panic: trap type 4, code=0, pc=ffffffff818a219f
Starting stack trace...
panic(ffffffff82828330) at panic+0x159 sys/kern/subr_prf.c:229
kerntrap(ffff8000378010f0) at kerntrap+0x1c7 sys/arch/amd64/amd64/trap.c:327
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
ktrops(ffff80002a6787d0,deafbeaddeafbead,0,a0c7df9b,fffffd805f157d88,fffffd807f7d76e8) at ktrops+0x4f ktrcanset sys/kern/kern_ktrace.c:718 [inline]
ktrops(ffff80002a6787d0,deafbeaddeafbead,0,a0c7df9b,fffffd805f157d88,fffffd807f7d76e8) at ktrops+0x4f sys/kern/kern_ktrace.c:561
doktrace(fffffd805f157d88,4,20c7df9b,0,ffff80002a6787d0) at doktrace+0x514 ktrsetchildren sys/kern/kern_ktrace.c:586 [inline]
doktrace(fffffd805f157d88,4,20c7df9b,0,ffff80002a6787d0) at doktrace+0x514 sys/kern/kern_ktrace.c:508
sys_ktrace(ffff80002a6787d0,ffff800037801500,ffff800037801450) at sys_ktrace+0xd6 sys/kern/kern_ktrace.c:549
syscall(ffff800037801500) at syscall+0x72a sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xe7f4f3c6d60, count: 249
End of stack trace.
syncing disks...24 4 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2  giving up

dump to dev 4,1 not possible
rebooting...
SeaBIOS (version 1.8.2-google)
Total RAM Size = 0x0000000080000000 = 2048 MiB
CPUs found: 2     Max CPUs supported: 2
SeaBIOS (version 1.8.2-google)
Machine UUID 8a8635c2-f252-d190-235a-0f50a6ed73cd
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f27f0: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Sending Seabios boot VM event.
Booting from Hard Disk 0...
>> OpenBSD/amd64 BOOT 3.65
boot> machine ddbcpu 0
machine: syntax error
boot> trace
|/-\|/-\|/booting hd0a:trace: -\|/open hd0a:trace: No such file or directory
 failed(2). will try /bsd
boot> machine ddbcpu 1
machine: syntax error
boot> trace