drm/amdgpu: allocate VM PDs/PTs on demand

Let's start to allocate VM PDs/PTs on demand instead of pre-allocating
them during mapping.

Signed-off-by: Christian König <[e-mail]>
Reviewed-by: Felix Kuehling <[e-mail]>
Acked-by: Huang Rui <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c

···
 	if (p_bo_va_entry)
 		*p_bo_va_entry = bo_va_entry;
 
-	/* Allocate new page tables if needed and validate
-	 * them.
-	 */
-	ret = amdgpu_vm_alloc_pts(adev, vm, va, amdgpu_bo_size(bo));
-	if (ret) {
-		pr_err("Failed to allocate pts, err=%d\n", ret);
-		goto err_alloc_pts;
-	}
-
+	/* Allocate validate page tables if needed */
 	ret = vm_validate_pt_pd_bos(vm);
 	if (ret) {
 		pr_err("validate_pt_pd_bos() failed\n");

drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c

···
 		return -ENOMEM;
 	}
 
-	r = amdgpu_vm_alloc_pts(adev, (*bo_va)->base.vm, csa_addr,
-				size);
-	if (r) {
-		DRM_ERROR("failed to allocate pts for static CSA, err=%d\n", r);
-		amdgpu_vm_bo_rmv(adev, *bo_va);
-		ttm_eu_backoff_reservation(&ticket, &list);
-		return r;
-	}
-
 	r = amdgpu_vm_bo_map(adev, *bo_va, csa_addr, 0, size,
 			     AMDGPU_PTE_READABLE | AMDGPU_PTE_WRITEABLE |
 			     AMDGPU_PTE_EXECUTABLE);

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

···
 
 	switch (args->operation) {
 	case AMDGPU_VA_OP_MAP:
-		r = amdgpu_vm_alloc_pts(adev, bo_va->base.vm, args->va_address,
-					args->map_size);
-		if (r)
-			goto error_backoff;
-
 		va_flags = amdgpu_gmc_get_pte_flags(adev, args->flags);
 		r = amdgpu_vm_bo_map(adev, bo_va, args->va_address,
 				     args->offset_in_bo, args->map_size,
···
 						args->map_size);
 		break;
 	case AMDGPU_VA_OP_REPLACE:
-		r = amdgpu_vm_alloc_pts(adev, bo_va->base.vm, args->va_address,
-					args->map_size);
-		if (r)
-			goto error_backoff;
-
 		va_flags = amdgpu_gmc_get_pte_flags(adev, args->flags);
 		r = amdgpu_vm_bo_replace_map(adev, bo_va, args->va_address,
 					     args->offset_in_bo, args->map_size,

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

···
 }
 
 /**
- * amdgpu_vm_pt_first_leaf - get first leaf PD/PT
- *
- * @adev: amdgpu_device pointer
- * @vm: amdgpu_vm structure
- * @start: start addr of the walk
- * @cursor: state to initialize
- *
- * Start a walk and go directly to the leaf node.
- */
-static void amdgpu_vm_pt_first_leaf(struct amdgpu_device *adev,
-				    struct amdgpu_vm *vm, uint64_t start,
-				    struct amdgpu_vm_pt_cursor *cursor)
-{
-	amdgpu_vm_pt_start(adev, vm, start, cursor);
-	while (amdgpu_vm_pt_descendant(adev, cursor));
-}
-
-/**
- * amdgpu_vm_pt_next_leaf - get next leaf PD/PT
- *
- * @adev: amdgpu_device pointer
- * @cursor: current state
- *
- * Walk the PD/PT tree to the next leaf node.
- */
-static void amdgpu_vm_pt_next_leaf(struct amdgpu_device *adev,
-				   struct amdgpu_vm_pt_cursor *cursor)
-{
-	amdgpu_vm_pt_next(adev, cursor);
-	if (cursor->pfn != ~0ll)
-		while (amdgpu_vm_pt_descendant(adev, cursor));
-}
-
-/**
- * for_each_amdgpu_vm_pt_leaf - walk over all leaf PDs/PTs in the hierarchy
- */
-#define for_each_amdgpu_vm_pt_leaf(adev, vm, start, end, cursor)		\
-	for (amdgpu_vm_pt_first_leaf((adev), (vm), (start), &(cursor));		\
-	     (cursor).pfn <= end; amdgpu_vm_pt_next_leaf((adev), &(cursor)))
-
-/**
  * amdgpu_vm_pt_first_dfs - start a deep first search
  *
  * @adev: amdgpu_device structure
···
  * Returns:
  * 0 on success, errno otherwise.
  */
-int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
-			struct amdgpu_vm *vm,
-			uint64_t saddr, uint64_t size)
+static int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
+			       struct amdgpu_vm *vm,
+			       struct amdgpu_vm_pt_cursor *cursor)
 {
-	struct amdgpu_vm_pt_cursor cursor;
+	struct amdgpu_vm_pt *entry = cursor->entry;
+	struct amdgpu_bo_param bp;
 	struct amdgpu_bo *pt;
-	uint64_t eaddr;
 	int r;
 
