[Intel-xe] [PATCH 1/4] drm/xe: Ensure that we don't access the placements array out-of-bounds

[Thomas Hellström]

Ensure, using xe_assert that the various try_add_<placement> functions
don't access the bo placements array out-of-bounds.

Suggested-by: Ohad Sharabi <osharabi at habana.ai>
Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/946
Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
 drivers/gpu/drm/xe/xe_bo.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 4305f5cbc2ab..915910b87faa 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -121,9 +121,11 @@ static struct xe_mem_region *res_to_mem_region(struct ttm_resource *res)
 	return to_xe_ttm_vram_mgr(mgr)->vram;
 }
 
-static void try_add_system(struct xe_bo *bo, struct ttm_place *places,
-			   u32 bo_flags, u32 *c)
+static void try_add_system(struct xe_device *xe, struct xe_bo *bo,
+			   struct ttm_place *places, u32 bo_flags, u32 *c)
 {
+	xe_assert(xe, *c < ARRAY_SIZE(bo->placements));
+
 	if (bo_flags & XE_BO_CREATE_SYSTEM_BIT) {
 		places[*c] = (struct ttm_place) {
 			.mem_type = XE_PL_TT,
@@ -172,6 +174,8 @@ static void add_vram(struct xe_device *xe, struct xe_bo *bo,
 static void try_add_vram(struct xe_device *xe, struct xe_bo *bo,
 			 struct ttm_place *places, u32 bo_flags, u32 *c)
 {
+	xe_assert(xe, *c < ARRAY_SIZE(bo->placements));
+
 	if (bo->props.preferred_gt == XE_GT1) {
 		if (bo_flags & XE_BO_CREATE_VRAM1_BIT)
 			add_vram(xe, bo, places, bo_flags, XE_PL_VRAM1, c);
@@ -188,6 +192,8 @@ static void try_add_vram(struct xe_device *xe, struct xe_bo *bo,
 static void try_add_stolen(struct xe_device *xe, struct xe_bo *bo,
 			   struct ttm_place *places, u32 bo_flags, u32 *c)
 {
+	xe_assert(xe, *c < ARRAY_SIZE(bo->placements));
+
 	if (bo_flags & XE_BO_CREATE_STOLEN_BIT) {
 		places[*c] = (struct ttm_place) {
 			.mem_type = XE_PL_STOLEN,
@@ -210,11 +216,11 @@ static int __xe_bo_placement_for_flags(struct xe_device *xe, struct xe_bo *bo,
 	/* The order of placements should indicate preferred location */
 
 	if (bo->props.preferred_mem_class == DRM_XE_MEM_REGION_CLASS_SYSMEM) {
-		try_add_system(bo, places, bo_flags, &c);
+		try_add_system(xe, bo, places, bo_flags, &c);
 		try_add_vram(xe, bo, places, bo_flags, &c);
 	} else {
 		try_add_vram(xe, bo, places, bo_flags, &c);
-		try_add_system(bo, places, bo_flags, &c);
+		try_add_system(xe, bo, places, bo_flags, &c);
 	}
 	try_add_stolen(xe, bo, places, bo_flags, &c);
 
-- 
2.41.0