I believe only Virtuozzo. I've heard nothing about KVM on KnownHost, but don't quote me on that. Can I ask why you need or prefer KVM?
Well we'll see what an official from KnownHost has to say, but I'm fairly sure I recall they did offer KVM.
I'm actually helping someone else find a new provider, they're using WireTree, and the service is not living up to their expectations. Notably, they're experiencing an issue I know another site had with them.
I recommend to them KnownHost having experienced their support myself (very professional, easy to work with, and friendly) and also I've helped migrate a few people here.
I would assume KVM so they can update and manage their own kernel.