From 6d1bdc2b556a0082b92fbbcbf79dca35969be348 Mon Sep 17 00:00:00 2001
From: Diat Siah Yap <diat.siah.yap@intel.com>
Date: Thu, 23 Jan 2025 20:25:13 -0800
Subject: [PATCH] StandaloneMmPkg: Produce StandaloneMM Entry/Exit Notify
 Protocol.

Produce StandaloneMM Entry/Exit Notify Protocol for PlatformHook.
This replaces the SMM core platform hook implementation in the
traditional SMM (Edk2\MdeModulePkg\Include\Library\SmmCorePlatformHookLib.h).
Unlike traditional SMM, Standalone MM prefers a more generic method to
perform platform-specific tasks before and after the SMI handler. Therefore,
it introduces the gMmEntryNotifyProtocolGuid and gMmExitNotifyProtocolGuid
protocols to notify the SMM entry and exit. This approach is more flexible
for the platform, eliminating the need to place all tasks in
PlatformHookBeforeSmmDispatch() and PlatformHookAfterSmmDispatch(), thus
platform code can depend on the protocol notification to perform
platform-specific tasks.

Signed-off-by: Diat Siah Yap <diat.siah.yap@intel.com>
---
 StandaloneMmPkg/Core/StandaloneMmCore.c   | 36 +++++++++++++++++++++--
 StandaloneMmPkg/Core/StandaloneMmCore.inf |  2 ++
 StandaloneMmPkg/StandaloneMmPkg.dec       |  4 +++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.c b/StandaloneMmPkg/Core/StandaloneMmCore.c
index 6ce09176e3..36be31ca53 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.c
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.c
@@ -505,6 +505,7 @@ MmEntryPoint (
   EFI_MM_COMMUNICATE_HEADER  *CommunicateHeader;
   MM_COMM_BUFFER_STATUS      *CommunicationStatus;
   UINTN                      BufferSize;
+  EFI_HANDLE                 MmHandle;
 
   DEBUG ((DEBUG_INFO, "MmEntryPoint ...\n"));
 
@@ -514,9 +515,22 @@ MmEntryPoint (
   CopyMem (&gMmCoreMmst.MmStartupThisAp, MmEntryContext, sizeof (EFI_MM_ENTRY_CONTEXT));
 
   //
-  // Call platform hook before Mm Dispatch
+  // Install a protocol to notify BeforeMmDispatch.
   //
-  // PlatformHookBeforeMmDispatch ();
+  MmHandle = NULL;
+  Status   = MmInstallProtocolInterface (
+               &MmHandle,
+               &gEfiMmEntryNotifyProtocolGuid,
+               EFI_NATIVE_INTERFACE,
+               NULL
+               );
+  if (!EFI_ERROR (Status)) {
+    MmUninstallProtocolInterface (
+      MmHandle,
+      &gEfiMmEntryNotifyProtocolGuid,
+      NULL
+      );
+  }
 
   //
   // Check to see if this is a Synchronous MMI sent through the MM Communication
@@ -589,6 +603,24 @@ MmEntryPoint (
   //
   MmiManage (NULL, NULL, NULL, NULL);
 
+  //
+  // Install a protocol to notify AfterMmDispatch.
+  //
+  MmHandle = NULL;
+  Status   = MmInstallProtocolInterface (
+               &MmHandle,
+               &gEfiMmExitNotifyProtocolGuid,
+               EFI_NATIVE_INTERFACE,
+               NULL
+               );
+  if (!EFI_ERROR (Status)) {
+    MmUninstallProtocolInterface (
+      MmHandle,
+      &gEfiMmExitNotifyProtocolGuid,
+      NULL
+      );
+  }
+
   //
   // TBD: Do not use private data structure ?
   //
diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.inf b/StandaloneMmPkg/Core/StandaloneMmCore.inf
index f825a98fa1..f3340d26f9 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.inf
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.inf
@@ -63,6 +63,8 @@
   gEfiLoadedImageProtocolGuid                   ## PRODUCES
   gEfiMmConfigurationProtocolGuid               ## CONSUMES
   gEfiMmEndOfPeiProtocol                        ## PRODUCES
+  gEfiMmEntryNotifyProtocolGuid                 ## PRODUCES
+  gEfiMmExitNotifyProtocolGuid                  ## PRODUCES
 
 [Guids]
   gAprioriGuid                                  ## SOMETIMES_CONSUMES   ## File
diff --git a/StandaloneMmPkg/StandaloneMmPkg.dec b/StandaloneMmPkg/StandaloneMmPkg.dec
index 00ec8c076e..8292c8ebe5 100644
--- a/StandaloneMmPkg/StandaloneMmPkg.dec
+++ b/StandaloneMmPkg/StandaloneMmPkg.dec
@@ -43,6 +43,10 @@
 
   gEventMmDispatchGuid                     = { 0x7e6efffa, 0x69b4, 0x4c1b, { 0xa4, 0xc7, 0xaf, 0xf9, 0xc9, 0x24, 0x4f, 0xee }}
 
+[Protocols]
+  gEfiMmEntryNotifyProtocolGuid            = { 0x9bfbcc5f, 0x6435, 0x46d3, { 0xb9, 0xa5, 0x70, 0xfb, 0xa4, 0x71, 0xe1, 0x26 }}
+  gEfiMmExitNotifyProtocolGuid             = { 0x0e265f48, 0x47c0, 0x471f, { 0x9c, 0x83, 0xc6, 0xd6, 0x57, 0x64, 0x21, 0xa4 }}
+
 [Ppis]
   gMmCoreFvLocationPpiGuid                 = { 0x47a00618, 0x237a, 0x4386, { 0x8f, 0xc5, 0x2a, 0x86, 0xd8, 0xac, 0x41, 0x05 }}