<domain type='kvm'>
  <os>
    <type>hvm</type>
    <boot dev='hd'/>
  </os>
  <devices>
    <interface type='network'>
      <source network='default'/>
    </interface>
    <serial type='null'>
      <target port='0'/>
    </serial>
    <graphics type='vnc' autoport='yes' listen='127.0.0.1'>
      <listen type='address' address='127.0.0.1'/>
    </graphics>
    <video/>
  </devices>
</domain>

<domain type='kvm'>
  <os>
    <type>hvm</type>
    <boot dev='hd'/>
  </os>
  <devices>
    <interface type='network'>
      <source network='default'/>
    </interface>
    <serial type='pty'>
      <source path='/dev/pts/3'/>
      <target port='0'/>
    </serial>
    <graphics type='vnc' autoport='yes' listen='127.0.0.1'>
      <listen type='address' address='127.0.0.1'/>
    </graphics>
    <video/>
  </devices>
</domain>

Make serial available through "virsh console"
Make serial available through "virsh console"

By default. --log-console-output changes this.
