Refactoring the MM implementation to support both Standalone MM and T…

…raditional MM (#461)

# Preface

Please ensure you have read the [contribution
docs](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md) prior
to submitting the pull request. In particular,
[pull request
guidelines](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md#pull-request-best-practices).

## Description

Refactoring the MM implementation to support both Standalone MM and
Traditional MM

1. Add DXE_SMM_DRIVER to LIBRARY_CLASS of MmPolicyLib.inf
2. Refactor the PolicyMm module to have a common entrypoint, and both
Standalone MM and Traditional MM entrypoint call the common entrypoint.
3. Add Traditional MM description to Readme.md.

This PR resolves #460.

For each item, place an "x" in between `[` and `]` if true. Example:
`[x]`.
_(you can also check items in the GitHub UI)_

- [x] Impacts functionality?
- **Functionality** - Does the change ultimately impact how firmware
functions?
- Examples: Add a new library, publish a new PPI, update an algorithm,
...
- [ ] Impacts security?
- **Security** - Does the change have a direct security impact on an
application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
- **Breaking change** - Will anyone consuming this change experience a
break
    in build or boot behavior?
- Examples: Add a new library class, move a module to a different repo,
call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [x] Includes documentation?
- **Documentation** - Does the change contain explicit documentation
additions
    outside direct code modifications (and comments)?
- Examples: Update readme file, add feature readme file, link to
documentation
    on an a separate Web page, ...

## How This Was Tested

Verified with the CI build

## Integration Instructions

N/A

PolicyServicePkg/Library/MmPolicyLib/MmPolicyLib.inf

@@ -14,7 +14,7 @@
   FILE_GUID                      = C2A9C781-8D58-46DA-BC39-5385AB8D5C8A
   MODULE_TYPE                    = MM_STANDALONE
   VERSION_STRING                 = 1.0
-  LIBRARY_CLASS                  = PolicyLib | MM_STANDALONE
+  LIBRARY_CLASS                  = PolicyLib | DXE_SMM_DRIVER MM_STANDALONE
 
 [Sources]
   ../PolicyLibCommon.c

PolicyServicePkg/PolicyService/DxeMm/PolicyMm.c

@@ -1,5 +1,5 @@
 /** @file
-  Implements the Standalone MM policy protocol, providing services to publish and
+  Implements the MM policy protocol, providing services to publish and
   access system policy.
 
   Copyright (c) Microsoft Corporation
@@ -87,20 +87,15 @@ InstallPolicyIndicatorProtocol (
 }
 
 /**
-  Entry to the Standalone MM policy service module.
-
-  @param[in] ImageHandle                The image handle.
-  @param[in] SystemTable                The system table.
+  Common Entry of the MM policy service module.
 
   @retval Status                        From internal routine or boot object, should not fail
 **/
 EFI_STATUS
 EFIAPI
-PolicyStandaloneEntry (
-  IN EFI_HANDLE           ImageHandle,
-  IN EFI_MM_SYSTEM_TABLE  *SystemTable
+PolicyMmCommonEntry (
+  VOID
   )
-
 {
   EFI_STATUS  Status;
 

PolicyServicePkg/PolicyService/DxeMm/PolicyMm.inf

@@ -14,9 +14,10 @@
   FILE_GUID                      = 9FF65AAD-5982-4609-9702-05EFD584148C
   MODULE_TYPE                    = MM_STANDALONE
   VERSION_STRING                 = 1.0
-  ENTRY_POINT                    = PolicyStandaloneEntry
+  ENTRY_POINT                    = PolicyStandaloneMmEntry
 
 [Sources]
+  PolicyStandaloneMm.c
   PolicyMm.c
   PolicyCommon.c
   PolicyCommon.h

PolicyServicePkg/PolicyService/DxeMm/PolicyStandaloneMm.c

@@ -0,0 +1,40 @@
+/** @file
+  Implements the Standalone MM policy protocol, providing services to publish and
+  access system policy.
+
+  Copyright (c) Microsoft Corporation
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+#include <Library/MmServicesTableLib.h>
+
+/**
+  Common Entry of the MM policy service module.
+
+  @retval Status                        From internal routine or boot object, should not fail
+**/
+EFI_STATUS
+EFIAPI
+PolicyMmCommonEntry (
+  VOID
+  );
+
+/**
+  Entry to the Standalone MM policy service module.
+
+  @param[in] ImageHandle                The image handle.
+  @param[in] SystemTable                The system table.
+
+  @retval Status                        From internal routine or boot object, should not fail
+**/
+EFI_STATUS
+EFIAPI
+PolicyStandaloneMmEntry (
+  IN EFI_HANDLE           ImageHandle,
+  IN EFI_MM_SYSTEM_TABLE  *SystemTable
+  )
+{
+  return PolicyMmCommonEntry ();
+}

PolicyServicePkg/PolicyService/DxeMm/PolicyTraditionalMm.c

@@ -0,0 +1,39 @@
+/** @file
+  Implements the Traditional MM policy protocol, providing services to publish and
+  access system policy.
+
+  Copyright (c) Microsoft Corporation
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Uefi.h>
+
+/**
+  Common Entry of the MM policy service module.
+
+  @retval Status                        From internal routine or boot object, should not fail
+**/
+EFI_STATUS
+EFIAPI
+PolicyMmCommonEntry (
+  VOID
+  );
+
+/**
+  Entry to the Traditional MM policy service module.
+
+  @param[in] ImageHandle                The image handle.
+  @param[in] SystemTable                The system table.
+
+  @retval Status                        From internal routine or boot object, should not fail
+**/
+EFI_STATUS
+EFIAPI
+PolicyTraditionalMmEntry (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  return PolicyMmCommonEntry ();
+}

