[PATCH v5 00/11] Support repeated mappings in GPUVM and Panthor

[Adrián Larumbe <adrian.larumbe@collabora.com>]

This patch series adds OP_MAP_REPEAT flag, which lets the user map a BO
region over an address range repeatedly with just one map operation.

Sparse resources in the Vulkan API let the user leave regions of a
resource unmapped (from the API perspective.) Accesses to such regions
must not result in program termination, but loads produce undefined
values.

To implement this feature on Mali hardware, Vulkan sparse unmap is
implemented by mapping the specified region to a "dummy bo" so that the
accesses do not fault. A newly created sparse resource starts off
unmapped, and therefore also has to be mapped to the "dummy bo".  This
"dummy bo" is small (a page size) in comparison to the sizes of va
ranges that we might want to map to it, and a large number of vm_bind
ops can be necessary. For example, if the user were to create a
100e6-byte sparse resident resource, we'd have to poke VM_BIND with
ceil(100e6/0x1000)=24415 map operations.

OP_MAP_REPEAT addresses this particular inefficiency by letting us
implement a single Vulkan sparse unmap operation and sparse resident
resource initialization with just one map operation.

The panvk changes making use of this uapi can be found at [1]
Link to the conversation for the previous patch series revision at [2]

[1] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40400
[2] https://lore.kernel.org/dri-devel/20250707170442.1437009-1-caterina.shablia@collabora.com/

Changes in v5:
 - Minor fixes to drm_gpuvm.c.
 - Add panthor MMU page sizes device queriable param.
 - Add helper to make sure unmaps of repeated regions are correct.
 - Some fixes to Panthor's repeat mappings implementation.
 - Lump arguments to panthor_vm_prepare_map_op_ctx into a single struct.

Changes in v4:
 - Fixed the warnings reported by the kernel test robot.
  https://lore.kernel.org/oe-kbuild-all/202507041635.WyDu3TQ1-lkp@intel.com/
 - Fixed the warnings reported by the CI.
  https://patchwork.freedesktop.org/series/151264/

No changes in v3.

Changes in v2:
 - Make panthor use this stuff.
 - Make it possible to express a repeated mappina of any suitably sized
  and aligned range of a BO, rather than strictly the page size -sized
  prefix, generalizing the API. Rename DRM_GPUVA_SINGLE_PAGE to
  DRM_GPUVA_REPEAT.
 - Clean up parts of drm/gpuvm affected by these changes.

Adrián Larumbe (7):
  drm/panthor: Expose GPU page sizes to UM
  drm/gpuvm: Remove dead code
  drm/gpuvm: Fix comment to reflect remap operation operand status
  drm/gpuvm: Ensure correctness of unmap/remaps of repeated regions
  drm/panthor: Handle remap case for repeated mappings
  drm/panthor: Pass vm_bind_op to vm_prepare_map_op_ctx
  drm/panthor: Bump the driver version to 1.8

Asahi Lina (2):
  drm/gpuvm: Add a flags field to drm_gpuva_op_map
  drm/gpuvm: Add DRM_GPUVA_REPEAT flag and logic

Boris Brezillon (2):
  drm/gpuvm: Add a helper to check if two VA can be merged
  drm/panthor: Add support for repeated mappings

 drivers/gpu/drm/drm_gpuvm.c              | 214 ++++++++++++++++++-----
 drivers/gpu/drm/panthor/panthor_device.h |   3 +
 drivers/gpu/drm/panthor/panthor_drv.c    |  12 +-
 drivers/gpu/drm/panthor/panthor_mmu.c    | 176 +++++++++++++++----
 include/drm/drm_gpuvm.h                  |  63 ++++++-
 include/uapi/drm/panthor_drm.h           |  33 ++++
 6 files changed, 427 insertions(+), 74 deletions(-)

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2.53.0