From 4253a9dcdbfb025f8422129af78f2a2ab1bfee27 Mon Sep 17 00:00:00 2001
From: Maurice Ma <maurice.ma@intel.com>
Date: Tue, 23 Mar 2021 09:52:47 -0700
Subject: [PATCH] Fix Shell MTRR print issue

Current MTRR lib assumes the MTRR number is always 10. Instead,
this patch follows the IA manual to get the actual MTRR number
through MTRR capability register.

Signed-off-by: Maurice Ma <maurice.ma@intel.com>
---
 BootloaderCommonPkg/Library/MtrrLib/MtrrLib.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/BootloaderCommonPkg/Library/MtrrLib/MtrrLib.c b/BootloaderCommonPkg/Library/MtrrLib/MtrrLib.c
index 6d018df5..1524dace 100644
--- a/BootloaderCommonPkg/Library/MtrrLib/MtrrLib.c
+++ b/BootloaderCommonPkg/Library/MtrrLib/MtrrLib.c
@@ -9,6 +9,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/BaseLib.h>
 #include <Library/DebugLib.h>
 #include <Library/ConsoleOutLib.h>
+#include <Register/Intel/ArchitecturalMsr.h>
 
 /**
   Convert the MTRR memory type to a readable str
@@ -67,6 +68,7 @@ PrintMtrr (
   UINT64      Mask;
   UINT64      Range;
   UINT64      Limit;
+  MSR_IA32_MTRRCAP_REGISTER MtrrCap;
 
   if (Str != NULL) {
     CONSOLE_PRINT_CONDITION (ConsoleOut, (DEBUG_INFO, "%a\n", Str));
@@ -85,7 +87,8 @@ PrintMtrr (
 
   // Dump Variable MTRR registers
   CONSOLE_PRINT_CONDITION (ConsoleOut, (DEBUG_INFO, "Variable MTRRs\n"));
-  for (Index = 0; Index < 10; Index++) {
+  MtrrCap.Uint64 = AsmReadMsr64 (MSR_IA32_MTRRCAP);
+  for (Index = 0; Index < MtrrCap.Bits.VCNT; Index++) {
     BaseMsr = 0x200 + (Index * 2);
     MaskMsr = BaseMsr + 1;