6.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Harish Kasiviswanathan Harish.Kasiviswanathan@amd.com
[ Upstream commit eac32ff42393efa6657efc821231b8d802c1d485 ]
Fix the following corner case:- Consider a 2M huge page SVM allocation, followed by prefetch call for the first 4K page. The whole range is initially mapped with single PTE. After the prefetch, this range gets split to first page + rest of the pages. Currently, the first page mapping is not updated on MI300A (APU) since page hasn't migrated. However, after range split PTE mapping it not valid.
Fix this by forcing page table update for the whole range when prefetch is called. Calling prefetch on APU doesn't improve performance. If all it deteriotes. However, functionality has to be supported.
v2: Use apu_prefer_gtt as this issue doesn't apply to APUs with carveout VRAM
v3: Simplify by setting the flag for all ASICs as it doesn't affect dGPU
v4: Remove v2 and v3 changes. Force update_mapping when range is split at a size that is not aligned to prange granularity
Suggested-by: Philip Yang Philip.Yang@amd.com Signed-off-by: Harish Kasiviswanathan Harish.Kasiviswanathan@amd.com Reviewed-by: Philip YangPhilip.Yang@amd.com Reviewed-by: Felix Kuehling felix.kuehling@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com (cherry picked from commit 076470b9f6f8d9c7c8ca73a9f054942a686f9ba7) Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c index 827507cfed7aa..fab6e7721c803 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c @@ -3688,6 +3688,8 @@ svm_range_set_attr(struct kfd_process *p, struct mm_struct *mm, svm_range_apply_attrs(p, prange, nattr, attrs, &update_mapping); /* TODO: unmap ranges from GPU that lost access */ } + update_mapping |= !p->xnack_enabled && !list_empty(&remap_list); + list_for_each_entry_safe(prange, next, &remove_list, update_list) { pr_debug("unlink old 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms, prange, prange->start,