[PATCH v4 3/7] MdeModulePkg: VariableSmmRuntimeDxe: Added request unblock memory interface

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

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>
---

Notes:
    v4:
    - Added reviewed-by tag. [Hao]
    
    v3:
    - Removed Dxe prefix to match interface change. [Jiewen]
    
    v2:
    - Newly added in v2.

 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c   | 42 ++++++++++++++++++++
 MdeModulePkg/MdeModulePkg.dsc                                        |  1 +
 MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf |  1 +
 3 files changed, 44 insertions(+)

diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.c
index c47e614d81f4..a166d284dfe4 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/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.
   //
diff --git a/MdeModulePkg/MdeModulePkg.dsc b/MdeModulePkg/MdeModulePkg.dsc
index 7ca4a1bb3080..9272da89a998 100644
--- a/MdeModulePkg/MdeModulePkg.dsc
+++ b/MdeModulePkg/MdeModulePkg.dsc
@@ -100,6 +100,7 @@ [LibraryClasses]
   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
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
index b6dbc839e023..a0d8b2267e92 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmmRuntimeDxe.inf
@@ -60,6 +60,7 @@ [LibraryClasses]
   TpmMeasurementLib
   SafeIntLib
   PcdLib
+  MmUnblockMemoryLib
 
 [Protocols]
   gEfiVariableWriteArchProtocolGuid             ## PRODUCES
-- 
2.30.0.windows.1