[PATCH v4 1/8] UefiCpuPkg/MpInitLib: Enable 5-level paging for AP when BSP's enabled

["Ni, Ray" <ray.ni@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2008

MpInitLib is the library that's responsible to wake up APs to provide
MP PPI and Protocol services.

The patch synchronizes BSP's CR4.LA57 to each AP's CR4.LA57.
Without this change, AP may enter to GP fault when BSP's 5-level page
table is set to AP during AP wakes up.

Signed-off-by: Ray Ni <ray.ni@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
---
 UefiCpuPkg/Library/MpInitLib/MpLib.c          | 13 +++++++++++++
 UefiCpuPkg/Library/MpInitLib/MpLib.h          |  4 ++++
 UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc    |  3 ++-
 UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm | 14 +++++++++++++-
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c b/UefiCpuPkg/Library/MpInitLib/MpLib.c
index 572495ec36..d2f18027cd 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
@@ -790,6 +790,7 @@ FillExchangeInfoData (
   volatile MP_CPU_EXCHANGE_INFO    *ExchangeInfo;
   UINTN                            Size;
   IA32_SEGMENT_DESCRIPTOR          *Selector;
+  IA32_CR4                         Cr4;
 
   ExchangeInfo                  = CpuMpData->MpCpuExchangeInfo;
   ExchangeInfo->Lock            = 0;
@@ -814,6 +815,18 @@ FillExchangeInfoData (
 
   ExchangeInfo->InitializeFloatingPointUnitsAddress = (UINTN)InitializeFloatingPointUnits;
 
+  //
+  // We can check either CPUID(7).ECX[bit16] or check CR4.LA57[bit12]
+  //  to determin whether 5-Level Paging is enabled.
+  // CPUID(7).ECX[bit16] shows CPU's capability, CR4.LA57[bit12] shows
+  // current system setting.
+  // Using latter way is simpler because it also eliminates the needs to
+  //  check whether platform wants to enable it.
+  //
+  Cr4.UintN = AsmReadCr4 ();
+  ExchangeInfo->Enable5LevelPaging = (BOOLEAN) (Cr4.Bits.LA57 == 1);
+  DEBUG ((DEBUG_INFO, "%a: 5-Level Paging = %d\n", gEfiCallerBaseName, ExchangeInfo->Enable5LevelPaging));
+
   //
   // Get the BSP's data of GDT and IDT
   //
diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.h b/UefiCpuPkg/Library/MpInitLib/MpLib.h
index effa235778..4b12f91d47 100644
--- a/UefiCpuPkg/Library/MpInitLib/MpLib.h
+++ b/UefiCpuPkg/Library/MpInitLib/MpLib.h
@@ -185,6 +185,10 @@ typedef struct {
   UINT16                ModeTransitionSegment;
   UINT32                ModeHighMemory;
   UINT16                ModeHighSegment;
+  //
+  // Enable5LevelPaging indicates whether 5-level paging is enabled in long mode.
+  //
+  BOOLEAN               Enable5LevelPaging;
 } MP_CPU_EXCHANGE_INFO;
 
 #pragma pack()
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
index 467f54a860..58ef369342 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpEqu.inc
@@ -1,5 +1,5 @@
 ;------------------------------------------------------------------------------ ;
-; Copyright (c) 2015 - 2017, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2015 - 2019, Intel Corporation. All rights reserved.<BR>
 ; SPDX-License-Identifier: BSD-2-Clause-Patent
 ;
 ; Module Name:
@@ -40,3 +40,4 @@ ModeTransitionMemoryLocation        equ  LockLocation + 94h
 ModeTransitionSegmentLocation       equ  LockLocation + 98h
 ModeHighMemoryLocation              equ  LockLocation + 9Ah
 ModeHighSegmentLocation             equ  LockLocation + 9Eh
+Enable5LevelPagingLocation          equ  LockLocation + 0A0h
diff --git a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
index cea90f3d4d..87f2523e85 100644
--- a/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
+++ b/UefiCpuPkg/Library/MpInitLib/X64/MpFuncs.nasm
@@ -1,5 +1,5 @@
 ;------------------------------------------------------------------------------ ;
-; Copyright (c) 2015 - 2018, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2015 - 2019, Intel Corporation. All rights reserved.<BR>
 ; SPDX-License-Identifier: BSD-2-Clause-Patent
 ;
 ; Module Name:
@@ -100,6 +100,18 @@ SkipEnableExecuteDisableBit:
     ;
     mov        eax, cr4
     bts        eax, 5
+
+    mov        esi, Enable5LevelPagingLocation
+    cmp        byte [ebx + esi], 0
+    jz         SkipEnable5LevelPaging
+
+    ;
+    ; Enable 5 Level Paging
+    ;
+    bts        eax, 12                     ; Set LA57=1.
+
+SkipEnable5LevelPaging:
+
     mov        cr4, eax
 
     ;
-- 
2.21.0.windows.1