A live image of SmartOS from Joyent with KVM was released today together with the source for the whole illumos KVM implementation. Much effort have been put into this by the Joyent team and the illumos community is blessed to have such great contributors. This is the first major feature that stands out from OpenSolaris/Solaris 11 Express.
This does not only makes illumos capable of running various fully virtualized guests, it also provides several other unique features for the guest compared to other virtualization hosts. First the security is better than vanilla KVM since there is a specific zone brand for KVM instances that also isolates it inside a zone even if a bug is exploited in KVM. Add to that the fully virtualized network stack with QOS that crossbow provides, all the features of ZFS (with bandwidth throttling in SmartOS) and DTrace!
This will bring most of the features of natives zones on illumos to a variety of other guest operating systems running under KVM and all common operating systems are already working including Windows, FreeBSD and Linux.
Have a look at Bryans slides from the presentation at KVM summit 2011, especially those with visualized DTrace statistics from KVM instances! There are also some screenshots of various guests running under KVM.
SmartOS (Live ISO image)
KVM on illumos
Talks I have given
5 months ago