diff --git a/OvmfPkg/Include/Library/MemEncryptSevLib.h b/OvmfPkg/Include/Library/MemEncryptSevLib.h
index 99f15a7d12..b91490d5d4 100644
--- a/OvmfPkg/Include/Library/MemEncryptSevLib.h
+++ b/OvmfPkg/Include/Library/MemEncryptSevLib.h
@@ -203,4 +203,29 @@ MemEncryptSevGetAddressRangeState (
   IN UINTN                    Length
   );
 
+/**
+  This function clears memory encryption bit for the MMIO region specified by
+  BaseAddress and NumPages.
+
+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
+                                      current CR3)
+  @param[in]  BaseAddress             The physical address that is the start
+                                      address of a MMIO region.
+  @param[in]  NumPages                The number of pages from start memory
+                                      region.
+
+  @retval RETURN_SUCCESS              The attributes were cleared for the
+                                      memory region.
+  @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
+  @retval RETURN_UNSUPPORTED          Clearing the memory encryption attribute
+                                      is not supported
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevClearMmioPageEncMask (
+  IN PHYSICAL_ADDRESS         Cr3BaseAddress,
+  IN PHYSICAL_ADDRESS         BaseAddress,
+  IN UINTN                    NumPages
+  );
+
 #endif // _MEM_ENCRYPT_SEV_LIB_H_
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
index 12a5bf495b..169d3118e4 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/Ia32/MemEncryptSevLib.c
@@ -111,3 +111,34 @@ MemEncryptSevGetAddressRangeState (
   //
   return MemEncryptSevAddressRangeEncrypted;
 }
+
+/**
+  This function clears memory encryption bit for the MMIO region specified by
+  BaseAddress and NumPages.
+
+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
+                                      current CR3)
+  @param[in]  BaseAddress             The physical address that is the start
+                                      address of a MMIO region.
+  @param[in]  NumPages                The number of pages from start memory
+                                      region.
+
+  @retval RETURN_SUCCESS              The attributes were cleared for the
+                                      memory region.
+  @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
+  @retval RETURN_UNSUPPORTED          Clearing the memory encryption attribute
+                                      is not supported
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevClearMmioPageEncMask (
+  IN PHYSICAL_ADDRESS         Cr3BaseAddress,
+  IN PHYSICAL_ADDRESS         BaseAddress,
+  IN UINTN                    NumPages
+  )
+{
+  //
+  // Memory encryption bit is not accessible in 32-bit mode
+  //
+  return RETURN_UNSUPPORTED;
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
index 4fea6a6be0..a2bf698bcd 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/MemEncryptSevLib.c
@@ -118,3 +118,36 @@ MemEncryptSevGetAddressRangeState (
            Length
            );
 }
+
+/**
+  This function clears memory encryption bit for the mmio region specified by
+  BaseAddress and NumPages.
+
+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
+                                      current CR3)
+  @param[in]  BaseAddress             The physical address that is the start
+                                      address of a mmio region.
+  @param[in]  NumPages                The number of pages from start memory
+                                      region.
+
+  @retval RETURN_SUCCESS              The attributes were cleared for the
+                                      memory region.
+  @retval RETURN_INVALID_PARAMETER    Number of pages is zero.
+  @retval RETURN_UNSUPPORTED          Clearing the memory encryption attribute
+                                      is not supported
+**/
+RETURN_STATUS
+EFIAPI
+MemEncryptSevClearMmioPageEncMask (
+  IN PHYSICAL_ADDRESS         Cr3BaseAddress,
+  IN PHYSICAL_ADDRESS         BaseAddress,
+  IN UINTN                    NumPages
+  )
+{
+  return InternalMemEncryptSevClearMmioPageEncMask (
+           Cr3BaseAddress,
+           BaseAddress,
+           EFI_PAGES_TO_SIZE (NumPages)
+           );
+
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
index d3455e812b..a18d336a87 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/PeiDxeVirtualMemory.c
@@ -891,3 +891,36 @@ InternalMemEncryptSevSetMemoryEncrypted (
            Flush
            );
 }
+
+/**
+  This function clears memory encryption bit for the MMIO region specified by
+  PhysicalAddress and Length.
+
+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
+                                      current CR3)
+  @param[in]  PhysicalAddress         The physical address that is the start
+                                      address of a MMIO region.
+  @param[in]  Length                  The length of memory region
+
+  @retval RETURN_SUCCESS              The attributes were cleared for the
+                                      memory region.
+  @retval RETURN_INVALID_PARAMETER    Length is zero.
+  @retval RETURN_UNSUPPORTED          Clearing the memory encyrption attribute
+                                      is not supported
+**/
+RETURN_STATUS
+EFIAPI
+InternalMemEncryptSevClearMmioPageEncMask (
+  IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
+  IN  PHYSICAL_ADDRESS        PhysicalAddress,
+  IN  UINTN                   Length
+  )
+{
+  return SetMemoryEncDec (
+           Cr3BaseAddress,
+           PhysicalAddress,
+           Length,
+           ClearCBit,
+           FALSE
+           );
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
index bca5e3febb..e0d3a15e85 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/SecVirtualMemory.c
@@ -98,3 +98,33 @@ InternalMemEncryptSevSetMemoryEncrypted (
   //
   return RETURN_UNSUPPORTED;
 }
+
+/**
+  This function clears memory encryption bit for the MMIO region specified by
+  PhysicalAddress and Length.
+
+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
+                                      current CR3)
+  @param[in]  PhysicalAddress         The physical address that is the start
+                                      address of a MMIO region.
+  @param[in]  Length                  The length of memory region
+
+  @retval RETURN_SUCCESS              The attributes were cleared for the
+                                      memory region.
+  @retval RETURN_INVALID_PARAMETER    Length is zero.
+  @retval RETURN_UNSUPPORTED          Clearing the memory encyrption attribute
+                                      is not supported
+**/
+RETURN_STATUS
+EFIAPI
+InternalMemEncryptSevClearMmioPageEncMask (
+  IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
+  IN  PHYSICAL_ADDRESS        PhysicalAddress,
+  IN  UINTN                   Length
+  )
+{
+  //
+  // This function is not available during SEC.
+  //
+  return RETURN_UNSUPPORTED;
+}
diff --git a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
index fe2a0b2826..8dc39e647b 100644
--- a/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
+++ b/OvmfPkg/Library/BaseMemEncryptSevLib/X64/VirtualMemory.h
@@ -126,4 +126,27 @@ InternalMemEncryptSevGetAddressRangeState (
   IN UINTN                    Length
   );
 
+/**
+  This function clears memory encryption bit for the MMIO region specified by
+  PhysicalAddress and Length.
+
+  @param[in]  Cr3BaseAddress          Cr3 Base Address (if zero then use
+                                      current CR3)
+  @param[in]  PhysicalAddress         The physical address that is the start
+                                      address of a MMIO region.
+  @param[in]  Length                  The length of memory region
+
+  @retval RETURN_SUCCESS              The attributes were cleared for the
+                                      memory region.
+  @retval RETURN_INVALID_PARAMETER    Length is zero.
+  @retval RETURN_UNSUPPORTED          Clearing the memory encyrption attribute
+                                      is not supported
+**/
+RETURN_STATUS
+EFIAPI
+InternalMemEncryptSevClearMmioPageEncMask (
+  IN  PHYSICAL_ADDRESS        Cr3BaseAddress,
+  IN  PHYSICAL_ADDRESS        PhysicalAddress,
+  IN  UINTN                   Length
+  );
 #endif