This value is filled using KeQuerySystemTime (equal to user-mode NtQuerySystemTime). Here is the short description:
“System time is a count of 100-nanosecond intervals since January 1, 1601. System time is typically updated approximately every ten milliseconds. This value is computed for the GMT time zone.” (Windows DDK help)
In order to convert the m_SystemTime to SYSTEMTIME structure do the following:
1) Copy m_SystemTime to FILETIME structure (don’t use simple typecast, because alignment can be different).
2) Call FileTimeToSystemTime.