diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
index 5193fea2b3..a45e2dd3d7 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c
@@ -451,6 +451,7 @@ SetRegister (
 
   InitApicId = GetInitialApicId ();
   RegisterTable = NULL;
+  ProcIndex = (UINTN)-1;
   for (Index = 0; Index < mAcpiCpuData.NumberOfCpus; Index++) {
     if (RegisterTables[Index].InitialApicId == InitApicId) {
       RegisterTable = &RegisterTables[Index];