Fix bhyve w/ INVARIANTS post D13573

[kmacy]

Summary

D13573 broke bhyve if INVARIANTS is enabled with passthrough. This fixes the lock recursion without making the vcpu lock recursive.

[grehan]

Only minor issue I had was the trailing underscores in the inline routine name: wasn't too sure if that was idiomatic FreeBSD. Maybe "_int" ?

[tychon]

If you capture VMCS_GUEST_INTR_STATUS in the EXIT_REASON_HLT case of vmx_exit_process() then you can use that value in vmx_pending_intr() without having to use a vmx_getreg(). That circumvents the locking issue, removes the need for the special case #ifdef INVARIANTS/#endif code and may even improve the latency by skipping an iteration of VMPTRLD() and VMCLEAR().

[cem]

sys/amd64/vmm/intel/vmx.c

2949

style(9) nit: Prefer bool + true/false in new code

sys/amd64/vmm/vmm.c

314

style(9) nit: ampersand inside the parentheses?

[dch]

@kmacy tyvm works brilliantly here - I'll close the PR in bugzilla when this lands. Many many thanks!

[tychon]

The changes I proposed in the comments here, and reviewed in D14548, have been committed.