[PATCH] drm/amdgpu: Verify root PD is mapped into kernel address space.

[andrey.grodzovsky@xxxxxxx (Andrey Grodzovsky)]

Problem: When PD/PT update made by CPU root PD was not yet mapped causing
page fault.

Fix: Move amdgpu_bo_kmap into amdgpu_vm_bo_base_init to cover
all cases and avoid code duplication with amdgpu_vm_alloc_levels.

Link: https://bugs.freedesktop.org/show_bug.cgi?id=107065
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 47 ++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 845f73a..f546afa 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -143,25 +143,36 @@ struct amdgpu_prt_cb {
  * Initialize a bo_va_base structure and add it to the appropriate lists
  *
  */
-static void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
+static int amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
 				   struct amdgpu_vm *vm,
 				   struct amdgpu_bo *bo)
 {
+	int r = 0;
 	base->vm = vm;
 	base->bo = bo;
 	INIT_LIST_HEAD(&base->bo_list);
 	INIT_LIST_HEAD(&base->vm_status);
 
 	if (!bo)
-		return;
+		return r;
+
 	list_add_tail(&base->bo_list, &bo->va);
 
+	if (vm->use_cpu_for_update && bo->tbo.type == ttm_bo_type_kernel) {
+		r = amdgpu_bo_kmap(bo, NULL);
+		if (r) {
+			amdgpu_bo_unref(&bo->shadow);
+			amdgpu_bo_unref(&bo);
+			return r;
+		}
+	}
+
 	if (bo->tbo.resv != vm->root.base.bo->tbo.resv)
-		return;
+		return r;
 
 	if (bo->preferred_domains &
 	    amdgpu_mem_type_to_domain(bo->tbo.mem.mem_type))
-		return;
+		return r;
 
 	/*
 	 * we checked all the prerequisites, but it looks like this per vm bo
@@ -169,6 +180,8 @@ static void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
 	 * is validated on next vm use to avoid fault.
 	 * */
 	list_move_tail(&base->vm_status, &vm->evicted);
+
+	return r;
 }
 
 /**
@@ -525,21 +538,15 @@ static int amdgpu_vm_alloc_levels(struct amdgpu_device *adev,
 				return r;
 			}
 
-			if (vm->use_cpu_for_update) {
-				r = amdgpu_bo_kmap(pt, NULL);
-				if (r) {
-					amdgpu_bo_unref(&pt->shadow);
-					amdgpu_bo_unref(&pt);
-					return r;
-				}
-			}
-
 			/* Keep a reference to the root directory to avoid
 			* freeing them up in the wrong order.
 			*/
 			pt->parent = amdgpu_bo_ref(parent->base.bo);
 
-			amdgpu_vm_bo_base_init(&entry->base, vm, pt);
+			r = amdgpu_vm_bo_base_init(&entry->base, vm, pt);
+			if (r)
+				return r;
+
 			list_move(&entry->base.vm_status, &vm->relocated);
 		}
 
@@ -1992,12 +1999,17 @@ struct amdgpu_bo_va *amdgpu_vm_bo_add(struct amdgpu_device *adev,
 				      struct amdgpu_bo *bo)
 {
 	struct amdgpu_bo_va *bo_va;
+	int r;
 
 	bo_va = kzalloc(sizeof(struct amdgpu_bo_va), GFP_KERNEL);
 	if (bo_va == NULL) {
 		return NULL;
 	}
-	amdgpu_vm_bo_base_init(&bo_va->base, vm, bo);
+
+	if ((r = amdgpu_vm_bo_base_init(&bo_va->base, vm, bo))) {
+		WARN_ONCE(1,"r = %d\n", r);
+		return NULL;
+	}
 
 	bo_va->ref_count = 1;
 	INIT_LIST_HEAD(&bo_va->valids);
@@ -2613,7 +2625,10 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 	if (r)
 		goto error_unreserve;
 
-	amdgpu_vm_bo_base_init(&vm->root.base, vm, root);
+	r = amdgpu_vm_bo_base_init(&vm->root.base, vm, root);
+	if (r)
+			goto error_unreserve;
+
 	amdgpu_bo_unreserve(vm->root.base.bo);
 
 	if (pasid) {
-- 
2.7.4