Comment by marcan_42

It hasn't really started yet, other than some discussions on IRC, but the TL;DR is on every other ARM64 system those features are handled by either a hypervisor or a supervisor, via special PSCI calls. These machines don't have the option for a supervisor (and no nested virtualization, so an under-OS hypervisor would preclude VMs). Rather than introducing a special snowflake driver for these machines, the current thinking is we can introduce some kind of third PSCI mechanism to make these calls into code set up by the bootloader (a la EFI runtime services), without switching to a higher privilege level. That means we need to define how all that would work first.