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[OpenBSD :: Virtualization] No login screen ; no login!

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As a reminder, the vmm(4) hypervisor on OpenBSD not have graphic support on the VM guests. Only serial console access is available.

When you do virtualization on OpenBSD am64, i386, OpenBSD handles all correctly. So, the serial console access is configured on /etc/boot.conf; tty00 to use correctly the serial console.

The following problem results when you have the idea to create VM under another OS, Linux for example, unless you answer specifically yes when the installer asks to configure com0:

No login screen ; no login!

To illustrate: once OpenBSD VM is copied on the OpenBSD host, here is the boot:

$ vmctl start -c vm-test
Using drive 0, partition 3.
probing: pc0 com0 mem[638K 1022M a20=on]
disk: hd0+
>> OpenBSD/amd64 BOOT 3.52
booting hd0a:/bsd: 14329128+3191816+337072+0+872448 [999468+128+1135344+859361]=0x14ba488
entry point at 0xffffffff81001000
[ using 2995336 bytes of bsd ELF symbol table ]
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.
Copyright (c) 1995-2020 OpenBSD. All rights reserved.  https://www.OpenBSD.org

OpenBSD 6.8 (GENERIC) #4: Mon Jan 11 10:34:36 MST 2021
real mem = 1056956416 (1007MB)
avail mem = 1010040832 (963MB)
random: good seed from bootblocks
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.4 @ 0xf3f40 (10 entries)
bios0: vendor SeaBIOS version "1.11.0p3-OpenBSD-vmm" date 01/01/2011
bios0: OpenBSD VMM
acpi at bios0 not configured
cpu0 at mainbus0: (uniprocessor)
cpu0: AMD FX-8320E Eight-Core Processor, 3211.59 MHz, 15-02-00
cpu0: 64KB 64b/line 2-way I-cache, 16KB 64b/line 4-way D-cache, 2MB 64b/line 16-way L2 cache, 8MB 64b/line 64-way L3 cache
cpu0: ITLB 48 4KB entries fully associative, 24 4MB entries fully associative
cpu0: DTLB 64 4KB entries fully associative, 64 4MB entries fully associative
cpu0: smt 0, core 0, package 0
pvbus0 at mainbus0: OpenBSD
pvclock0 at pvbus0
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "OpenBSD VMM Host" rev 0x00
virtio0 at pci0 dev 1 function 0 "Qumranet Virtio RNG" rev 0x00
viornd0 at virtio0
virtio0: irq 3
virtio1 at pci0 dev 2 function 0 "Qumranet Virtio Network" rev 0x00
vio0 at virtio1: address fe:e1:bb:d1:a9:7b
virtio1: irq 5
virtio2 at pci0 dev 3 function 0 "Qumranet Virtio Storage" rev 0x00
vioblk0 at virtio2
scsibus1 at vioblk0: 1 targets
sd0 at scsibus1 targ 0 lun 0: <VirtIO, Block Device, >
sd0: 51200MB, 512 bytes/sector, 104857600 sectors
virtio2: irq 6
virtio3 at pci0 dev 4 function 0 "OpenBSD VMM Control" rev 0x00
vmmci0 at virtio3
virtio3: irq 7
isa0 at mainbus0
isadma0 at isa0
com0 at isa0 port 0x3f8/8 irq 4: ns8250, no fifo
com0: console
vscsi0 at root
scsibus2 at vscsi0: 256 targets
softraid0 at root
scsibus3 at softraid0: 256 targets
root on sd0a (6dc570f70e2c7991.a) swap on sd0b dump on sd0b
Automatic boot in progress: starting file system checks.
/dev/sd0a (6dc570f70e2c7991.a): file system is clean; not checking
/dev/sd0m (6dc570f70e2c7991.m): file system is clean; not checking
/dev/sd0d (6dc570f70e2c7991.d): file system is clean; not checking
/dev/sd0f (6dc570f70e2c7991.f): file system is clean; not checking
/dev/sd0g (6dc570f70e2c7991.g): file system is clean; not checking
/dev/sd0h (6dc570f70e2c7991.h): file system is clean; not checking
/dev/sd0j (6dc570f70e2c7991.j): file system is clean; not checking
/dev/sd0i (6dc570f70e2c7991.i): file system is clean; not checking
/dev/sd0e (6dc570f70e2c7991.e): file system is clean; not checking
/dev/sd0k (6dc570f70e2c7991.k): file system is clean; not checking
/dev/sd0l (6dc570f70e2c7991.l): file system is clean; not checking
pf enabled
kern.seminfo.semmni: 10 -> 60
kern.seminfo.semmns: 60 -> 1024
starting network
reordering libraries: done.
starting early daemons: syslogd pflogd nsd ntpd.
starting RPC daemons:.
savecore: no core dump
checking quotas: done.
clearing /tmp
kern.securelevel: 0 -> 1
creating runtime link editor directory cache.
preserving editor files.
starting network daemons: sshd smtpd.
starting local daemons: cron.
Thu Feb 18 12:25:45 CET 2021

It stops at the time display… and the session login screen will never come up!

No, it’s not due to a corruption during the copy/synchronisation. Tests based on sha256 checksum were done before and after the copy, such as:

⇒ on Linux:

$ cat vm-test.qcow2.sha256
73054a89bb2e0b13d78e8cb446424baa01f7761099d8681a59137655b28c979c  vm-test.qcow2

⇒ then, on OpenBSD:

$ sha256 vm-test.qcow2                                                                                                                                                                    
SHA256 (vm-test.qcow2) = 73054a89bb2e0b13d78e8cb446424baa01f7761099d8681a59137655b28c979c

$ sha256 -C vm-test.qcow2.sha256 vm-test.qcow2
(SHA256) vm-test.qcow2: OK

What to do?!

On your OS source, where the VM has been created, connect you on the VM, and make the two following necessary modifications:



The /etc/boot.conf/ file config was not created. It must contain at least:

set tty com0

By default, the connection rate is 9200 baups.

Since the future host is OpenBSD, write:

stty com0 115200
set tty com0

So, we configure to use secure tty at 115200 baups.


The second modification is to set the terminal session tty00.

You need to change the line matching tty00 into the /etc/ttys file:

tty00   "/usr/libexec/getty std.115200" vt220    on secure


When the VM is copied on OpenBSD, you will have the login screen.