[PATCH v3 1/7] MdePkg: MmUnblockMemoryLib: Added definition and null instance

["Kun Qin" <kun.q@outlook.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3168

This interface definition provides an abstraction layer for applicable
drivers to request certain memory blocks to be mapped/unblocked for
accessibility inside MM environment.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>

Signed-off-by: Kun Qin <kun.q@outlook.com>
---

Notes:
    v3:
    - Move interface to MdePkg [Hao, Liming, Jiewen]
    - Remove Dxe prefix [Jiewen]
    
    v2:
    - Resend with practical usage. No change [Hao]

 MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.c   | 40 ++++++++++++++++++++
 MdePkg/Include/Library/MmUnblockMemoryLib.h                  | 40 ++++++++++++++++++++
 MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf | 29 ++++++++++++++
 MdePkg/MdePkg.dec                                            |  5 +++
 MdePkg/MdePkg.dsc                                            |  1 +
 5 files changed, 115 insertions(+)

diff --git a/MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.c b/MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.c
new file mode 100644
index 000000000000..ed9a45587b64
--- /dev/null
+++ b/MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.c
@@ -0,0 +1,40 @@
+/** @file
+  Null instance of MM Unblock Page Library.
+
+  This library provides an abstraction layer of requesting certain page access to be unblocked
+  by MM environment if applicable.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+
+/**
+  This API provides a way to unblock certain data pages to be accessible inside MM environment.
+
+  @param  UnblockAddress          The address of buffer caller requests to unblock, the address
+                                  has to be page aligned.
+  @param  NumberOfPages           The number of pages requested to be unblocked from MM
+                                  environment.
+
+  @return EFI_SUCCESS             The request goes through successfully.
+  @return EFI_NOT_AVAILABLE_YET   The requested functionality is not produced yet.
+  @return EFI_UNSUPPORTED         The requested functionality is not supported on current platform.
+  @return EFI_SECURITY_VIOLATION  The requested address failed to pass security check for
+                                  unblocking.
+  @return EFI_INVALID_PARAMETER   Input address either NULL pointer or not page aligned.
+  @return EFI_ACCESS_DENIED       The request is rejected due to system has passed certain boot
+                                  phase.
+
+**/
+EFI_STATUS
+EFIAPI
+MmUnblockMemoryRequest (
+  IN EFI_PHYSICAL_ADDRESS   UnblockAddress,
+  IN UINT64                 NumberOfPages
+  )
+{
+  return EFI_UNSUPPORTED;
+}
diff --git a/MdePkg/Include/Library/MmUnblockMemoryLib.h b/MdePkg/Include/Library/MmUnblockMemoryLib.h
new file mode 100644
index 000000000000..adff8ddc8063
--- /dev/null
+++ b/MdePkg/Include/Library/MmUnblockMemoryLib.h
@@ -0,0 +1,40 @@
+/** @file
+  MM Unblock Memory Library Interface.
+
+  This library provides an abstraction layer of requesting certain page access to be unblocked
+  by MM environment if applicable.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef MM_UNBLOCK_MEMORY_LIB_H_
+#define MM_UNBLOCK_MEMORY_LIB_H_
+
+/**
+  This API provides a way to unblock certain data pages to be accessible inside MM environment.
+
+  @param  UnblockAddress          The address of buffer caller requests to unblock, the address
+                                  has to be page aligned.
+  @param  NumberOfPages           The number of pages requested to be unblocked from MM
+                                  environment.
+
+  @return EFI_SUCCESS             The request goes through successfully.
+  @return EFI_NOT_AVAILABLE_YET   The requested functionality is not produced yet.
+  @return EFI_UNSUPPORTED         The requested functionality is not supported on current platform.
+  @return EFI_SECURITY_VIOLATION  The requested address failed to pass security check for
+                                  unblocking.
+  @return EFI_INVALID_PARAMETER   Input address either NULL pointer or not page aligned.
+  @return EFI_ACCESS_DENIED       The request is rejected due to system has passed certain boot
+                                  phase.
+
+**/
+EFI_STATUS
+EFIAPI
+MmUnblockMemoryRequest (
+  IN EFI_PHYSICAL_ADDRESS   UnblockAddress,
+  IN UINT64                 NumberOfPages
+);
+
+#endif // MM_UNBLOCK_MEMORY_LIB_H_
diff --git a/MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf b/MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf
new file mode 100644
index 000000000000..4c1f3d1c8e87
--- /dev/null
+++ b/MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf
@@ -0,0 +1,29 @@
+## @file
+#  Null instance of MM Unblock Page Library.
+#
+#  This library provides an abstraction layer of requesting certain page access to be unblocked
+#  by MM environment if applicable.
+#
+#  Copyright (c) Microsoft Corporation.
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001B
+  BASE_NAME                      = MmUnblockMemoryLibNull
+  FILE_GUID                      = 9E890F68-5C95-4C31-95DD-59E6286F85EA
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = MmUnblockMemoryLib
+
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources]
+  MmUnblockMemoryLibNull.c
+
+[Packages]
+  MdePkg/MdePkg.dec
diff --git a/MdePkg/MdePkg.dec b/MdePkg/MdePkg.dec
index 3928db65d188..32a9e009c813 100644
--- a/MdePkg/MdePkg.dec
+++ b/MdePkg/MdePkg.dec
@@ -257,6 +257,11 @@ [LibraryClasses]
   #
   UnitTestHostBaseLib|Test/UnitTest/Include/Library/UnitTestHostBaseLib.h
 
+  ##  @libraryclass  This library provides an interface for DXE drivers to request MM environment
+  #   to map/unblock a memory region for accessibility inside MM.
+  #
+  MmUnblockMemoryLib|Include/Library/MmUnblockMemoryLib.h
+
 [LibraryClasses.IA32, LibraryClasses.X64]
   ##  @libraryclass  Abstracts both S/W SMI generation and detection.
   ##
diff --git a/MdePkg/MdePkg.dsc b/MdePkg/MdePkg.dsc
index ce009086815f..79629e3f93ba 100644
--- a/MdePkg/MdePkg.dsc
+++ b/MdePkg/MdePkg.dsc
@@ -168,6 +168,7 @@ [Components.IA32, Components.X64]
   MdePkg/Library/SmmPciExpressLib/SmmPciExpressLib.inf
   MdePkg/Library/SmiHandlerProfileLibNull/SmiHandlerProfileLibNull.inf
   MdePkg/Library/MmServicesTableLib/MmServicesTableLib.inf
+  MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf
 
 [Components.EBC]
   MdePkg/Library/BaseIoLibIntrinsic/BaseIoLibIntrinsic.inf
-- 
2.30.0.windows.1