From 7fc08c68cd64ccf30e4d46d1a60fcdd61b31f1ec Mon Sep 17 00:00:00 2001
From: Zhiguang Liu <zhiguang.liu@intel.com>
Date: Tue, 28 May 2024 11:22:10 +0800
Subject: [PATCH] UefiCpuPkg: Sync the init timer count instead of current
 timer count

BSP should save and sync to AP the init timer count instead of
current timer count.
Also, BSP can check the init timer count to know if the local apic
timer is enabled. Only sync the setting when it is enabled.

Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c | 51 +++++++++++++++-------------
 UefiCpuPkg/Library/MpInitLib/MpLib.h |  2 +-
 2 files changed, 29 insertions(+), 24 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 69c53c6228..5cbcef70e8 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -167,16 +167,19 @@ SaveLocalApicTimerSetting (
   IN CPU_MP_DATA  *CpuMpData
   )
 {
-  //
-  // Record the current local APIC timer setting of BSP
-  //
-  GetApicTimerState (
-    &CpuMpData->DivideValue,
-    &CpuMpData->PeriodicMode,
-    &CpuMpData->Vector
-    );
-  CpuMpData->CurrentTimerCount   = GetApicTimerCurrentCount ();
-  CpuMpData->TimerInterruptState = GetApicTimerInterruptState ();
+  CpuMpData->InitTimerCount = GetApicTimerInitCount ();
+  if (CpuMpData->InitTimerCount != 0) {
+    //
+    // Record the current local APIC timer setting of BSP
+    //
+    GetApicTimerState (
+      &CpuMpData->DivideValue,
+      &CpuMpData->PeriodicMode,
+      &CpuMpData->Vector
+      );
+
+    CpuMpData->TimerInterruptState = GetApicTimerInterruptState ();
+  }
 }
 
 /**
@@ -189,19 +192,21 @@ SyncLocalApicTimerSetting (
   IN CPU_MP_DATA  *CpuMpData
   )
 {
-  //
-  // Sync local APIC timer setting from BSP to AP
-  //
-  InitializeApicTimer (
-    CpuMpData->DivideValue,
-    CpuMpData->CurrentTimerCount,
-    CpuMpData->PeriodicMode,
-    CpuMpData->Vector
-    );
-  //
-  // Disable AP's local APIC timer interrupt
-  //
-  DisableApicTimerInterrupt ();
+  if (CpuMpData->InitTimerCount != 0) {
+    //
+    // Sync local APIC timer setting from BSP to AP
+    //
+    InitializeApicTimer (
+      CpuMpData->DivideValue,
+      CpuMpData->InitTimerCount,
+      CpuMpData->PeriodicMode,
+      CpuMpData->Vector
+      );
+    //
+    // Disable AP's local APIC timer interrupt
+    //
+    DisableApicTimerInterrupt ();
+  }
 }
 
 /**
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 88b31fecca..8742fa175b 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -289,7 +289,7 @@ struct _CPU_MP_DATA {
   CPU_AP_DATA                      *CpuData;
   volatile MP_CPU_EXCHANGE_INFO    *MpCpuExchangeInfo;
 
-  UINT32                           CurrentTimerCount;
+  UINT32                           InitTimerCount;
   UINTN                            DivideValue;
   UINT8                            Vector;
   BOOLEAN                          PeriodicMode;