Hi Chris,

I use the following command to get a USB device on VM:
--8<---------------cut here---------------start------------->8---
qemu-system-x86_64 \
     -daemonize \
     -m 4096 \
     -smp 2 \
     -enable-kvm \
     -hda /srv/virt/vm.qcow2 \
     -smb /srv/share \
     -M q35 \
     -usb \
     -device usb-host,hostbus=2,hostaddr=4 \
     -net 'user,hostfwd=tcp::3389-:3389,hostfwd=tcp::445-:445' \
     -net nic
--8<---------------cut here---------------end--------------->8---

I'm not sure I could help you with spotting the mistake though, because
I got this command almost randomly trying different flags and
suggestions on the internet :-)