docs: UML: Mention telnetd for port channel

It is not obvious from the documentation that using the "port" channel
for the console requires telnetd to be installed (see port_connection()
in arch/um/drivers/port_user.c).  Mention this, and the fact that UML
will not boot until a client connects.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Link: https://lore.kernel.org/r/20220310124230.3069354-1-vincent.whitchurch@axis.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Vincent Whitchurch 2022-03-10 13:42:30 +01:00 committed by Jonathan Corbet
parent ffce1439fe
commit 89ee9301ac

View file

@ -664,7 +664,11 @@ one is input, the second one output.
* The fd channel - use file descriptor numbers for input/output. Example:
``con1=fd:0,fd:1.``
* The port channel - listen on TCP port number. Example: ``con1=port:4321``
* The port channel - start a telnet server on TCP port number. Example:
``con1=port:4321``. The host must have /usr/sbin/in.telnetd (usually part of
a telnetd package) and the port-helper from the UML utilities (see the
information for the xterm channel below). UML will not boot until a client
connects.
* The pty and pts channels - use system pty/pts.