install_msg() {
    cat << __EOF__
===> IMPORTANT NOTICES:

In order to complete the installation, and enable Xen,
at the very least you must:
1. Edit your GRUB2 config files as specified at
    https://wiki.archlinux.org/index.php/Xen#Bootloader_Configuration
2. Issue the following commands to allow you to create and start VMs:
    systemctl enable xenstored.service
    systemctl enable xenconsoled.service
3. If you want some domains to automatically start up/shutdown, run the following:
    systemctl enable xendomains.service
4. xen 4.4 no longer includes the xend daemon or the xm binary

For more information refer to the Wiki:
    https://wiki.archlinux.org/index.php/Xen

__EOF__

}

upgrade_msg() {
    cat << __EOF__

Note: If you are upgrading from one of the previous 4.2 xen builds, and are having issues
      with graphics card passthrough, the default device model used has changed and the 
      newer model can sometimes have issues. To resolve, add (or change ) the following
      line into your domain config file:
         device_model_version = "qemu-xen-traditional"

      Also remember to rebuild your grub configuration if upgrading from a non-xen 4.4.1
           install.

      xen 4.4 no longer includes the xend daemon or the xm toolset by default, however
      this build does enable it.

      This install is now using a new version of the 09_xen file, used when generating
      a new grub.cfg file. The new version inherits the default linux kernel command
      line settings; to use the old method, uncomment the 'XEN_LINUX_CMDLINE_OVERRIDE'
      option in /etc/xen/grub.conf and change the '0' to '1'
__EOF__

}

post_install() {
    install_msg
    upgrade_msg
}

post_upgrade() {
    upgrade_msg
}

pre_remove() {
   systemctl stop xendomains.service
   systemctl stop xenconsoled.service
   systemctl stop xenstored.service

   systemctl disable xendomains.service
   systemctl disable xenconsoled.service
   systemctl disable xenstored.service
}

post_remove() {
    cat << __EOF__
===> IMPORTANT NOTICE:

In order to finish removing Xen, you will need to modify
your bootloader configuration files to load your Linux
kernel instead of Xen kernel.
__EOF__
}