1 files changed, 14 insertions, 7 deletions
diff --git a/MdePkg/Include/Uefi/UefiSpec.h b/MdePkg/Include/Uefi/UefiSpec.h
index 57cb4e804f..4eb9384c1b 100644
--- a/MdePkg/Include/Uefi/UefiSpec.h
+++ b/MdePkg/Include/Uefi/UefiSpec.h
@@ -5,7 +5,7 @@
   If a code construct is defined in the UEFI 2.6 specification it must be included
   by this include file.
 
-Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials are licensed and made available under 
 the terms and conditions of the BSD License that accompanies this distribution.  
 The full text of the license may be found at
@@ -103,21 +103,28 @@ typedef enum {
 ///
 typedef struct {
   ///
-  /// Type of the memory region.  See EFI_MEMORY_TYPE.
+  /// Type of the memory region.
+  /// Type EFI_MEMORY_TYPE is defined in the
+  /// AllocatePages() function description.
   ///
   UINT32                Type;
   ///
-  /// Physical address of the first byte of the memory region.  Must aligned 
-  /// on a 4 KB boundary.
+  /// Physical address of the first byte in the memory region. PhysicalStart must be
+  /// aligned on a 4 KiB boundary, and must not be above 0xfffffffffffff000. Type
+  /// EFI_PHYSICAL_ADDRESS is defined in the AllocatePages() function description
   ///
   EFI_PHYSICAL_ADDRESS  PhysicalStart;
   ///
-  /// Virtual address of the first byte of the memory region.  Must aligned 
-  /// on a 4 KB boundary.
+  /// Virtual address of the first byte in the memory region.
+  /// VirtualStart must be aligned on a 4 KiB boundary,
+  /// and must not be above 0xfffffffffffff000.
   ///
   EFI_VIRTUAL_ADDRESS   VirtualStart;
   ///
-  /// Number of 4KB pages in the memory region.
+  /// NumberOfPagesNumber of 4 KiB pages in the memory region.
+  /// NumberOfPages must not be 0, and must not be any value
+  /// that would represent a memory page with a start address,
+  /// either physical or virtual, above 0xfffffffffffff000.
   ///
   UINT64                NumberOfPages;
   ///