[PATCH 03/10] CpuPageTableLib: Fix a bug when a bit is 1 in Attribute, 0 in Mask

["Ni, Ray" <ray.ni@intel.com>]

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>
Cc: Eric Dong <eric.dong@intel.com>
---
 UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
index 17bca5e351..429b014b7b 100644
--- a/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
+++ b/UefiCpuPkg/Library/CpuPageTableLib/CpuPageTableMap.c
@@ -308,7 +308,7 @@ PageTableLibMapInLevel (
     //
     PleBAttribute.Uint64 = PageTableLibGetPleBMapAttribute (&ParentPagingEntry->PleB, &NopAttribute);
     if ((IA32_MAP_ATTRIBUTE_ATTRIBUTES (&PleBAttribute) & IA32_MAP_ATTRIBUTE_ATTRIBUTES (Mask))
-        == IA32_MAP_ATTRIBUTE_ATTRIBUTES (Attribute))
+        == (IA32_MAP_ATTRIBUTE_ATTRIBUTES (Attribute) & IA32_MAP_ATTRIBUTE_ATTRIBUTES (Mask)))
     {
       //
       // This function is called when the memory length is less than the region length of the parent level.
-- 
2.35.1.windows.2