From 520e345ffe05aabef1db82beda4288afb1757ff2 Mon Sep 17 00:00:00 2001 From: Xiaogang Chen Date: Sun, 23 Aug 2026 15:47:15 -0500 Subject: [PATCH] drm/amdkfd: Fix the case that vm range is hole at svm_migrate_copy_to_vram When migration vm range is hole at cpu side(MIGRATE_PFN_MIGRATE set + MIGRATE_PFN_VALID unset) driver still allocates device pages. There is no dma map of src pages and migration. j is 0 and svm_migrate_copy_memory_gart() will return an uninitialized r. That can trigger out_free_vram_pages to drop all VRAM just set up. Initialize r and only call the last svm_migrate_copy_memory_gart if j > 0. Current code postponed the last page to the final copy. This patch flushes on the last page when reach to the end of current drm_buddy_block; avoids another svm_migrate_copy_memory_gart. Cc: stable@vger.kernel.org Signed-off-by: Xiaogang Chen Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c index a6bb41fdc8c1..253365a8257e 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c @@ -134,7 +134,7 @@ svm_migrate_copy_memory_gart(struct amdgpu_device *adev, dma_addr_t *sys, u64 gart_s, gart_d; struct dma_fence *next; u64 size; - int r; + int r = 0; ring = to_amdgpu_ring(adev->mman.buffer_funcs_scheds[0]); entity = &adev->mman.move_entities[0]; @@ -284,7 +284,7 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange, dma_addr_t *src; u64 *dst; u64 i, j; - int r; + int r = 0; pr_debug("svms 0x%p [0x%lx 0x%lx 0x%llx]\n", prange->svms, prange->start, prange->last, ttm_res_offset); @@ -310,6 +310,7 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange, DMA_BIDIRECTIONAL); r = dma_mapping_error(dev, src[i]); if (r) { + src[i] = 0; dev_err(dev, "%s: fail %d dma_map_page\n", __func__, r); goto out_free_vram_pages; @@ -334,7 +335,8 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange, pr_debug_ratelimited("dma mapping src to 0x%llx, pfn 0x%lx\n", src[i] >> PAGE_SHIFT, page_to_pfn(spage)); - if (j >= (cursor.size >> PAGE_SHIFT) - 1 && i < npages - 1) { + /* accumulated j + 1 pages reach end of current drm_buddy_block */ + if (j + 1 >= (cursor.size >> PAGE_SHIFT)) { r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j + 1, FROM_RAM_TO_VRAM, @@ -348,7 +350,8 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange, } } - r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j, + if (j > 0) + r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j, FROM_RAM_TO_VRAM, mfence); out_free_vram_pages: