On Fri, May 10, 2024 at 11:01:06AM GMT, Christian Haumesser via Users wrote: > Hello, > > I have an OpenBSD 7.5 guest running on Debian bookworm with libvirt > (9.0) and qemu (7.2). > > I'd like to use the qemu guest agent in this guest, but I can't > seem to figure out how to craft the libvirt xml to expose the > serial port in a way that OpenBSD and libvirt can use it together > (or if it’s even possible). > > Per the libvirt docs > <https://wiki.libvirt.org/Qemu_guest_agent.html>, I’m currently > using: > > > <channel type='unix'> > > <source mode='bind'/> > > <target type='virtio' name='org.qemu.guest_agent.0'/> > > </channel> > > But OpenBSD doesn’t directly support the virtio console driver. > Consistent with this 2020 thread > <https://undeadly.org/cgi?action=article;sid=20200514073852> from > the OpenBSD ports making list, I see the following message in my > guest’s dmesg output: > > > virtio5 at pci0 dev 10 function 0 "Qumranet Virtio Console" rev 0x00 > > virtio5: no matching child driver; not configured > > Thanks to this libvir-list thread > <https://listman.redhat.com/archives/libvir-list/2015-October/120250.html> > from 2015, I’ve realized that I can manually expose an ISA serial > console that will allow me to connect to the guest agent using > native qemu tooling; but there doesn’t seem to be a way to create a > channel that libvirt can communicate over without virtio console > support in the guest. The thread discusses a couple of approaches > to resolving this issue with code changes, but it seems like the > discussion stalled out before anything happened. > > Am I missing something or is it still impossible?
I just tried on both FreeBSD 14.0 and OpenBSD 7.5. It works out of the box on the former, doesn't seem to work at all on the latter. What I find weird is that a driver seems to exist already: https://man.openbsd.org/viocon.4 A few limitations are listed, and I'm not sure whether any of those are relevant for this scenario. But I've also tried to set up a virtio-console (rather than virtio-serial) and I couldn't get that to work either, despite it supposedly being the whole purpose of the driver. I'm not very familiar with OpenBSD though, so it's entirely possible that I've simply made a mistake somewhere :) In any case, my opinion is that the solution isn't changing libvirt so that exposing multiple isa-serial devices becomes possible, but rather enhancing the OpenBSD driver so that it supports virtio-serial channels, the same way that other operating systems can. The FreeBSD driver can likely be used as inspiration. -- Andrea Bolognani / Red Hat / Virtualization _______________________________________________ Users mailing list -- users@lists.libvirt.org To unsubscribe send an email to users-le...@lists.libvirt.org
