[edk2] [PATCH v5 7/7] MdeModulePkg/PiSmmCore: Implement heap guard feature for SMM mode

Jian J Wang posted 7 patches 7 years, 1 month ago
There is a newer version of this series
[edk2] [PATCH v5 7/7] MdeModulePkg/PiSmmCore: Implement heap guard feature for SMM mode
Posted by Jian J Wang 7 years, 1 month ago
> v5
> a. Remove lib and pcd no longer needed from PiSmmCore.inf

> v4
> a. According to Ray's feedback, change the name of new protocol definitions
     from EFI_ to EDKII_.
> b. Coding style cleanup

> v3
> According to Jiewen's feedback, use new added protocol
>     gEdkiiSmmMemoryAttributeProtocolGuid
> to update memory attribute.

>
> v2
> According to Eric's feedback:
> a. Remove local variable initializer with memory copy from globals
> b. Change map table dump code to use DEBUG_PAGE|DEBUG_POOL level
>    message
> c. Remove unnecessary debug code
> d. Change name of function InitializePageTableLib to
>    InitializePageTableGlobals
>
> Other changes:
> e. Fix issues in 32-bit boot mode
> f. Coding style cleanup

This feature makes use of paging mechanism to add a hidden (not present)
page just before and after the allocated memory block. If the code tries
to access memory outside of the allocated part, page fault exception will
be triggered.

This feature is controlled by three PCDs:

    gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask
    gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPoolType
    gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPageType

BIT2 and BIT3 of PcdHeapGuardPropertyMask can be used to enable or disable
memory guard for SMM page and pool respectively. PcdHeapGuardPoolType and/or
PcdHeapGuardPageType are used to enable or disable guard for specific type
of memory. For example, we can turn on guard only for EfiRuntimeServicesCode
and EfiRuntimeServicesData by setting the PCD with value 0x60.

Pool memory is not ususally integer multiple of one page, and is more likely
less than a page. There's no way to monitor the overflow at both top and
bottom of pool memory. BIT7 of PcdHeapGuardPropertyMask is used to control
how to position the head of pool memory so that it's easier to catch memory
overflow in memory growing direction or in decreasing direction.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>
---
 MdeModulePkg/Core/PiSmmCore/HeapGuard.c   | 1467 +++++++++++++++++++++++++++++
 MdeModulePkg/Core/PiSmmCore/HeapGuard.h   |  398 ++++++++
 MdeModulePkg/Core/PiSmmCore/Page.c        |   52 +-
 MdeModulePkg/Core/PiSmmCore/PiSmmCore.c   |    7 +-
 MdeModulePkg/Core/PiSmmCore/PiSmmCore.h   |   81 +-
 MdeModulePkg/Core/PiSmmCore/PiSmmCore.inf |    6 +
 MdeModulePkg/Core/PiSmmCore/Pool.c        |   81 +-
 7 files changed, 2064 insertions(+), 28 deletions(-)
 create mode 100644 MdeModulePkg/Core/PiSmmCore/HeapGuard.c
 create mode 100644 MdeModulePkg/Core/PiSmmCore/HeapGuard.h

