diff --git a/doc/usage/cmd/mtrr.rst b/doc/usage/cmd/mtrr.rst
index 531153b..c656189 100644
--- a/doc/usage/cmd/mtrr.rst
+++ b/doc/usage/cmd/mtrr.rst
@@ -1,5 +1,8 @@
 .. SPDX-License-Identifier: GPL-2.0+:
 
+.. index::
+   single: mtrr (command)
+
 mtrr command
 ============