Require sys-usb to start before starting qubes with persistently attached USB devices

[tzwcfq]

The problem you're addressing (if any)

I've stumbled upon the same problem as described here:
https://forum.qubes-os.org/t/persistent-usb-device-prevents-sys-net-from-starting-on-boot/4446
I need to have qube that start automatically on boot and have USB device attached from sys-usb.
When I check "Start qube automatically on boot" tick in Qubes Settings for my qube then my qube try to start on boot but it fails because the sys-usb is not yet started and the persistently attached USB device is not found.

The solution you'd like

Make it the same way as for net qubes:
Check at boot time if the qube is flagged as "Start qube automatically on boot" and has persistently attached USB device then wait until sys-usb is started before starting the qube.

The value to a user, and who that user might be

User won't have to manually start qubes with persistently attached USB devices after every boot.

[tzwcfq]

For now I had to solve it like this:
Run these commands in dom0:

sudo mkdir /etc/libvirt/hooks/
sudo nano /etc/libvirt/hooks/libxl

Paste this script inside:

#!/bin/bash
guest_name="$1"
libvirt_operation="$2"
timeout=60
guest_to_start_on_usb=myvmname
guest_usb_dev_name="my-usb-device-name-or-id"

if [ "$guest_name" = "sys-usb" ] && [ "$libvirt_operation" = "started" ]; then
    (
        exec 0</dev/null
        exec 1>/dev/null
        exec 2>/dev/null
        for i in $(seq 1 $timeout);
        do
            if qvm-ls --running $guest_name | grep -q Running; then
                if qvm-usb list -q $guest_to_start_on_usb | grep -q $guest_usb_dev_name; then
                    qvm-start --skip-if-running -q $guest_to_start_on_usb
                    break
                fi
            fi
            sleep 1
        done
    ) & disown
fi

Then set execute permission:

sudo chmod +x /etc/libvirt/hooks/libxl

Reboot.