typedef struct _MM_PAGE_ACCESS_INFO
{
     union
     {
          MM_PAGE_ACCESS_INFO_FLAGS Flags;
          UINT64 FileOffset;
          PVOID VirtualAddress;
          ULONG DontUse0: 3;
          ULONG Spare0: 29;
     };
     PVOID PointerProtoPte;
} MM_PAGE_ACCESS_INFO, *PMM_PAGE_ACCESS_INFO;

Windows Vista Kernel Structures