Technique for processing lookup requests, in a cache storage able to store data items of multiple supported types, in the presence of a pending invalidation request

Abstract

Each entry in a cache has type information associated therewith to indicate a type associated with the data item stored in that entry. Lookup circuitry responds to a given lookup request by performing a lookup procedure to determine whether a hit is detected, by default performing the lookup procedure for a given subset of multiple supported types. Invalidation circuitry processes an invalidation request specifying invalidation parameters used to determine an invalidation address range and invalidation type information, in order to invalidate any data items held in the cache storage that are both associated with the invalidation address range and have an associated type that is indicated by the invalidation type information. Whilst processing of the invalidation request is yet to be completed, filtering circuitry performs a filtering operation for a received lookup request, in order to determine, in dependence on an address indication provided by the received lookup request and one or more of the invalidation parameters of the invalidation request, intersection indication data identifying, for a given type in the given subset, whether an intersection is considered to exist between any entries that would be accessed during performance of the lookup procedure for the received lookup request for the given type and any entries that will be invalidated during processing of the invalidation request, and operation of the lookup circuitry is controlled in dependence on the intersection indication data.