-	/* validate the parameters */
-	if (saddr & AMDGPU_GPU_PAGE_MASK || size & AMDGPU_GPU_PAGE_MASK)
-		return -EINVAL;
+	if (cursor->level < AMDGPU_VM_PTB && !entry->entries) {
+		unsigned num_entries;
 
-	eaddr = saddr + size - 1;
-
-	saddr /= AMDGPU_GPU_PAGE_SIZE;
-	eaddr /= AMDGPU_GPU_PAGE_SIZE;
-
-	if (eaddr >= adev->vm_manager.max_pfn) {
-		dev_err(adev->dev, "va above limit (0x%08llX >= 0x%08llX)\n",
-			eaddr, adev->vm_manager.max_pfn);
-		return -EINVAL;
+		num_entries = amdgpu_vm_num_entries(adev, cursor->level);
+		entry->entries = kvmalloc_array(num_entries,
+						sizeof(*entry->entries),
+						GFP_KERNEL | __GFP_ZERO);
+		if (!entry->entries)
+			return -ENOMEM;
 	}
 
-	for_each_amdgpu_vm_pt_leaf(adev, vm, saddr, eaddr, cursor) {
-		struct amdgpu_vm_pt *entry = cursor.entry;
-		struct amdgpu_bo_param bp;
+	if (entry->base.bo)
+		return 0;
 
-		if (cursor.level < AMDGPU_VM_PTB) {
-			unsigned num_entries;
+	amdgpu_vm_bo_param(adev, vm, cursor->level, &bp);
 
-			num_entries = amdgpu_vm_num_entries(adev, cursor.level);
-			entry->entries = kvmalloc_array(num_entries,
-							sizeof(*entry->entries),
-							GFP_KERNEL |
-							__GFP_ZERO);
-			if (!entry->entries)
-				return -ENOMEM;
-		}
+	r = amdgpu_bo_create(adev, &bp, &pt);
+	if (r)
+		return r;
 
-
-		if (entry->base.bo)
-			continue;
-
-		amdgpu_vm_bo_param(adev, vm, cursor.level, &bp);
-
-		r = amdgpu_bo_create(adev, &bp, &pt);
-		if (r)
-			return r;
-
-		if (vm->use_cpu_for_update) {
-			r = amdgpu_bo_kmap(pt, NULL);
-			if (r)
-				goto error_free_pt;
-		}
-
-		/* Keep a reference to the root directory to avoid
-		* freeing them up in the wrong order.
-		*/
-		pt->parent = amdgpu_bo_ref(cursor.parent->base.bo);
-
-		amdgpu_vm_bo_base_init(&entry->base, vm, pt);
-
-		r = amdgpu_vm_clear_bo(adev, vm, pt);
+	if (vm->use_cpu_for_update) {
+		r = amdgpu_bo_kmap(pt, NULL);
 		if (r)
 			goto error_free_pt;
 	}
+
+	/* Keep a reference to the root directory to avoid
+	 * freeing them up in the wrong order.
+	 */
+	pt->parent = amdgpu_bo_ref(cursor->parent->base.bo);
+	amdgpu_vm_bo_base_init(&entry->base, vm, pt);
+
+	r = amdgpu_vm_clear_bo(adev, vm, pt);
+	if (r)
+		goto error_free_pt;
 
 	return 0;
 
···
 	struct amdgpu_vm_pt_cursor cursor;
 	uint64_t frag_start = start, frag_end;
 	unsigned int frag;
+	int r;
 
 	/* figure out the initial fragment */
 	amdgpu_vm_fragment(params, frag_start, end, flags, &frag, &frag_end);
···
 	/* walk over the address space and update the PTs */
 	amdgpu_vm_pt_start(adev, params->vm, start, &cursor);
 	while (cursor.pfn < end) {
-		struct amdgpu_bo *pt = cursor.entry->base.bo;
 		unsigned shift, parent_shift, mask;
 		uint64_t incr, entry_end, pe_start;
+		struct amdgpu_bo *pt;
 
-		if (!pt)
-			return -ENOENT;
+		r = amdgpu_vm_alloc_pts(params->adev, params->vm, &cursor);
+		if (r)
+			return r;
+
+		pt = cursor.entry->base.bo;
 
 		/* The root level can't be a huge page */
 		if (cursor.level == adev->vm_manager.root_level) {

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h

···
 int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 			      int (*callback)(void *p, struct amdgpu_bo *bo),
 			      void *param);
-int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
-			struct amdgpu_vm *vm,
-			uint64_t saddr, uint64_t size);
 int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_pipe_sync);
 int amdgpu_vm_update_directories(struct amdgpu_device *adev,
 				 struct amdgpu_vm *vm);