diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 031f7ea8e72b..4171788b8754 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -519,15 +519,26 @@ u8 mtrr_type_lookup(u64 start, u64 end, u8 *uniform)
 		return MTRR_TYPE_INVALID;
 
 	for (i = 0; i < cache_map_n && start < end; i++) {
+		/* Region after current map entry? -> continue with next one. */
 		if (start >= cache_map[i].end)
 			continue;
-		if (start < cache_map[i].start)
+
+		/* Start of region not covered by current map entry? */
+		if (start < cache_map[i].start) {
+			/* At least some part of region has default type. */
 			type = type_merge(type, mtrr_state.def_type, uniform);
+			/* End of region not covered, too? -> lookup done. */
+			if (end <= cache_map[i].start)
+				return type;
+		}
+
+		/* At least part of region covered by map entry. */
 		type = type_merge(type, cache_map[i].type, uniform);
 
 		start = cache_map[i].end;
 	}
 
+	/* End of region past last entry in map? -> use default type. */
 	if (start < end)
 		type = type_merge(type, mtrr_state.def_type, uniform);