diff --git a/MdeModulePkg/Core/PiSmmCore/HeapGuard.c b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
new file mode 100644
index 0000000000..8dd109b619
--- /dev/null
+++ b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
@@ -0,0 +1,1467 @@
+/** @file
+  UEFI Heap Guard functions.
+
+Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "HeapGuard.h"
+
+//
+// Global to avoid infinite reentrance of memory allocation when updating
+// page table attributes, which may need allocating pages for new PDE/PTE.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED BOOLEAN mOnGuarding = FALSE;
+
+//
+// Pointer to table tracking the Guarded memory with bitmap, in which  '1'
+// is used to indicate memory guarded. '0' might be free memory or Guard
+// page itself, depending on status of memory adjacent to it.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED UINT64 mGuardedMemoryMap = 0;
+
+//
+// Current depth level of map table pointed by mGuardedMemoryMap.
+// mMapLevel must be initialized at least by 1. It will be automatically
+// updated according to the address of memory just tracked.
+//
+GLOBAL_REMOVE_IF_UNREFERENCED UINTN mMapLevel = 1;
+
+//
+// Shift and mask for each level of map table
+//
+GLOBAL_REMOVE_IF_UNREFERENCED UINTN mLevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH]
+                                    = GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS;
+GLOBAL_REMOVE_IF_UNREFERENCED UINTN mLevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH]
+                                    = GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS;
+
+//
+// SMM memory attribute protocol
+//
+EDKII_SMM_MEMORY_ATTRIBUTE_PROTOCOL *mSmmMemoryAttribute = NULL;
+
+/**
+  Set corresponding bits in bitmap table to 1 according to the address.
+
+  @param[in]  Address     Start address to set for.
+  @param[in]  BitNumber   Number of bits to set.
+  @param[in]  BitMap      Pointer to bitmap which covers the Address.
+
+  @return VOID
+**/
+STATIC
+VOID
+SetBits (
+  IN EFI_PHYSICAL_ADDRESS    Address,
+  IN UINTN                   BitNumber,
+  IN UINT64                  *BitMap
+  )
+{
+  UINTN           Lsbs;
+  UINTN           Qwords;
+  UINTN           Msbs;
+  UINTN           StartBit;
+  UINTN           EndBit;
+
+  StartBit  = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
+  EndBit    = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+
+  if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) {
+    Msbs    = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %
+              GUARDED_HEAP_MAP_ENTRY_BITS;
+    Lsbs    = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+    Qwords  = (BitNumber - Msbs) / GUARDED_HEAP_MAP_ENTRY_BITS;
+  } else {
+    Msbs    = BitNumber;
+    Lsbs    = 0;
+    Qwords  = 0;
+  }
+
+  if (Msbs > 0) {
+    *BitMap |= LShiftU64 (LShiftU64 (1, Msbs) - 1, StartBit);
+    BitMap  += 1;
+  }
+
+  if (Qwords > 0) {
+    SetMem64 ((VOID *)BitMap, Qwords * GUARDED_HEAP_MAP_ENTRY_BYTES,
+              (UINT64)-1);
+    BitMap += Qwords;
+  }
+
+  if (Lsbs > 0) {
+    *BitMap |= (LShiftU64 (1, Lsbs) - 1);
+  }
+}
+
+/**
+  Set corresponding bits in bitmap table to 0 according to the address.
+
+  @param[in]  Address     Start address to set for.
+  @param[in]  BitNumber   Number of bits to set.
+  @param[in]  BitMap      Pointer to bitmap which covers the Address.
+
+  @return VOID.
+**/
+STATIC
+VOID
+ClearBits (
+  IN EFI_PHYSICAL_ADDRESS    Address,
+  IN UINTN                   BitNumber,
+  IN UINT64                  *BitMap
+  )
+{
+  UINTN           Lsbs;
+  UINTN           Qwords;
+  UINTN           Msbs;
+  UINTN           StartBit;
+  UINTN           EndBit;
+
+  StartBit  = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
+  EndBit    = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+
+  if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) {
+    Msbs    = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %
+              GUARDED_HEAP_MAP_ENTRY_BITS;
+    Lsbs    = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+    Qwords  = (BitNumber - Msbs) / GUARDED_HEAP_MAP_ENTRY_BITS;
+  } else {
+    Msbs    = BitNumber;
+    Lsbs    = 0;
+    Qwords  = 0;
+  }
+
+  if (Msbs > 0) {
+    *BitMap &= ~LShiftU64 (LShiftU64 (1, Msbs) - 1, StartBit);
+    BitMap  += 1;
+  }
+
+  if (Qwords > 0) {
+    SetMem64 ((VOID *)BitMap, Qwords * GUARDED_HEAP_MAP_ENTRY_BYTES, 0);
+    BitMap += Qwords;
+  }
+
+  if (Lsbs > 0) {
+    *BitMap &= ~(LShiftU64 (1, Lsbs) - 1);
+  }
+}
+
+/**
+  Get corresponding bits in bitmap table according to the address.
+
+  The value of bit 0 corresponds to the status of memory at given Address.
+  No more than 64 bits can be retrieved in one call.
+
+  @param[in]  Address     Start address to retrieve bits for.
+  @param[in]  BitNumber   Number of bits to get.
+  @param[in]  BitMap      Pointer to bitmap which covers the Address.
+
+  @return An integer containing the bits information.
+**/
+STATIC
+UINT64
+GetBits (
+  IN EFI_PHYSICAL_ADDRESS    Address,
+  IN UINTN                   BitNumber,
+  IN UINT64                  *BitMap
+  )
+{
+  UINTN           StartBit;
+  UINTN           EndBit;
+  UINTN           Lsbs;
+  UINTN           Msbs;
+  UINT64          Result;
+
+  ASSERT (BitNumber <= GUARDED_HEAP_MAP_ENTRY_BITS);
+
+  StartBit  = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);
+  EndBit    = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+
+  if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) {
+    Msbs = GUARDED_HEAP_MAP_ENTRY_BITS - StartBit;
+    Lsbs = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;
+  } else {
+    Msbs = BitNumber;
+    Lsbs = 0;
+  }
+
+  Result    = RShiftU64 ((*BitMap), StartBit) & (LShiftU64 (1, Msbs) - 1);
+  if (Lsbs > 0) {
+    BitMap  += 1;
+    Result  |= LShiftU64 ((*BitMap) & (LShiftU64 (1, Lsbs) - 1), Msbs);
+  }
+
+  return Result;
+}
+
+/**
+  Helper function to allocate pages without Guard for internal uses.
+
+  @param[in]  Pages       Page number.
+
+  @return Address of memory allocated.
+**/
+VOID *
+PageAlloc (
+  IN UINTN  Pages
+  )
+{
+  EFI_STATUS              Status;
+  EFI_PHYSICAL_ADDRESS    Memory;
+
+  Status = SmmInternalAllocatePages (AllocateAnyPages, EfiRuntimeServicesData,
+                                     Pages, &Memory, FALSE);
+  if (EFI_ERROR (Status)) {
+    Memory = 0;
+  }
+
+  return (VOID *)(UINTN)Memory;
+}
+
+/**
+  Locate the pointer of bitmap from the guarded memory bitmap tables, which
+  covers the given Address.
+
+  @param[in]  Address       Start address to search the bitmap for.
+  @param[in]  AllocMapUnit  Flag to indicate memory allocation for the table.
+  @param[out] BitMap        Pointer to bitmap which covers the Address.
+
+  @return The bit number from given Address to the end of current map table.
+**/
+UINTN
+FindGuardedMemoryMap (
+  IN  EFI_PHYSICAL_ADDRESS    Address,
+  IN  BOOLEAN                 AllocMapUnit,
+  OUT UINT64                  **BitMap
+  )
+{
+  UINTN                   Level;
+  UINT64                  *GuardMap;
+  UINT64                  MapMemory;
+  UINTN                   Index;
+  UINTN                   Size;
+  UINTN                   BitsToUnitEnd;
+
+  //
+  // Adjust current map table depth according to the address to access
+  //
+  while (mMapLevel < GUARDED_HEAP_MAP_TABLE_DEPTH
+         &&
+         RShiftU64 (
+           Address,
+           mLevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1]
+           ) != 0) {
+
+    if (mGuardedMemoryMap != 0) {
+      Size = (mLevelMask[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1] + 1)
+             * GUARDED_HEAP_MAP_ENTRY_BYTES;
+      MapMemory = (UINT64)(UINTN)PageAlloc (EFI_SIZE_TO_PAGES (Size));
+      ASSERT (MapMemory != 0);
+
+      SetMem ((VOID *)(UINTN)MapMemory, Size, 0);
+
+      *(UINT64 *)(UINTN)MapMemory = mGuardedMemoryMap;
+      mGuardedMemoryMap = MapMemory;
+    }
+
+    mMapLevel++;
+
+  }
+
+  GuardMap = &mGuardedMemoryMap;
+  for (Level = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+       Level < GUARDED_HEAP_MAP_TABLE_DEPTH;
+       ++Level) {
+
+    if (*GuardMap == 0) {
+      if (!AllocMapUnit) {
+        GuardMap = NULL;
+        break;
+      }
+
+      Size = (mLevelMask[Level] + 1) * GUARDED_HEAP_MAP_ENTRY_BYTES;
+      MapMemory = (UINT64)(UINTN)PageAlloc (EFI_SIZE_TO_PAGES (Size));
+      ASSERT (MapMemory != 0);
+
+      SetMem ((VOID *)(UINTN)MapMemory, Size, 0);
+      *GuardMap = MapMemory;
+    }
+
+    Index     = (UINTN)RShiftU64 (Address, mLevelShift[Level]);
+    Index     &= mLevelMask[Level];
+    GuardMap  = (UINT64 *)(UINTN)((*GuardMap) + Index * sizeof (UINT64));
+
+  }
+
+  BitsToUnitEnd = GUARDED_HEAP_MAP_BITS - GUARDED_HEAP_MAP_BIT_INDEX (Address);
+  *BitMap       = GuardMap;
+
+  return BitsToUnitEnd;
+}
+
+/**
+  Set corresponding bits in bitmap table to 1 according to given memory range.
+
+  @param[in]  Address       Memory address to guard from.
+  @param[in]  NumberOfPages Number of pages to guard.
+
+  @return VOID
+**/
+VOID
+EFIAPI
+SetGuardedMemoryBits (
+  IN EFI_PHYSICAL_ADDRESS    Address,
+  IN UINTN                   NumberOfPages
+  )
+{
+  UINT64            *BitMap;
+  UINTN             Bits;
+  UINTN             BitsToUnitEnd;
+
+  while (NumberOfPages > 0) {
+    BitsToUnitEnd = FindGuardedMemoryMap (Address, TRUE, &BitMap);
+    ASSERT (BitMap != NULL);
+
+    if (NumberOfPages > BitsToUnitEnd) {
+      // Cross map unit
+      Bits = BitsToUnitEnd;
+    } else {
+      Bits  = NumberOfPages;
+    }
+
+    SetBits (Address, Bits, BitMap);
+
+    NumberOfPages -= Bits;
+    Address       += EFI_PAGES_TO_SIZE (Bits);
+  }
+}
+
+/**
+  Clear corresponding bits in bitmap table according to given memory range.
+
+  @param[in]  Address       Memory address to unset from.
+  @param[in]  NumberOfPages Number of pages to unset guard.
+
+  @return VOID
+**/
+VOID
+EFIAPI
+ClearGuardedMemoryBits (
+  IN EFI_PHYSICAL_ADDRESS    Address,
+  IN UINTN                   NumberOfPages
+  )
+{
+  UINT64            *BitMap;
+  UINTN             Bits;
+  UINTN             BitsToUnitEnd;
+
+  while (NumberOfPages > 0) {
+    BitsToUnitEnd = FindGuardedMemoryMap (Address, TRUE, &BitMap);
+    ASSERT (BitMap != NULL);
+
+    if (NumberOfPages > BitsToUnitEnd) {
+      // Cross map unit
+      Bits = BitsToUnitEnd;
+    } else {
+      Bits  = NumberOfPages;
+    }
+
+    ClearBits (Address, Bits, BitMap);
+
+    NumberOfPages -= Bits;
+    Address       += EFI_PAGES_TO_SIZE (Bits);
+  }
+}
+
+/**
+  Retrieve corresponding bits in bitmap table according to given memory range.
+
+  @param[in]  Address       Memory address to retrieve from.
+  @param[in]  NumberOfPages Number of pages to retrieve.
+
+  @return VOID
+**/
+UINTN
+GetGuardedMemoryBits (
+  IN EFI_PHYSICAL_ADDRESS    Address,
+  IN UINTN                   NumberOfPages
+  )
+{
+  UINT64            *BitMap;
+  UINTN             Bits;
+  UINTN             Result;
+  UINTN             Shift;
+  UINTN             BitsToUnitEnd;
+
+  ASSERT (NumberOfPages <= GUARDED_HEAP_MAP_ENTRY_BITS);
+
+  Result = 0;
+  Shift  = 0;
+  while (NumberOfPages > 0) {
+    BitsToUnitEnd = FindGuardedMemoryMap (Address, FALSE, &BitMap);
+
+    if (NumberOfPages > BitsToUnitEnd) {
+      // Cross map unit
+      Bits  = BitsToUnitEnd;
+    } else {
+      Bits  = NumberOfPages;
+    }
+
+    if (BitMap != NULL) {
+      Result |= LShiftU64 (GetBits (Address, Bits, BitMap), Shift);
+    }
+
+    Shift         += Bits;
+    NumberOfPages -= Bits;
+    Address       += EFI_PAGES_TO_SIZE (Bits);
+  }
+
+  return Result;
+}
+
+/**
+  Get bit value in bitmap table for the given address.
+
+  @param[in]  Address     The address to retrieve for.
+
+  @return 1 or 0.
+**/
+UINTN
+EFIAPI
+GetGuardMapBit (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  UINT64        *GuardMap;
+
+  FindGuardedMemoryMap (Address, FALSE, &GuardMap);
+  if (GuardMap != NULL) {
+    if (RShiftU64 (*GuardMap,
+                   GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address)) & 1) {
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
+/**
+  Set the bit in bitmap table for the given address.
+
+  @param[in]  Address     The address to set for.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+SetGuardMapBit (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  UINT64        *GuardMap;
+  UINT64        BitMask;
+
+  FindGuardedMemoryMap (Address, TRUE, &GuardMap);
+  if (GuardMap != NULL) {
+    BitMask = LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address));
+    *GuardMap |= BitMask;
+  }
+}
+
+/**
+  Clear the bit in bitmap table for the given address.
+
+  @param[in]  Address     The address to clear for.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+ClearGuardMapBit (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  UINT64        *GuardMap;
+  UINT64        BitMask;
+
+  FindGuardedMemoryMap (Address, TRUE, &GuardMap);
+  if (GuardMap != NULL) {
+    BitMask = LShiftU64 (1, GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address));
+    *GuardMap &= ~BitMask;
+  }
+}
+
+/**
+  Check to see if the page at the given address is a Guard page or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is a Guard page.
+  @return FALSE The page at Address is not a Guard page.
+**/
+BOOLEAN
+EFIAPI
+IsGuardPage (
+  IN EFI_PHYSICAL_ADDRESS    Address
+)
+{
+  UINTN       BitMap;
+
+  BitMap = GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 3);
+  return ((BitMap == 0b001) || (BitMap == 0b100) || (BitMap == 0b101));
+}
+
+/**
+  Check to see if the page at the given address is a head Guard page or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is a head Guard page.
+  @return FALSE The page at Address is not a head Guard page.
+**/
+BOOLEAN
+EFIAPI
+IsHeadGuard (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  return (GetGuardedMemoryBits (Address, 2) == 0b10);
+}
+
+/**
+  Check to see if the page at the given address is a tail Guard page or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is a tail Guard page.
+  @return FALSE The page at Address is not a tail Guard page.
+**/
+BOOLEAN
+EFIAPI
+IsTailGuard (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  return (GetGuardedMemoryBits (Address - EFI_PAGE_SIZE, 2) == 0b01);
+}
+
+/**
+  Check to see if the page at the given address is guarded or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is guarded.
+  @return FALSE The page at Address is not guarded.
+**/
+BOOLEAN
+EFIAPI
+IsMemoryGuarded (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  )
+{
+  return (GetGuardMapBit (Address) == 1);
+}
+
+/**
+  Set the page at the given address to be a Guard page.
+
+  This is done by changing the page table attribute to be NOT PRSENT.
+
+  @param[in]  BaseAddress     Page address to Guard at.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+SetGuardPage (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress
+  )
+{
+  if (mSmmMemoryAttribute != NULL) {
+    mOnGuarding = TRUE;
+    mSmmMemoryAttribute->SetMemoryAttributes (
+                           mSmmMemoryAttribute,
+                           BaseAddress,
+                           EFI_PAGE_SIZE,
+                           EFI_MEMORY_RP
+                           );
+    mOnGuarding = FALSE;
+  }
+}
+
+/**
+  Unset the Guard page at the given address to the normal memory.
+
+  This is done by changing the page table attribute to be PRSENT.
+
+  @param[in]  BaseAddress     Page address to Guard at.
+
+  @return VOID.
+**/
+VOID
+EFIAPI
+UnsetGuardPage (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress
+  )
+{
+  if (mSmmMemoryAttribute != NULL) {
+    mOnGuarding = TRUE;
+    mSmmMemoryAttribute->ClearMemoryAttributes (
+                           mSmmMemoryAttribute,
+                           BaseAddress,
+                           EFI_PAGE_SIZE,
+                           EFI_MEMORY_RP
+                           );
+    mOnGuarding = FALSE;
+  }
+}
+
+/**
+  Check to see if the memory at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Memory type to check.
+  @param[in]  AllocateType    Allocation type to check.
+  @param[in]  PageOrPool      Indicate a page allocation or pool allocation.
+
+
+  @return TRUE  The given type of memory should be guarded.
+  @return FALSE The given type of memory should not be guarded.
+**/
+BOOLEAN
+IsMemoryTypeToGuard (
+  IN EFI_MEMORY_TYPE        MemoryType,
+  IN EFI_ALLOCATE_TYPE      AllocateType,
+  IN UINT8                  PageOrPool
+  )
+{
+  UINT64 TestBit;
+  UINT64 ConfigBit;
+
+  if ((PcdGet8 (PcdHeapGuardPropertyMask) & PageOrPool) == 0
+      || mOnGuarding
+      || AllocateType == AllocateAddress) {
+    return FALSE;
+  }
+
+  ConfigBit = 0;
+  if ((PageOrPool & GUARD_HEAP_TYPE_POOL) != 0) {
+    ConfigBit |= PcdGet64 (PcdHeapGuardPoolType);
+  }
+
+  if ((PageOrPool & GUARD_HEAP_TYPE_PAGE) != 0) {
+    ConfigBit |= PcdGet64 (PcdHeapGuardPageType);
+  }
+
+  if (MemoryType == EfiRuntimeServicesData ||
+      MemoryType == EfiRuntimeServicesCode) {
+    TestBit = LShiftU64 (1, MemoryType);
+  } else if (MemoryType == EfiMaxMemoryType) {
+    TestBit = (UINT64)-1;
+  } else {
+    TestBit = 0;
+  }
+
+  return ((ConfigBit & TestBit) != 0);
+}
+
+/**
+  Check to see if the pool at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Pool type to check.
+
+
+  @return TRUE  The given type of pool should be guarded.
+  @return FALSE The given type of pool should not be guarded.
