Esteemed maintainer,

First and foremost, thank you very much for your hard work: passt is awesome and allows one to run more useful user-space VM-s.

I have encountered 2 particular issues with the usage of passt with Debian, and wanted to bring them to your attention as I think you are probably the best person to deal with this. I do plan on sending a report to the Debian team afterwards.

For reference, I tested these on Debian Testing Daily Image dated 28 January 2025, with updates, and the version of passt available with it is passt 0.0~git20250121.4f2c8e7-1

  1. Passt's default Apparmor config needs to allow writes to $XDG_RUNTIME_DIR (which is at /run/user/$UID). Currently it doesn't. Virt-manager, at least, tries to create the necessary sockets in the directory but apparmor prevents that from happening (and the error message Virt-Manager gives isn't helpful either: the first time around I falsely believed it was a segfault or similar issue). I managed to get passt​ working past this flaw (pun intended) by manually disabling apparmor for the binary. Passt works just fine in Fedora 41 as it doesn't use Apparmor but uses SELinux, and thus the configs don't affect it.
  2. This second issue is perhaps a bit more Debian-specific, but I am going to mention it so that you might drop some hints for the Debian maintainers to debug this: Once Apparmor is disabled and a VM is configured to work with passt, DNS resolution doesn't work in the VM (IP Addresses work just fine) i.e. ping fsf.org​ doesn't work but `ping 209.51.188.174` does. The hypervisor details follow:
    $ virsh version # on Debian Testing a.k.a. 'Trixie'
    Compiled against library: libvirt 11.0.0
    Using library: libvirt 11.0.0
    Using API: QEMU 11.0.0
    Running hypervisor: QEMU 9.2.0
    This, again, isn't an issue with Fedora 41, where everything just works. The hypervisor details for Fedora 41 are:
    $ virsh version # on Fedora 41
    Compiled against library: libvirt 10.6.0
    Using library: libvirt 10.6.0
    Using API: QEMU 10.6.0
    Running hypervisor: QEMU 9.1.2

Again, I will be making a report to the Debian maintainers, should they wish to chime in regarding Apparmor configs or the DNS resolution issue.

Thank you once again for this awesome tool.