Ubuntu in bhyve

Hi all,

I am running bhyve (via TrueNAS Core 13) and have some Ubuntu 20.04 and 
22.04 guests.

One of them rather regularly seizes up hard, where I cannot ssh to it, 
then after a few minutes works again. This happens repeatedly and on and 
off.  In the Ubuntu logs I see messages like:

```
clocksource: timekeeping watchdog on CPU2: Marking clocksource 'tsc' as 
unstable because the skew is too large:
clocksource:                       'hpet' wd_nsec: 536417782 wd_now: 
638cb3ff wd_last: 63036152 mask: ffffffff
clocksource:                       'tsc' cs_nsec: 536821277 cs_now: 
225a9f9e1250b cs_last: 225a9b3891749 mask: ffffffffffffffff
clocksource:                       'tsc' is current clocksource.
tsc: Marking TSC unstable due to clocksource watchdog
TSC found unstable after boot, most likely due to broken BIOS. Use 
'tsc=unstable'.
sched_clock: Marking unstable (12899572906362, 
9192186981)<-(12908811630850, -46250627)
clocksource: Checking clocksource tsc synchronization from CPU 2 to CPUs 
0-1,3.
clocksource: Switched to clocksource hpet
loop8: detected capacity change from 0 to 114000
```

Although I don't fully grok these messages, they sound like something 
that could be bhyve's fault.  Anyone know if that may indeed be the 
case?

There is a thread about this on the TrueNAS forum too, but with no 
answers really:

https://www.truenas.com/community/threads/debian-vms-under-bhyve-clock.108376/

Thanks,

Sean