QEMU Guest Agent (qemu-ga) is a daemon intended to be run within
virtual machines. It allows the hypervisor host to perform various
operations in the guest, such as:
- get information from the guest,
- set the guest's system time,
- read/write a file,
- sync and freeze the filesystems,
- suspend the guest,
- reconfigure guest local processors,
- set user's password.

Note that qemu-ga (QEMU Guest Agent) is also part of the standard QEMU
installation. This package is intended for guests only, so that you
do not have to install the full qemu package just to get qemu-ga.
In general, do not install both qemu-guest-agent and qemu packages at
the same time on the same machine.

Use rc.qemu-ga to launch the daemon at boot and to stop it at shutdown.
You will need to perform host side setup too, to take the advantage of
qemu-ga.
