SmartOS includes the KVM kernel virtual machine manager, originally ported from Linux. KVM supports most Intel and AMD processors for running hardware based virtual machines.
In general, Bhyve is preferred, but KVM has wider compatibility with operating systems and is somewhat easier to use when building HVM images that can run in either KVM or Bhyve.
SmartOS: Virtualization with ZFS and KVM¶
Article from LWN.net, an excellent deep dive for Linux users by Koen Vervloesem concludes that: "For Linux users who were interested in these Solaris technologies but wouldn't want to lose their favorite hypervisor KVM, SmartOS and OpenIndiana are now able offer the best of both worlds."