+**/
+BOOLEAN
+IsPoolTypeToGuard (
+  IN EFI_MEMORY_TYPE        MemoryType
+  )
+{
+  return IsMemoryTypeToGuard (MemoryType, AllocateAnyPages,
+                              GUARD_HEAP_TYPE_POOL);
+}
+
+/**
+  Check to see if the page at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Page type to check.
+  @param[in]  AllocateType    Allocation type to check.
+
+  @return TRUE  The given type of page should be guarded.
+  @return FALSE The given type of page should not be guarded.
+**/
+BOOLEAN
+IsPageTypeToGuard (
+  IN EFI_MEMORY_TYPE        MemoryType,
+  IN EFI_ALLOCATE_TYPE      AllocateType
+  )
+{
+  return IsMemoryTypeToGuard (MemoryType, AllocateType, GUARD_HEAP_TYPE_PAGE);
+}
+
+/**
+  Check to see if the heap guard is enabled for page and/or pool allocation.
+
+  @return TRUE/FALSE.
+**/
+BOOLEAN
+IsHeapGuardEnabled (
+  VOID
+  )
+{
+  return IsMemoryTypeToGuard (EfiMaxMemoryType, AllocateAnyPages,
+                              GUARD_HEAP_TYPE_POOL|GUARD_HEAP_TYPE_PAGE);
+}
+
+/**
+  Set head Guard and tail Guard for the given memory range.
+
+  @param[in]  Memory          Base address of memory to set guard for.
+  @param[in]  NumberOfPages   Memory size in pages.
+
+  @return VOID.
+**/
+VOID
+SetGuardForMemory (
+  IN EFI_PHYSICAL_ADDRESS   Memory,
+  IN UINTN                  NumberOfPages
+  )
+{
+  EFI_PHYSICAL_ADDRESS    GuardPage;
+
+  //
+  // Set tail Guard
+  //
+  GuardPage = Memory + EFI_PAGES_TO_SIZE (NumberOfPages);
+  if (!IsGuardPage (GuardPage)) {
+    SetGuardPage (GuardPage);
+  }
+
+  // Set head Guard
+  GuardPage = Memory - EFI_PAGES_TO_SIZE (1);
+  if (!IsGuardPage (GuardPage)) {
+    SetGuardPage (GuardPage);
+  }
+
+  //
+  // Mark the memory range as Guarded
+  //
+  SetGuardedMemoryBits (Memory, NumberOfPages);
+}
+
+/**
+  Unset head Guard and tail Guard for the given memory range.
+
+  @param[in]  Memory          Base address of memory to unset guard for.
+  @param[in]  NumberOfPages   Memory size in pages.
+
+  @return VOID.
+**/
+VOID
+UnsetGuardForMemory (
+  IN EFI_PHYSICAL_ADDRESS   Memory,
+  IN UINTN                  NumberOfPages
+  )
+{
+  EFI_PHYSICAL_ADDRESS  GuardPage;
+
+  if (NumberOfPages == 0) {
+    return;
+  }
+
+  //
+  // Head Guard must be one page before, if any.
+  //
+  GuardPage = Memory - EFI_PAGES_TO_SIZE (1);
+  if (IsHeadGuard (GuardPage)) {
+    if (!IsMemoryGuarded (GuardPage - EFI_PAGES_TO_SIZE (1))) {
+      //
+      // If the head Guard is not a tail Guard of adjacent memory block,
+      // unset it.
+      //
+      UnsetGuardPage (GuardPage);
+    }
+  } else if (IsMemoryGuarded (GuardPage)) {
+    //
+    // Pages before memory to free are still in Guard. It's a partial free
+    // case. Turn first page of memory block to free into a new Guard.
+    //
+    SetGuardPage (Memory);
+  }
+
+  //
+  // Tail Guard must be the page after this memory block to free, if any.
+  //
+  GuardPage = Memory + EFI_PAGES_TO_SIZE (NumberOfPages);
+  if (IsTailGuard (GuardPage)) {
+    if (!IsMemoryGuarded (GuardPage + EFI_PAGES_TO_SIZE (1))) {
+      //
+      // If the tail Guard is not a head Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      UnsetGuardPage (GuardPage);
+    }
+  } else if (IsMemoryGuarded (GuardPage)) {
+    //
+    // Pages after memory to free are still in Guard. It's a partial free
+    // case. We need to keep one page to be a head Guard.
+    //
+    SetGuardPage (GuardPage - EFI_PAGES_TO_SIZE (1));
+  }
+
+  //
+  // No matter what, we just clear the mark of the Guarded memory.
+  //
+  ClearGuardedMemoryBits(Memory, NumberOfPages);
+}
+
+/**
+  Adjust address of free memory according to existing and/or required Guard.
+
+  This function will check if there're existing Guard pages of adjacent
+  memory blocks, and try to use it as the Guard page of the memory to be
+  allocated.
+
+  @param[in]  Start           Start address of free memory block.
+  @param[in]  Size            Size of free memory block.
+  @param[in]  SizeRequested   Size of memory to allocate.
+
+  @return The end address of memory block found.
+  @return 0 if no enough space for the required size of memory and its Guard.
+**/
+UINT64
+AdjustMemoryS (
+  IN UINT64                  Start,
+  IN UINT64                  Size,
+  IN UINT64                  SizeRequested
+  )
+{
+  UINT64  Target;
+
+  Target = Start + Size - SizeRequested;
+
+  //
+  // At least one more page needed for Guard page.
+  //
+  if (Size < (SizeRequested + EFI_PAGES_TO_SIZE (1))) {
+    return 0;
+  }
+
+  if (!IsGuardPage (Start + Size)) {
+    // No Guard at tail to share. One more page is needed.
+    Target -= EFI_PAGES_TO_SIZE (1);
+  }
+
+  // Out of range?
+  if (Target < Start) {
+    return 0;
+  }
+
+  // At the edge?
+  if (Target == Start) {
+    if (!IsGuardPage (Target - EFI_PAGES_TO_SIZE (1))) {
+      // No enough space for a new head Guard if no Guard at head to share.
+      return 0;
+    }
+  }
+
+  // OK, we have enough pages for memory and its Guards. Return the End of the
+  // free space.
+  return Target + SizeRequested - 1;
+}
+
+/**
+  Adjust the start address and number of pages to free according to Guard.
+
+  The purpose of this function is to keep the shared Guard page with adjacent
+  memory block if it's still in guard, or free it if no more sharing. Another
+  is to reserve pages as Guard pages in partial page free situation.
+
+  @param[in,out]  Memory          Base address of memory to free.
+  @param[in,out]  NumberOfPages   Size of memory to free.
+
+  @return VOID.
+**/
+VOID
+AdjustMemoryF (
+  IN OUT EFI_PHYSICAL_ADDRESS    *Memory,
+  IN OUT UINTN                   *NumberOfPages
+  )
+{
+  EFI_PHYSICAL_ADDRESS  Start;
+  EFI_PHYSICAL_ADDRESS  MemoryToTest;
+  UINTN                 PagesToFree;
+
+  if (Memory == NULL || NumberOfPages == NULL || *NumberOfPages == 0) {
+    return;
+  }
+
+  Start = *Memory;
+  PagesToFree = *NumberOfPages;
+
+  //
+  // Head Guard must be one page before, if any.
+  //
+  MemoryToTest = Start - EFI_PAGES_TO_SIZE (1);
+  if (IsHeadGuard (MemoryToTest)) {
+    if (!IsMemoryGuarded (MemoryToTest - EFI_PAGES_TO_SIZE (1))) {
+      //
+      // If the head Guard is not a tail Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      Start       -= EFI_PAGES_TO_SIZE (1);
+      PagesToFree += 1;
+    }
+  } else if (IsMemoryGuarded (MemoryToTest)) {
+    //
+    // Pages before memory to free are still in Guard. It's a partial free
+    // case. We need to keep one page to be a tail Guard.
+    //
+    Start       += EFI_PAGES_TO_SIZE (1);
+    PagesToFree -= 1;
+  }
+
+  //
+  // Tail Guard must be the page after this memory block to free, if any.
+  //
+  MemoryToTest = Start + EFI_PAGES_TO_SIZE (PagesToFree);
+  if (IsTailGuard (MemoryToTest)) {
+    if (!IsMemoryGuarded (MemoryToTest + EFI_PAGES_TO_SIZE (1))) {
+      //
+      // If the tail Guard is not a head Guard of adjacent memory block,
+      // free it; otherwise, keep it.
+      //
+      PagesToFree += 1;
+    }
+  } else if (IsMemoryGuarded (MemoryToTest)) {
+    //
+    // Pages after memory to free are still in Guard. It's a partial free
+    // case. We need to keep one page to be a head Guard.
+    //
+    PagesToFree -= 1;
+  }
+
+  *Memory         = Start;
+  *NumberOfPages  = PagesToFree;
+}
+
+/**
+  Adjust the base and number of pages to really allocate according to Guard.
+
+  @param[in,out]  Memory          Base address of free memory.
+  @param[in,out]  NumberOfPages   Size of memory to allocate.
+
+  @return VOID.
+**/
+VOID
+AdjustMemoryA (
+  IN OUT EFI_PHYSICAL_ADDRESS    *Memory,
+  IN OUT UINTN                   *NumberOfPages
+  )
+{
+  //
+  // FindFreePages() has already taken the Guard into account. It's safe to
+  // adjust the start address and/or number of pages here, to make sure that
+  // the Guards are also "allocated".
+  //
+  if (!IsGuardPage (*Memory + EFI_PAGES_TO_SIZE (*NumberOfPages))) {
+    // No tail Guard, add one.
+    *NumberOfPages += 1;
+  }
+
+  if (!IsGuardPage (*Memory - EFI_PAGE_SIZE)) {
+    // No head Guard, add one.
+    *Memory        -= EFI_PAGE_SIZE;
+    *NumberOfPages += 1;
+  }
+}
+
+/**
+  Adjust the pool head position to make sure the Guard page is adjavent to
+  pool tail or pool head.
+
+  @param[in]  Memory    Base address of memory allocated.
+  @param[in]  NoPages   Number of pages actually allocated.
+  @param[in]  Size      Size of memory requested.
+                        (plus pool head/tail overhead)
+
+  @return Address of pool head
+**/
+VOID *
+AdjustPoolHeadA (
+  IN EFI_PHYSICAL_ADDRESS    Memory,
+  IN UINTN                   NoPages,
+  IN UINTN                   Size
+  )
+{
+  if ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0) {
+    //
+    // Pool head is put near the head Guard
+    //
+    return (VOID *)(UINTN)Memory;
+  }
+
+  //
+  // Pool head is put near the tail Guard
+  //
+  return (VOID *)(UINTN)(Memory + EFI_PAGES_TO_SIZE (NoPages) - Size);
+}
+
+/**
+  Get the page base address according to pool head address.
+
+  @param[in]  Memory    Head address of pool to free.
+
+  @return Address of pool head.
+**/
+VOID *
+AdjustPoolHeadF (
+  IN EFI_PHYSICAL_ADDRESS    Memory
+  )
+{
+  if ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) != 0) {
+    //
+    // Pool head is put near the head Guard
+    //
+    return (VOID *)(UINTN)Memory;
+  }
+
+  //
+  // Pool head is put near the tail Guard
+  //
+  return (VOID *)(UINTN)(Memory & ~EFI_PAGE_MASK);
+}
+
+/**
+  Helper function of memory allocation with Guard pages.
+
+  @param  FreePageList           The free page node.
+  @param  NumberOfPages          Number of pages to be allocated.
+  @param  MaxAddress             Request to allocate memory below this address.
+  @param  MemoryType             Type of memory requested.
+
+  @return Memory address of allocated pages.
+**/
+UINTN
+InternalAllocMaxAddressWithGuard (
+  IN OUT LIST_ENTRY           *FreePageList,
+  IN     UINTN                NumberOfPages,
+  IN     UINTN                MaxAddress,
+  IN     EFI_MEMORY_TYPE      MemoryType
+
+  )
+{
+  LIST_ENTRY      *Node;
+  FREE_PAGE_LIST  *Pages;
+  UINTN           PagesToAlloc;
+  UINTN           HeadGuard;
+  UINTN           TailGuard;
+  UINTN           Address;
+
+  for (Node = FreePageList->BackLink; Node != FreePageList;
+        Node = Node->BackLink) {
+    Pages = BASE_CR (Node, FREE_PAGE_LIST, Link);
+    if (Pages->NumberOfPages >= NumberOfPages &&
+        (UINTN)Pages + EFI_PAGES_TO_SIZE (NumberOfPages) - 1 <= MaxAddress) {
+
+      //
+      // We may need 1 or 2 more pages for Guard. Check it out.
+      //
+      PagesToAlloc = NumberOfPages;
+      TailGuard = (UINTN)Pages + EFI_PAGES_TO_SIZE (Pages->NumberOfPages);
+      if (!IsGuardPage (TailGuard)) {
+        //
+        // Add one if no Guard at the end of current free memory block.
+        //
+        PagesToAlloc += 1;
+        TailGuard     = 0;
+      }
+
+      HeadGuard = (UINTN)Pages +
+                  EFI_PAGES_TO_SIZE (Pages->NumberOfPages - PagesToAlloc) -
+                  EFI_PAGE_SIZE;
+      if (!IsGuardPage (HeadGuard)) {
+        //
+        // Add one if no Guard at the page before the address to allocate
+        //
+        PagesToAlloc += 1;
+        HeadGuard     = 0;
+      }
+
+      if (Pages->NumberOfPages < PagesToAlloc) {
+        // Not enough space to allocate memory with Guards? Try next block.
+        continue;
+      }
+
+      Address = InternalAllocPagesOnOneNode (Pages, PagesToAlloc, MaxAddress);
+      ConvertSmmMemoryMapEntry(MemoryType, Address, PagesToAlloc, FALSE);
+      CoreFreeMemoryMapStack();
+      if (HeadGuard == 0) {
+        // Don't pass the Guard page to user.
+        Address += EFI_PAGE_SIZE;
+      }
+      SetGuardForMemory (Address, NumberOfPages);
+      return Address;
+    }
+  }
+
+  return (UINTN)(-1);
+}
+
+/**
+  Helper function of memory free with Guard pages.
+
+  @param[in]  Memory                 Base address of memory being freed.
+  @param[in]  NumberOfPages          The number of pages to free.
+  @param[in]  AddRegion              If this memory is new added region.
+
+  @retval EFI_NOT_FOUND          Could not find the entry that covers the range.
+  @retval EFI_INVALID_PARAMETER  Address not aligned, Address is zero or NumberOfPages is zero.
+  @return EFI_SUCCESS            Pages successfully freed.
+**/
+EFI_STATUS
+SmmInternalFreePagesExWithGuard (
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NumberOfPages,
+  IN BOOLEAN               AddRegion
+  )
+{
+  EFI_PHYSICAL_ADDRESS    MemoryToFree;
+  UINTN                   PagesToFree;
+
+  MemoryToFree  = Memory;
+  PagesToFree   = NumberOfPages;
+
+  AdjustMemoryF (&MemoryToFree, &PagesToFree);
+  UnsetGuardForMemory (Memory, NumberOfPages);
+
+  return SmmInternalFreePagesEx (MemoryToFree, PagesToFree, AddRegion);
+}
+
+/**
+  Set all Guard pages which cannot be set during the non-SMM mode time.
+**/
+VOID
+SetAllGuardPages (
+  VOID
+  )
+{
+  UINTN     Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN     Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN     Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    TableEntry;
+  UINT64    Address;
+  UINT64    GuardPage;
+  INTN      Level;
+  UINTN     Index;
+  BOOLEAN   OnGuarding;
+
+  if (mGuardedMemoryMap == 0) {
+    return;
+  }
+
+  CopyMem (Entries, mLevelMask, sizeof (Entries));
+  CopyMem (Shifts, mLevelShift, sizeof (Shifts));
+
+  SetMem (Tables, sizeof(Tables), 0);
+  SetMem (Addresses, sizeof(Addresses), 0);
+  SetMem (Indices, sizeof(Indices), 0);
+
+  Level         = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+  Tables[Level] = mGuardedMemoryMap;
+  Address       = 0;
+  OnGuarding    = FALSE;
+
+  DEBUG_CODE (
+    DumpGuardedMemoryBitmap ();
+  );
+
+  while (TRUE) {
+    if (Indices[Level] > Entries[Level]) {
+      Tables[Level] = 0;
+      Level        -= 1;
+    } else {
+
+      TableEntry  = ((UINT64 *)(UINTN)(Tables[Level]))[Indices[Level]];
+      Address     = Addresses[Level];
+
+      if (TableEntry == 0) {
+
+        OnGuarding = FALSE;
+
+      } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+
+        Level            += 1;
+        Tables[Level]     = TableEntry;
+        Addresses[Level]  = Address;
+        Indices[Level]    = 0;
+
+        continue;
+
+      } else {
+
+        Index = 0;
+        while (Index < GUARDED_HEAP_MAP_ENTRY_BITS) {
+          if ((TableEntry & 1) == 1) {
+            if (OnGuarding) {
+              GuardPage = 0;
+            } else {
+              GuardPage = Address - EFI_PAGE_SIZE;
+            }
+            OnGuarding = TRUE;
+          } else {
+            if (OnGuarding) {
+              GuardPage = Address;
+            } else {
+              GuardPage = 0;
+            }
+            OnGuarding = FALSE;
+          }
+
+          if (GuardPage != 0) {
+            SetGuardPage (GuardPage);
+          }
+
+          if (TableEntry == 0) {
+            break;
+          }
+
+          TableEntry = RShiftU64 (TableEntry, 1);
+          Address   += EFI_PAGE_SIZE;
+          Index     += 1;
+        }
+      }
+    }
+
+    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {
+      break;
+    }
+
+    Indices[Level] += 1;
+    Address = (Level == 0) ? 0 : Addresses[Level - 1];
+    Addresses[Level] = Address | LShiftU64(Indices[Level], Shifts[Level]);
+
+  }
+}
+
+/**
+  Hook function used to set all Guard pages after entering SMM mode.
+**/
+VOID
+SmmEntryPointMemoryManagementHook (
+  VOID
+  )
+{
+  EFI_STATUS  Status;
+
+  if (mSmmMemoryAttribute == NULL) {
+    Status = SmmLocateProtocol (
+               &gEdkiiSmmMemoryAttributeProtocolGuid,
+               NULL,
+               (VOID **)&mSmmMemoryAttribute
+               );
+    if (!EFI_ERROR(Status)) {
+      SetAllGuardPages ();
+    }
+  }
+}
+
+/**
+  Helper function to convert a UINT64 value in binary to a string.
+
+  @param[in]  Value       Value of a UINT64 integer.
+  @param[out] BinString   String buffer to contain the conversion result.
+
+  @return VOID.
+**/
+VOID
+Uint64ToBinString (
+  IN  UINT64      Value,
+  OUT CHAR8       *BinString
+  )
+{
+  UINTN Index;
+
+  if (BinString == NULL) {
+    return;
+  }
+
+  for (Index = 64; Index > 0; --Index) {
+    BinString[Index - 1] = '0' + (Value & 1);
+    Value = RShiftU64 (Value, 1);
+  }
+  BinString[64] = '\0';
+}
+
+/**
+  Dump the guarded memory bit map.
+**/
+VOID
+EFIAPI
+DumpGuardedMemoryBitmap (
+  VOID
+  )
+{
+  UINTN     Entries[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN     Shifts[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINTN     Indices[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    Tables[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    Addresses[GUARDED_HEAP_MAP_TABLE_DEPTH];
+  UINT64    TableEntry;
+  UINT64    Address;
+  INTN      Level;
+  UINTN     RepeatZero;
+  CHAR8     String[GUARDED_HEAP_MAP_ENTRY_BITS + 1];
+  CHAR8     *Ruler1;
+  CHAR8     *Ruler2;
+
+  if (mGuardedMemoryMap == 0) {
+    return;
+  }
+
+  Ruler1 = "               3               2               1               0";
+  Ruler2 = "FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210FEDCBA9876543210";
+
+  DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "============================="
+                                  " Guarded Memory Bitmap "
+                                  "==============================\r\n"));
