System Space Mapping to Users Virtual Address Space

System address space (and Session space, if applicable) is mapped to all the User Process Virtual address space. System Address space consists of shared memory which can be accessed by all the processes. These memory are shared using the Section objects which uses Page tables that can be shared. How exactly this sharing is achieved can be discussed in another post sometime later.

At each Process initialization and when its Page Directory is being initialized, its also get updated for the PDEs that corresponds to System Space Virtual addresses.