[PATCH v2 2/6] MdeModulePkg: VariableSmmRuntimeDxe: Added request unblock memory interface

["Kun Qin" <kun.q@outlook.com>]

This changes added usage of DxeMmUnblockMemoryLib 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>
---

Notes:
    v2:
    - Newly added in v2.

 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c   | 42 ++++++++++++++++++++
 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf |  1 +
 2 files changed, 43 insertions(+)

diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
index c47e614d81f4..b96ca4b89ee4 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
+++ b/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/DxeMmUnblockMemoryLib.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 = DxeMmUnblockMemoryRequest (
+            (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 = DxeMmUnblockMemoryRequest (
+            (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 = DxeMmUnblockMemoryRequest (
+            (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 = DxeMmUnblockMemoryRequest (
+            (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.
   //
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
index b6dbc839e023..b84a407833c2 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
@@ -60,6 +60,7 @@ [LibraryClasses]
   TpmMeasurementLib
   SafeIntLib
   PcdLib
+  DxeMmUnblockMemoryLib
 
 [Protocols]
   gEfiVariableWriteArchProtocolGuid             ## PRODUCES
-- 
2.30.0.windows.1