diff --git a/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf b/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf
index f61a22f8ff..938a48a642 100644
--- a/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf
+++ b/OvmfPkg/Csm/CsmSupportLib/CsmSupportLib.inf
@@ -34,6 +34,7 @@
   LegacyInterrupt.c
   LegacyInterrupt.h
   LegacyPlatform.c
+  LegacyPlatform.h
   LegacyRegion.c
 
 [Packages]