Installing-Virtualbox-on-Acer-C720

Install-Vbox-Ace-C720.md

Please note:

Full credit and original source can be found at:
https://github.com/dnschneid/crouton/wiki/Build-kernel-headers-and-install-Virtualbox-%28x86%29/_edit

General info

This guide is tested on:
HP chromebook 14 (Celeron 2955U)
Acer c720 (i3-4005U)

However, it should work for any x86 chromebook. Just be sure you clone the right kernel source for your device.

For installing virtualbox we need a kernel headers package to compile the virtualbox modules. However there are no kernel headers available to install that work with the kernel of your chromebook. That is why we need to build our own. In the section below we explain how you can do that.

NOTE: If you are just interested in installing kernel headers and virtualbox you can go and read this README.md It is a ppa with most of the kernel versions and architectures for chromebooks. You can post any problems by creating a new issue on divx118/crouton-packages git

Getting the kernel source

There are two git repos kernel and kernel-next where the kernel sources can be found, but you have to know which branch you're on. Branches can be identified by chromeos-version where version is your kernel version.
NOTE: Mostly you will need the kernel repo.
On the HP chromebook 14 I have kernel 3.8.11 so I need the chromeos-3.8 branch in the kernel repo.

First we need some tools installed in our chroot. I did this on a precise with xfce chroot, but it should also work on others.

Note: All the shell commands on this page need to be done in the shell of your chroot if not specified otherwise.

$ sudo apt-get install git-core make kernel-package

Cloning the kernel branch chromeos-3.8 to our home folder.

$ cd ~
$ git clone https://chromium.googlesource.com/chromiumos/third_party/kernel -b chromeos-3.8

Before we start building we need to setup our kernel config. More info can be found on the chromium dev pages

First I had to run with -Werror, because I got one small problem when building some wifi module. This could be a problem with the gcc compiler I used.
Just use your favorite text editor and edit "chromeos/config/base.config" in the kernel dir.

$ cd kernel
$ vi chromeos/config/base.config

Search for CONFIG_ERROR_ON_WARNING=y and make it CONFIG_ERROR_ON_WARNING=n

Look at which flavor you need for your chromebook. We have x86_64 so we setup the config for chromeos-intel-pineview.
More info on which flavor to choose see the kernel config info site mentioned above.

$ ./chromeos/scripts/prepareconfig chromeos-intel-pineview
$ make oldconfig

Building kernel headers and kernel image

Now we can start building kernel_headers and kernel_image. Note that this will take some time.

$ make-kpkg --rootcmd fakeroot kernel_image kernel_headers

After it is finished without errors you should now see two *.deb files in the directory above kernel. If you followed this guide to the letter it should be your home dir.

$ ls -al ~ | grep .deb
-rw-r--r--  1 root    root    8340026 Dec 27 18:08 linux-headers-3.8.11_3.8.11-10.00.Custom_amd64.deb
-rw-r--r--  1 root    root    7656850 Dec 27 18:07 linux-image-3.8.11_3.8.11-10.00.Custom_amd64.deb

Installing kernel headers/image

Before we can install we need to umount /lib/modules which is bind mounted in enter-chroot.
We also need to disable module_locking for loading the vboxdrv kernel modules and actually load the modules.
Loading the modules can be done in rc.local. For disable module_locking we need to change the kernel flags. See Repack-kernel-to-Enable-VT_x-for-Virtualbox.
I also created a script change-kernel-flags to do this that can be found on divx118/crouton-packages.

Create the following /etc/rc.local or add this to your /etc/rc.local if you already have one.

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# umount bindmounts /lib/modules from enter-chroot
for m in `cat /proc/mounts | /usr/bin/cut -d ' ' -f2 | grep /lib/modules| grep -v "^/$" `; do
        umount "$m"
done
# try to load vboxdrv modules
if [ `find /lib/modules/"\`uname -r\`" -name vboxdrv.ko` ]; then
    # check if module_locking is disabled
    if ! grep -q "module_locking=0" /proc/cmdline; then
        exit 2
    fi
    modprobe vboxdrv
    modprobe vboxpci
    modprobe vboxnetadp
    modprobe vboxnetflt
fi

exit 0

Also be sure to change the execution bit

$ sudo chmod +x /etc/rc.local

You can now logout and login again in your chroot to see if the script rc.local works.
If all is well, everything in /lib/modules is umounted so we can install our two deb files.
You can check this with the following.

$ cat /proc/mounts | grep /lib/modules

Only if you build the kernel headers yourself install them by running dpkg

sudo dpkg -i linux-image-3.8.11_3.8.11-10.00.Custom_amd64.deb
sudo dpkg -i linux-headers-3.8.11_3.8.11-10.00.Custom_amd64.deb

Now you can download virtualbox and install it. After installing, logout of your chroot and log back in. Virtualbox drivers should now be loaded. You can check it by looking at lsmod or cat /proc/modules. Note: If you don't download virtualbox from the site, but install it from ubuntu repo with apt, then you will be missing the /etc/init.d/vboxdrv script.
Note: The vboxdrv will stay loaded when you log out of your chroot.
You can unload it before logging out with

$ sudo /etc/init.d/vboxdrv stop

Or in a chronos shell

$ sudo /sbin/rmmod vboxpci
$ sudo /sbin/rmmod vboxnetadp
$ sudo /sbin/rmmod vboxnetflt
$ sudo /sbin/rmmod vboxdrv