FetchBench: Systematic Identification and Characterization of Proprietary Prefetchers
Till Schlüter, Amit Choudhari, Lorenz Hetterich, Leon Trampert, Hamed Nemati, Ahmad Faqih Ibrahim, Michael Schwarz, Christian Rossow, Nils Ole Tippenhauer
Abstract
Prefetchers speculatively fetch memory using predictions on future memory use by applications. Different CPUs may use different prefetcher types, and two implementations of the same prefetcher can differ in details of their characteristics, leading to distinct runtime behavior. For a few implementations, security researchers showed through manual analysis how to exploit specific prefetchers to leak data. Identifying such vulnerabilities required tedious reverse-engineering, as prefetcher implementations are proprietary and undocumented. So far, no systematic study of prefetchers in common CPUs is available, preventing further security assessment.