SlackBuildsOrg/system/virtualbox-kernel

This is the supplementary kernel driver for the VirtualBox
virtualisation environment.

To build the package for a kernel different from the running one,
start the script setting the KERNEL variable as in
  KERNEL=2.6.38.8 ./virtualbox-kernel.SlackBuild

Note that if you have built virtualbox with HARDENING=no, then you
have to do the same for virtualbox-kernel.

If you want to build a kernel module for an other virtualbox version
you can use the included "virtualbox-kernel-mksrctarball.sh" which will
generate the needed source package for you. You will need to have
the coresponding virtualbox-ose version already installed.