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

["Wang, Jian J" <jian.j.wang@intel.com>]

Thanks for fixing this issue.

Reviewed-by: Jian J Wang <jian.j.wang@intel.com>

> -----Original Message-----
> From: Dong, Eric
> Sent: Tuesday, October 09, 2018 9:51 AM
> To: edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>; Wang,
> Jian J <jian.j.wang@intel.com>
> Subject: [Patch] UefiCpuPkg/S3Resume2Pei: disable paging before creating new
> page table.
> 
> 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.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>
> Signed-off-by: Eric Dong <eric.dong@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