1 files changed, 37 insertions, 3 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 9892f13bcbc0..2bb9420b77a1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -489,6 +489,7 @@ static int amdgpu_move_vram_ram(struct ttm_buffer_object *bo, bool evict,
 	placements.flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_TT;
 	r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
 	if (unlikely(r)) {
+		pr_err("Failed to find GTT space for blit from VRAM\n");
 		return r;
 	}
 
@@ -547,6 +548,7 @@ static int amdgpu_move_ram_vram(struct ttm_buffer_object *bo, bool evict,
 	placements.flags = TTM_PL_MASK_CACHING | TTM_PL_FLAG_TT;
 	r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
 	if (unlikely(r)) {
+		pr_err("Failed to find GTT space for blit to VRAM\n");
 		return r;
 	}
 
@@ -567,6 +569,30 @@ out_cleanup:
 }
 
 /**
+ * amdgpu_mem_visible - Check that memory can be accessed by ttm_bo_move_memcpy
+ *
+ * Called by amdgpu_bo_move()
+ */
+static bool amdgpu_mem_visible(struct amdgpu_device *adev,
+			       struct ttm_mem_reg *mem)
+{
+	struct drm_mm_node *nodes = mem->mm_node;
+
+	if (mem->mem_type == TTM_PL_SYSTEM ||
+	    mem->mem_type == TTM_PL_TT)
+		return true;
+	if (mem->mem_type != TTM_PL_VRAM)
+		return false;
+
+	/* ttm_mem_reg_ioremap only supports contiguous memory */
+	if (nodes->size != mem->num_pages)
+		return false;
+
+	return ((nodes->start + nodes->size) << PAGE_SHIFT)
+		<= adev->gmc.visible_vram_size;
+}
+
+/**
  * amdgpu_bo_move - Move a buffer object to a new memory location
  *
  * Called by ttm_bo_handle_move_mem()
@@ -610,8 +636,10 @@ static int amdgpu_bo_move(struct ttm_buffer_object *bo, bool evict,
 		return 0;
 	}
 
-	if (!adev->mman.buffer_funcs_enabled)
+	if (!adev->mman.buffer_funcs_enabled) {
+		r = -ENODEV;
 		goto memcpy;
+	}
 
 	if (old_mem->mem_type == TTM_PL_VRAM &&
 	    new_mem->mem_type == TTM_PL_SYSTEM) {
@@ -626,10 +654,16 @@ static int amdgpu_bo_move(struct ttm_buffer_object *bo, bool evict,
 
 	if (r) {
 memcpy:
-		r = ttm_bo_move_memcpy(bo, ctx, new_mem);
-		if (r) {
+		/* Check that all memory is CPU accessible */
+		if (!amdgpu_mem_visible(adev, old_mem) ||
+		    !amdgpu_mem_visible(adev, new_mem)) {
+			pr_err("Move buffer fallback to memcpy unavailable\n");
 			return r;
 		}
+
+		r = ttm_bo_move_memcpy(bo, ctx, new_mem);
+		if (r)
+			return r;
 	}
 
 	if (bo->type == ttm_bo_type_device &&