20.16.14. Consoles, Serial, Parallel, and Channel Devices

A character device provides a way to interact with the virtual machine. Paravirtualized consoles, serial ports, parallel ports and channels are all classed as character devices and so represented using the same syntax.

To specify the consols, channel and other devices configuration settings, use a management tool to make the following changes to the domain XML:

  ...
  <devices>
    <parallel type='pty'>
      <source path='/dev/pts/2'/>
      <target port='0'/>
    </parallel>
    <serial type='pty'>
      <source path='/dev/pts/3'/>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <source path='/dev/pts/4'/>
      <target port='0'/>
    </console>
    <channel type='unix'>
      <source mode='bind' path='/tmp/guestfwd'/>
      <target type='guestfwd' address='10.0.2.1' port='4600'/>
    </channel>
  </devices>
  ...

In each of these directives, the top-level element name (parallel, serial, console, channel) describes how the device is presented to the guest virtual machine. The guest virtual machine interface is configured by the target element. The interface presented to the host physical machine is given in the type attribute of the top-level element. The host physical machine interface is configured by the source element. The source element may contain an optional seclabel to override the way that labelling is done on the socket path. If this element is not present, the security label is inherited from the per-domain setting. Each character device element has an optional sub-element address which can tie the device to a particular controller or PCI slot.