This week we've seen
Xen and
KVM updates for the Linux 2.6.23 kernel and now LGuest was merged into the Linux kernel yesterday. LGuest is a simple hypervisor for Linux on Linux that doesn't require AMD or Intel virtualization technology. This 5,000 line hypervisor does take about a 30% performance hit but the performance will likely improve with time. With this minimal hypervisor you just "modprobe and go". More information on LGuest is available in the
kernel git commit and at
Kernel Trap.