1. A method for providing multiple layers of virtualization in a computing environment, the method comprising: executing one or more instructions by a physical machine, wherein a first virtual machine is executed on the physical machine and a second virtual machine is executed on the first virtual machine in a nested execution environment; executing a first instruction loaded by the first virtual machine, in a first mode, according to information provided in a first control structure associated with the first virtual machine, wherein the first control structure comprises information about state or execution environment of the first virtual machine; executing a second instruction loaded by the second virtual machine, in the first mode, according to information provided in a second control structure associated with the second virtual machine, wherein the second control structure comprises information about state or execution environment of the second virtual machine; and in response to determining that a target instruction loaded by the second virtual machine is to be executed by the physical machine in a second mode as controlled by the first virtual machine, creating a secondary control structure, wherein the secondary control structure is implemented based on information in both the first control structure and the second control structure to allow the physical machine execute the target instruction according to execution environment information for the second virtual machine and state information for the first virtual machine in the second mode.