The UVIRT attribute may be associated with a number of structures, for example:
In general UVIRT allocations are 'convenience' mappings, which map memory to selector allocation. The attribute is used by Memory Management to signal minimal processsing requirements. Typically they are created by device drivers using the DevHlp_PhysToUvirt facility. They are also created by the system where a 'quick' form of aliasing is required without the alias being associated with any memory object. Examples of this are:
VDM private arena memory
Selectors 5b and 53, 32-bit Code and Data selectors which are used by most 32-bit application programs.
Selector 30, the TASKAREA selector, which aliases the current process' TSD, TCB and PTDA.