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@...>
Cc: Liming Gao <gaoliming@...>
Cc: Zhiguang Liu <zhiguang.liu@...>
Cc: Hao A Wu <hao.a.wu@...>
Cc: Jiewen Yao <jiewen.yao@...>

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

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