MdeModulePkg: VariableSmmRuntimeDxe: Added request unblock memory interface

This changes added usage of MmUnblockMemoryLib to explicitly request
runtime cache regions(and its indicators) to be accessible from MM
environment when PcdEnableVariableRuntimeCache is enabled. It will bring
in compatibility with architectures that supports full memory blockage
inside MM.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>

Signed-off-by: Kun Qin <kun.q@outlook.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
Message-Id: <MWHPR06MB31026EA41F28F2CE12B68574F3969@MWHPR06MB3102.namprd06.prod.outlook.com>

MdeModulePkg/MdeModulePkg.dsc

@@ -100,6 +100,7 @@
   SafeIntLib|MdePkg/Library/BaseSafeIntLib/BaseSafeIntLib.inf
   DisplayUpdateProgressLib|MdeModulePkg/Library/DisplayUpdateProgressLibGraphics/DisplayUpdateProgressLibGraphics.inf
   VariablePolicyHelperLib|MdeModulePkg/Library/VariablePolicyHelperLib/VariablePolicyHelperLib.inf
+  MmUnblockMemoryLib|MdePkg/Library/MmUnblockMemoryLib/MmUnblockMemoryLibNull.inf
 
 [LibraryClasses.EBC.PEIM]
   IoLib|MdePkg/Library/PeiIoLibCpuIo/PeiIoLibCpuIo.inf

MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c

@@ -35,6 +35,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #include <Library/DebugLib.h>
 #include <Library/UefiLib.h>
 #include <Library/BaseLib.h>
+#include <Library/MmUnblockMemoryLib.h>
 
 #include <Guid/EventGroup.h>
 #include <Guid/SmmVariableCommon.h>
@@ -165,6 +166,7 @@ InitVariableCache (
   )
 {
   VARIABLE_STORE_HEADER   *VariableCacheStorePtr;
+  EFI_STATUS              Status;
 
   if (TotalVariableCacheSize == NULL) {
     return EFI_INVALID_PARAMETER;
@@ -186,6 +188,18 @@ InitVariableCache (
   if (*VariableCacheBuffer == NULL) {
     return EFI_OUT_OF_RESOURCES;
   }
+
+  //
+  // Request to unblock the newly allocated cache region to be accessible from inside MM
+  //
+  Status = MmUnblockMemoryRequest (
+            (EFI_PHYSICAL_ADDRESS) (UINTN) *VariableCacheBuffer,
+            EFI_SIZE_TO_PAGES (*TotalVariableCacheSize)
+            );
+  if (Status != EFI_UNSUPPORTED && EFI_ERROR (Status)) {
+    return Status;
+  }
+
   VariableCacheStorePtr = *VariableCacheBuffer;
   SetMem32 ((VOID *) VariableCacheStorePtr, *TotalVariableCacheSize, (UINT32) 0xFFFFFFFF);
 
@@ -1536,6 +1550,34 @@ SendRuntimeVariableCacheContextToSmm (
   SmmRuntimeVarCacheContext->ReadLock = &mVariableRuntimeCacheReadLock;
   SmmRuntimeVarCacheContext->HobFlushComplete = &mHobFlushComplete;
 
+  //
+  // Request to unblock this region to be accessible from inside MM environment
+  // These fields "should" be all on the same page, but just to be on the safe side...
+  //
+  Status = MmUnblockMemoryRequest (
+            (EFI_PHYSICAL_ADDRESS) ALIGN_VALUE ((UINTN) SmmRuntimeVarCacheContext->PendingUpdate - EFI_PAGE_SIZE + 1, EFI_PAGE_SIZE),
+            EFI_SIZE_TO_PAGES (sizeof(mVariableRuntimeCachePendingUpdate))
+            );
+  if (Status != EFI_UNSUPPORTED && EFI_ERROR (Status)) {
+    goto Done;
+  }
+
+  Status = MmUnblockMemoryRequest (
+            (EFI_PHYSICAL_ADDRESS) ALIGN_VALUE ((UINTN) SmmRuntimeVarCacheContext->ReadLock - EFI_PAGE_SIZE + 1, EFI_PAGE_SIZE),
+            EFI_SIZE_TO_PAGES (sizeof(mVariableRuntimeCacheReadLock))
+            );
+  if (Status != EFI_UNSUPPORTED && EFI_ERROR (Status)) {
+    goto Done;
+  }
+
+  Status = MmUnblockMemoryRequest (
+            (EFI_PHYSICAL_ADDRESS) ALIGN_VALUE ((UINTN) SmmRuntimeVarCacheContext->HobFlushComplete - EFI_PAGE_SIZE + 1, EFI_PAGE_SIZE),
+            EFI_SIZE_TO_PAGES (sizeof(mHobFlushComplete))
+            );
+  if (Status != EFI_UNSUPPORTED && EFI_ERROR (Status)) {
+    goto Done;
+  }
+
   //
   // Send data to SMM.
   //

MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf

@@ -60,6 +60,7 @@
   TpmMeasurementLib
   SafeIntLib
   PcdLib
+  MmUnblockMemoryLib
 
 [Protocols]
   gEfiVariableWriteArchProtocolGuid             ## PRODUCES