1 files changed, 16 insertions, 0 deletions
diff --git a/MdePkg/Include/Pi/PiMultiPhase.h b/MdePkg/Include/Pi/PiMultiPhase.h
index a5056799e1..89280d9d35 100644
--- a/MdePkg/Include/Pi/PiMultiPhase.h
+++ b/MdePkg/Include/Pi/PiMultiPhase.h
@@ -133,6 +133,22 @@ typedef struct {
 
 typedef EFI_MMRAM_DESCRIPTOR  EFI_SMRAM_DESCRIPTOR;
 
+///
+/// Structure describing a MMRAM region which cannot be used for the MMRAM heap.
+///
+typedef struct _EFI_MM_RESERVED_MMRAM_REGION {
+  ///
+  /// Starting address of the reserved MMRAM area, as it appears while MMRAM is open.
+  /// Ignored if MmramReservedSize is 0.
+  ///
+  EFI_PHYSICAL_ADDRESS    MmramReservedStart;
+  ///
+  /// Number of bytes occupied by the reserved MMRAM area. A size of zero indicates the
+  /// last MMRAM area.
+  ///
+  UINT64                  MmramReservedSize;
+} EFI_MM_RESERVED_MMRAM_REGION;
+
 typedef enum {
   EFI_PCD_TYPE_8,
   EFI_PCD_TYPE_16,