Q?EJuMQ11InmWSvEB2QyXbee4kgKeY/PbBrIVmKNMvj4stC3eSL7RozelVJoVo?= =?us-ascii?Q?44XFIjdeEZnzdb09qPNGi/njjKZMs5NwMWb7/P9cYCbh5HE/YdByp81sZO4R?= =?us-ascii?Q?XGP/SPYdsYe0NC1ckgCqwSjODinCei388QaHjjfPvUUuCCL1mti4yw3Oyxit?= =?us-ascii?Q?05ioUHbQNV0+Gdtj0X7l0FouBL3t1B27UkTjPN6q?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: f4d7caab-751a-4bb2-77c3-08da91b53d6f X-MS-Exchange-CrossTenant-AuthSource: MN2PR12MB4192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Sep 2022 16:14:43.4200 (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: hov2lXuRoI9HiQ5O5iBgBzBu+ifG5c+sRk5XINO5fJejfnzolvke5urr8RtE47as X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV2PR12MB5943 On Thu, Sep 08, 2022 at 03:28:22PM +0200, Joerg Roedel wrote: > > It has been 3 months since EMEDIUMTYPE was first proposed and 6 > > iterations of the series, don't you think it is a bit late in the game > > to try to experiment with rust error handling idioms? > > If I am not mistaken, I am the person who gets blamed when crappy IOMMU > code is sent upstream. So it is also up to me to decide in which state > and how close to merging a given patch series is an whether it is > already 'late in the game'. I don't think the maintainer is the one who gets blamed. The community is responsible as a collective group for it's decisions. The maintainer is the leader of the community, responsible to foster it, and contributes their guidance, but doesn't bare an unlimited responsibility for what is merged. In a case like this I am the advocate, Nicolin wrote the patches, Kevin reviewed, Alex ack'd them - we as a group are ultimately responsible to repair, defend, or whatever is needed. > I am wondering if this can be solved by better defining what the return > codes mean and adjust the call-back functions to match the definition. > Something like: > > -ENODEV : Device not mapped my an IOMMU > -EBUSY : Device attached and domain can not be changed > -EINVAL : Device and domain are incompatible > ... Yes, this was gone over in a side thread the pros/cons, so lets do it. Nicolin will come with something along these lines. Thanks, Jason