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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?l0rT0Zo9O1ikDyGLx+iCFOgNlfjG/OcNPZm0copU7pLNgK0IBltsOHEizYi2?= =?us-ascii?Q?JeuZHKENGJ+qNI3+1PO9oiA7uThYKAkeCpMu/Cyu+DeWVTeu6f8ZhYlDpZ7e?= =?us-ascii?Q?3qVPinIBRFwe2ETJwAlaLFgNbYACo/cMEJt/t3duZ+GVPivDz5GLE+b9QaDz?= =?us-ascii?Q?VRMwkRm4lL7cBsAqLESq9dN80QFQGa2XWChcf0BGPxhSyOTMRl+PgR4KNsWx?= =?us-ascii?Q?nMQJ/rlyh39gdkqYiobeYS5rm4jLuh+jtXhE/F1Tte3dgmUsQGtKKzEKSQ/I?= =?us-ascii?Q?IN/1XfW+HdvWLl4q/z04i4ksbX7hnkyhPuMvnIPMFYZNlIkZzYnavKKqZyyI?= =?us-ascii?Q?Gn3WqyNUN73zFW/CKuOabpdvlA4MzzAz142r0sqsMbMP1PZcvoc2rr6Kp04S?= =?us-ascii?Q?xkmKX962r4Iqp+gxzvRWJjAr0ZOmZ940x92XxdnBnYU3KC6L2W2mjr79zUrb?= =?us-ascii?Q?zx0dYKr/KRJ9Xes8r/MjZucNyEwPwSIy/mpvthqorJc26XrwuZ3LslZUfn+i?= =?us-ascii?Q?sKJplcg1TsRZ+AMVGhC6gO5NVaBoDARNeQ8l5Qp1EgzhJYPi+mrNnNwT0Ss3?= =?us-ascii?Q?AXBLTq7ilsuoTtTc6j6kVgJxwdCdDAz/X8k5hBfedhkFvPr7NwvbDOh7dStV?= =?us-ascii?Q?tiIps15F9apWScMSQFB8BoIXq0twNw03xjIKn40Am7JH2AQSiYtXqbU8xN3q?= =?us-ascii?Q?M7f6CJuHO4WV/4U63Pas06pLuvXEdwQtf4YLXr7yISoSqx+guDpFWuiwOrAa?= =?us-ascii?Q?FsBz1aPdN48AQX5hkKt3GsKjMFzqOgvjh/+gK+RY1ot7Z/6xeuiidJsvLBGd?= =?us-ascii?Q?YjSTMLe6fKAn0ei5DHn4+AEgLeb2uuAdAex2tAL4KWUcGKcAQN8cjJvCeFZd?= =?us-ascii?Q?aV4J0KeFif8WRgmwqZSNAoL8z8ESKttNCS5laxOraprfRTMdgR2a8FYz5KqK?= =?us-ascii?Q?w+2uN8Ci8WZ1QaxuRJn+prweMWGXT6DZj7XOv6nKLX5G0JtQdmy3FOvXlW+L?= =?us-ascii?Q?350JzK6xhKGTzvzFTifuE4dhss/yEXaCgPqPBcwPdjBWgxgs+Z16aS6cGhSN?= =?us-ascii?Q?wswjyeTRLjO9NGIOuGX/uXD7sYtj+HS6LFYswsCB/c+kbtkvkoJJw0eyxcpi?= =?us-ascii?Q?z3PB+bpE14tAx8g1hsZfchqIjQf3x1cMt86qAmilk/qd1xVdJ+7Tk/55YppM?= =?us-ascii?Q?fu7Gv8Ox5jrPils5l+HtIFbJ1izekA9dnHEr7saKjmP8xVKDp36u5N2Lbs65?= =?us-ascii?Q?q1faketEzDiPzYw3ATZRdex1i9JVcPfO/JX7dqUh4/JYxQQjETsjE/CUzsMA?= =?us-ascii?Q?bkA5gXnCoPKqeXfZNMleGpaRmjxhhqtIkOT/4+F1bNAUmobIb0cqbupaCgPf?= =?us-ascii?Q?FIMNTxcjw/cPOY8HiBLgX/fUDiOi8CKD9TStWyAaGv4kg+/xvkl0qCjPB0gO?= =?us-ascii?Q?+HcQrhaxmqub/AlKbcVO0iadbCXz4nS2irHe1/wNlIA5Mr7Pw+5OzwcDOLyn?= =?us-ascii?Q?+St4Ra5WA8R1F6/+q9IDBovjgLOi/oYHG3wy3GVmyXfC8RLGVMmkYOX3a3Za?= =?us-ascii?Q?Ak7EXaG5AzyNo9r47bA=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 760a6393-32eb-4cb5-5278-08dd35630fb4 X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB8659.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jan 2025 12:49:33.9725 (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: KxR6aHrZeGeANIpFGv1OIwOWt/iiOQa91hv7If8Ws7WaM9Uu9DvYfJQmhUBKpuDl X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB6867 On Wed, Jan 15, 2025 at 02:39:55PM +1100, Alexey Kardashevskiy wrote: > > The thread was talking about the built-in support in iommufd to split > > mappings. > > Just to clarify - I am talking about splitting only "iommufd areas", not > large pages. In generality it is the same thing as you cannot generally guarantee that an area split doesn't also cross a large page. > If all IOMMU PTEs are 4k and areas are bigger than 4K => the hw > support is not needed to allow splitting. The comments above and below seem > to confuse large pages with large areas (well, I am consufed, at least). Yes, in that special case yes. > > That built-in support is only accessible through legacy APIs > > and should never be used in new qemu code. To use that built in > > support in new code we need to build new APIs. > > Why would not IOMMU_IOAS_MAP/UNMAP uAPI work? Thanks, I don't want to overload those APIs, I prefer to see a new API that is just about splitting areas. Splitting is a special operation that can fail depending on driver support. Jason