US Patent 10387686 Hardware based isolation for secure execution of virtual machines

Hardware based isolation for secure execution of virtual machines (VMs). At least one virtual machine is executed via operation of a hypervisor and an ultravisor. A first memory component is configured for access by the hypervisor and the ultravisor, and a second memory component is configured for access by the ultravisor and not by the hypervisor. A first mode of operation is operated, such that the virtual machine is executed using the hypervisor, wherein the first memory component is accessible to the virtual machine and the second memory component is not accessible to the virtual machine. A second mode of operation is operated, such that the virtual machine is executed using the ultravisor, wherein the first memory component and the second memory component are accessible to the virtual machine, thereby executing application code and operating system code using the second memory component without code changes.