From 243212b0d0bb33d0a64db8cd974d243e5aefdf3d Mon Sep 17 00:00:00 2001
From: "Xie, Yuanhao" <yuanhao.xie@intel.com>
Date: Wed, 28 Jun 2023 16:47:21 +0800
Subject: [PATCH] UefiCpuPkg: Refactor the logic for placing APs in
 Mwait/Runloop.

Refactor the logic for placing APs in
Mwait/Runloop into a separate function.

Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Yuanhao Xie <yuanhao.xie@intel.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c | 83 +++++++++++++++++-----------
 1 file changed, 50 insertions(+), 33 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 9560b39220..e8dd640f9b 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -658,6 +658,54 @@ PlaceAPInHltLoop (
   }
 }
 
+/**
+  This function place APs in Mwait or Run loop.
+
+  @param[in] ApLoopMode                   Ap Loop Mode
+  @param[in] ApStartupSignalBuffer        Pointer to Ap Startup Signal Buffer
+  @param[in] ApTargetCState               Ap Target CState
+**/
+VOID
+PlaceAPInMwaitLoopOrRunLoop (
+  IN UINT8            ApLoopMode,
+  IN volatile UINT32  *ApStartupSignalBuffer,
+  IN UINT8            ApTargetCState
+  )
+{
+  while (TRUE) {
+    DisableInterrupts ();
+    if (ApLoopMode == ApInMwaitLoop) {
+      //
+      // Place AP in MWAIT-loop
+      //
+      AsmMonitor ((UINTN)ApStartupSignalBuffer, 0, 0);
+      if (*ApStartupSignalBuffer != WAKEUP_AP_SIGNAL) {
+        //
+        // Check AP start-up signal again.
+        // If AP start-up signal is not set, place AP into
+        // the specified C-state
+        //
+        AsmMwait (ApTargetCState << 4, 0);
+      }
+    } else if (ApLoopMode == ApInRunLoop) {
+      //
+      // Place AP in Run-loop
+      //
+      CpuPause ();
+    } else {
+      ASSERT (FALSE);
+    }
+
+    //
+    // If AP start-up signal is written, AP is waken up
+    // otherwise place AP in loop again
+    //
+    if (*ApStartupSignalBuffer == WAKEUP_AP_SIGNAL) {
+      break;
+    }
+  }
+}
+
 /**
   This function will be called from AP reset code if BSP uses WakeUpAP.
 
@@ -838,39 +886,8 @@ ApWakeupFunction (
       //
       // Never run here
       //
-    }
-
-    while (TRUE) {
-      DisableInterrupts ();
-      if (CpuMpData->ApLoopMode == ApInMwaitLoop) {
-        //
-        // Place AP in MWAIT-loop
-        //
-        AsmMonitor ((UINTN)ApStartupSignalBuffer, 0, 0);
-        if (*ApStartupSignalBuffer != WAKEUP_AP_SIGNAL) {
-          //
-          // Check AP start-up signal again.
-          // If AP start-up signal is not set, place AP into
-          // the specified C-state
-          //
-          AsmMwait (CpuMpData->ApTargetCState << 4, 0);
-        }
-      } else if (CpuMpData->ApLoopMode == ApInRunLoop) {
-        //
-        // Place AP in Run-loop
-        //
-        CpuPause ();
-      } else {
-        ASSERT (FALSE);
-      }
-
-      //
-      // If AP start-up signal is written, AP is waken up
-      // otherwise place AP in loop again
-      //
-      if (*ApStartupSignalBuffer == WAKEUP_AP_SIGNAL) {
-        break;
-      }
+    } else {
+      PlaceAPInMwaitLoopOrRunLoop (CpuMpData->ApLoopMode, ApStartupSignalBuffer, CpuMpData->ApTargetCState);
     }
   }
 }