Re: Page Table initialization and update in SMM mode

[Laszlo Ersek <lersek@redhat.com>]

Jiewen,

On 03/22/17 15:14, William Tambe wrote:
> Dear all,
> 
> When building OVMF with SMM_REQUIRE:
> 
> - Would you know where in the code base the Page Table set in the Cr3
> register is initialized during boot ?
> 
> - Where does it get updated when a new page needs to be allocated or freed ?
> 
> - Or is there a hook I can register myself to in order to get a chance to
> review an entry to be added or removed from the Page Tables ?

can you please help answer these questions? I seem to remember that we
discussed code around this when we were looking into the SMM stack
overflow experienced with OVMF:

509f8425b75d UefiCpuPkg: change PcdCpuSmmStackGuard default to TRUE
0d0c245dfb14 OvmfPkg: set SMM stack size to 16KB

William: I suggest to check out the following files:

UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/PageTbl.c
UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c

and/or to grep the code for "PcdCpuSmmStackGuard", to get a feel for
what to investigate.

Thanks
Laszlo