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

[Laszlo Ersek <lersek@redhat.com>]

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