+  DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "                  %a\r\n", Ruler1));
+  DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "                  %a\r\n", Ruler2));
+
+  CopyMem (Entries, mLevelMask, sizeof (Entries));
+  CopyMem (Shifts, mLevelShift, sizeof (Shifts));
+
+  SetMem (Indices, sizeof(Indices), 0);
+  SetMem (Tables, sizeof(Tables), 0);
+  SetMem (Addresses, sizeof(Addresses), 0);
+
+  Level         = GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel;
+  Tables[Level] = mGuardedMemoryMap;
+  Address       = 0;
+  RepeatZero    = 0;
+
+  while (TRUE) {
+    if (Indices[Level] > Entries[Level]) {
+
+      Tables[Level] = 0;
+      Level        -= 1;
+      RepeatZero    = 0;
+
+      DEBUG ((
+        HEAP_GUARD_DEBUG_LEVEL,
+        "========================================="
+        "=========================================\r\n"
+        ));
+
+    } else {
+
+      TableEntry  = ((UINT64 *)(UINTN)Tables[Level])[Indices[Level]];
+      Address     = Addresses[Level];
+
+      if (TableEntry == 0) {
+
+        if (Level == GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+          if (RepeatZero == 0) {
+            Uint64ToBinString(TableEntry, String);
+            DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "%016lx: %a\r\n", Address, String));
+          } else if (RepeatZero == 1) {
+            DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "...             : ...\r\n"));
+          }
+          RepeatZero += 1;
+        }
+
+      } else if (Level < GUARDED_HEAP_MAP_TABLE_DEPTH - 1) {
+
+        Level            += 1;
+        Tables[Level]     = TableEntry;
+        Addresses[Level]  = Address;
+        Indices[Level]    = 0;
+        RepeatZero        = 0;
+
+        continue;
+
+      } else {
+
+        RepeatZero = 0;
+        Uint64ToBinString(TableEntry, String);
+        DEBUG ((HEAP_GUARD_DEBUG_LEVEL, "%016lx: %a\r\n", Address, String));
+
+      }
+    }
+
+    if (Level < (GUARDED_HEAP_MAP_TABLE_DEPTH - (INTN)mMapLevel)) {
+      break;
+    }
+
+    Indices[Level] += 1;
+    Address = (Level == 0) ? 0 : Addresses[Level - 1];
+    Addresses[Level] = Address | LShiftU64(Indices[Level], Shifts[Level]);
+
+  }
+}
+
+/**
+  Debug function used to verify if the Guard page is well set or not.
+
+  @param[in]  BaseAddress     Address of memory to check.
+  @param[in]  NumberOfPages   Size of memory in pages.
+
+  @return TRUE    The head Guard and tail Guard are both well set.
+  @return FALSE   The head Guard and/or tail Guard are not well set.
+**/
+BOOLEAN
+VerifyMemoryGuard (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
+  IN  UINTN                     NumberOfPages
+  )
+{
+  EFI_STATUS            Status;
+  UINT64                Attribute;
+  EFI_PHYSICAL_ADDRESS  Address;
+
+  if (mSmmMemoryAttribute == NULL) {
+    return TRUE;
+  }
+
+  Attribute = 0;
+  Address = BaseAddress - EFI_PAGE_SIZE;
+  Status = mSmmMemoryAttribute->GetMemoryAttributes (
+                                  mSmmMemoryAttribute,
+                                  Address,
+                                  EFI_PAGE_SIZE,
+                                  &Attribute
+                                  );
+  if (EFI_ERROR (Status) || (Attribute & EFI_MEMORY_RP) == 0) {
+    DEBUG ((DEBUG_ERROR, "Head Guard is not set at: %016lx (%016lX)!!!\r\n",
+            Address, Attribute));
+    DumpGuardedMemoryBitmap ();
+    return FALSE;
+  }
+
+  Attribute = 0;
+  Address = BaseAddress + EFI_PAGES_TO_SIZE (NumberOfPages);
+  Status = mSmmMemoryAttribute->GetMemoryAttributes (
+                                  mSmmMemoryAttribute,
+                                  Address,
+                                  EFI_PAGE_SIZE,
+                                  &Attribute
+                                  );
+  if (EFI_ERROR (Status) || (Attribute & EFI_MEMORY_RP) == 0) {
+    DEBUG ((DEBUG_ERROR, "Tail Guard is not set at: %016lx (%016lX)!!!\r\n",
+            Address, Attribute));
+    DumpGuardedMemoryBitmap ();
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
diff --git a/MdeModulePkg/Core/PiSmmCore/HeapGuard.h b/MdeModulePkg/Core/PiSmmCore/HeapGuard.h
new file mode 100644
index 0000000000..a6f92a2042
--- /dev/null
+++ b/MdeModulePkg/Core/PiSmmCore/HeapGuard.h
@@ -0,0 +1,398 @@
+/** @file
+  Data structure and functions to allocate and free memory space.
+
+Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef _HEAPGUARD_H_
+#define _HEAPGUARD_H_
+
+#include "PiSmmCore.h"
+
+//
+// Following macros are used to define and access the guarded memory bitmap
+// table.
+//
+// To simplify the access and reduce the memory used for this table, the
+// table is constructed in the similar way as page table structure but in
+// reverse direction, i.e. from bottom growing up to top.
+//
+//    - 1-bit tracks 1 page (4KB)
+//    - 1-UINT64 map entry tracks 256KB memory
+//    - 1K-UINT64 map table tracks 256MB memory
+//    - Five levels of tables can track any address of memory of 64-bit
+//      system, like below.
+//
+//       512   *   512   *   512   *   512    *    1K   *  64b *     4K
+//    111111111 111111111 111111111 111111111 1111111111 111111 111111111111
+//    63        54        45        36        27         17     11         0
+//       9b        9b        9b        9b         10b      6b       12b
+//       L0   ->   L1   ->   L2   ->   L3   ->    L4   -> bits  ->  page
+//      1FF       1FF       1FF       1FF         3FF      3F       FFF
+//
+// L4 table has 1K * sizeof(UINT64) = 8K (2-page), which can track 256MB
+// memory. Each table of L0-L3 will be allocated when its memory address
+// range is to be tracked. Only 1-page will be allocated each time. This
+// can save memories used to establish this map table.
+//
+// For a normal configuration of system with 4G memory, two levels of tables
+// can track the whole memory, because two levels (L3+L4) of map tables have
+// already coverred 37-bit of memory address. And for a normal UEFI BIOS,
+// less than 128M memory would be consumed during boot. That means we just
+// need
+//
+//          1-page (L3) + 2-page (L4)
+//
+// memory (3 pages) to track the memory allocation works. In this case,
+// there's no need to setup L0-L2 tables.
+//
+
+//
+// Each entry occupies 8B/64b. 1-page can hold 512 entries, which spans 9
+// bits in address. (512 = 1 << 9)
+//
+#define BYTE_LENGTH_SHIFT                   3             // (8 = 1 << 3)
+
+#define GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT  \
+        (EFI_PAGE_SHIFT - BYTE_LENGTH_SHIFT)
+
+#define GUARDED_HEAP_MAP_TABLE_DEPTH        5
+
+// Use UINT64_index + bit_index_of_UINT64 to locate the bit in may
+#define GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT    6             // (64 = 1 << 6)
+
+#define GUARDED_HEAP_MAP_ENTRY_BITS         \
+        (1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)
+
+#define GUARDED_HEAP_MAP_ENTRY_BYTES        \
+        (GUARDED_HEAP_MAP_ENTRY_BITS / 8)
+
+// L4 table address width: 64 - 9 * 4 - 6 - 12 = 10b
+#define GUARDED_HEAP_MAP_ENTRY_SHIFT              \
+        (GUARDED_HEAP_MAP_ENTRY_BITS              \
+         - GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 4 \
+         - GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT       \
+         - EFI_PAGE_SHIFT)
+
+// L4 table address mask: (1 << 10 - 1) = 0x3FF
+#define GUARDED_HEAP_MAP_ENTRY_MASK               \
+        ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1)
+
+// Size of each L4 table: (1 << 10) * 8 = 8KB = 2-page
+#define GUARDED_HEAP_MAP_SIZE                     \
+        ((1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) * GUARDED_HEAP_MAP_ENTRY_BYTES)
+
+// Memory size tracked by one L4 table: 8KB * 8 * 4KB = 256MB
+#define GUARDED_HEAP_MAP_UNIT_SIZE                \
+        (GUARDED_HEAP_MAP_SIZE * 8 * EFI_PAGE_SIZE)
+
+// L4 table entry number: 8KB / 8 = 1024
+#define GUARDED_HEAP_MAP_ENTRIES_PER_UNIT         \
+        (GUARDED_HEAP_MAP_SIZE / GUARDED_HEAP_MAP_ENTRY_BYTES)
+
+// L4 table entry indexing
+#define GUARDED_HEAP_MAP_ENTRY_INDEX(Address)                       \
+        (RShiftU64 (Address, EFI_PAGE_SHIFT                         \
+                             + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)    \
+         & GUARDED_HEAP_MAP_ENTRY_MASK)
+
+// L4 table entry bit indexing
+#define GUARDED_HEAP_MAP_ENTRY_BIT_INDEX(Address)       \
+        (RShiftU64 (Address, EFI_PAGE_SHIFT)            \
+         & ((1 << GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT) - 1))
+
+//
+// Total bits (pages) tracked by one L4 table (65536-bit)
+//
+#define GUARDED_HEAP_MAP_BITS                               \
+        (1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT                 \
+               + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT))
+
+//
+// Bit indexing inside the whole L4 table (0 - 65535)
+//
+#define GUARDED_HEAP_MAP_BIT_INDEX(Address)                     \
+        (RShiftU64 (Address, EFI_PAGE_SHIFT)                    \
+         & ((1 << (GUARDED_HEAP_MAP_ENTRY_SHIFT                 \
+                   + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT)) - 1))
+
+//
+// Memory address bit width tracked by L4 table: 10 + 6 + 12 = 28
+//
+#define GUARDED_HEAP_MAP_TABLE_SHIFT                                      \
+        (GUARDED_HEAP_MAP_ENTRY_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT  \
+         + EFI_PAGE_SHIFT)
+
+//
+// Macro used to initialize the local array variable for map table traversing
+// {55, 46, 37, 28, 18}
+//
+#define GUARDED_HEAP_MAP_TABLE_DEPTH_SHIFTS                                 \
+  {                                                                         \
+    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 3,  \
+    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT * 2,  \
+    GUARDED_HEAP_MAP_TABLE_SHIFT + GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT,      \
+    GUARDED_HEAP_MAP_TABLE_SHIFT,                                           \
+    EFI_PAGE_SHIFT + GUARDED_HEAP_MAP_ENTRY_BIT_SHIFT                       \
+  }
+
+//
+// Masks used to extract address range of each level of table
+// {0x1FF, 0x1FF, 0x1FF, 0x1FF, 0x3FF}
+//
+#define GUARDED_HEAP_MAP_TABLE_DEPTH_MASKS                                  \
+  {                                                                         \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_TABLE_ENTRY_SHIFT) - 1,                          \
+    (1 << GUARDED_HEAP_MAP_ENTRY_SHIFT) - 1                                 \
+  }
+
+//
+// Memory type to guard (matching the related PCD definition)
+//
+#define GUARD_HEAP_TYPE_POOL        BIT2
+#define GUARD_HEAP_TYPE_PAGE        BIT3
+
+//
+// Debug message level
+//
+#define HEAP_GUARD_DEBUG_LEVEL  (DEBUG_POOL|DEBUG_PAGE)
+
+typedef struct {
+  UINT32                TailMark;
+  UINT32                HeadMark;
+  EFI_PHYSICAL_ADDRESS  Address;
+  LIST_ENTRY            Link;
+} HEAP_GUARD_NODE;
+
+/**
+  Set head Guard and tail Guard for the given memory range.
+
+  @param[in]  Memory          Base address of memory to set guard for.
+  @param[in]  NumberOfPages   Memory size in pages.
+
+  @return VOID.
+**/
+VOID
+SetGuardForMemory (
+  IN EFI_PHYSICAL_ADDRESS   Memory,
+  IN UINTN                  NumberOfPages
+  );
+
+/**
+  Unset head Guard and tail Guard for the given memory range.
+
+  @param[in]  Memory          Base address of memory to unset guard for.
+  @param[in]  NumberOfPages   Memory size in pages.
+
+  @return VOID.
+**/
+VOID
+UnsetGuardForMemory (
+  IN EFI_PHYSICAL_ADDRESS   Memory,
+  IN UINTN                  NumberOfPages
+  );
+
+/**
+  Adjust the base and number of pages to really allocate according to Guard.
+
+  @param[in,out]  Memory          Base address of free memory.
+  @param[in,out]  NumberOfPages   Size of memory to allocate.
+
+  @return VOID.
+**/
+VOID
+AdjustMemoryA (
+  IN OUT EFI_PHYSICAL_ADDRESS    *Memory,
+  IN OUT UINTN                   *NumberOfPages
+  );
+
+/**
+  Adjust the start address and number of pages to free according to Guard.
+
+  The purpose of this function is to keep the shared Guard page with adjacent
+  memory block if it's still in guard, or free it if no more sharing. Another
+  is to reserve pages as Guard pages in partial page free situation.
+
+  @param[in,out]  Memory          Base address of memory to free.
+  @param[in,out]  NumberOfPages   Size of memory to free.
+
+  @return VOID.
+**/
+VOID
+AdjustMemoryF (
+  IN OUT EFI_PHYSICAL_ADDRESS    *Memory,
+  IN OUT UINTN                   *NumberOfPages
+  );
+
+/**
+  Check to see if the pool at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Pool type to check.
+
+
+  @return TRUE  The given type of pool should be guarded.
+  @return FALSE The given type of pool should not be guarded.
+**/
+BOOLEAN
+IsPoolTypeToGuard (
+  IN EFI_MEMORY_TYPE        MemoryType
+  );
+
+/**
+  Check to see if the page at the given address should be guarded or not.
+
+  @param[in]  MemoryType      Page type to check.
+  @param[in]  AllocateType    Allocation type to check.
+
+  @return TRUE  The given type of page should be guarded.
+  @return FALSE The given type of page should not be guarded.
+**/
+BOOLEAN
+IsPageTypeToGuard (
+  IN EFI_MEMORY_TYPE        MemoryType,
+  IN EFI_ALLOCATE_TYPE      AllocateType
+  );
+
+/**
+  Check to see if the page at the given address is guarded or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is guarded.
+  @return FALSE The page at Address is not guarded.
+**/
+BOOLEAN
+EFIAPI
+IsMemoryGuarded (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  );
+
+/**
+  Check to see if the page at the given address is a Guard page or not.
+
+  @param[in]  Address     The address to check for.
+
+  @return TRUE  The page at Address is a Guard page.
+  @return FALSE The page at Address is not a Guard page.
+**/
+BOOLEAN
+EFIAPI
+IsGuardPage (
+  IN EFI_PHYSICAL_ADDRESS    Address
+  );
+
+/**
+  Dump the guarded memory bit map.
+**/
+VOID
+EFIAPI
+DumpGuardedMemoryBitmap (
+  VOID
+  );
+
+/**
+  Adjust the pool head position to make sure the Guard page is adjavent to
+  pool tail or pool head.
+
+  @param[in]  Memory    Base address of memory allocated.
+  @param[in]  NoPages   Number of pages actually allocated.
+  @param[in]  Size      Size of memory requested.
+                        (plus pool head/tail overhead)
+
+  @return Address of pool head.
+**/
+VOID *
+AdjustPoolHeadA (
+  IN EFI_PHYSICAL_ADDRESS    Memory,
+  IN UINTN                   NoPages,
+  IN UINTN                   Size
+  );
+
+/**
+  Get the page base address according to pool head address.
+
+  @param[in]  Memory    Head address of pool to free.
+
+  @return Address of pool head.
+**/
+VOID *
+AdjustPoolHeadF (
+  IN EFI_PHYSICAL_ADDRESS    Memory
+  );
+
+/**
+  Helper function of memory allocation with Guard pages.
+
+  @param  FreePageList           The free page node.
+  @param  NumberOfPages          Number of pages to be allocated.
+  @param  MaxAddress             Request to allocate memory below this address.
+  @param  MemoryType             Type of memory requested.
+
+  @return Memory address of allocated pages.
+**/
+UINTN
+InternalAllocMaxAddressWithGuard (
+  IN OUT LIST_ENTRY           *FreePageList,
+  IN     UINTN                NumberOfPages,
+  IN     UINTN                MaxAddress,
+  IN     EFI_MEMORY_TYPE      MemoryType
+  );
+
+/**
+  Helper function of memory free with Guard pages.
+
+  @param[in]  Memory                 Base address of memory being freed.
+  @param[in]  NumberOfPages          The number of pages to free.
+  @param[in]  AddRegion              If this memory is new added region.
+
+  @retval EFI_NOT_FOUND          Could not find the entry that covers the range.
+  @retval EFI_INVALID_PARAMETER  Address not aligned, Address is zero or
+                                 NumberOfPages is zero.
+  @return EFI_SUCCESS            Pages successfully freed.
+**/
+EFI_STATUS
+SmmInternalFreePagesExWithGuard (
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NumberOfPages,
+  IN BOOLEAN               AddRegion
+  );
+
+/**
+  Check to see if the heap guard is enabled for page and/or pool allocation.
+
+  @return TRUE/FALSE.
+**/
+BOOLEAN
+IsHeapGuardEnabled (
+  VOID
+  );
+
+/**
+  Debug function used to verify if the Guard page is well set or not.
+
+  @param[in]  BaseAddress     Address of memory to check.
+  @param[in]  NumberOfPages   Size of memory in pages.
+
+  @return TRUE    The head Guard and tail Guard are both well set.
+  @return FALSE   The head Guard and/or tail Guard are not well set.
+**/
+BOOLEAN
+VerifyMemoryGuard (
+  IN  EFI_PHYSICAL_ADDRESS      BaseAddress,
+  IN  UINTN                     NumberOfPages
+  );
+
+extern BOOLEAN mOnGuarding;
+
+#endif
diff --git a/MdeModulePkg/Core/PiSmmCore/Page.c b/MdeModulePkg/Core/PiSmmCore/Page.c
index 4154c2e6a1..8909d46a00 100644
--- a/MdeModulePkg/Core/PiSmmCore/Page.c
+++ b/MdeModulePkg/Core/PiSmmCore/Page.c
@@ -64,6 +64,8 @@ LIST_ENTRY   mFreeMemoryMapEntryList = INITIALIZE_LIST_HEAD_VARIABLE (mFreeMemor
   @param[out]  Memory                 A pointer to receive the base allocated memory
                                       address.
   @param[in]   AddRegion              If this memory is new added region.
+  @param[in]   NeedGuard              Flag to indicate Guard page is needed
+                                      or not
 
