drm/xe/display: Avoid dereferencing xe_ggtt_node

Start using xe_ggtt_node_addr, and avoid comparing the base offset
as vma->node is dynamically allocated.

Also sneak in a xe_bo_size() for stolen, too small to put as separate
commit.

Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/20260108101014.579906-13-dev@lankhorst.se

Author: Maarten Lankhorst

drivers/gpu/drm/xe/compat-i915-headers/i915_vma.h

@@ -8,7 +8,7 @@
 
 #include <uapi/drm/i915_drm.h>
 
-#include "xe_ggtt_types.h"
+#include "xe_ggtt.h"
 
 #include <linux/refcount.h>
 
@@ -30,7 +30,7 @@ struct i915_vma {
 
 static inline u32 i915_ggtt_offset(const struct i915_vma *vma)
 {
-	return vma->node->base.start;
+	return xe_ggtt_node_addr(vma->node);
 }
 
 #endif

drivers/gpu/drm/xe/display/xe_fb_pin.c

@@ -206,7 +206,7 @@ static void write_ggtt_rotated_node(struct xe_ggtt *ggtt, struct xe_ggtt_node *n
 	struct fb_rotate_args *args = data;
 	struct xe_bo *bo = args->bo;
 	const struct intel_rotation_info *rot_info = &args->view->rotated;
-	u32 ggtt_ofs = node->base.start;
+	u32 ggtt_ofs = xe_ggtt_node_addr(node);
 
 	for (u32 i = 0; i < ARRAY_SIZE(rot_info->plane); i++)
 		write_ggtt_rotated(ggtt, &ggtt_ofs, pte_flags, write_pte,
@@ -353,7 +353,7 @@ static void __xe_unpin_fb_vma(struct i915_vma *vma)
 	if (vma->dpt)
 		xe_bo_unpin_map_no_vm(vma->dpt);
 	else if (!xe_ggtt_node_allocated(vma->bo->ggtt_node[tile_id]) ||
-		 vma->bo->ggtt_node[tile_id]->base.start != vma->node->base.start)
+		 vma->bo->ggtt_node[tile_id] != vma->node)
 		xe_ggtt_node_remove(vma->node, false);
 
 	ttm_bo_reserve(&vma->bo->ttm, false, false, NULL);

drivers/gpu/drm/xe/display/xe_stolen.c

@@ -78,7 +78,7 @@ static u64 xe_stolen_node_address(const struct intel_stolen_node *node)
 
 static u64 xe_stolen_node_size(const struct intel_stolen_node *node)
 {
-	return node->bo->ttm.base.size;
+	return xe_bo_size(node->bo);
 }
 
 static struct intel_stolen_node *xe_stolen_node_alloc(struct drm_device *drm)