zlacker

That CPU is set up by the kernel at boot time, given the code to run, then some hardware bits are toggled such that the main CPU can't write later, it can only access the separate CPU via a defined API.

The kernel could do the same with an in-kernel process. It wouldn't have quite the same depth of defense against userspace sandbox escapes, but could be done. That's roughly how /dev/random was implemented for many years.

Look at the APIs provided — it's nothing new. It's nothing OSes haven't provided before, it's just further removed from a Chrome/FF/Safari sandbox escape, because overcoming the write-once hardware toggles is harder than getting kernel read/write primitives for a sandbox privilege escalation.