I am trying to get USB redirection working with libvirt, but I am
hitting a snag. [...] I am now getting a new error:
Error setting USB device node ACL: 'Error PoliciKit error:
GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Action
org.spice-space.lowlevelusbaccess is not registered' (0)
It fails no matter which client I use (virt-manager, virt-viewer,
gnome-boxes). Is there a way to fix that permission so I can redirect my
USB devices?
I had the same problem some time ago. It can be fixed by extending
polkit-service-type with spice-gtk, i.e.
(operating-system
...
(services
...
(simple-service 'spice-polkit polkit-service-type (list spice-gtk))))