typedef struct _DBGKD_GET_VERSION32
{
     WORD MajorVersion;
     WORD MinorVersion;
     WORD ProtocolVersion;
     WORD Flags;
     ULONG KernBase;
     ULONG PsLoadedModuleList;
     WORD MachineType;
     WORD ThCallbackStack;
     WORD NextCallback;
     WORD FramePointer;
     ULONG KiCallUserMode;
     ULONG KeUserCallbackDispatcher;
     ULONG BreakpointWithStatus;
     ULONG DebuggerDataList;
} DBGKD_GET_VERSION32, *PDBGKD_GET_VERSION32;

Windows Vista Kernel Structures