2 files changed, 64 insertions, 0 deletions
diff --git a/MdeModulePkg/Include/Guid/VariableRuntimeCacheInfo.h b/MdeModulePkg/Include/Guid/VariableRuntimeCacheInfo.h
new file mode 100644
index 0000000..2f807b8
--- /dev/null
+++ b/MdeModulePkg/Include/Guid/VariableRuntimeCacheInfo.h
@@ -0,0 +1,61 @@
+/** @file
+  This Variable Runtime Cache Info HOB is used to store the address
+  and the size of the buffer that will be used for variable runtime
+  service when the PcdEnableVariableRuntimeCache is TRUE.
+
+  Copyright (c) 2024, Intel Corporation. All rights reserved.<BR>
+
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#ifndef VARIABLE_RUNTIME_CACHE_INFO_H_
+#define VARIABLE_RUNTIME_CACHE_INFO_H_
+
+#define VARIABLE_RUNTIME_CACHE_INFO_HOB_REVISION  1
+
+#define VARIABLE_RUNTIME_CACHE_INFO_GUID \
+  { \
+    0x0f472f7d, 0x6713, 0x4915, {0x96, 0x14, 0x5d, 0xda, 0x28, 0x40, 0x10, 0x56}  \
+  }
+
+typedef struct {
+  ///
+  /// TRUE indicates GetVariable () or GetNextVariable () is being called.
+  /// When the value is FALSE, the given update (and any other pending updates)
+  /// can be flushed to the runtime cache.
+  ///
+  BOOLEAN    ReadLock;
+  ///
+  /// TRUE indicates there is pending update for the given variable store needed
+  /// to be flushed to the runtime cache.
+  ///
+  BOOLEAN    PendingUpdate;
+  ///
+  /// TRUE indicates all HOB variables have been flushed in flash.
+  ///
+  BOOLEAN    HobFlushComplete;
+} CACHE_INFO_FLAG;
+
+typedef struct {
+  EFI_PHYSICAL_ADDRESS    CacheInfoFlagBuffer;
+  ///
+  /// Base address of the runtime Hob variable cache Buffer.
+  ///
+  EFI_PHYSICAL_ADDRESS    RuntimeHobCacheBuffer;
+  UINT64                  RuntimeHobCachePages;
+  ///
+  /// Base address of the non-volatile variable runtime cache Buffer.
+  ///
+  EFI_PHYSICAL_ADDRESS    RuntimeNvCacheBuffer;
+  UINT64                  RuntimeNvCachePages;
+  ///
+  /// Base address of the volatile variable runtime cache Buffer.
+  ///
+  EFI_PHYSICAL_ADDRESS    RuntimeVolatileCacheBuffer;
+  UINT64                  RuntimeVolatileCachePages;
+} VARIABLE_RUNTIME_CACHE_INFO;
+
+extern EFI_GUID  gEdkiiVariableRuntimeCacheInfoHobGuid;
+
+#endif
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index 02f330a..fdd1d48 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -468,6 +468,9 @@
   ## This GUID will be used to save MTRR_SETTINGS at EndOfDxe by LockBox and restore at S3 boot PEI phase for s3 usage.
   gEdkiiS3MtrrSettingGuid = { 0xd77baa84, 0xb332, 0x4463, { 0x9f, 0x1d, 0xce, 0x81, 0x00, 0xfe, 0x7f, 0x35 }}
 
+  ## Include/Guid/VariableRuntimeCacheInfo.h
+  gEdkiiVariableRuntimeCacheInfoHobGuid = { 0x0f472f7d, 0x6713, 0x4915, { 0x96, 0x14, 0x5d, 0xda, 0x28, 0x40, 0x10, 0x56 }}
+
 [Ppis]
   ## Include/Ppi/FirmwareVolumeShadowPpi.h
   gEdkiiPeiFirmwareVolumeShadowPpiGuid = { 0x7dfe756c, 0xed8d, 0x4d77, {0x9e, 0xc4, 0x39, 0x9a, 0x8a, 0x81, 0x51, 0x16 } }