[edk2] [Patch] UefiCpuPkg/S3Resume2Pei: disable paging before creating new page table.

[Eric Dong]

PEI Stack Guard needs to enable paging. This might cause #GP in the
transition from 32-bit PEI to 64-bit SMM due to the code trying to
write CR3 register with PML4 page table while the processor is enabled
with PAE paging.

Simply disabling paging before updating CR3 can solve this conflict.

Change-Id: I99bfdba5daa48a95a4c4ef97eeca1af086558957
Cc: Ruiyu Ni <ruiyu...@intel.com>
Cc: Laszlo Ersek <ler...@redhat.com>
Cc: Jian J Wang <jian.j.w...@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by:Eric Dong <eric.d...@intel.com>
Signed-off-by: Eric Dong <eric.d...@intel.com>
---
 UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c       | 7 +++++++
 UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf | 1 +
 2 files changed, 8 insertions(+)

diff --git a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c 
b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
index f164c1713b..b3bf56e13d 100644
--- a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
+++ b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
@@ -1105,6 +1105,13 @@ S3RestoreConfig2 (
       //
       SetInterruptState (InterruptStatus);
 
+      if (PcdGetBool (PcdCpuStackGuard)) {
+        //
+        // Paging already been enabled, to avoid conflict configuration,
+        // disable paging first anyway.
+        //
+        AsmWriteCr0 (AsmReadCr0 () & (~BIT31));
+      }
       AsmWriteCr3 ((UINTN)SmmS3ResumeState->SmmS3Cr3);
 
       //
diff --git a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf 
b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf
index 6ce1bf944c..0f131d19df 100644
--- a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf
+++ b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume2Pei.inf
@@ -90,6 +90,7 @@
 [Pcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdUse1GPageTable  ## SOMETIMES_CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrMask    ## 
CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard                       ## 
CONSUMES
 
 [Depex]
   TRUE
-- 
2.15.0.windows.1

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