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195 | How to use USB devices |
This page is part of device handling in qubes.
If you are looking to handle USB storage devices (thumbdrives or USB-drives), please have a look at the block device page.
Note: Attaching USB devices to qubes requires a USB qube.
Important security warning: USB passthrough comes with many security implications. Please make sure you carefully read and understand the security considerations. Whenever possible, attach a block device instead.
Examples of valid cases for USB-passthrough:
- microcontroller programming
- external audio devices
- optical drives for recording
(If you are thinking to use a two-factor-authentication device, there is an app for that. But it has some issues.)
Attaching and detaching a USB device
With Qubes device manager
Click the device-manager-icon: 
A list of available devices appears.
USB-devices have a USB-icon to their right: 
Hover on one device to display a list of qubes you may attach it to.
Click one of those. The USB device will be attached to it. You're done.
After you finished using the USB-device, you can detach it the same way by clicking on the Devices Widget.
You will see an entry in bold for your device such as sys-usb:2-5 - 058f_USB_2.0_Camera.
Hover on the attached device to display a list of running qubes
The one to which your device is connected will have an eject button 
next to it.
Click that and your device will be detached.
With the command line tool
In dom0, you can use qvm-usb from the commandline to attach and detach devices.
Listing available USB devices:
[user@dom0 ~]$ qvm-usb
BACKEND:DEVID DESCRIPTION USED BY
sys-usb:2-4 04ca:300d 04ca_300d
sys-usb:2-5 058f:3822 058f_USB_2.0_Camera
sys-usb:2-1 03f0:0641 PixArt_HP_X1200_USB_Optical_Mouse
Attaching selected USB device:
[user@dom0 ~]$ qvm-usb attach work sys-usb:2-5
[user@dom0 ~]$ qvm-usb
BACKEND:DEVID DESCRIPTION USED BY
sys-usb:2-4 04ca:300d 04ca_300d
sys-usb:2-5 058f:3822 058f_USB_2.0_Camera work
sys-usb:2-1 03f0:0641 PixArt_Optical_Mouse
Now, you can use your USB device (camera in this case) in the work qube.
If you see the error ERROR: qubes-usb-proxy not installed in the qube instead, please refer to the Installation Section.
When you finish, detach the device.
[user@dom0 ~]$ qvm-usb detach work sys-usb:2-5
[user@dom0 ~]$ qvm-usb
BACKEND:DEVID DESCRIPTION USED BY
sys-usb:2-4 04ca:300d 04ca_300d
sys-usb:2-5 058f:3822 058f_USB_2.0_Camera
sys-usb:2-1 03f0:0641 PixArt_Optical_Mouse
Maintenance and customisation
Creating and using a USB qube
If you've selected to install a usb-qube during system installation, everything is already set up for you in sys-usb.
If you've later decided to create a usb-qube, please follow this guide.
Installation of qubes-usb-proxy
To use this feature, the qubes-usb-proxy package needs to be installed in the templates used for the USB qube and qubes you want to connect USB devices to.
This section exists for reference or in case something broke and you need to reinstall qubes-usb-proxy.
Under normal conditions, qubes-usb-proxy should already be installed and good to go.
If you receive this error: ERROR: qubes-usb-proxy not installed in the qube, you can install the qubes-usb-proxy with the package manager in the qube you want to attach the USB device to.
- Fedora:
sudo dnf install qubes-usb-proxy - Debian/Ubuntu:
sudo apt-get install qubes-usb-proxy
Using USB keyboards and other input devices
Warning: especially keyboards need to be accepted by default when using them to login! Please make sure you carefully read and understood the security considerations before continuing!
Mouse and keyboard setup are part of setting up a USB qube.
Finding the right USB controller
Some USB devices are not compatible with the USB pass-through method Qubes employs. In situations like these, you can try to pass through the entire USB controller to a qube as PCI device. However, with this approach you cannot attach single USB devices but have to attach the whole USB controller with whatever USB devices are connected to it.
You can find your controller and its BDF address using the method described below, using the command-line tools lsusb and readlink.
If you have multiple USB controllers, you must first figure out which PCI device is the right controller.
First, find out which USB bus the device is connected to (note that these steps need to be run from a terminal inside your USB qube):
lsusb
For example, I want to attach a broadband modem to the NetVM.
In the output of lsusb it may be listed as something like:
Bus 003 Device 003: ID 413c:818d Dell Computer Corp.
(In this case, the device isn't fully identified)
The device is connected to USB bus #3. Check which other devices are connected to the same bus, since all of them will be attached to the target qube.
To find the right controller, follow the usb bus:
readlink /sys/bus/usb/devices/usb3
This should output something like:
../../../devices/pci-0/pci0000:00/0000:00:1a.0/usb3
Now you see the path: the text between /pci0000:00/0000: and /usb3 i.e. 00:1a.0 is the BDF address. Strip the address and pass it to the qvm-pci tool to attach the controller to the target qube, like this:
qvm-pci attach --persistent personal dom0:00_1a.0
It is possible that on some system configurations the readlink method produces output which is different from the example above, For example, you might see output like this:
../../../devices/pci0000:00/0000:00:1c.0/0000:01:00.0/usb1
In this case, there is a PCI bridge, and the BDF address of the controller is the last item, 01:00.0
If the output format does not match this example, or you are unsure if it contains the correct BDF address, you can try finding the address using using the Qube Manager instead.
Identifying controllers using the Qube Manager
Using Qube Manager you can quickly determine the controllers on your system and their BDF addresses, but not which controller a particular device is attached to.
Open the Qube Manager, then right click on one of the qubes and open the settings. Go to the tab "Devices".
Here you should see your available devices along with their BDF addresses. Look for the lines containing "USB controller".
They should look something like: 01:00.0 USB controller: Name of manufacturer
The first part is the BDF address, in this example: 01:00.0
If, for example, you have 2 USB controllers in your system because you added one you should see 2 such lines and you can probably guess which controller is the one on the mainboard and which one you added. For example, if you have a mainboard with an Intel chipset, it is possible that all of the mainboard devices show as "Intel Corporation", while the added controller shows another manufacturer's name.
Now you should be able to tell which is the BDF address of the mainboard USB controller or the added USB controller.