On Fri, Jun 12, 2026 at 01:56:40AM +0000, Mike Larkin wrote:
> 
> yes this is where we are headed.
> 
> your full diff available somewhere?

This is my diff so far:

https://github.com/openbsd/src/compare/master...nomadium:src:vmd-multi-vcpu.patch

It boots a multi-VCPU guest to single-user via vmctl start -b /bsd.
I've tested with 1, 2, 3, and 4 VCPUs (8 also works but is noticeably slower).

Known limitations:

- Firmware (SeaBIOS) boot is broken. Not yet investigated.

- LAPIC timer is not implemented. APs execute work dispatched to them,
  but the guest scheduler cannot do preemptive time-slicing on them
  without timer interrupts.

- Tested on Intel (i5-8350U / Kaby Lake-R, Thinkpad T480) only. AMD not tested.

A few diagnostic log_warnx commits are still in the branch, happy to
strip them if you'd prefer a cleaner diff.