   @retval EFI_INVALID_PARAMETER  Parameters violate checking rules defined in spec.
   @retval EFI_NOT_FOUND          Could not allocate pages match the requirement.
@@ -77,7 +79,8 @@ SmmInternalAllocatePagesEx (
   IN  EFI_MEMORY_TYPE       MemoryType,
   IN  UINTN                 NumberOfPages,
   OUT EFI_PHYSICAL_ADDRESS  *Memory,
-  IN  BOOLEAN               AddRegion
+  IN  BOOLEAN               AddRegion,
+  IN  BOOLEAN               NeedGuard
   );
 
 /**
@@ -112,7 +115,8 @@ AllocateMemoryMapEntry (
                EfiRuntimeServicesData,
                EFI_SIZE_TO_PAGES (RUNTIME_PAGE_ALLOCATION_GRANULARITY),
                &Mem,
-               TRUE
+               TRUE,
+               FALSE
                );
     ASSERT_EFI_ERROR (Status);
     if(!EFI_ERROR (Status)) {
@@ -688,6 +692,8 @@ InternalAllocAddress (
   @param[out]  Memory                 A pointer to receive the base allocated memory
                                       address.
   @param[in]   AddRegion              If this memory is new added region.
+  @param[in]   NeedGuard              Flag to indicate Guard page is needed
+                                      or not
 
