drm/amdkfd: Unmap svm range from GPU set to no-access

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When KFD_IOCTL_SVM_ATTR_NO_ACCESS is applied to a GPU that has an SVM
range mapped, unmap the range from that GPU. Once no GPU maps the range,
the MMU notifier can skip queue eviction on CPU page faults.

Replace the mapped_to_gpu boolean with bitmap_mapped to track which
GPUs currently have the range mapped. Set bits in svm_range_map_to_gpus()
and clear them in svm_range_unmap_from_gpus(). This is separate from
bitmap_access/bitmap_aip which track user-requested attributes and must
not be used to determine mapping state.

Add bitmap_needs_unmap to svm_range, set for each GPU given no-access.
Add svm_range_needs_unmap() to unmap the range from those GPUs when the
app sets the no-access attribute.

Bump the checkpoint timestamp on unmap so retry faults queued before the
no-access unmap are dropped instead of restoring the mapping.

v4:
 - Rename and set prange->mapping_done to false if validate and map not
   complete successfully (Felix)
v3:
 - Correct error handling, support app retry update mapping (Felix)
v2:
 - Add bitmap_mapped to not break get_attr (Felix)

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

Philip Yang 2026-06-03 11:10:48 -04:00 • committed by Alex Deucher

parent 48f1d2a10e

commit b96f261049

3 changed files with 76 additions and 42 deletions

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5

drivers/gpu/drm/amd/amdkfd/kfd_queue.c

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106

drivers/gpu/drm/amd/amdkfd/kfd_svm.c

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7

drivers/gpu/drm/amd/amdkfd/kfd_svm.h

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