On 1/5/2026 1:46 AM, [email protected] wrote:
It has a number of limitations that makes it only usable for very specific use cases.
Sadly, it doesn't look like my use case of the guest agent integrated with libvirt is one of those :(.
1) It does not support to be used as kernel boot console.
While para-virtualized is almost always preferable over emulating physical hardware, how much of a benefit does a virtio-serial console give over an emulated isa serial port console? Generally there's not a lot of output on the console other than during the initial boot.
distinct set of device nodes for non-TTY-ports. But freebsd seems to allocate a tty for every port, so maybe all this is not necessary after
I haven't tested it myself, but it appears that freebsd can run a guest agent using a virtio-serial port as configured by libvirt.
A problem with the missing multiport feature is that libvirt has a rather fixed notion of how the ports are to be used.
Yah. I'd be perfectly happy using an emulated isa serial port for the guest agent, but there's no way to get libvirt to do that :(. There was talk on the mailing list years ago about extending it to support isa serial ports for the guest agent, but it seems it never went anywhere.
Given these limitations, I think having viocon disabled by default is the correct choice.
Thanks for the response and the detailed technical feedback. Fortunately OpenBSD shuts down cleanly using ACPI calls when the guest agent is not available, so not having it isn't overly critical...
