Xen was a standalone hypervisor that run under the Linux kernel. It was developed independently of Linux. Linux was a guest along for the ride. With KVM the

Xen was a standalone hypervisor that run under the Linux kernel. It was developed independently of Linux. Linux was a guest along for the ride. With KVM the hypervisor is over the Linux kernel and gets to use the facilities of the host kernel. Less code, less complexity. Why wouldn't Linux kernel hackers prefer KVM over Xen? They get full control (aka the ability to get crap fixed without hounding an external party) and get to reuse code they already have to write anyway. Preferring the KVM approach over Xen makes 100% sense to me in the long term for the Linux folks.