Principles for enabling power management techniques for virtual machines. In a virtual machine environment, a physical computer system may maintain management facilities to direct and control one or more virtual machines executing thereon. In some techniques described herein, the management facilities may be adapted to place a virtual processor in an idle state in response to commands from a guest operating system. One or more signaling mechanisms may be supported such that the guest operating system will command the management facilities to place virtual processors in the idle state.