diff --git a/drivers/gpu/drm/xe/xe_guc_ads.c b/drivers/gpu/drm/xe/xe_guc_ads.c
index 79d6fd8d919b..6910179aff48 100644
--- a/drivers/gpu/drm/xe/xe_guc_ads.c
+++ b/drivers/gpu/drm/xe/xe_guc_ads.c
@@ -251,14 +251,35 @@ static size_t calculate_regset_size(struct xe_gt *gt)
 	return count * sizeof(struct guc_mmio_reg);
 }
 
-static u32 engine_enable_mask(struct xe_gt *gt, enum xe_engine_class class)
+static inline enum xe_engine_class guc_class_to_engine_class(u16 guc_class)
+{
+	switch (guc_class) {
+	case GUC_RENDER_CLASS:
+		return XE_ENGINE_CLASS_RENDER;
+	case GUC_VIDEO_CLASS:
+		return XE_ENGINE_CLASS_VIDEO_DECODE;
+	case GUC_VIDEOENHANCE_CLASS:
+		return XE_ENGINE_CLASS_VIDEO_ENHANCE;
+	case GUC_BLITTER_CLASS:
+		return XE_ENGINE_CLASS_COPY;
+	case GUC_COMPUTE_CLASS:
+		return XE_ENGINE_CLASS_COMPUTE;
+	case GUC_GSC_OTHER_CLASS:
+		return XE_ENGINE_CLASS_OTHER;
+	default:
+		XE_WARN_ON(guc_class);
+		return -1;
+	}
+}
+
+static u32 engine_enable_mask(struct xe_gt *gt, u16 guc_class)
 {
 	struct xe_hw_engine *hwe;
 	enum xe_hw_engine_id id;
 	u32 mask = 0;
 
 	for_each_hw_engine(hwe, gt, id)
-		if (hwe->class == class)
+		if (xe_engine_class_to_guc_class(hwe->class) == guc_class)
 			mask |= BIT(hwe->instance);
 
 	return mask;
@@ -268,10 +289,13 @@ static size_t calculate_golden_lrc_size(struct xe_guc_ads *ads)
 {
 	struct xe_gt *gt = ads_to_gt(ads);
 	size_t total_size = 0, alloc_size, real_size;
-	int class;
+	u16 guc_class;
 
-	for (class = 0; class < XE_ENGINE_CLASS_MAX; ++class) {
-		if (!engine_enable_mask(gt, class))
+	for (guc_class = 0; guc_class <= GUC_LAST_ENGINE_CLASS; ++guc_class) {
+		enum xe_engine_class class =
+			guc_class_to_engine_class(guc_class);
+
+		if (!engine_enable_mask(gt, guc_class))
 			continue;
 
 		real_size = xe_gt_lrc_size(gt, class);
@@ -472,20 +496,11 @@ static void fill_engine_enable_masks(struct xe_gt *gt,
 				     struct iosys_map *info_map)
 {
 	struct xe_device *xe = gt_to_xe(gt);
+	u16 guc_class;
 
-	info_map_write(xe, info_map, engine_enabled_masks[GUC_RENDER_CLASS],
-		       engine_enable_mask(gt, XE_ENGINE_CLASS_RENDER));
-	info_map_write(xe, info_map, engine_enabled_masks[GUC_BLITTER_CLASS],
-		       engine_enable_mask(gt, XE_ENGINE_CLASS_COPY));
-	info_map_write(xe, info_map, engine_enabled_masks[GUC_VIDEO_CLASS],
-		       engine_enable_mask(gt, XE_ENGINE_CLASS_VIDEO_DECODE));
-	info_map_write(xe, info_map,
-		       engine_enabled_masks[GUC_VIDEOENHANCE_CLASS],
-		       engine_enable_mask(gt, XE_ENGINE_CLASS_VIDEO_ENHANCE));
-	info_map_write(xe, info_map, engine_enabled_masks[GUC_COMPUTE_CLASS],
-		       engine_enable_mask(gt, XE_ENGINE_CLASS_COMPUTE));
-	info_map_write(xe, info_map, engine_enabled_masks[GUC_GSC_OTHER_CLASS],
-		       engine_enable_mask(gt, XE_ENGINE_CLASS_OTHER));
+	for (guc_class = 0; guc_class <= GUC_LAST_ENGINE_CLASS; ++guc_class)
+		info_map_write(xe, info_map, engine_enabled_masks[guc_class],
+			       engine_enable_mask(gt, guc_class));
 }
 
 /*
@@ -500,15 +515,14 @@ static void guc_golden_lrc_init(struct xe_guc_ads *ads)
 			offsetof(struct __guc_ads_blob, system_info));
 	size_t alloc_size, real_size;
 	u32 addr_ggtt, offset;
-	int class;
+	u16 guc_class;
 
 	offset = guc_ads_golden_lrc_offset(ads);
 	addr_ggtt = xe_bo_ggtt_addr(ads->bo) + offset;
 
-	for (class = 0; class < XE_ENGINE_CLASS_MAX; ++class) {
-		u8 guc_class;
-
-		guc_class = xe_engine_class_to_guc_class(class);
+	for (guc_class = 0; guc_class <= GUC_LAST_ENGINE_CLASS; ++guc_class) {
+		enum xe_engine_class class =
+			guc_class_to_engine_class(guc_class);
 
 		if (!info_map_read(xe, &info_map,
 				   engine_enabled_masks[guc_class]))
@@ -957,14 +971,13 @@ static void guc_golden_lrc_populate(struct xe_guc_ads *ads)
 			offsetof(struct __guc_ads_blob, system_info));
 	size_t total_size = 0, alloc_size, real_size;
 	u32 offset;
-	int class;
+	u16 guc_class;
 
 	offset = guc_ads_golden_lrc_offset(ads);
 
-	for (class = 0; class < XE_ENGINE_CLASS_MAX; ++class) {
-		u8 guc_class;
-
-		guc_class = xe_engine_class_to_guc_class(class);
+	for (guc_class = 0; guc_class <= GUC_LAST_ENGINE_CLASS; ++guc_class) {
+		enum xe_engine_class class =
+			guc_class_to_engine_class(guc_class);
 
 		if (!info_map_read(xe, &info_map,
 				   engine_enabled_masks[guc_class]))