Re: [PATCH v2] UefiCpuPkg/SmmCpu: Block access-out only when static paging is used

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

I agree my 1st version commit message is too general.
Because I don't know if RAS can be mentioned:)

> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Wednesday, November 7, 2018 10:46 PM
> To: Ni, Ruiyu <ruiyu.ni@intel.com>; edk2-devel@lists.01.org
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Dong, Eric <eric.dong@intel.com>
> Subject: Re: [edk2] [PATCH v2] UefiCpuPkg/SmmCpu: Block access-out only
> when static paging is used
> 
> On 11/07/18 09:59, Ruiyu Ni wrote:
> > From: Jiewen Yao <jiewen.yao@intel.com>
> >
> > When static paging is disabled, page table for below 4GB is created
> > and page table for above 4GB is created dynamically in page fault
> > handler.
> >
> > Today's implementation only allow SMM access-out to below types of
> > memory address no matter static paging is enabled or not:
> > 1. Reserved, run time and ACPI NVS type 2. MMIO
> >
> > But certain platform feature like RAS may need to access other types
> > of memory from SMM. Today's code blocks these platforms.
> > This patch simplifies the policy to only block when static paging is
> > used so that the static paging can be disabled in these platforms to
> > meet their SMM access-out need.
> >
> > Setting PcdCpuSmmStaticPageTable to FALSE can disable the static
> > paging.
> >
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
> > Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
> > Cc: Eric Dong <eric.dong@intel.com>
> > Cc: Jiewen Yao <jiewen.yao@intel.com>
> > Acked-by: Laszlo Ersek <lersek@redhat.com>
> > ---
> >  UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> Thanks, this has improved a lot!
> Laszlo