Patent attributes
A system, method and computer program product for optimizing handling of guest code in a Virtual Machine include code for identifying, in the guest code, a predetermined pattern that includes privileged but unsafe instructions and an instruction that raises an exception; code for executing the guest code in a native mode; code for, upon encountering the instruction that raise the exception, transferring control to a Virtual Machine Monitor; code for emulating the pattern in the Virtual Machine Monitor; and code for rolling back the effects of privileged but unsafe instructions and any intervening instructions to ensure correct Virtual Machine Monitor context. The pattern can include, for example, a privileged but unsafe instruction, followed by safe instructions, followed by an exception raising instruction, followed by safe instructions, followed by a privileged but unsafe instruction. Optionally, the most frequently occurring patterns can be placed in a cache, for use by the Virtual Machine Monitor to verify their presence in the guest code.
