wiki/gofurther/evdev.md

title	description	published	date	tags	editor	dateCreated
Share an input device with a guest using evdev		true	2024-05-15T19:20:21.209Z		markdown	2022-08-13T00:26:02.801Z

Share an input device

In this section, we'll explore how to share a locally attached input device with a guest virtual machine.

With evdev

As of libvirt version 7.4.0, the Linux evdev event interface can be used to share an input device physically attached to the host with a guest, in a low-latency manner.

Preparation

Before sharing an input device, follow these steps:

• List available input devices on your host system, excluding those containing if in their name, including those containing event in their name:

ls /dev/input/by-id/* | grep event | grep -v if

This command should output the names of eligible devices.

Example output:

/dev/input/by-id/usb-Corsair_CORSAIR_HARPOON_RGB_PRO_Gaming_Mouse_1902B02BAF5E04655DEB612AF5001C05-event-mouse
/dev/input/by-id/usb-Logitech_G513_RGB_MECHANICAL_GAMING_KEYBOARD_156930783132-event-kbd
/dev/input/by-id/usb-Logitech_USB_Keyboard-event-kbd
/dev/input/by-id/usb-Logitech_USB_Optical_Mouse-event-mouse

• Make sure that the correct one is selected by registering its inputs in your console:

cat /dev/input/by-id/usb-Logitech_G513_RGB_MECHANICAL_GAMING_KEYBOARD_156930783132-event-kbd

This step ensures you're working with the desired input device.

• Test the device by interacting with it on the host system. You should see gibberish characters displayed on your screen:

<EFBFBD><EFBFBD>c      $
<0A><>c<EFBFBD><63><EFBFBD>c<EFBFBD><63><EFBFBD>c<EFBFBD>$<24><>c<EFBFBD>$<24><>c׏<63><D78F>c׏<63><D78F>c                                             

Adding the input device to your virtual machine

• To share the input device with your virtual machine, add the following XML snippet to its domain definition (inside the section):

<input type='evdev'>
      <source dev='/dev/input/by-id/usb-Logitech_G513_RGB_MECHANICAL_GAMING_KEYBOARD_156930783132-event-kbd' grab='all' repeat='on'/>
</input>

Usage

Once the virtual machine is started, the input device will be captured by the guest system.

Press Left Ctrl + Right Ctrl simultaneously to switch your devices between the guest and the host. {.is-info}

Resources

• https://libvirt.org/formatdomain.html#input-devices

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