1. A computer program product for handling a hierarchical cache structure, said computer program product comprising: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: initiating requests by a real indexed cache at one level of a hierarchical cache structure to a real indexed cache at another level of the hierarchical cache structure; initiating requests by a virtually indexed cache to said real indexed cache at the one level; and initiating other requests by said virtually indexed cache to said real indexed cache at the one level and to said real indexed cache at the another level.