Reviewed-by: Ray Ni <ray...@intel.com> > -----Original Message----- > From: Tan, Dun <dun....@intel.com> > Sent: Wednesday, August 10, 2022 1:34 PM > To: devel@edk2.groups.io > Cc: Bi, Dandan <dandan...@intel.com>; Gao, Liming > <gaolim...@byosoft.com.cn>; Ni, Ray <ray...@intel.com> > Subject: [Patch V2 1/2] MdeModulePkg/DxeIpl: Remove clearing CR0.WP > when protecting pagetable > > Remove clearing CR0.WP when marking the memory used for page table > as read-only in the page table itself created by DxeIpl. This page > table address is written to Cr3 after these protection steps. Till > this, the memory used for page table is always RW. > > Signed-off-by: Dun Tan <dun....@intel.com> > Cc: Dandan Bi <dandan...@intel.com> > Cc: Liming Gao <gaolim...@byosoft.com.cn> > Cc: Ray Ni <ray...@intel.com> > --- > MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > index a451ca1604..18b121d768 100644 > --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c > @@ -626,12 +626,7 @@ EnablePageTableProtection ( > } > > // > - // Disable write protection, because we need to mark page table to be > write > - // protected. > - // > - AsmWriteCr0 (AsmReadCr0 () & ~CR0_WP); > - > - // > + // No need to clear CR0.WP since PageTableBase has't been written to CR3 > yet. > // SetPageTablePoolReadOnly might update mPageTablePool. It's safer to > // remember original one in advance. > // > -- > 2.31.1.windows.1
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