Testing networking without physical NICs - virtual adapters?

I’m running Qubes as a nested domU, but I can’t test the network stack as I have no available devices. I’ve tried both ioemu and vif types in the cfg file to no avail :

  • passthrough-ing emulated adapters (type=ioemu) to sys-net won’t work, I get PCI resets.
    I’ve tried different (but not all yet) models : e1000, virtio-net-pci, virtio-net-pci-non-transitional, virtio-net-pci-transitional. Are some known to work ?

  • by Qubes design, the PV adapters (type=vif) are blocked from loading via (at least) dracut. I’ve tried to modprobe xen_netback to no avail (in modules.d/ or after boot)

So I wanted to create a totally virtual stack.
How would I do that on Qubes ? Is there a known method for testing that ?