StandaloneMmPkg/Core: Introduce MM Communication Buffer

Get the MM Communication context from the MM Communication Buffer,
instead of the pointer inside gMmCorePrivate.
In the MmEntryPoint, check IsCommBufferValid from MM_COMM_BUFFER to
decide whether the MMI is Synchronous MMI or Asynchronous MMI. If it
is a Synchronous MMI, MM Core shadows the communication buffer into
a internal copy, then invokes the MMI handlers, lastly copies data
back to the MM Communication Buffer and set the return status.

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>

3 files changed, 120 insertions, 24 deletions

diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.c b/StandaloneMmPkg/Core/StandaloneMmCore.c
index 14e76fa67e..7e129832fc 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.c
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.c
@@ -88,6 +88,8 @@ MM_CORE_MMI_HANDLERS  mMmCoreMmiHandlers[] = {
 

 UINTN                 mMmramRangeCount;

 EFI_MMRAM_DESCRIPTOR  *mMmramRanges;

+MM_COMM_BUFFER        *mMmCommunicationBuffer;

+VOID                  *mInternalCommBufferCopy;

 

 /**

   Place holder function until all the MM System Table Service are available.

@@ -398,6 +400,62 @@ MmCoreInstallLoadedImage (
 }

 

 /**

+  Prepare communication buffer for MMI.

+**/

+VOID

+MmCorePrepareCommunicationBuffer (

+  VOID

+  )

+{

+  EFI_STATUS            Status;

+  EFI_HOB_GUID_TYPE     *GuidHob;

+  EFI_PHYSICAL_ADDRESS  Buffer;

+

+  mMmCommunicationBuffer  = NULL;

+  mInternalCommBufferCopy = NULL;

+

+  GuidHob = GetFirstGuidHob (&gMmCommBufferHobGuid);

+  ASSERT (GuidHob != NULL);

+  if (GuidHob == NULL) {

+    return;

+  }

+

+  mMmCommunicationBuffer = (MM_COMM_BUFFER *)GET_GUID_HOB_DATA (GuidHob);

+  DEBUG ((

+    DEBUG_INFO,

+    "MM Communication Buffer is at %x, number of pages is %x\n",

+    mMmCommunicationBuffer->PhysicalStart,

+    mMmCommunicationBuffer->NumberOfPages

+    ));

+  ASSERT (mMmCommunicationBuffer->PhysicalStart != 0 && mMmCommunicationBuffer->NumberOfPages != 0);

+

+  if (!MmIsBufferOutsideMmValid (

+         mMmCommunicationBuffer->PhysicalStart,

+         EFI_PAGES_TO_SIZE (mMmCommunicationBuffer->NumberOfPages)

+         ))

+  {

+    mMmCommunicationBuffer = NULL;

+    DEBUG ((DEBUG_ERROR, "MM Communication Buffer is invalid!\n"));

+    ASSERT (FALSE);

+    return;

+  }

+

+  Status = MmAllocatePages (

+             AllocateAnyPages,

+             EfiRuntimeServicesData,

+             mMmCommunicationBuffer->NumberOfPages,

+             &Buffer

+             );

+  ASSERT_EFI_ERROR (Status);

+  if (EFI_ERROR (Status)) {

+    return;

+  }

+

+  mInternalCommBufferCopy = (VOID *)(UINTN)Buffer;

+  DEBUG ((DEBUG_INFO, "Internal Communication Buffer Copy is at %p\n", mInternalCommBufferCopy));

+}

+

+/**

   The main entry point to MM Foundation.

 

   Note: This function is only used by MMRAM invocation.  It is never used by DXE invocation.

@@ -414,6 +472,8 @@ MmEntryPoint (
 {

   EFI_STATUS                 Status;

   EFI_MM_COMMUNICATE_HEADER  *CommunicateHeader;

+  MM_COMM_BUFFER_STATUS      *CommunicationStatus;

+  UINTN                      BufferSize;

 

   DEBUG ((DEBUG_INFO, "MmEntryPoint ...\n"));

 

@@ -440,33 +500,65 @@ MmEntryPoint (
   // Check to see if this is a Synchronous MMI sent through the MM Communication

   // Protocol or an Asynchronous MMI

   //

-  if (gMmCorePrivate->CommunicationBuffer != 0) {

-    //

-    // Synchronous MMI for MM Core or request from Communicate protocol

-    //

-    if (!MmIsBufferOutsideMmValid ((UINTN)gMmCorePrivate->CommunicationBuffer, gMmCorePrivate->BufferSize)) {

-      //

-      // If CommunicationBuffer is not in valid address scope, return EFI_INVALID_PARAMETER

-      //

-      gMmCorePrivate->CommunicationBuffer = 0;

-      gMmCorePrivate->ReturnStatus        = EFI_INVALID_PARAMETER;

-    } else {

-      CommunicateHeader           = (EFI_MM_COMMUNICATE_HEADER *)(UINTN)gMmCorePrivate->CommunicationBuffer;

-      gMmCorePrivate->BufferSize -= OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data);

-      Status                      = MmiManage (

-                                      &CommunicateHeader->HeaderGuid,

-                                      NULL,

-                                      CommunicateHeader->Data,

-                                      (UINTN *)&gMmCorePrivate->BufferSize

-                                      );

