From 56dfab9a8a143aa486d07eafc3d5a78bff540228 Mon Sep 17 00:00:00 2001
From: Wei6 Xu <wei6.xu@intel.com>
Date: Mon, 21 Oct 2024 10:13:54 +0800
Subject: [PATCH] StandaloneMmPkg/Core: Shadow Standalone BFV into MMRAM

BFV is outside the MMRAM. Currently, StandaloneMmIplPei uses the API
MmUnblockMemoryRequest() to unblock the access for the BFV. However,
the BFV's memory might be gone after ExitBootService event. If any
access to the memory, unexpected error would happen.
To fix the above issue, StandaloneMmCore should shadow standalone BFV
into MMRAM before processing it, then free the shadowed BFV after MM
driver dispatch is done.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Signed-off-by: Wei6 Xu <wei6.xu@intel.com>
---
 StandaloneMmPkg/Core/Dispatcher.c             |  7 ++++++
 StandaloneMmPkg/Core/StandaloneMmCore.c       | 23 ++++++++++++++-----
 StandaloneMmPkg/Core/StandaloneMmCore.h       |  7 +++---
 .../StandaloneMmIplPei/StandaloneMmIplPei.c   |  8 -------
 4 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/StandaloneMmPkg/Core/Dispatcher.c b/StandaloneMmPkg/Core/Dispatcher.c
index e55fdbabf2..8e6b85caee 100644
--- a/StandaloneMmPkg/Core/Dispatcher.c
+++ b/StandaloneMmPkg/Core/Dispatcher.c
@@ -766,6 +766,13 @@ MmDriverDispatchHandler (
 
   MmiHandlerUnRegister (DispatchHandle);
 
+  //
+  // Free shadowed standalone BFV
+  //
+  if (mBfv != NULL) {
+    FreePool (mBfv);
+  }
+
   return EFI_SUCCESS;
 }
 
diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.c b/StandaloneMmPkg/Core/StandaloneMmCore.c
index 970a06045b..127248afab 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.c
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.c
@@ -83,9 +83,10 @@ MM_CORE_MMI_HANDLERS  mMmCoreMmiHandlers[] = {
   { NULL,                     NULL,                              NULL, FALSE },
 };
 
-BOOLEAN         mMmEntryPointRegistered = FALSE;
-MM_COMM_BUFFER  *mMmCommunicationBuffer;
-VOID            *mInternalCommBufferCopy;
+BOOLEAN                     mMmEntryPointRegistered = FALSE;
+MM_COMM_BUFFER              *mMmCommunicationBuffer;
+VOID                        *mInternalCommBufferCopy;
+EFI_FIRMWARE_VOLUME_HEADER  *mBfv = NULL;
 
 /**
   Place holder function until all the MM System Table Service are available.
@@ -844,9 +845,19 @@ StandaloneMmMain (
     // Dispatch standalone BFV
     //
     if (BfvHob->BaseAddress != 0) {
-      DEBUG ((DEBUG_INFO, "Mm Dispatch StandaloneBfvAddress - 0x%08x\n", BfvHob->BaseAddress));
-      MmCoreFfsFindMmDriver ((EFI_FIRMWARE_VOLUME_HEADER *)(UINTN)BfvHob->BaseAddress, 0);
-      MmDispatcher ();
+      //
+      // Shadow standalone BFV into MMRAM
+      //
+      mBfv = AllocatePool (BfvHob->Length);
+      if (mBfv != NULL) {
+        CopyMem ((VOID *)mBfv, (VOID *)(UINTN)BfvHob->BaseAddress, BfvHob->Length);
+        DEBUG ((DEBUG_INFO, "Mm Dispatch StandaloneBfvAddress - 0x%08x\n", mBfv));
+        MmCoreFfsFindMmDriver (mBfv, 0);
+        MmDispatcher ();
+        if (!FeaturePcdGet (PcdRestartMmDispatcherOnceMmEntryRegistered)) {
+          FreePool (mBfv);
+        }
+      }
     }
   }
 
diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.h b/StandaloneMmPkg/Core/StandaloneMmCore.h
index 093a35fb56..7bff1cde14 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.h
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.h
@@ -178,9 +178,10 @@ typedef struct {
 //
 // MM Core Global Variables
 //
-extern EFI_MM_SYSTEM_TABLE  gMmCoreMmst;
-extern LIST_ENTRY           gHandleList;
-extern BOOLEAN              mMmEntryPointRegistered;
+extern EFI_MM_SYSTEM_TABLE         gMmCoreMmst;
+extern LIST_ENTRY                  gHandleList;
+extern BOOLEAN                     mMmEntryPointRegistered;
+extern EFI_FIRMWARE_VOLUME_HEADER  *mBfv;
 
 /**
   Called to initialize the memory service.
diff --git a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c
index b1cd3c1d81..1a01d7a465 100644
--- a/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c
+++ b/StandaloneMmPkg/Drivers/StandaloneMmIplPei/StandaloneMmIplPei.c
@@ -513,14 +513,6 @@ ExecuteMmCoreFromMmram (
   Status = LocateMmCoreFv (&MmFvBase, &MmFvSize, &MmCoreFileName, &ImageContext.Handle);
   ASSERT_EFI_ERROR (Status);
 
-  //
-  // Unblock the MM FV range to be accessible from inside MM
-  //
-  if ((MmFvBase != 0) && (MmFvSize != 0)) {
-    Status = MmUnblockMemoryRequest (MmFvBase, EFI_SIZE_TO_PAGES (MmFvSize));
-    ASSERT_EFI_ERROR (Status);
-  }
-
   //
   // Initialize ImageContext
   //