[Patch V5 04/14] UefiCpuPkg: Add DEBUG_CODE for special case when clear RP

["duntan" <dun.tan@intel.com>]

In ConvertMemoryPageAttributes() function, when clear RP for a
specific range [BaseAddress, BaseAddress + Length], it means to
set the present bit to 1 and assign default value for other
attributes in page table. The default attributes for the input
specific range are NX disabled and ReadOnly. If there is existing
present range in [BaseAddress, BaseAddress + Length] and the
attributes are not NX disabled or not ReadOnly, then output the
DEBUG message to indicate that the NX and ReadOnly attributes of
the existing present range are modified in the function.

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/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
index 12723e5750..862b3e9720 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmmCpuMemoryManagement.c
@@ -349,6 +349,8 @@ ConvertMemoryPageAttributes (
   IA32_MAP_ENTRY        *Map;
   UINTN                 Count;
   UINTN                 Index;
+  UINT64                OverlappedRangeBase;
+  UINT64                OverlappedRangeLimit;
 
   ASSERT (Attributes != 0);
   ASSERT ((Attributes & ~EFI_MEMORY_ATTRIBUTE_MASK) == 0);
@@ -430,6 +432,52 @@ ConvertMemoryPageAttributes (
       // By default memory is Ring 3 accessble.
       //
       PagingAttribute.Bits.UserSupervisor = 1;
+
+      DEBUG_CODE_BEGIN ();
+      if (((Attributes & EFI_MEMORY_RO) == 0) || (((Attributes & EFI_MEMORY_XP) == 0) && (mXdSupported))) {
+        //
+        // When mapping a range to present and EFI_MEMORY_RO or EFI_MEMORY_XP is not specificed,
+        // check if [BaseAddress, BaseAddress + Length] contains present range.
+        // Existing Present range in [BaseAddress, BaseAddress + Length] is set to NX disable or ReadOnly.
+        //
+        Count  = 0;
+        Map    = NULL;
+        Status = PageTableParse (PageTableBase, mPagingMode, NULL, &Count);
+
+        while (Status == RETURN_BUFFER_TOO_SMALL) {
+          if (Map != NULL) {
+            FreePool (Map);
+          }
+
+          Map = AllocatePool (Count * sizeof (IA32_MAP_ENTRY));
+          ASSERT (Map != NULL);
+          Status = PageTableParse (PageTableBase, mPagingMode, Map, &Count);
+        }
+
+        ASSERT_RETURN_ERROR (Status);
+        for (Index = 0; Index < Count; Index++) {
+          if (Map[Index].LinearAddress >= BaseAddress + Length) {
+            break;
+          }
+
+          if ((BaseAddress < Map[Index].LinearAddress + Map[Index].Length) && (BaseAddress + Length > Map[Index].LinearAddress)) {
+            OverlappedRangeBase  = MAX (BaseAddress, Map[Index].LinearAddress);
+            OverlappedRangeLimit = MIN (BaseAddress + Length, Map[Index].LinearAddress + Map[Index].Length);
+
+            if (((Attributes & EFI_MEMORY_RO) == 0) && (Map[Index].Attribute.Bits.ReadWrite == 1)) {
+              DEBUG ((DEBUG_ERROR, "SMM ConvertMemoryPageAttributes: [0x%lx, 0x%lx] is set from ReadWrite to ReadOnly\n", OverlappedRangeBase, OverlappedRangeLimit));
+            }
+
+            if (((Attributes & EFI_MEMORY_XP) == 0) && (mXdSupported) && (Map[Index].Attribute.Bits.Nx == 1)) {
+              DEBUG ((DEBUG_ERROR, "SMM ConvertMemoryPageAttributes: [0x%lx, 0x%lx] is set from NX enabled to NX disabled\n", OverlappedRangeBase, OverlappedRangeLimit));
+            }
+          }
+        }
+
+        FreePool (Map);
+      }
+
+      DEBUG_CODE_END ();
     }
   }
 
-- 
2.31.1.windows.1