1. A method of performing a context switch from a first virtual machine to a second virtual machine, the method comprising: in a hypervisor, causing a plurality of instructions in a context switch routine to be executed by a processing unit to perform a context switch from an outgoing context associated with the first virtual machine to an incoming context associated with the second virtual machine, wherein the plurality of instructions includes a plurality of secure clear instructions defined in an instruction set architecture for the processing unit, wherein each secure clear instruction targets at least one hardware component that stores an architected state of the processing unit; in security logic disposed in the processing unit, and in response to the processing unit receiving at least one secure clear instruction among the plurality of secure clear instructions, clearing architected state information from each of a plurality of hardware components in the processing unit, wherein the plurality of hardware components includes at least one cache, at least one cache directory, at least one execution unit pipeline, at least one register file, and at least one special purpose register; and in the security logic, and in response to the processing unit receiving at least one secure clear instruction among the plurality of secure clear instructions and associated with program code having a hypervisor privilege, restricting virtual machine privilege access for each entry in an address translation data structure in the processing unit while retaining hypervisor privilege access to each entry in the address translation data structure indicating hypervisor privilege, wherein restricting virtual machine privilege access includes overwriting a first entry in the address translation data structure not indicating hypervisor privilege and removing an indication of virtual machine privilege from a second entry in the address translation data structure indicating both hypervisor and virtual machine privilege.