From 8ea0ac749ff4cde85305544f79787b82f764b97e Mon Sep 17 00:00:00 2001
From: Patrick Rudolph <patrick.rudolph@9elements.com>
Date: Tue, 8 Sep 2020 09:40:41 +0200
Subject: [PATCH] UefiCpuPkg: Disable MTRR programming for UefiPayloadPkg

The MTRRs have already been programmed by FSB.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Change-Id: I8c6e7657b789edac8ee83a89318209a598712db8
---
 UefiCpuPkg/Library/MtrrLib/MtrrLib.c   | 4 ++++
 UefiCpuPkg/Library/MtrrLib/MtrrLib.inf | 2 +-
 UefiCpuPkg/UefiCpuPkg.dec              | 4 ++++
 UefiCpuPkg/UefiCpuPkg.uni              | 8 ++++++--
 UefiPayloadPkg/UefiPayloadPkg.dsc      | 3 +++
 5 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index 4d4b52a4c3b2..dbae575ee932 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -161,6 +161,10 @@ MtrrLibIsMtrrSupported (
   CPUID_VERSION_INFO_EDX     Edx;
   MSR_IA32_MTRRCAP_REGISTER  MtrrCap;
 
+  if (PcdGetBool(PcdCpuDisableMtrrProgramming)) {
+    return FALSE;
+  }
+
   //
   // Check CPUID(1).EDX[12] for MTRR capability
   //
diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.inf b/UefiCpuPkg/Library/MtrrLib/MtrrLib.inf
index 4c9ea2def3bd..611fdc704722 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.inf
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.inf
@@ -37,4 +37,4 @@
 
 [Pcd]
   gUefiCpuPkgTokenSpaceGuid.PcdCpuNumberOfReservedVariableMtrrs   ## SOMETIMES_CONSUMES
-
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuDisableMtrrProgramming ## CONSUMES
diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
index c026cf535b86..0203e1321e32 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -287,6 +287,10 @@
   # @Prompt SMM Code Access Check.
   gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmCodeAccessCheckEnable|TRUE|BOOLEAN|0x60000013
 
+  ## Disables MTRR programming in case it's already programmed by FSB.
+  # @Prompt Disable MTRR programming.
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuDisableMtrrProgramming|FALSE|BOOLEAN|0x00000017
+
   ## Specifies the number of variable MTRRs reserved for OS use. The default number of
   #  MTRRs reserved for OS use is 2.
   # @Prompt Number of reserved variable MTRRs.
diff --git a/UefiCpuPkg/UefiCpuPkg.uni b/UefiCpuPkg/UefiCpuPkg.uni
index 25a7176194f1..81f9525860c1 100644
--- a/UefiCpuPkg/UefiCpuPkg.uni
+++ b/UefiCpuPkg/UefiCpuPkg.uni
@@ -156,9 +156,13 @@
 
 #string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuHotPlugDataAddress_HELP  #language en-US "Contains the pointer to a CPU Hot Plug Data structure if CPU hot-plug is supported."
 
-#string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuNumberOfReservedVariableMtrrs_PROMPT  #language en-US "Number of reserved variable MTRRs"
+#string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuDisableMtrrProgramming_PROMPT  #language en-US "Number of reserved variable MTRRs"
 
-#string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuNumberOfReservedVariableMtrrs_HELP  #language en-US "Specifies the number of variable MTRRs reserved for OS use."
+#string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuDisableMtrrProgramming_HELP  #language en-US "Specifies the number of variable MTRRs reserved for OS use."
+
+#string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuNumberOfReservedVariableMtrrs_PROMPT  #language en-US "Disable MTRR programming."
+
+#string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuNumberOfReservedVariableMtrrs_HELP  #language en-US "Disables MTRR programming in case it's already programmed by FSB."
 
 #string STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuApLoopMode_PROMPT  #language en-US "The AP wait loop state"
 
diff --git a/UefiPayloadPkg/UefiPayloadPkg.dsc b/UefiPayloadPkg/UefiPayloadPkg.dsc
index e94a7db886f7..0d141b442182 100644
--- a/UefiPayloadPkg/UefiPayloadPkg.dsc
+++ b/UefiPayloadPkg/UefiPayloadPkg.dsc
@@ -514,6 +514,9 @@
 !endif
 !endif
 
+  # Disable MTRR programming
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuDisableMtrrProgramming|TRUE
+
 [PcdsPatchableInModule.X64]
 !if $(NETWORK_DRIVER_ENABLE) == TRUE
   gEfiNetworkPkgTokenSpaceGuid.PcdAllowHttpConnections|TRUE