[Patch v3] UefiCpuPkg/S3Resume2Pei: disable paging before creating new page table.

[Eric Dong <eric.dong@intel.com>]

V3 changes:
No need to change inf file. Also update commit message to include regression info.

V2 changes:
Only disable paging in 32 bit mode, no matter it is enable or not.

V1 changes:
PEI Stack Guard needs to enable paging. This might cause #GP if 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.

It's an regression caused by change: 0a0d5296e448fc350de1594c49b9c0deff7fad60

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1232

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by:Eric Dong <eric.dong@intel.com>
---
 UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
index f164c1713b..53ed76c6e6 100644
--- a/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
+++ b/UefiCpuPkg/Universal/Acpi/S3Resume2Pei/S3Resume.c
@@ -1105,6 +1105,14 @@ S3RestoreConfig2 (
       //
       SetInterruptState (InterruptStatus);
 
+      if (sizeof(UINTN) == sizeof(UINT32)) {
+        //
+        // Paging maybe enabled. If current mode is 32 bit mode and code try to
+        // enable 64 bit mode page table, it will cause GP fault.
+        // To avoid conflict configuration, disable paging first anyway.
+        //
+        AsmWriteCr0 (AsmReadCr0 () & (~BIT31));
+      }
       AsmWriteCr3 ((UINTN)SmmS3ResumeState->SmmS3Cr3);
 
       //
-- 
2.15.0.windows.1