Power ISA/Privilege States
- ultravisor privileged state
- hypervisor privileged state
- privileged state / supervisor mode
- problem state / user mode
At the moment very little information exists about the ultravisor state. It is not mentioned in Power ISA version 2.07 documents at all, and version 3.0B only mentions it as a possible classification for instructions:
|P||Yes||Yes||a privileged instruction.|
|O||Yes||Yes||an instruction that is treated as privileged or nonprivileged (or hypervisor, for mtspr), depend-
ing on the SPR or PMR number.
|PI||No||Yes||an instruction that is illegal in privileged state.|
|H||Yes||Yes||an instruction that can be executed only in hypervisor state|
|PH||Yes||No||a hypervisor privileged instruction if Category Embedded.Hypervisor is implemented; otherwise
denotes a privileged instruction.
|M||Yes||No||an instruction that is treated as privileged or nonprivileged, depending on the value of the UCLE
bit in the MSR
|U||No||Yes||an instruction that can be executed only in ultravisor state|