Re: [PATCH v3 0/2] Enable page table write protection

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

Hi Laszlo,

Thanks for the test.

Jian
> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Wednesday, December 06, 2017 4:05 AM
> To: Wang, Jian J <jian.j.wang@intel.com>; edk2-devel@lists.01.org
> Subject: Re: [edk2] [PATCH v3 0/2] Enable page table write protection
> 
> On 12/05/17 09:16, Jian J Wang wrote:
> >> v3 changes:
> >>  a. According to code review comments, remove the public definitions of
> >>     page table pool. Now the DxeIpl and CpuDxe will have their own page
> >>     table pool but in the same mechanism. Related PCDs, GUDI and headers
> >>     are also removed.
> >>  b. Apply protection to all page tables, including new ones added in
> >>     CpuDxe driver.
> >>  c. Code/comments cleanup.
> >
> >> 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 (2):
> >   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/Ia32/DxeLoadFunc.c  |   8 +-
> >  MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 301
> ++++++++++++++++++++++-
> >  MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.h |  26 ++
> >  UefiCpuPkg/CpuDxe/CpuDxe.c                       |  17 +-
> >  UefiCpuPkg/CpuDxe/CpuDxe.h                       |   2 +
> >  UefiCpuPkg/CpuDxe/CpuPageTable.c                 | 226 ++++++++++++++++-
> >  UefiCpuPkg/CpuDxe/CpuPageTable.h                 |  34 +++
> >  8 files changed, 635 insertions(+), 13 deletions(-)
> >
> 
> series
> Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
> 
> Thanks
> Laszlo