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>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
---
UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
index 127b65183f..ad68792ca8 100644
--- a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
+++ b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
@@ -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) + PagingEntryIndex * RegionLength;
+ PhysicalAddrInAttr = (IA32_MAP_ATTRIBUTE_PAGE_TABLE_BASE_ADDRESS (Attribute) + Offset) & (~RegionMask);
+ if (PhysicalAddrInEntry == PhysicalAddrInAttr) {
+ return RETURN_SUCCESS;
+ }
}
ASSERT (Buffer == NULL || *BufferSize >= SIZE_4KB);
--
2.31.1.windows.1
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