But if the cache is in a different set, and each security partition has exclusive access to particular slices, you can't get contention because access is forbid

But if the cache is in a different set, and each security partition has exclusive access to particular slices, you can't get contention because access is forbidden. Also, time slicing might not be sufficient due to the queues in each LLC slice. If you can fill the queue the bus access will retry I guess.