   @retval EFI_INVALID_PARAMETER  Parameters violate checking rules defined in spec.
   @retval EFI_NOT_FOUND          Could not allocate pages match the requirement.
@@ -701,7 +707,8 @@ SmmInternalAllocatePagesEx (
   IN  EFI_MEMORY_TYPE       MemoryType,
   IN  UINTN                 NumberOfPages,
   OUT EFI_PHYSICAL_ADDRESS  *Memory,
-  IN  BOOLEAN               AddRegion
+  IN  BOOLEAN               AddRegion,
+  IN  BOOLEAN               NeedGuard
   )
 {
   UINTN  RequestedAddress;
@@ -723,6 +730,21 @@ SmmInternalAllocatePagesEx (
     case AllocateAnyPages:
       RequestedAddress = (UINTN)(-1);
     case AllocateMaxAddress:
+      if (NeedGuard) {
+        *Memory = InternalAllocMaxAddressWithGuard (
+                      &mSmmMemoryMap,
+                      NumberOfPages,
+                      RequestedAddress,
+                      MemoryType
+                      );
+        if (*Memory == (UINTN)-1) {
+          return EFI_OUT_OF_RESOURCES;
+        } else {
+          ASSERT (VerifyMemoryGuard (*Memory, NumberOfPages) == TRUE);
+          return EFI_SUCCESS;
+        }
+      }
+
       *Memory = InternalAllocMaxAddress (
                   &mSmmMemoryMap,
                   NumberOfPages,
@@ -766,6 +788,8 @@ SmmInternalAllocatePagesEx (
   @param[in]   NumberOfPages          The number of pages to allocate.
   @param[out]  Memory                 A pointer to receive the base allocated memory
                                       address.
+  @param[in]   NeedGuard              Flag to indicate Guard page is needed
+                                      or not
 
