(If you are searching the latest Windows drivers, go [here])
Most Linux distros already have KVM kernel modules and userspace tools available through their packaging systems. This is the easiest and recommended way of using KVM.
If you want to use the latest version of KVM kernel modules and supporting userspace, you can download the latest version from http://sourceforge.net/project/showfiles.php?group_id=180599.
For the userspace components, you will find both qemu-kvm-<version> and kvm-<version> there. qemu-kvm is the stable branch of kvm, it's based off of qemu's point releases with the kvm extras on top; kvm-NN releases are so called development releases.
You can consult the ChangeLog page on this wiki.
If you use a kernel from http://www.kernel.org or one provided from your distribution and do not use the modules provided by kvm releases:
- your kernel has to be 2.6.25 or newer to run the kvm 76 userspace (or any newer release)
- the modules provided by Linux 2.6.22 or later require kvm-22 or any later version. Some features are available only with newer kernels or userspace. It is recommended to use the latest available version.
- the modules provided by Linux 2.6.21 require kvm-17. If you use the external module, use the latest available version.
- the modules provided by Linux 2.6.20 require kvm-12. If you use the external module, use the latest available version.
Refer to choose the right kvm & kernel version for more information.