Stephen John Smoogen wrote:
> The main issue seems to be cost of porting fixes and Xen itself to
> newer kernels. The fact that Xen did not get into mainstream kernel
> made the costs higher and higher. KVM got into mainstream kernel and
> thus has more eyes on it.
>
Another point... KVM only runs on new CPUs that have hardware
virtualization, this makes its job, and therefore implementation,
simpler. Xen runs on older processors but requires special drivers
("paravirtualization") for most guest environments, and is more complex
because of this.