struct DBGKD_WRITE_MEMORY64

typedef struct _DBGKD_WRITE_MEMORY64
{
     UINT64 TargetBaseAddress;
     ULONG TransferCount;
     ULONG ActualBytesWritten;
} DBGKD_WRITE_MEMORY64, *PDBGKD_WRITE_MEMORY64;

Windows Vista Kernel Structures