   @retval EFI_INVALID_PARAMETER  Parameters violate checking rules defined in spec.
   @retval EFI_NOT_FOUND          Could not allocate pages match the requirement.
@@ -779,10 +803,12 @@ SmmInternalAllocatePages (
   IN  EFI_ALLOCATE_TYPE     Type,
   IN  EFI_MEMORY_TYPE       MemoryType,
   IN  UINTN                 NumberOfPages,
-  OUT EFI_PHYSICAL_ADDRESS  *Memory
+  OUT EFI_PHYSICAL_ADDRESS  *Memory,
+  IN  BOOLEAN               NeedGuard
   )
 {
-  return SmmInternalAllocatePagesEx (Type, MemoryType, NumberOfPages, Memory, FALSE);
+  return SmmInternalAllocatePagesEx (Type, MemoryType, NumberOfPages, Memory,
+                                     FALSE, NeedGuard);
 }
 
 /**
@@ -811,8 +837,11 @@ SmmAllocatePages (
   )
 {
   EFI_STATUS  Status;
+  BOOLEAN     NeedGuard;
 
-  Status = SmmInternalAllocatePages (Type, MemoryType, NumberOfPages, Memory);
+  NeedGuard = IsPageTypeToGuard (MemoryType, Type);
+  Status = SmmInternalAllocatePages (Type, MemoryType, NumberOfPages, Memory,
+                                     NeedGuard);
   if (!EFI_ERROR (Status)) {
     SmmCoreUpdateProfile (
       (EFI_PHYSICAL_ADDRESS) (UINTN) RETURN_ADDRESS (0),
@@ -931,6 +960,7 @@ SmmInternalFreePagesEx (
 
   @param[in]  Memory                 Base address of memory being freed.
   @param[in]  NumberOfPages          The number of pages to free.
+  @param[in]  IsGuarded              Is the memory to free guarded or not.
 
   @retval EFI_NOT_FOUND          Could not find the entry that covers the range.
   @retval EFI_INVALID_PARAMETER  Address not aligned, Address is zero or NumberOfPages is zero.
@@ -941,9 +971,13 @@ EFI_STATUS
 EFIAPI
 SmmInternalFreePages (
   IN EFI_PHYSICAL_ADDRESS  Memory,
-  IN UINTN                 NumberOfPages
+  IN UINTN                 NumberOfPages,
+  IN BOOLEAN               IsGuarded
   )
 {
+  if (IsGuarded) {
+    return SmmInternalFreePagesExWithGuard (Memory, NumberOfPages, FALSE);
+  }
   return SmmInternalFreePagesEx (Memory, NumberOfPages, FALSE);
 }
 
@@ -966,8 +1000,10 @@ SmmFreePages (
   )
 {
   EFI_STATUS  Status;
+  BOOLEAN     IsGuarded;
 
-  Status = SmmInternalFreePages (Memory, NumberOfPages);
+  IsGuarded = IsHeapGuardEnabled () && IsMemoryGuarded (Memory);
+  Status = SmmInternalFreePages (Memory, NumberOfPages, IsGuarded);
   if (!EFI_ERROR (Status)) {
     SmmCoreUpdateProfile (
       (EFI_PHYSICAL_ADDRESS) (UINTN) RETURN_ADDRESS (0),
diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c
index b833763f9a..a7467aca20 100644
--- a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c
+++ b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.c
@@ -506,6 +506,11 @@ SmmEntryPoint (
   //
   PlatformHookBeforeSmmDispatch ();
 
+  //
+  // Call memory management hook function
+  //
+  SmmEntryPointMemoryManagementHook ();
+
   //
   // If a legacy boot has occured, then make sure gSmmCorePrivate is not accessed
   //
@@ -699,7 +704,7 @@ SmmMain (
   //
   gSmmCorePrivate->Smst          = &gSmmCoreSmst;
   gSmmCorePrivate->SmmEntryPoint = SmmEntryPoint;
-  
+
   //
   // No need to initialize memory service.
   // It is done in constructor of PiSmmCoreMemoryAllocationLib(),
diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.h b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.h
index 6cc824b047..cdc491c324 100644
--- a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.h
+++ b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.h
@@ -33,6 +33,7 @@
 #include <Protocol/SmmLegacyBoot.h>
 #include <Protocol/SmmReadyToBoot.h>
 #include <Protocol/SmmEndOfS3Resume.h>
+#include <Protocol/SmmMemoryAttribute.h>
 
 #include <Guid/Apriori.h>
 #include <Guid/EventGroup.h>
@@ -60,6 +61,7 @@
 #include <Library/SmmMemLib.h>
 
 #include "PiSmmCorePrivateData.h"
+#include "HeapGuard.h"
 
 //
 // Used to build a table of SMI Handlers that the SMM Core registers
@@ -318,6 +320,7 @@ SmmAllocatePages (
   @param  NumberOfPages          The number of pages to allocate
   @param  Memory                 A pointer to receive the base allocated memory
                                  address
+  @param  NeedGuard              Flag to indicate Guard page is needed or not
 
   @retval EFI_INVALID_PARAMETER  Parameters violate checking rules defined in spec.
   @retval EFI_NOT_FOUND          Could not allocate pages match the requirement.
@@ -331,7 +334,8 @@ SmmInternalAllocatePages (
   IN      EFI_ALLOCATE_TYPE         Type,
   IN      EFI_MEMORY_TYPE           MemoryType,
   IN      UINTN                     NumberOfPages,
-  OUT     EFI_PHYSICAL_ADDRESS      *Memory
+  OUT     EFI_PHYSICAL_ADDRESS      *Memory,
+  IN      BOOLEAN                   NeedGuard
   );
 
 /**
@@ -357,6 +361,8 @@ SmmFreePages (
 
   @param  Memory                 Base address of memory being freed
   @param  NumberOfPages          The number of pages to free
+  @param  IsGuarded              Flag to indicate if the memory is guarded
+                                 or not
 
   @retval EFI_NOT_FOUND          Could not find the entry that covers the range
   @retval EFI_INVALID_PARAMETER  Address not aligned, Address is zero or NumberOfPages is zero.
@@ -367,7 +373,8 @@ EFI_STATUS
 EFIAPI
 SmmInternalFreePages (
   IN      EFI_PHYSICAL_ADDRESS      Memory,
-  IN      UINTN                     NumberOfPages
+  IN      UINTN                     NumberOfPages,
+  IN      BOOLEAN                   IsGuarded
   );
 
 /**
@@ -1255,4 +1262,74 @@ typedef enum {
 
 extern LIST_ENTRY  mSmmPoolLists[SmmPoolTypeMax][MAX_POOL_INDEX];
 
