From 9ebcf0f4005239abcde5141414703e2676200550 Mon Sep 17 00:00:00 2001
From: Jeff Fan <jeff.fan@intel.com>
Date: Wed, 20 Jul 2016 23:32:17 +0800
Subject: [PATCH] UefiCpuPkg/MpInitLib: Get ApLoopMode and MointorFilter size

Firstly, get ApLoopMode from PcdCpuApLoopMode. If MonitorMwait feature is not
supported, update ApLoopMode to ApHltLoop. If MonitorMwait feature is supported,
get MointorFilter size by CPUID.[EAX=05H]:EBX.BIT0-15.

v5:
  1. Add comment block for enum AP_LOOP_MODE.

Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Giri P Mudusuru <giri.p.mudusuru@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Michael Kinney <michael.d.kinney@intel.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c | 63 ++++++++++++++++++++++++++++
 UefiCpuPkg/Library/MpInitLib/MpLib.h | 10 +++++
 2 files changed, 73 insertions(+)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 3ac79b6a90..32bbaee5cc 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -15,6 +15,65 @@
 #include "MpLib.h"
 
 
+/**
+  Detect whether Mwait-monitor feature is supported.
+
+  @retval TRUE    Mwait-monitor feature is supported.
+  @retval FALSE   Mwait-monitor feature is not supported.
+**/
+BOOLEAN
+IsMwaitSupport (
+  VOID
+  )
+{
+  CPUID_VERSION_INFO_ECX        VersionInfoEcx;
+
+  AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, &VersionInfoEcx.Uint32, NULL);
+  return (VersionInfoEcx.Bits.MONITOR == 1) ? TRUE : FALSE;
+}
+
+/**
+  Get AP loop mode.
+
+  @param[out] MonitorFilterSize  Returns the largest monitor-line size in bytes.
+
+  @return The AP loop mode.
+**/
+UINT8
+GetApLoopMode (
+  OUT UINT32     *MonitorFilterSize
+  )
+{
+  UINT8                         ApLoopMode;
+  CPUID_MONITOR_MWAIT_EBX       MonitorMwaitEbx;
+
+  ASSERT (MonitorFilterSize != NULL);
+
+  ApLoopMode = PcdGet8 (PcdCpuApLoopMode);
+  ASSERT (ApLoopMode >= ApInHltLoop && ApLoopMode <= ApInRunLoop);
+  if (ApLoopMode == ApInMwaitLoop) {
+    if (!IsMwaitSupport ()) {
+      //
+      // If processor does not support MONITOR/MWAIT feature,
+      // force AP in Hlt-loop mode
+      //
+      ApLoopMode = ApInHltLoop;
+    }
+  }
+
+  if (ApLoopMode != ApInMwaitLoop) {
+    *MonitorFilterSize = sizeof (UINT32);
+  } else {
+    //
+    // CPUID.[EAX=05H]:EBX.BIT0-15: Largest monitor-line size in bytes
+    // CPUID.[EAX=05H].EDX: C-states supported using MWAIT
+    //
+    AsmCpuid (CPUID_MONITOR_MWAIT, NULL, &MonitorMwaitEbx.Uint32, NULL, NULL);
+    *MonitorFilterSize = MonitorMwaitEbx.Bits.LargestMonitorLineSize;
+  }
+
+  return ApLoopMode;
+}
 /**
   MP Initialize Library initialization.
 
@@ -35,10 +94,14 @@ MpInitLibInitialize (
   )
 {
   MP_ASSEMBLY_ADDRESS_MAP  AddressMap;
+  UINT32                   MonitorFilterSize;
+  UINT8                    ApLoopMode;
   UINTN                    ApResetVectorSize;
 
   AsmGetAddressMap (&AddressMap);
   ApResetVectorSize = AddressMap.RendezvousFunnelSize + sizeof (MP_CPU_EXCHANGE_INFO);
+  ApLoopMode  = GetApLoopMode (&MonitorFilterSize);
+
   return EFI_SUCCESS;
 }
 
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index 2be13516aa..317facc80c 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -35,6 +35,16 @@
 #include <Library/MtrrLib.h>
 #include <Library/HobLib.h>
 
+//
+// AP loop state when APs are in idle state
+// It's value is the same with PcdCpuApLoopMode
+//
+typedef enum {
+  ApInHltLoop   = 1,
+  ApInMwaitLoop = 2,
+  ApInRunLoop   = 3
+} AP_LOOP_MODE;
+
 //
 // AP reset code information including code address and size,
 // this structure will be shared be C code and assembly code.