A unified main TLB handles misses from the micro TLBs. This is a 512-entry, 4-way, set-associative structure. The main TLB supports all VMSAv8 block sizes, except 1GB. If a 1GB block is fetched, it is split into 512MB blocks and the appropriate block for the lookup stored.
Accesses to the main TLB take a variable number of cycles, based on:
Competing requests from each of the micro TLBs.
The TLB maintenance operations in flight.
The different page size mappings in use.