With following paging structure to map
[2M-4K, 2M] as P = 1, RW = 0,
[2M, 4M] as P = 1, RW = 1:
PML4[0] -> PDPTE[0] -> PDE[0](RW = 0) -> PTE[255](P = 0, RW = 0)
-> PDE[1](RW = 1)
When a new request to map [2M-4K, 2M+4K] as P = 1, RW = 1,
CpuPageTableMap() wrongly requests 4K buffer size for the new mapping
request.
But in fact, for [2M-4K, 2M] request, PTE[255] can be changed in place,
for [2M, 2M+4K], no change is needed because PDE[1].RW = 1 already.
The change fixes the bug.
Signed-off-by: Ray Ni <ray...@intel.com>
Signed-off-by: Zhiguang Liu <zhiguang....@intel.com>
Cc: Eric Dong <eric.d...@intel.com>
---
.../Library/CpuPageTableLib/CpuPageTableMap.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
index 1205119fc8..16e6697ed4 100644
--- a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
+++ b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
@@ -272,6 +272,7 @@ PageTableLibMapInLevel (
IA32_MAP_ATTRIBUTE ChildAttribute;
IA32_MAP_ATTRIBUTE ChildMask;
IA32_MAP_ATTRIBUTE CurrentMask;
+ IA32_MAP_ATTRIBUTE LocalParentAttribute;
ASSERT (Level != 0);
ASSERT ((Attribute != NULL) && (Mask != NULL));
@@ -284,6 +285,9 @@ PageTableLibMapInLevel (
NopAttribute.Bits.ReadWrite = 1;
NopAttribute.Bits.UserSupervisor = 1;
+ LocalParentAttribute.Uint64 = ParentAttribute->Uint64;
+ ParentAttribute = &LocalParentAttribute;
+
//
// ParentPagingEntry ONLY is deferenced for checking Present and MustBeOne
bits
// when Modify is FALSE.
@@ -420,7 +424,7 @@ PageTableLibMapInLevel (
}
if (IsPle (&PagingEntry[Index], Level)) {
- PageTableLibSetPle (Level - 1, &PagingEntry[Index], 0,
&ChildAttribute, &ChildMask);
+ PageTableLibSetPle (Level, &PagingEntry[Index], 0,
&ChildAttribute, &ChildMask);
} else {
PageTableLibSetPnle (&PagingEntry[Index].Pnle, &ChildAttribute,
&ChildMask);
}
@@ -664,13 +668,6 @@ PageTableMap (
//
// Update the page table when the supplied buffer is sufficient.
//
- ParentAttribute.Uint64 = 0;
- ParentAttribute.Bits.PageTableBaseAddress = 1;
- ParentAttribute.Bits.Present = 1;
- ParentAttribute.Bits.ReadWrite = 1;
- ParentAttribute.Bits.UserSupervisor = 1;
- ParentAttribute.Bits.Nx = 0;
-
Status = PageTableLibMapInLevel (
&TopPagingEntry,
&ParentAttribute,
--
2.35.1.windows.2
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