[Install VirtualBox]
$ sudo pacman -S virtualbox
[Install VirtualBox Host Module on Arch Linux]
$ sudo pacman -S virtualbox-host-modules-arch
After successfully installation of virtualbox & virtualbox host module, enter the following command to add the VirtualBox module to the kernel
[Load VirtualBox module to the kernel]
$ sudo modprobe vboxdrv
Arch Linux LTS
On linux-lts instead of installing ~~ virtualbox-host-modules-arch~~ install virtualbox-host-dkms
$ sudo pacman -S virtualbox-host-dkms
Make sure to have linux-lts-headers installed.