# LXC USB Passthrough

Passing through a USB device with LXC allows your LXC guest access to a physical USB device plugged into the host system.

<p class="callout info">The information on this page is written for a host running Proxmox but should be easy to adapt to any machine running LXC/LXD.</p>

#### Locate Bus/Device

```bash
root@vault:~# lsusb 
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 13d3:3273 IMC Networks 802.11 n/g/b Wireless LAN USB Mini-Card
Bus 001 Device 004: ID 10c4:8a2a Silicon Labs HubZ Smart Home Controller
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
```

#### Determine Device Major/Minor Numbers

```bash
root@vault:~# ls -l /dev/bus/usb/001/004 
crw-rw-r-- 1 root root 189, 3 Oct  3 17:17 /dev/bus/usb/001/004
```

From that you can see the major device number is `189` and the minor is `3`.

#### Provide LXC Access

In the configuration file you'd then add lines to allow the LXC guest access to that device and then also bind mount the devices from the host into the guest. In the example above since both devices share the same major number it is possible to use a shorthand notation of `189:*` to represent all minor numbers with major number `189`.

```diff
# /etc/pve/lxc/*.conf
+ lxc.cgroup.devices.allow: c 189:* rwm
+ lxc.mount.entry: /dev/bus/usb/001/020 dev/bus/usb/001/020 none bind,optional,create=file,mode=664
```

#### Allow `unprivileged` Containers Access

<p class="callout warn">incomplete</p>

#### Resources

[USB Passthrough to an LXC (Proxmox)](https://medium.com/@konpat/usb-passthrough-to-an-lxc-proxmox-15482674f11d)