In current developer builds of VirtualBox, KVM support appears for the first time. The function is experimental and only available through manual source builds.

Nested Virtualization lets you run a Hypervisor inside of a Virtual Machine. Windows 10 introduced Nested Virtualization. Whether you need it or not, here is some information that might interest you.

Two years ago, we visited the subject of free desktop virtualization hypervisors. At the time, the two preferred free solutions were Sun's xVM VirtualBox and and VMware Server 2.0. Things have changed ...