diff --git a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
index f7f9a205f9..14c8417d43 100644
--- a/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
+++ b/OvmfPkg/Library/GenericQemuLoadImageLib/GenericQemuLoadImageLib.c
@@ -151,7 +151,7 @@ QemuLoadKernelImage (
     //
     // Drop the terminating NUL, convert to UTF-16.
     //
-    KernelLoadedImage->LoadOptionsSize = (CommandLineSize - 1) * 2;
+    KernelLoadedImage->LoadOptionsSize = (UINT32)((CommandLineSize - 1) * 2);
   }
 
   QemuFwCfgSelectItem (QemuFwCfgItemInitrdSize);