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 the non-1:1 mapping issue 

In previous code logic, when splitting a leaf parent entry to
smaller granularity child page table, if the parent entry
Attribute&Mask(without PageTableBaseAddress field) is equal to the
input attribute&mask(without PageTableBaseAddress field), the split
process won't happen. This may lead to failure in non-1:1 mapping.

For example, there is a page table in which [0, 1G] is mapped(Lv4[0]
,Lv3[0,0], a non-leaf level4 entry and a leaf level3 entry). And we
want to remap [0, 2M] linear address range to [1G, 1G + 2M] with the
same attibute. The expected behaviour should be: split Lv3[0,0]
entry into 512 level2 entries and remap the first level2 entry to
cover [0, 2M]. But the split won't happen in previous code since
PageTableBaseAddress of input Attribute is not checked.

So, when checking if a leaf parent entry needs to be splitted, we
should also check if PageTableBaseAddress calculated by parent entry
is equal to the value caculated by input attribute.

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 2023-03-16 10:34:40 +08:00 committed by mergify[bot]
parent 563a2d2695
commit 4904a2b1ec
1 changed files with 11 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
View File

@ -274,6 +274,8 @@ PageTableLibMapInLevel (
IA32_MAP_ATTRIBUTE ChildMask;
IA32_MAP_ATTRIBUTE CurrentMask;
IA32_MAP_ATTRIBUTE LocalParentAttribute;
UINT64 PhysicalAddrInEntry;
UINT64 PhysicalAddrInAttr;
ASSERT (Level != 0);
ASSERT ((Attribute != NULL) && (Mask != NULL));
@ -341,7 +343,15 @@ PageTableLibMapInLevel (
// This function is called when the memory length is less than the region length of the parent level.
// No need to split the page when the attributes equal.
//
return RETURN_SUCCESS;
if (Mask->Bits.PageTableBaseAddress == 0) {
return RETURN_SUCCESS;
}
PhysicalAddrInEntry = IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (&PleBAttribute) + MultU64x32 (RegionLength, (UINT32)PagingEntryIndex);
PhysicalAddrInAttr = (IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (Attribute) + Offset) & (~RegionMask);
if (PhysicalAddrInEntry == PhysicalAddrInAttr) {
return RETURN_SUCCESS;
}
}
ASSERT (Buffer == NULL || *BufferSize >= SIZE_4KB);