Re: Choice is good
Xen never got upstreamed into the Linux kernel because it’s bloated. It has it’s own memory management, scheduler, IPC model, and so forth.
It turns out that what starts as “a minimal hypervisor” very quickly becomes an entire Kernel of its own. There are other projects that seem to suffer the same fate (Grub and BusyBox spring to mind).
KVM solves this problem by just treating a VM as a Linux process with a funny ABI.
Sometimes the choice is just wrong, unfortunately. Maybe there is something useful in here, but I doubt there’s anything KVM couldn’t already do...