VMware has also had a patent on live VM cloning (called it VMfork) for quite a few years now. I worked on the team that built related features. Feature itself was in the desktop product. https://blogs.vmware.com/euc/2016/02/horizon-7-view-instant-...

Live migration had some very cool demos. They would have an intensive workload such as a game playing and cause a crash and the VM would resume with 0 buffering.