+  if ((mMmCommunicationBuffer != NULL) && (mInternalCommBufferCopy != NULL)) {

+    CommunicationStatus = (MM_COMM_BUFFER_STATUS *)(UINTN)mMmCommunicationBuffer->Status;

+    if (CommunicationStatus->IsCommBufferValid) {

       //

-      // Update CommunicationBuffer, BufferSize and ReturnStatus

-      // Communicate service finished, reset the pointer to CommBuffer to NULL

+      // Synchronous MMI for MM Core or request from Communicate protocol

       //

-      gMmCorePrivate->BufferSize         += OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data);

-      gMmCorePrivate->CommunicationBuffer = 0;

-      gMmCorePrivate->ReturnStatus        = (Status == EFI_SUCCESS) ? EFI_SUCCESS : EFI_NOT_FOUND;

+      CommunicateHeader = (EFI_MM_COMMUNICATE_HEADER *)(UINTN)mMmCommunicationBuffer->PhysicalStart;

+      BufferSize        = OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data) + CommunicateHeader->MessageLength;

+      if (BufferSize <= EFI_PAGES_TO_SIZE (mMmCommunicationBuffer->NumberOfPages)) {

+        //

+        // Shadow the data from MM Communication Buffer to internal buffer

+        //

+        CopyMem (

+          mInternalCommBufferCopy,

+          (VOID *)(UINTN)mMmCommunicationBuffer->PhysicalStart,

+          BufferSize

+          );

+        ZeroMem (

+          (UINT8 *)mInternalCommBufferCopy + BufferSize,

+          EFI_PAGES_TO_SIZE (mMmCommunicationBuffer->NumberOfPages) - BufferSize

+          );

+

+        CommunicateHeader = (EFI_MM_COMMUNICATE_HEADER *)mInternalCommBufferCopy;

+        BufferSize        = CommunicateHeader->MessageLength;

+        Status            = MmiManage (

+                              &CommunicateHeader->HeaderGuid,

+                              NULL,

+                              CommunicateHeader->Data,

+                              &BufferSize

+                              );

+

+        BufferSize = BufferSize + OFFSET_OF (EFI_MM_COMMUNICATE_HEADER, Data);

+        if (BufferSize <= EFI_PAGES_TO_SIZE (mMmCommunicationBuffer->NumberOfPages)) {

+          //

+          // Copy the data back to MM Communication Buffer

+          //

+          CopyMem (

+            (VOID *)(UINTN)mMmCommunicationBuffer->PhysicalStart,

+            mInternalCommBufferCopy,

+            BufferSize

+            );

+        } else {

+          DEBUG ((DEBUG_ERROR, "Returned buffer size is larger than the size of MM Communication Buffer\n"));

+          ASSERT (FALSE);

+        }

+

+        //

+        // Update CommunicationBuffer, BufferSize and ReturnStatus

+        // Communicate service finished, reset the pointer to CommBuffer to NULL

+        //

+        CommunicationStatus->ReturnBufferSize = BufferSize;

+        CommunicationStatus->ReturnStatus     = (Status == EFI_SUCCESS) ? EFI_SUCCESS : EFI_NOT_FOUND;

+      } else {

+        DEBUG ((DEBUG_ERROR, "Input buffer size is larger than the size of MM Communication Buffer\n"));

+        ASSERT (FALSE);

+      }

     }

+  } else {

+    DEBUG ((DEBUG_ERROR, "No valid communication buffer, no Synchronous MMI will be processed\n"));

   }

 

   //

@@ -738,6 +830,8 @@ StandaloneMmMain (
     DEBUG ((DEBUG_INFO, "MmiHandlerRegister - GUID %g - Status %d\n", mMmCoreMmiHandlers[Index].HandlerType, Status));

   }

 

+  MmCorePrepareCommunicationBuffer ();

+

   //

   // Install Loaded Image Protocol form MM Core

   //

diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.h b/StandaloneMmPkg/Core/StandaloneMmCore.h
index c08d1d76c0..1d34bb643e 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.h
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.h
@@ -30,6 +30,7 @@
 #include <Guid/HobList.h>

 #include <Guid/MmFvDispatch.h>

 #include <Guid/MmramMemoryReserve.h>

+#include <Guid/MmCommBuffer.h>

 

 #include <Library/StandaloneMmCoreEntryPoint.h>

 #include <Library/BaseLib.h>

diff --git a/StandaloneMmPkg/Core/StandaloneMmCore.inf b/StandaloneMmPkg/Core/StandaloneMmCore.inf
index 8cc9638db5..726a946883 100644
--- a/StandaloneMmPkg/Core/StandaloneMmCore.inf
+++ b/StandaloneMmPkg/Core/StandaloneMmCore.inf
@@ -76,6 +76,7 @@
   gEfiEventLegacyBootGuid

   gEfiEventExitBootServicesGuid

   gEfiEventReadyToBootGuid

+  gMmCommBufferHobGuid

 

 [Pcd]

   gStandaloneMmPkgTokenSpaceGuid.PcdFwVolMmMaxEncapsulationDepth    ##CONSUMES