+/**
+  Internal Function. Allocate n pages from given free page node.
+
+  @param  Pages                  The free page node.
+  @param  NumberOfPages          Number of pages to be allocated.
+  @param  MaxAddress             Request to allocate memory below this address.
+
+  @return Memory address of allocated pages.
+
+**/
+UINTN
+InternalAllocPagesOnOneNode (
+  IN OUT FREE_PAGE_LIST   *Pages,
+  IN     UINTN            NumberOfPages,
+  IN     UINTN            MaxAddress
+  );
+
+/**
+  Update SMM memory map entry.
+
+  @param[in]  Type                   The type of allocation to perform.
+  @param[in]  Memory                 The base of memory address.
+  @param[in]  NumberOfPages          The number of pages to allocate.
+  @param[in]  AddRegion              If this memory is new added region.
+**/
+VOID
+ConvertSmmMemoryMapEntry (
+  IN EFI_MEMORY_TYPE       Type,
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NumberOfPages,
+  IN BOOLEAN               AddRegion
+  );
+
+/**
+  Internal function.  Moves any memory descriptors that are on the
+  temporary descriptor stack to heap.
+
+**/
+VOID
+CoreFreeMemoryMapStack (
+  VOID
+  );
+
+/**
+  Frees previous allocated pages.
+
+  @param[in]  Memory                 Base address of memory being freed.
+  @param[in]  NumberOfPages          The number of pages to free.
+  @param[in]  AddRegion              If this memory is new added region.
+
+  @retval EFI_NOT_FOUND          Could not find the entry that covers the range.
+  @retval EFI_INVALID_PARAMETER  Address not aligned, Address is zero or NumberOfPages is zero.
+  @return EFI_SUCCESS            Pages successfully freed.
+
+**/
+EFI_STATUS
+SmmInternalFreePagesEx (
+  IN EFI_PHYSICAL_ADDRESS  Memory,
+  IN UINTN                 NumberOfPages,
+  IN BOOLEAN               AddRegion
+  );
+
+/**
+  Hook function used to set all Guard pages after entering SMM mode.
+**/
+VOID
+SmmEntryPointMemoryManagementHook (
+  VOID
+  );
+
 #endif
diff --git a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.inf b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.inf
index a01ef7ed57..1583641887 100644
--- a/MdeModulePkg/Core/PiSmmCore/PiSmmCore.inf
+++ b/MdeModulePkg/Core/PiSmmCore/PiSmmCore.inf
@@ -40,6 +40,7 @@
   SmramProfileRecord.c
   MemoryAttributesTable.c
   SmiHandlerProfile.c
+  HeapGuard.c
 
 [Packages]
   MdePkg/MdePkg.dec
@@ -89,6 +90,8 @@
   gEfiSmmGpiDispatch2ProtocolGuid               ## SOMETIMES_CONSUMES
   gEfiSmmIoTrapDispatch2ProtocolGuid            ## SOMETIMES_CONSUMES
   gEfiSmmUsbDispatch2ProtocolGuid               ## SOMETIMES_CONSUMES
+  gEfiSmmCpuProtocolGuid                        ## SOMETIMES_CONSUMES
+  gEdkiiSmmMemoryAttributeProtocolGuid          ## CONSUMES
 
 [Pcd]
   gEfiMdeModulePkgTokenSpaceGuid.PcdLoadFixAddressSmmCodePageNumber     ## SOMETIMES_CONSUMES
@@ -97,6 +100,9 @@
   gEfiMdeModulePkgTokenSpaceGuid.PcdMemoryProfilePropertyMask           ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdMemoryProfileDriverPath             ## CONSUMES
   gEfiMdeModulePkgTokenSpaceGuid.PcdSmiHandlerProfilePropertyMask       ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPageType                   ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPoolType                   ## CONSUMES
+  gEfiMdeModulePkgTokenSpaceGuid.PcdHeapGuardPropertyMask               ## CONSUMES
 
 [Guids]
   gAprioriGuid                                  ## SOMETIMES_CONSUMES   ## File
diff --git a/MdeModulePkg/Core/PiSmmCore/Pool.c b/MdeModulePkg/Core/PiSmmCore/Pool.c
index 36317563c4..798d66994b 100644
--- a/MdeModulePkg/Core/PiSmmCore/Pool.c
+++ b/MdeModulePkg/Core/PiSmmCore/Pool.c
@@ -144,7 +144,9 @@ InternalAllocPoolByIndex (
   Status = EFI_SUCCESS;
   Hdr = NULL;
   if (PoolIndex == MAX_POOL_INDEX) {
-    Status = SmmInternalAllocatePages (AllocateAnyPages, PoolType, EFI_SIZE_TO_PAGES (MAX_POOL_SIZE << 1), &Address);
+    Status = SmmInternalAllocatePages (AllocateAnyPages, PoolType,
+                                       EFI_SIZE_TO_PAGES (MAX_POOL_SIZE << 1),
+                                       &Address, FALSE);
     if (EFI_ERROR (Status)) {
       return EFI_OUT_OF_RESOURCES;
     }
@@ -243,6 +245,9 @@ SmmInternalAllocatePool (
   EFI_STATUS            Status;
   EFI_PHYSICAL_ADDRESS  Address;
   UINTN                 PoolIndex;
+  BOOLEAN               HasPoolTail;
+  BOOLEAN               NeedGuard;
+  UINTN                 NoPages;
 
   Address = 0;
 
@@ -251,25 +256,47 @@ SmmInternalAllocatePool (
     return EFI_INVALID_PARAMETER;
   }
 
+  NeedGuard   = IsPoolTypeToGuard (PoolType);
+  HasPoolTail = !(NeedGuard &&
+                  ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) == 0));
+
   //
   // Adjust the size by the pool header & tail overhead
   //
   Size += POOL_OVERHEAD;
-  if (Size > MAX_POOL_SIZE) {
-    Size = EFI_SIZE_TO_PAGES (Size);
-    Status = SmmInternalAllocatePages (AllocateAnyPages, PoolType, Size, &Address);
+  if (Size > MAX_POOL_SIZE || NeedGuard) {
+    if (!HasPoolTail) {
+      Size -= sizeof (POOL_TAIL);
+    }
+
+    NoPages = EFI_SIZE_TO_PAGES (Size);
+    Status = SmmInternalAllocatePages (AllocateAnyPages, PoolType, NoPages,
+                                       &Address, NeedGuard);
     if (EFI_ERROR (Status)) {
       return Status;
     }
 
+    if (NeedGuard) {
+      ASSERT (VerifyMemoryGuard (Address, NoPages) == TRUE);
+      Address = (EFI_PHYSICAL_ADDRESS)(UINTN)AdjustPoolHeadA (
+                                               Address,
+                                               NoPages,
+                                               Size
+                                               );
+    }
+
     PoolHdr = (POOL_HEADER*)(UINTN)Address;
     PoolHdr->Signature = POOL_HEAD_SIGNATURE;
-    PoolHdr->Size = EFI_PAGES_TO_SIZE (Size);
+    PoolHdr->Size = Size;
     PoolHdr->Available = FALSE;
     PoolHdr->Type = PoolType;
-    PoolTail = HEAD_TO_TAIL(PoolHdr);
-    PoolTail->Signature = POOL_TAIL_SIGNATURE;
-    PoolTail->Size = PoolHdr->Size;
+
+    if (HasPoolTail) {
+      PoolTail = HEAD_TO_TAIL (PoolHdr);
+      PoolTail->Signature = POOL_TAIL_SIGNATURE;
+      PoolTail->Size = PoolHdr->Size;
+    }
+
     *Buffer = PoolHdr + 1;
     return Status;
   }
@@ -341,28 +368,47 @@ SmmInternalFreePool (
 {
   FREE_POOL_HEADER  *FreePoolHdr;
   POOL_TAIL         *PoolTail;
+  BOOLEAN           HasPoolTail;
+  BOOLEAN           MemoryGuarded;
 
   if (Buffer == NULL) {
     return EFI_INVALID_PARAMETER;
   }
 
+  MemoryGuarded = IsHeapGuardEnabled () &&
+                  IsMemoryGuarded ((EFI_PHYSICAL_ADDRESS)(UINTN)Buffer);
+  HasPoolTail   = !(MemoryGuarded &&
+                    ((PcdGet8 (PcdHeapGuardPropertyMask) & BIT7) == 0));
+
   FreePoolHdr = (FREE_POOL_HEADER*)((POOL_HEADER*)Buffer - 1);
   ASSERT (FreePoolHdr->Header.Signature == POOL_HEAD_SIGNATURE);
   ASSERT (!FreePoolHdr->Header.Available);
-  PoolTail = HEAD_TO_TAIL(&FreePoolHdr->Header);
-  ASSERT (PoolTail->Signature == POOL_TAIL_SIGNATURE);
-  ASSERT (FreePoolHdr->Header.Size == PoolTail->Size);
-
   if (FreePoolHdr->Header.Signature != POOL_HEAD_SIGNATURE) {
     return EFI_INVALID_PARAMETER;
   }
 
-  if (PoolTail->Signature != POOL_TAIL_SIGNATURE) {
-    return EFI_INVALID_PARAMETER;
+  if (HasPoolTail) {
+    PoolTail = HEAD_TO_TAIL (&FreePoolHdr->Header);
+    ASSERT (PoolTail->Signature == POOL_TAIL_SIGNATURE);
+    ASSERT (FreePoolHdr->Header.Size == PoolTail->Size);
+    if (PoolTail->Signature != POOL_TAIL_SIGNATURE) {
+      return EFI_INVALID_PARAMETER;
+    }
+
+    if (FreePoolHdr->Header.Size != PoolTail->Size) {
+      return EFI_INVALID_PARAMETER;
+    }
+  } else {
+    PoolTail = NULL;
   }
 
-  if (FreePoolHdr->Header.Size != PoolTail->Size) {
-    return EFI_INVALID_PARAMETER;
+  if (MemoryGuarded) {
+    Buffer = AdjustPoolHeadF ((EFI_PHYSICAL_ADDRESS)(UINTN)FreePoolHdr);
+    return SmmInternalFreePages (
+             (EFI_PHYSICAL_ADDRESS)(UINTN)Buffer,
+             EFI_SIZE_TO_PAGES (FreePoolHdr->Header.Size),
+             TRUE
+             );
   }
 
   if (FreePoolHdr->Header.Size > MAX_POOL_SIZE) {
@@ -370,7 +416,8 @@ SmmInternalFreePool (
     ASSERT ((FreePoolHdr->Header.Size & EFI_PAGE_MASK) == 0);
     return SmmInternalFreePages (
              (EFI_PHYSICAL_ADDRESS)(UINTN)FreePoolHdr,
-             EFI_SIZE_TO_PAGES (FreePoolHdr->Header.Size)
+             EFI_SIZE_TO_PAGES (FreePoolHdr->Header.Size),
+             FALSE
              );
   }
   return InternalFreePoolByIndex (FreePoolHdr, PoolTail);
-- 
2.14.1.windows.1

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