Re: [PATCH 5/5] UefiCpuPkg/PiSmmCpuDxeSmm: Disable page table protection

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

Hi Jian,

> +  if (!mCpuSmmStaticPageTable || (PcdGet8 (PcdHeapGuardPropertyMask)
> &
> + BIT3 | BIT2) != 0) {

I think above code logic is not correct, the "&" will be handled before the "|" which is not an expected order, right?

Thanks,
Eric

> -----Original Message-----
> From: Wang, Jian J
> Sent: Wednesday, October 11, 2017 11:18 AM
> To: edk2-devel@lists.01.org
> Cc: Dong, Eric <eric.dong@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>;
> Kinney, Michael D <michael.d.kinney@intel.com>; Wolman, Ayellet
> <ayellet.wolman@intel.com>
> Subject: [PATCH 5/5] UefiCpuPkg/PiSmmCpuDxeSmm: Disable page table
> protection
> 
> Heap guard feature will update page attributes frequently. The page table
> should not set to be read-only if heap guard feature is enabled for SMM
> mode. Otherwise this feature cannot work.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Michael Kinney <michael.d.kinney@intel.com>
> Cc: Ayellet Wolman <ayellet.wolman@intel.com>
> Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
> ---
>  UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.inf | 1 +
>  UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c      | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.inf
> b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.inf
> index 099792e6ce..644709650c 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.inf
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.inf
> @@ -159,6 +159,7 @@
>    gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmStaticPageTable               ##
> CONSUMES
>    gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiS3Enable                   ##
> CONSUMES
> 
> gEfiMdeModulePkgTokenSpaceGuid.PcdPteMemoryEncryptionAddressOrM
> ask    ## CONSUMES
> +  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask
> ## CONSUMES
> 
>  [Depex]
>    gEfiMpServiceProtocolGuid
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> index 3dde80f9ba..4debce3a0f 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
> @@ -902,7 +902,7 @@ SetPageTableAttributes (
>    BOOLEAN               IsSplitted;
>    BOOLEAN               PageTableSplitted;
> 
> -  if (!mCpuSmmStaticPageTable) {
> +  if (!mCpuSmmStaticPageTable || (PcdGet8 (PcdHeapGuardPropertyMask)
> &
> + BIT3 | BIT2) != 0) {
>      return ;
>    }
> 
> --
> 2.14.1.windows.1