G-QED: Generalized QED Pre-silicon Verification beyond Non-Interfering Hardware Accelerators

Saranyu Chattopadhyay, Keerthikumara Devarajegowda, Bihan Zhao, Florian Lonsing, Brandon A. D'Agostino, Ioanna Vavelidou, Vijay Deep Bhatt, Sebastian Prebeck, Wolfgang Ecker, Caroline Trippel, Clark W. Barrett, Subhasish Mitra

Abstract: Hardware accelerators (HAs) underpin high-performance and energy-efficient digital systems. Correctness of these systems thus depends on the correctness of constituent HAs. Self-consistency-based pre-silicon verification techniques, like A-QED (Accelerator Quick Error Detection), provide a quick and provably thorough HA verification framework that does not require extensive design-specific properties or a full functional specification. However, A-QED is limited to verifying HAs which are non-interfering – i.e., they produce the same result for a given input independent of its context within a sequence of inputs. We present a new technique called G-QED (Generalized QED) which goes beyond non-interfering HAs while retaining A-QED’s benefits. Our extensive results as well as a detailed industrial case study show that: G-QED is highly thorough in detecting critical bugs in well-verified designs that otherwise escape traditional verification flows while simultaneously improving verification productivity 18-fold (from 370 person days to 21 person days). These results are backed by theoretical guarantees of soundness and completeness.