tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

UefiCpuPkg/CpuPageTableLib: Fix issue when splitting leaf entry 

When splitting leaf parent entry to smaller granularity, create
child page table before modifing parent entry. In previous code
logic, when splitting a leaf parent entry, parent entry will
point to a null 4k memory before child page table is created in
this 4k memory. When the page table to be modified is the page
table in CR3, if the executed CpuPageTableLib code is in the
range mapped by the modified leaf parent entry, then issue will
happen.

Signed-off-by: Dun Tan <dun.tan@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Dun Tan 2022-12-09 10:34:43 +08:00 committed by mergify[bot]
parent b6b54367c3
commit c90cb726f8
1 changed files with 11 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
View File

@ -363,21 +363,24 @@ PageTableLibMapInLevel (
//
// Create 512 child-level entries that map to 2M/4K.
//
ParentPagingEntry->Uintn = (UINTN)Buffer + *BufferSize;
ZeroMem ((VOID *)ParentPagingEntry->Uintn, SIZE_4KB);
PagingEntry = (IA32_PAGING_ENTRY *)((UINTN)Buffer + *BufferSize);
ZeroMem (PagingEntry, SIZE_4KB);
for (SubOffset = 0, Index = 0; Index < 512; Index++) {
PagingEntry[Index].Uint64 = OneOfPagingEntry.Uint64 + SubOffset;
SubOffset += RegionLength;
}
//
// Set NOP attributes
// Note: Should NOT inherit the attributes from the original entry because a zero RW bit
// will make the entire region read-only even the child entries set the RW bit.
//
// Non-leaf entry doesn't have PAT bit. So use ~IA32_PE_BASE_ADDRESS_MASK_40 is to make sure PAT bit
// (bit12) in original big-leaf entry is not assigned to PageTableBaseAddress field of non-leaf entry.
//
PageTableLibSetPnle (&ParentPagingEntry->Pnle, &NopAttribute, &AllOneMask);
PagingEntry = (IA32_PAGING_ENTRY *)(UINTN)IA32_PNLE_PAGE_TABLE_BASE_ADDRESS (&ParentPagingEntry->Pnle);
for (SubOffset = 0, Index = 0; Index < 512; Index++) {
PagingEntry[Index].Uint64 = OneOfPagingEntry.Uint64 + SubOffset;
SubOffset += RegionLength;
}
ParentPagingEntry->Uint64 = ((UINTN)(VOID *)PagingEntry) | (ParentPagingEntry->Uint64 & (~IA32_PE_BASE_ADDRESS_MASK_40));
}
} else {
//