diff --git a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
index 7d14341d59..e5f14035b0 100644
--- a/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
+++ b/OvmfPkg/Library/VmgExitLib/VmgExitVcHandler.c
@@ -1233,6 +1233,7 @@ IoioExit (
       }
 
       Ghcb->SaveArea.SwScratch = (UINT64) Ghcb->SharedBuffer;
+      VmgSetOffsetValid (Ghcb, GhcbSwScratch);
       Status = VmgExit (Ghcb, SVM_EXIT_IOIO_PROT, ExitInfo1, ExitInfo2);
       if (Status != 0) {
         return Status;