Comment # 1 on bug 1042726 from Larry Finger

In the RPM build system that comes from Oracle, there is code that builds the
kernel modules. In 2008, long before I became maintainer, this capability was
removed. The changes file does not say why.

A few weeks ago, Tumbleweed stopped the automatic startup of VB services from
the SysV init.d scripts. To fix that problem, I have been adding the necessary
systemd service files. These are in the current version of both TW and Leap
42.2. If the kernel modules if not available, the current version of the
VirtualBox GUI says that you should run 'sudo /sbin/vboxconfig'. That file is
now part of the openSUSE package. It will install the necessary prerequisites,
perform the build, and install the modules.

I can think of 3 cases in which the kernel host modules would not be available:

Case 1: A new default kernel is shipped without the corresponding host kmp
modules. This situation should never occur; however, it still happens. The
vboxconfig script should handle that case. If it does not, then is a bug.

Case 2: A kernel in installed from other than the Update repo. The script above
will not be able to satisfy the build requirements. If loading the kernel-devel
package does not acquire the correct set of kernel modules for that kernel,
then the build will fail. Further testing is required to see if this case is
satisfied.

Case 3: A kernel that was not supplied by openSUSE is being used. This case
will never be handled automatically. The user will need to install the 
virtualbox-host-source package and run the commands:

cd /usr/src/kernel-modules/virtualbox/src
sudo make && sudo make install && sudo modprobe -av vboxnetflt vboxnetadp \
vboxpci

Do you have the latest version, and does /sbin/vboxconfig handle your problem?