diff --git a/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf b/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf
index 938a48a642..2f576bf090 100644
--- a/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf
+++ b/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf
@@ -36,6 +36,7 @@
   LegacyPlatform.c
   LegacyPlatform.h
   LegacyRegion.c
+  LegacyRegion.h
 
 [Packages]
   MdePkg/MdePkg.dec