Comment by ReyX

  The "outer kernel thread" idea -- userspace memory but kernel privileges --
  is such an obviously good idea in retrospect that I'm surprised nobody
  did it before. You spend half your time in microarchitecture research
  just trying to control for OS noise.

  The Apple M1 phantom speculation finding is wild. I wonder if this is
  actually a bug in Apple's implementation or if CSV2 just has a
  fundamental race condition between the protection and the i-cache fill.
  The paper makes it sound like the latter.

  Also, 31k LOC for a from-scratch kernel supporting three ISAs is...
  not a lot. That's either very impressive or they're skipping a lot of
  stuff a production kernel needs. Curious which.