TurboFuzz: FPGA Accelerated Hardware Fuzzing for Processor Agile Verification

Abstract

TurboFuzz is an end-to-end hardware-accelerated verification framework that leverages a single FPGA to integrate the entire Test Generation, Simulation, and Coverage Feedback loop for modern processors. This architecture eliminates high host-FPGA communication overhead, enhancing both execution efficiency and test quality through optimized scheduling and hybrid fuzzer integration. Experimental results demonstrate significant improvements, achieving up to 571x performance speedup in defect detection and 2.23x faster coverage convergence compared to software-based fuzzers.

Report

Key Highlights

• FPGA-Accelerated Framework: TurboFuzz is an end-to-end hardware solution for processor verification fuzzing, designed to overcome the performance limits of software-based simulation.
• Single-Chip Integration: The entire verification pipeline (Test Generation, Simulation, and Coverage Feedback) is implemented on a single FPGA, successfully eliminating the high communication overhead typically seen between host machines and accelerators.
• Performance Metrics: Achieves up to a 571x performance speedup when detecting real-world issues (bugs) compared to traditional methods.
• Coverage Efficiency: Enables up to 2.23x more coverage collection within the same time budget, accelerating coverage convergence for agile verification.

Technical Details

• Target Application: Agile verification of complex processor designs, specifically addressing the needs of modern Instruction Set Architectures (ISAs) like RISC-V.
• Bottleneck Resolution: Focuses on mitigating host-FPGA communication overhead, improving inefficient test pattern generation, and optimizing the multi-step verification process.
• Core Methodologies:
  • Optimized test case (seed) control flow.
  • Efficient inter-seed scheduling.
  • Integration of hybrid fuzzer techniques to enhance test quality.
  • Utilization of a feedback-driven generation mechanism specifically designed to accelerate coverage convergence.
• Debugging Capabilities: The framework is explicitly designed to maintain full visibility and debugging capabilities despite the high acceleration rate, utilizing only moderate area overhead on the FPGA.

Implications

• Accelerating RISC-V Verification: Given the increasing complexity and rapid iteration speed of RISC-V core designs, TurboFuzz offers a crucial tool to ensure design correctness faster and more efficiently than previous methods.
• Shifting Verification Paradigm: By successfully consolidating the entire fuzzing loop onto hardware, TurboFuzz validates the approach of using dedicated FPGA resources for complex, feedback-driven verification tasks, moving beyond simple instruction-level simulation.
• Reducing Time-to-Market: The dramatic speedups (up to 571x) in bug detection mean that processor verification cycles can be significantly shortened, leading to faster deployment and reduced development costs.
• Improving Test Quality: The focus on better test case quality via hybrid fuzzing and optimized scheduling ensures that the verification time is spent finding difficult, deep-seated bugs, thus enhancing processor reliability.