1 files changed, 6 insertions, 4 deletions
diff --git a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
index 65400b95a2..e732371ddd 100644
--- a/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/PeiMpLib.c
@@ -89,7 +89,7 @@ EnableDebugAgent (
 /**
   Get pointer to CPU MP Data structure.
   For BSP, the pointer is retrieved from HOB.
-  For AP, the structure is just after IDT.
+  For AP, the structure is stored in the top of each AP's stack.
 
   @return  The pointer to CPU MP Data structure.
 **/
@@ -100,15 +100,17 @@ GetCpuMpData (
 {
   CPU_MP_DATA                  *CpuMpData;
   MSR_IA32_APIC_BASE_REGISTER  ApicBaseMsr;
-  IA32_DESCRIPTOR              Idtr;
+  UINTN                        ApTopOfStack;
+  AP_STACK_DATA                *ApStackData;
 
   ApicBaseMsr.Uint64 = AsmReadMsr64 (MSR_IA32_APIC_BASE);
   if (ApicBaseMsr.Bits.BSP == 1) {
     CpuMpData = GetCpuMpDataFromGuidedHob ();
     ASSERT (CpuMpData != NULL);
   } else {
-    AsmReadIdtr (&Idtr);
-    CpuMpData = (CPU_MP_DATA *)(Idtr.Base + Idtr.Limit + 1);
+    ApTopOfStack = ALIGN_VALUE ((UINTN)&ApTopOfStack, (UINTN)PcdGet32 (PcdCpuApStackSize));
+    ApStackData  = (AP_STACK_DATA *)((UINTN)ApTopOfStack- sizeof (AP_STACK_DATA));
+    CpuMpData    = (CPU_MP_DATA *)ApStackData->MpData;
   }
 
   return CpuMpData;