PolicyServicePkg/PolicyService/DxeMm/PolicyTraditionalMm.inf

@@ -0,0 +1,47 @@
+## @file
+#
+#  This is a driver for Traditional MM policy service module.
+#
+#  Copyright (C) Microsoft Corporation. All rights reserved.
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x00010017
+  PI_SPECIFICATION_VERSION       = 0x00010032
+  BASE_NAME                      = PolicyTraditionalMm
+  FILE_GUID                      = 51084E31-393D-4D06-A867-BDE321D4E4F5
+  MODULE_TYPE                    = DXE_SMM_DRIVER
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = PolicyTraditionalMmEntry
+
+[Sources]
+  PolicyTraditionalMm.c
+  PolicyMm.c
+  PolicyCommon.c
+  PolicyCommon.h
+
+[Packages]
+  MdePkg/MdePkg.dec
+  MdeModulePkg/MdeModulePkg.dec
+  PolicyServicePkg/PolicyServicePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  HobLib
+  UefiDriverEntryPoint
+  MmServicesTableLib
+  MemoryAllocationLib
+
+[Pcd]
+
+[Guids]
+  gPolicyHobGuid
+
+[Protocols]
+  gMmPolicyProtocolGuid               ## PRODUCES
+
+[Depex]
+  TRUE

PolicyServicePkg/PolicyServicePkg.dec

@@ -30,4 +30,5 @@
 [Protocols]
   ## Include/Protocol/Policy.h
   gPolicyProtocolGuid = { 0xd7c9b744, 0x13a5, 0x4377, { 0x8d, 0x2a, 0x6b, 0x37, 0xad, 0x1f, 0xd8, 0x2a } }
+  ## Include/Protocol/MmPolicy.h
   gMmPolicyProtocolGuid = { 0xe55ad3a1, 0xbd34, 0x46f4, { 0xbb, 0x6e, 0x72, 0x28, 0x0b, 0xdc, 0xbf, 0xd9 } }

PolicyServicePkg/PolicyServicePkg.dsc

@@ -67,17 +67,24 @@
   HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
   PolicyLib|PolicyServicePkg/Library/DxePolicyLib/DxePolicyLib.inf
 
+[LibraryClasses.common.DXE_SMM_DRIVER]
+  MemoryAllocationLib|MdePkg/Library/SmmMemoryAllocationLib/SmmMemoryAllocationLib.inf
+  UefiDriverEntryPoint|MdePkg/Library/UefiDriverEntryPoint/UefiDriverEntryPoint.inf
+  HobLib|MdePkg/Library/DxeHobLib/DxeHobLib.inf
+  MmServicesTableLib|MdePkg/Library/MmServicesTableLib/MmServicesTableLib.inf
+  SmmServicesTableLib|MdePkg/Library/SmmServicesTableLib/SmmServicesTableLib.inf
+
 [LibraryClasses.common.MM_STANDALONE]
   MemoryAllocationLib|StandaloneMmPkg/Library/StandaloneMmMemoryAllocationLib/StandaloneMmMemoryAllocationLib.inf
   StandaloneMmDriverEntryPoint|MdePkg/Library/StandaloneMmDriverEntryPoint/StandaloneMmDriverEntryPoint.inf
   HobLib|StandaloneMmPkg/Library/StandaloneMmHobLib/StandaloneMmHobLib.inf
   MmServicesTableLib|MdePkg/Library/StandaloneMmServicesTableLib/StandaloneMmServicesTableLib.inf
-  StandaloneMmDriverEntryPoint|MdePkg/Library/StandaloneMmDriverEntryPoint/StandaloneMmDriverEntryPoint.inf
   PolicyLib|PolicyServicePkg/Library/MmPolicyLib/MmPolicyLib.inf
 
 [Components]
   PolicyServicePkg/PolicyService/DxeMm/PolicyDxe.inf
   PolicyServicePkg/PolicyService/DxeMm/PolicyMm.inf
+  PolicyServicePkg/PolicyService/DxeMm/PolicyTraditionalMm.inf
   PolicyServicePkg/PolicyService/Pei/PolicyPei.inf
   PolicyServicePkg/Library/DxePolicyLib/DxePolicyLib.inf
   PolicyServicePkg/Library/PeiPolicyLib/PeiPolicyLib.inf

PolicyServicePkg/README.md

@@ -207,19 +207,19 @@ Like the PEIM, the DXE driver will install/reinstall a NULL protocol with the
 given policies GUID when it is created or updated to allow for notification and
 dispatch on the policy availability.
 
-### Standalone MM
+### Traditional/Standalone MM
 
 Like the DXE phase, the MM policy service will ingest any policies from the HOB
 list for architectures. The MM policy service is implemented identically to the
 DXE phase module with the exception of using the MM specific protocols.
 
 Policies in the MM service are isolated from PEI and DXE. The MM module will ingest
 any policies available in the hob list from PEI where applicable but no policies
-created or modified by PEI or DXE after Standalone MM has been launched will be
+created or modified by PEI or DXE after Traditional/Standalone MM has been launched will be
 available from the MM policy service. Similarly, no policy created or edited in
 the MM policy service will be readable from the PEI or DXE policies services.
 
-Policies are not shared with the standalone MM module after initialization. Any
+Policies are not shared with the traditional/standalone MM module after initialization. Any
 policy created in MM will not be readable by DXE and PEI, and any policy made after
 MM initialization will not be readable from MM.