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: Dong, Guo <guo.d...@intel.com>; Ni, Ray <ray...@intel.com>; Maurice > Ma <maurice...@intel.com>; You, Benjamin <benjamin....@intel.com>; > Rhodes, Sean <sean@starlabs.systems> > Subject: [Patch V2 2/2] UefiPayloadPkg: 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 UefiPayloadEntry. > 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: Guo Dong <guo.d...@intel.com> > Cc: Ray Ni <ray...@intel.com> > Cc: Maurice Ma <maurice...@intel.com> > Cc: Benjamin You <benjamin....@intel.com> > Cc: Sean Rhodes <sean@starlabs.systems> > --- > UefiPayloadPkg/UefiPayloadEntry/X64/VirtualMemory.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/UefiPayloadPkg/UefiPayloadEntry/X64/VirtualMemory.c > b/UefiPayloadPkg/UefiPayloadEntry/X64/VirtualMemory.c > index 74b667a62a..a586941352 100644 > --- a/UefiPayloadPkg/UefiPayloadEntry/X64/VirtualMemory.c > +++ b/UefiPayloadPkg/UefiPayloadEntry/X64/VirtualMemory.c > @@ -622,12 +622,7 @@ 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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