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Fri, 13 Jun 2025 13:45:08 -0700 Date: Fri, 13 Jun 2025 13:45:06 -0700 From: Nicolin Chen To: Jason Gunthorpe CC: , , , , , , , , , , , , , Subject: Re: [PATCH v1 05/12] iommu: Introduce get_viommu_size and viommu_init ops Message-ID: References: <20250613134117.GD1174925@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20250613134117.GD1174925@nvidia.com> X-NV-OnPremToCloud: AnonymousSubmission X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CO1PEPF000044F6:EE_|LV3PR12MB9168:EE_ X-MS-Office365-Filtering-Correlation-Id: b85714c8-ee46-4977-cb9b-08ddaabb3cc3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|7416014|376014|82310400026|36860700013; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?GPk0Rdw0jXAYSuwpikzNkhSoknGHF41/hDJpqRx+FFC8Jp3mWOlK1bmxgqY3?= =?us-ascii?Q?EHhWuheV7UthF2ABwvKg0tWPPA7311031BEkfeyKT73h2I78FiSeIx6n4GM0?= =?us-ascii?Q?lBQZf44R4Rl/Ja5Y9PFHxJ8i8qwyr3/iEvuhDMfhxu8xEuhVykehNort1xU9?= =?us-ascii?Q?bQyhsVRI9n9w3oyWhXsayRYQ1wtH3zdZLa6kfSwriuYH7q8Q3JWp5vUOYA7K?= =?us-ascii?Q?+iuyBG/yMXXwzZecGUdcBt/1rBJuI4BbCsFKH8h1ChhK+tii/dQ7smAqkDOm?= =?us-ascii?Q?95J6pJ6qLXkjABGhkoqB2HlYX8T6waPD1DwBqnILMJhulGHeZ11RxtUnvslB?= =?us-ascii?Q?79YX0vX9HkOK/9fS1yn5qW+2SAVkYcwOHPsgscKs4hFhno3XqhURcZbcdGUT?= =?us-ascii?Q?KPjzBBioDnaRgMpOvAnui4XPLX8rxRtTDaOaj7FhB5ywGJShjiXEyb/qetzx?= =?us-ascii?Q?tNmAgjZZlpWMXFg3zaXvL5Mi1AWpihUtyUN0SKu2yde9ntQQ5GUZj3pEOtUr?= =?us-ascii?Q?dyHtHABXl1O/PeDSkMGeMn9wRsYAVeq8+9pLVWS5zCCnvh9ZU22l4odPWJ4L?= =?us-ascii?Q?lG3NfgTANoDVSCbzrHprS/Hqv3sHjjcPpYN+Lyaowx42Xurg0/iMEFRIO/F0?= =?us-ascii?Q?WLzj7IOgZDiUEmXOKTW8sx6IJkYUcxcz+UFy4OW03oToQyyILu5E9Te68LTU?= =?us-ascii?Q?QZHH9fRP67rKRPl1j5fO/Fcpps7bEoDw5cIJJUO22q5mPzTn4jzCEjxie86m?= =?us-ascii?Q?Me0O59C2OY9pIeLWzeDETGZmhx6yRaAAdWo0FkDYO1VMQXYrisuPGjsSLC37?= =?us-ascii?Q?5vhyE/znQwEv8Y79EHUY71Q1kh55N2ymy5YXljfPJZl+rqsk3AgjiowLPtfA?= =?us-ascii?Q?lnDNrXWSU5cKRrIOnRiX+OoVoVkB33qT/wjhUapigaJean3iP1uGPxk8MpRy?= =?us-ascii?Q?4dVAqgJnqQDg6DXxCA8eLWErbqHDhccYAULNl/6gLhauSFxRrf//IWLOw2Cx?= =?us-ascii?Q?Wz8eZtpJhlXY+ThXxYdA+13uXan1ZBN+2bqh0k9rG0PGCUnvjbMYDofMi35L?= =?us-ascii?Q?o4qvHM4rUto+mZLyyWil9R6xxpS5U7rTcjDDIs/nlRJ9S+USeJwDEIKmOyuS?= =?us-ascii?Q?TxU8hu58pGRsKV5iA59Q3yuexdOx4w4A07WJ8Ud25zMUXwgTDXFW47XWDi/y?= =?us-ascii?Q?5mCrTAYRQ3/VrvxbB8sSGV3L8AcrE1DdU0pb9a6sTC5DlHFmHyEr4IIOYX7Z?= =?us-ascii?Q?F+pBniY5NBMzf8JSECudpe7eYVUTmVyPjVuyKaKALnyDgjqSbiqiPGvhwc03?= =?us-ascii?Q?U8Dhizzd1/C1DvxYbSNaKgfENRRVap2ZsxpFFJZLerXcHdlJuMawMGJirVbE?= =?us-ascii?Q?tCMbXe7s6b0k8VKr86Sk1xQaUJwqzSN1mTQvDC9tXoyKqLyYxs2T01pW9Y6Y?= =?us-ascii?Q?4ERllhVWQnAxFhk/JW9fOCfjmrWVOqQP7Gk1ZHHiWmQWba28n0bR6Q=3D=3D?= X-Forefront-Antispam-Report: CIP:216.228.117.160;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:dc6edge1.nvidia.com;CAT:NONE;SFS:(13230040)(1800799024)(7416014)(376014)(82310400026)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jun 2025 20:45:31.0144 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: b85714c8-ee46-4977-cb9b-08ddaabb3cc3 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CO1PEPF000044F6.namprd21.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV3PR12MB9168 On Fri, Jun 13, 2025 at 10:41:17AM -0300, Jason Gunthorpe wrote: > On Mon, Jun 09, 2025 at 10:13:28AM -0700, Nicolin Chen wrote: > > @@ -654,6 +665,10 @@ struct iommu_ops { > > > > int (*def_domain_type)(struct device *dev); > > > > + int (*get_viommu_size)(enum iommu_viommu_type viommu_type, > > + struct device *dev, size_t *viommu_size); > > I'd return the size in a size_t instead of using an output > pointer. Make 0 mean not supported.. Yes. Kevin pointed out the same. I found that the final version only has EOPNOTSUPP errno (had one of WIP versions reporting EINVAL). So, yea, doing a ssize_t would be cleaner and EOPNOTSUPP is probably enough. Will change in v2. Thanks Nicolin