Editing Building external kernel modules

This article describes how to build an kernel module which is not included into the stock Virtuozzo kernel.
(This article applies to Virtuozzo 7.)

== Building a kernel module (*.ko) ==

Here is an example how to build "via-rhine" kernel module which is in the Virtuozzo kernel source tree, but not enabled in kernel config by default.

 // You need to install some dev packages in advance (the list here may be incomplete).
 '''# yum install rpm-build gcc xmlto asciidoc hmaccalc python-devel newt-devel pesign'''

 // If you are going to build a kernel module against some kernel, you need kernel headers for that kernel.
 // Assume you want to build a kernel module against currently running kernel.
 '''# yum install vzkernel-devel.x86_64'''

 // Get sources of the module you'd like to build,
 // in this particular example the easiest way i believe is just to download the kernel src.rpm.
 '''# cd /tmp'''
 '''# wget https://download.openvz.org/virtuozzo/factory/source/SRPMS/v/vzkernel-3.10.0-327.3.1.vz7.10.10.src.rpm'''
 '''# rpm -ihv vzkernel-3.10.0-327.3.1.vz7.10.10.src.rpm'''
 
 // "Prepare" source tree, it's not enough just to take the archive stored in it,
 // you need to apply additional patch(es), rpmbuild does this for us.
 '''# rpmbuild -bp /root/rpmbuild/SPECS/kernel.spec --nodeps'''

 // Go to the module source directory.
 '''# cd /root/rpmbuild/BUILD/kernel-3.10.0-327.3.1.el7/linux-3.10.0-327.3.1.vz7.10.10/drivers/net/ethernet/via'''

 // Edit the Makefile so you get the required kernel module compiled.
 // In this particular example the via-rhine compiles in-kernel by default, so we need to force it to be built as a module.
 '''# sed -ie 's/$(CONFIG_VIA_RHINE)/m/' Makefile'''

 // Build and install the module.
 '''# make -C /lib/modules/`uname -r`/build M=$PWD'''
 '''# make -C /lib/modules/`uname -r`/build M=$PWD modules_install'''

 // Check the module has been really copied and load it.
 '''# find /lib/modules -name \*rhine\*'''
 /lib/modules/3.10.0-327.3.1.vz7.10.10/extra/via-rhine.ko
 
 '''# modprobe via-rhine'''
 '''# lsmod |grep rhine'''
 via_rhine 32501 0
 mii 13934 1 via_rhine

Here you are!

{{Note|Your case is a bit more complicated? Read [https://www.kernel.org/doc/Documentation/kbuild/modules.txt Building External Modules]}}

== Building a kernel module using Dynamic Kernel Module Support (DKMS) ==
TBD, you are welcome to put the description here. :)

== Building a kernel module rpm package (kmod) ==
TBD, you are welcome to put the description here. :)