> If you want to do any OS work, you need a system that implements the Privileged ISA. Supporting the Privileged ISA is synonymous to being able to run UNIX-like systems, because it brings user-/supervisor-mode distinction and paging. Working on real hardware is generally preferred to working in emulators, because the code eventually has to run on metal anyway and emulators can be too forgiving for certain classes of problems. There is a plethora of RISC-V microcontrollers for a couple of dollars that all don’t support the Privileged ISA. At the time of writing, the only board you can buy that does support it is the $1000 HiFive Unleased, which was beyond my “I just want to play around with this” budget.
Suggests to me that it's at least part of why Stephen Marz [0] isn't trying to target a specific board with his project (which has been posted here a few times and I'm sorta following along). That pretty much kills most of the interest in RISC-V that I had in me.
I guess I'll wait a few more years and check back again later.