# Core VM execution engine


def prepare_vm():
    """
    Prepares VM environment.
    """
    pass


def start_vm(vm):
    """
    Starts VM execution.
    """
    pass


def stop_vm(vm):
    """
    Stop VM execution.
    """
    pass


def exec_vm(vm):
    """
    Executes command in VM.
    """
    pass
