[PATCH 4/6] UefiCpuPkg/MpInitLib: Swap local APIC timer interrupt state

[Jeff Fan <jeff.fan@intel.com>]

We need to swap local APIC timer interrupt state between old BSP and new BSP.

Cc: Feng Tian <feng.tian@intel.com>
Cc: Kinney, Michael D <michael.d.kinney@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 9dae827..77d855a 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -1512,8 +1512,14 @@ SwitchBSPWorker (
   CPU_STATE                    State;
   MSR_IA32_APIC_BASE_REGISTER  ApicBaseMsr;
   BOOLEAN                      OldInterruptState;
+  BOOLEAN                      OldTimerInterruptState;
 
   //
+  // Save and Disable Local APIC timer interrupt
+  //
+  OldTimerInterruptState = GetApicTimerInterruptState ();
+  DisableApicTimerInterrupt ();
+  //
   // Before send both BSP and AP to a procedure to exchange their roles,
   // interrupt must be disabled. This is because during the exchange role
   // process, 2 CPU may use 1 stack. If interrupt happens, the stack will
@@ -1613,6 +1619,9 @@ SwitchBSPWorker (
   //
   SetInterruptState (OldInterruptState);
 
+  if (OldTimerInterruptState) {
+    EnableApicTimerInterrupt ();
+  }
 
   return EFI_SUCCESS;
 }
-- 
2.9.3.windows.2