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

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

You're right. "BIT3 | BIT2" should be enclosed by parentheses. Thanks for catching this issue.

> -----Original Message-----
> From: Dong, Eric
> Sent: Friday, October 13, 2017 9:24 AM
> To: Wang, Jian J <jian.j.wang@intel.com>; edk2-devel@lists.01.org
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Kinney, Michael D
> <michael.d.kinney@intel.com>; Wolman, Ayellet <ayellet.wolman@intel.com>
> Subject: RE: [PATCH 5/5] UefiCpuPkg/PiSmmCpuDxeSmm: Disable page table
> protection
> 
> 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