It's for sharing the pool between the DxeIpl and CpuDxe. If we don't care about wasting a little bit memory, it's ok to drop this definition. CpuDxe can reserve a block of memory for page table for its own uses.
> -----Original Message----- > From: Yao, Jiewen > Sent: Tuesday, December 05, 2017 10:27 AM > To: Wang, Jian J <[email protected]>; Zeng, Star <[email protected]>; > [email protected] > Cc: Ni, Ruiyu <[email protected]>; Dong, Eric <[email protected]> > Subject: RE: [edk2] [PATCH v2 0/4] Enable page table write protection > > I do not suggest we define PAGE_TABLE_POOL_HEADER. > If we can figure out other way, that will be better. > > Thank you > Yao Jiewen > > > > -----Original Message----- > > From: Wang, Jian J > > Sent: Monday, December 4, 2017 5:26 PM > > To: Zeng, Star <[email protected]>; [email protected] > > Cc: Yao, Jiewen <[email protected]>; Ni, Ruiyu <[email protected]>; > Dong, > > Eric <[email protected]> > > Subject: RE: [edk2] [PATCH v2 0/4] Enable page table write protection > > > > 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 <[email protected]>; [email protected] > > > Cc: Yao, Jiewen <[email protected]>; Ni, Ruiyu <[email protected]>; > > Dong, > > > Eric <[email protected]>; Zeng, Star <[email protected]> > > > 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:[email protected]] On Behalf Of > Jian > > J > > > Wang > > > Sent: Monday, December 4, 2017 4:36 PM > > > To: [email protected] > > > 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 > > > > > > _______________________________________________ > > > edk2-devel mailing list > > > [email protected] > > > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
