1. A computer program product for requesting a configuration change of a topology of a plurality of first processors (CPUs) of a first configuration, the computer program product comprising a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: executing a perform topology function instruction for requesting a polarization change, the execution comprising: any one of initiating a change of the polarization of the processors of the guest configuration according to the requested polarization change or rejecting the polarization change request; and setting a condition code to a value indicating whether a polarization change is initiated or rejected, wherein the condition code of an instruction set architecture provides branching criterion for branch on condition instructions.