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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?ipyMf6f3CY6RZhmPZp2tj51At/4Kj9U33nwDluClPkX8bGS27Zoh+EXUNJRt?= =?us-ascii?Q?+8vLTKe2nKRoBp+b2/ApBqSIl1QP49R0fRGliXxuDJreg29SnURtCsHSVuTJ?= =?us-ascii?Q?zS/B/YNo+i4hJokJKxe8fUVVS6/T1X2uvJKu7kcXeU1j4N846yGmOTHLvo7i?= =?us-ascii?Q?EFt6ZtTF3deCGT/bIgJ/vV3aO0SCuaSjhWzAFgRiIc4ca/sCKBj4sAXMjlUv?= =?us-ascii?Q?IeeL6MlefuRdnNC6LzZtOprLURUFwczTXH4whRQhlJTBch9YKIcXgPf7s+BV?= =?us-ascii?Q?fxE3kVZZaIg6++LwaBNal1u9MdalKJuPQ8Bof97eWPhw/g+piK2Hk0dd4ldl?= =?us-ascii?Q?J6V4siWgv3+WzFHY08Li0UK9pX9E0A7qW+BkdhjcVwaHELsjD0h6rHvISai0?= =?us-ascii?Q?KDqW0G5Y//c5NBKIuBPxsUVY7qT/aqCbDaYRiayYfTsvNUlsio0O7xXGrd5D?= =?us-ascii?Q?MeAAWHgkZT4/MRg0oU5qst/4vpUr3f7S5Hq21rwJ87x1nhGLY2sUEzb2GT1E?= =?us-ascii?Q?qvYC/7s9xp6v7hgXRPlamf+yTHXOCOnI2gYVph8q61ZEvR32NGTNC7iBqf0w?= =?us-ascii?Q?1NjCibhM3pFkche1771kQAbuV2EvzfDG9JgKsZWtRfTjNAZGTMoKgXfvpKdN?= =?us-ascii?Q?TYse9ypbTLc17EhtYm30nSN45mTV4CPSWmfKl+alDispdxb563oq4OZGQOYQ?= =?us-ascii?Q?eSRfIFbMsLbUCPVTQEZrhP0K5pcAFqPdp7VmxJGqRfwIxW4Q8aJss7j+1L0r?= =?us-ascii?Q?iFX/LtgCNX0Fjtz+Y87WSS4wm7jqf9XecmkmTXJYCLDd3ZVqKUydZ+kMjbHE?= =?us-ascii?Q?+woNnfiKIl97Qhmmnk/3wXK+pJudfMcoFv0rsG9SrivS7PDGCCzrZz1aUJqy?= =?us-ascii?Q?6C3+L8Jdq+YHAlmGUvWJV5lcjBl61WABRzp5dx1An/bsaCVt/kDhVTvy6gOS?= =?us-ascii?Q?Ip2Si0mkacdDqbDee3A0kSHc2esxVilxRG6sYtPH4iJqO4AjicuSgbbMz/qX?= =?us-ascii?Q?KOWJ9uM5fNxvN/z4jbc/RNQuWLSqch+yb6spirbL82hiJ66yh67ZfgkxDu7J?= =?us-ascii?Q?oqu5c3ph4AQbx0v9ywAN+GqP8A4LJY3jdXvWsWxTY11S1BuTJD2wgytj0t/1?= =?us-ascii?Q?cUX99fFSgWkUPqebX80wMifpumkU16vfoLEKvWJXUj3MhUVl29oZjGi2Y7yF?= =?us-ascii?Q?8IKd+al7Xr4kQ21LeDhCzH6dLcBE6eVoMmZ2Tnt+J2PhAoT1YEo9p4IW4c7N?= =?us-ascii?Q?t6IWKlym8J7Uqv3zL3SsNi/mqOmglQ8A4sMDnPmPXrKhoNP70KxAhuvenG+8?= =?us-ascii?Q?cdiRQQI5Zi06tVNSj6CSysTPBEbTDBddW7zqLQgZzI3gdrSr5SfrLrXm408h?= =?us-ascii?Q?FgOYgATaPPxT5AZnr5UY63XBpEwI++DHLCSHgCUK5omBxoPxWKapPiOZGZ2b?= =?us-ascii?Q?eEwCrE2nZDsGEG9HH/8FOnio/8UnXK0XPBg8vAADwS/MlosaXeg16IWGgCsZ?= =?us-ascii?Q?SbqsQnH1jmjL6vM9JjWBvkWS15tkW8bbT6JcFVLlFuWpwaSE674rLyWkoKAD?= =?us-ascii?Q?EXaf/wkYAYcLSbscnqgQrcJrIdMN4hwzMAmrokv6?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 34f47289-f38c-4eb3-3879-08db20024332 X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Mar 2023 18:23:49.4456 (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: 9bxWwcYjRhNns+7JD1qgbUl6yiEaU90d4UOfp7f4q3ZGuaN3V5qIJ7smoq5hKKMn X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR12MB4890 Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On Tue, Mar 07, 2023 at 02:32:09PM -0800, Jacob Pan wrote: > Hi Jason, > > On Fri, 3 Mar 2023 09:15:45 -0400, Jason Gunthorpe wrote: > > > On Fri, Mar 03, 2023 at 05:57:41PM +0800, Baolu Lu wrote: > > > On 2023/3/3 17:32, Jean-Philippe Brucker wrote: > > > > > I suppose the common thing is reserving some kind of special > > > > > PASIDs. > > > > Are you planning to use RID_PASID != 0 in VT-d? Otherwise we could > > > > just communicate min_pasid from the IOMMU driver the same way we do > > > > max_pasid. > > > > > > > > Otherwise I guess re-introduce a lighter ioasid_alloc() that the IOMMU > > > > driver calls to reserve PASID0/RID_PASID. > > > > > > Yes. We probably will use a non-zero RID_PASID in the future. An > > > interface to reserve (or allocate) a PASID from iommu_global_pasid_ida > > > should work then. > > > > Just allowing the driver to store XA_ZERO_ENTRY would be fine > > > It looks like there are incoming users of iommu_sva_find() > https://lore.kernel.org/lkml/20230306163138.587484-1-fenghua.yu@intel.com/T/#m1fc97725a0e56ea269c8bdabacee447070d51846 > Should we keep the xa here instead of the global ida? I'm not sure this should be in the iommu core, it is really gross. I would expect IDXD to keep track of the PASID's and mms it is using and do this kind of stuff itself. And why is this using access_remote_vm anyhow? If you know you are in a kthread then kthread_use_mm() is probably better anyhow. In any event we don't need a iommu_sva_find() function to wrapper xa_load for another function inside the same .c file. Jason