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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?UqxjBOVcup4F++cMvesxl1q+sH35ER1TFSZwBAb7drxpElRbWITf/ETsvdiM?= =?us-ascii?Q?DGIfvJzveQm7GiHip0s/5ViEgU3QhBHAMbtEuVWuox3rYIeYIY96Ep7FfnCh?= =?us-ascii?Q?C7lL1MZE0yH8KOIrqA+tOKksyuSPmI2GITBfLX7rz3wOapx2jsFTsN3lNXdg?= =?us-ascii?Q?99TdmbMP7LU0iQCaFJ6UPiwfoTRLz8oPxubfYlyKy+cdrDVri/kCoAqzzV0L?= =?us-ascii?Q?h8P/jP7eCwAYGoONIsopiufeVyFC2maISLKocjcpERfv5haqzUZBwCh+kysJ?= =?us-ascii?Q?Erx0yjbWTF+MaeN5DJn8NhetAvveCxR6dWqDGPuXQIGVkv0wNl0tevqSlIU4?= =?us-ascii?Q?xkCAv8TP8R9WpWio/WYw46qQ6ViN2Qhn4nkAEIZg/E+8aw/4tI9Txzju38uC?= =?us-ascii?Q?y5POlqMw1DKNakRmocIlxO2NxrLf/dCoAkE0sxL6rcLNhrIkYa/kg2gvdf5h?= =?us-ascii?Q?JDFbN/0xCVHpJcxZXb+SLIXZwIOrLBFyF7fFlfTAPPdmQSQQ7uqb6sw5Yj7C?= =?us-ascii?Q?R5vRej3YSX7w+RhfKLRj58rKqRS9x0NwIYwNaGlmpHvbSucHhIyizdTM1qiR?= =?us-ascii?Q?0IfCtT6p9hoL8skC5vKEvEfvzIaUDvdRCmgSJKfzskKJAkslLjmH7IrxdHaB?= =?us-ascii?Q?WBTte1RkU5tGoEb31ea+lAW3esKhILJEa3mBNng1G3KgQQZFQPXhDLYibN4L?= =?us-ascii?Q?93pvRVaTuomN2KbdAJbPTM2KFjkoPas/2zXf0vfGk3dNtZK2EWvgt+U5ldFG?= =?us-ascii?Q?tPgwxOQc2Ve744M4a6xaidaieC9HoDK1hYwB3QmGA0c4UD0X2bF3bjB7X2TL?= =?us-ascii?Q?vjso+jFs9FnpWc3TgBjK6QN0VIK9t831IoYNxaLya08Htu79tLxpZJrFcK13?= =?us-ascii?Q?kcNcke3TdDM8OBvSTcSlOCXEOeqKH2D964JvWXJa1HaLIRQBQhRd4C8TTDhA?= =?us-ascii?Q?/ZtnIJ3dQDuKlTCVOeIZt/d3tzNduiQnHAo2JhHMXvOL2kdY4YGMY4jQ3rPQ?= =?us-ascii?Q?XLtuc/hsEzChmrTxm0d2K6NDkWKT5vVko6bJ6d5urcaY++hnI0HA79+w1Nki?= =?us-ascii?Q?rvNrgaXUJ8OmhiuLrI9ekyONXzFtevo7EqJDg+Fz+6MetMe/zjVbiZec4U8k?= =?us-ascii?Q?zBYGElkWzOHjl0q6aAwm6bI+gK9NfFTMrAgNby39CH+3SZPladSie/oML7+w?= =?us-ascii?Q?2sfl1ftM18yTGrDZMT/mSihmTklbIfShxhsfCxi/d14HLs265YsEoneK9TNk?= =?us-ascii?Q?PWrU475DmFibGOxPAHJRrMH3l8LGLyJ4Wn5AS/ysiGSmAOe+6HcvAcCmtudF?= =?us-ascii?Q?LB6SvQqx+sh9u86KO6ZOEw55MgsuSa9yDrYkFlQSomcmdTC89hP/DRGnzPum?= =?us-ascii?Q?CKU7bY5wDufpgn2fehYf7j8CRDAl5ZoHn2N4n5LEb7jTPHpBSBsnnXOY1j6d?= =?us-ascii?Q?ZhCrlLQxCunWPlT5rIdNPHSeEei3NA2O8dKwubeBHdAkNSCtld/J9J5fJXT6?= =?us-ascii?Q?Lb47nAbfpmtnBJ6vtgBwnfAVQYApH+Ud1YnN2jLlkZUaXy9o6vg/qe+xh72r?= =?us-ascii?Q?drQZjOQThGlKLApJ7957HabXI0a/o/GVjutXlCofsOS1LzrMaaBtYK0RhI0P?= =?us-ascii?Q?7MhNeP2q8r+H0QsfMj47TLtfk4WGPKvuI1u7raL1F/9LjfFGs7GHzYrXCg4X?= =?us-ascii?Q?0sbHolZbLG/MfFjkUH/iT9OanZjBc/t6zzbpULuaAfa3Rx5fIoq3WnFmhL6X?= =?us-ascii?Q?rD46s4yDog=3D=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 71a40440-044c-4596-76d2-08de7479d8b5 X-MS-Exchange-CrossTenant-AuthSource: DS0PR12MB6486.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Feb 2026 14:26:21.1089 (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: 4jSnY2VNjF5P3ct8jgslBmK+LwiSJkxdVV+AGM3omzHiMp2X1Kr7EDz4Qy9+KRAF+3Ks5iLrSQSe+icsBgLD8w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4282 On 2026-02-25, Gary Guo wrote: > On 2026-02-24 22:53, Joel Fernandes wrote: >> +//! ## MMU v2 (Turing/Ampere/Ada) - 5 levels >> [...] >> +//! ## MMU v3 (Hopper+) - 6 levels > > I think this is called "4 levels" and "5 levels" in kernel MM rather than > "5 levels" and "6 levels". Actually, I think "5 levels" and "6 levels" is correct even by x86 kernel MM convention. In x86 "4-level paging", the 4 levels are PGD, PUD, PMD, PTE - the root page directory (PGD) IS counted as one of the 4 levels. Similarly, for the GPU MMU, counting the root PDB (L0) as a level gives us 5 levels for v2 (PDB/L0 through L4/PTE) and 6 levels for v3 (PDB/L0 through L5/PTE). This is also consistent with NVIDIA's own hardware definitions in the OpenRM headers (dev_mmu.h for Turing and Hopper) which define the page table entries for each of these levels. The virtual address bitfield spans L0 (bits 56:48) through L4 (bits 20:12) for v2, giving 5 distinct page table levels. FWIW, the existing nouveau driver also uses this convention - NVKM_VMM_LEVELS_MAX is defined as 6 in nvkm/subdev/mmu/vmm.c, and the GH100 page table descriptors in vmmgh100.c list all 6 levels. -- Joel Fernandes