Method and apparatus to support virtualization with code patches

A processing system to support virtual machines, the processing system comprising:

• a processor;
• a machine-accessible medium responsive to the processor;
• and
• instructions in the machine accessible medium, wherein the instructions, when executed by the processing system, cause the processing system to perform operations comprising:
• automatically determining whether a guest instruction of a guest virtual machine (VM) of the processing system is to be patched for emulation, based at least in part on a list of instructions to be patched, the list of instructions stored in a template map that further stores code templates;
• retrieving a code template from the template map that corresponds to the guest instruction to be patched, the code template including an instruction template;
• generating an emulation routine for emulating the guest instruction, including modifying the code template based on characteristics of the guest instruction, storing the emulation routine in an emulation database, assigning a value to the emulation routine, and storing an association of the emulation routine with the value in an emulation map;
• executing an emulation patch for the guest instruction, the emulation patch including data to facilitate identification of the emulation routine for emulating the guest instruction;
• in response to execution of the emulation patch, transferring control from the guest VM to a virtual machine monitor (VMM) without saving contextual data that defines a system state for the guest VM;
• and
• using the data from the emulation patch to access the emulation map to find the emulation routine for the guest instruction.

An apparatus to support virtual machines, the apparatus comprising:

• a tangible machine accessible medium;
• and
• instructions in the tangible machine accessible medium, wherein the instructions, when executed by a processing system, cause the processing system to perform operations comprising:
• automatically determining whether a guest instruction of a guest virtual machine (VM) of the processing system is to be patched for emulation, based at least in part on a list of instructions to be patched, the list of instructions stored in a template map that further stores code templates;
• retrieving a code template from the template map that corresponds to the guest instruction to be patched, the code template including an instruction template;
• generating an emulation routine for emulating the guest instruction, including modifying the code template based on characteristics of the guest instruction, storing the emulation routine in an emulation database, assigning a value to the emulation routine, and storing an association of the emulation routine with the value in an emulation map;
• executing an emulation patch for the guest instruction, the emulation patch including data to facilitate identification of the emulation routine for emulating the guest instruction;
• in response to execution of the emulation patch, transferring control from the guest VM to a virtual machine monitor (VMM) without saving contextual data that defines a system state for the guest VM;
• and
• using the data to find an emulation routine for the guest instruction.