CpuPageTableLib: Fix a bug when a bit is 1 in Attribute, 0 in Mask
To reproduce the issue:
UINTN PageTable;
VOID *Buffer;
UINTN PageTableBufferSize;
IA32_MAP_ATTRIBUTE Attribute;
IA32_MAP_ATTRIBUTE Mask;
RETURN_STATUS Status;
Attribute.Uint64 = 0;
Mask.Uint64 = 0;
PageTableBufferSize = 0;
PageTable = 0;
Buffer = NULL;
Attribute.Bits.Present = 1;
Attribute.Bits.Nx = 1;
Mask.Bits.Present = 1;
Mask.Uint64 = MAX_UINT64;
//
// Create page table to cover [0, 10M)
//
Status = PageTableMap (
&PageTable, PagingMode, Buffer, &PageTableBufferSize,
0, (UINT64)SIZE_2MB * 5, &Attribute, &Mask
);
ASSERT (Status == RETURN_BUFFER_TOO_SMALL);
Buffer = AllocatePages (EFI_SIZE_TO_PAGES (PageTableBufferSize));
Status = PageTableMap (
&PageTable, PagingMode, Buffer, &PageTableBufferSize,
0, (UINT64)SIZE_2MB * 5, &Attribute, &Mask
);
ASSERT (Status == RETURN_SUCCESS);
//
// Change the mapping for [0, 4KB)
// No change actually. Just clear Nx bit in Mask.
//
Mask.Bits.Nx = 0;
PageTableBufferSize = 0;
Status = PageTableMap (
&PageTable, PagingMode, NULL, &PageTableBufferSize,
0, (UINT64)SIZE_4KB, &Attribute, &Mask
);
ASSERT (Status == RETURN_SUCCESS); // FAIL!!
The root cause is when comparing the existing mapping attributes
against the requested one, Mask is not used but it should be used.
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
bf334513b3