Re: [PATCH v2 0/4] Enable page table write protection

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

That means we can't share page table pool between DxeIpl and CpuDxe. If this is
acceptable, I can remove them.

> -----Original Message-----
> From: Zeng, Star
> Sent: Monday, December 04, 2017 5:11 PM
> To: Wang, Jian J <jian.j.wang@intel.com>; edk2-devel@lists.01.org
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Ni, Ruiyu <ruiyu.ni@intel.com>; Dong,
> Eric <eric.dong@intel.com>; Zeng, Star <star.zeng@intel.com>
> Subject: RE: [edk2] [PATCH v2 0/4] Enable page table write protection
> 
> Recommend to not introduce the new header file and PCDs as new interfaces,
> but handle the page table pool separately in DxeIpl and CpuDxe.
> 
> Thanks,
> Star
> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Jian J
> Wang
> Sent: Monday, December 4, 2017 4:36 PM
> To: edk2-devel@lists.01.org
> Subject: [edk2] [PATCH v2 0/4] Enable page table write protection
> 
> > v2 changes:
> >  a. Enable protection on any newly added page table after DxeIpl.
> >  b. Introduce page table pool concept to make page table allocation
> >     and protection easier and error free.
> 
> Write Protect feature (CR0.WP) is always enabled in driver UefiCpuPkg/CpuDxe.
> But the memory pages used for page table are not set as read-only in the driver
> DxeIplPeim, after the paging is setup. This might jeopardize the page table
> integrity if there's buffer overflow occured in other part of system.
> 
> This patch series will change this situation by clearing R/W bit in page attribute
> of the pages used as page table.
> 
> Validation works include booting Windows (10/server 2016) and Linux
> (Fedora/Ubuntu) on OVMF and Intel real platform.
> 
> Jian J Wang (4):
>   MdeModulePkg/MdeModulePkg.dec: Add new PCDs and Guid
>   MdeModulePkg/PageTablePool.h: Page table pool GUID definition file
>   MdeModulePkg/DxeIpl: Mark page table as read-only
>   UefiCpuPkg/CpuDxe: Enable protection for newly added page table
> 
>  MdeModulePkg/Core/DxeIplPeim/DxeIpl.h            |  34 +++
>  MdeModulePkg/Core/DxeIplPeim/DxeIpl.inf          |   3 +
>  MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c  |   8 +-
>  MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 315
> +++++++++++++++++++++-
> MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h |  15 ++
>  MdeModulePkg/Include/Guid/PageTablePool.h        |  53 ++++
>  MdeModulePkg/MdeModulePkg.dec                    |  28 ++
>  UefiCpuPkg/CpuDxe/CpuDxe.c                       |  17 +-
>  UefiCpuPkg/CpuDxe/CpuDxe.h                       |   2 +
>  UefiCpuPkg/CpuDxe/CpuDxe.inf                     |   3 +
>  UefiCpuPkg/CpuDxe/CpuPageTable.c                 | 329
> ++++++++++++++++++++++-
>  UefiCpuPkg/CpuDxe/CpuPageTable.h                 |  22 ++
>  12 files changed, 816 insertions(+), 13 deletions(-)  create mode 100644
> MdeModulePkg/Include/Guid/PageTablePool.h
> 
> --
> 2.14.1.windows.1
> 
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