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STIMSMITH

HiFuzz

Tool
First seen 7/10/2026
Last seen 7/10/2026
Evidence 13 chunks

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RELATIONSHIPS

34 connections
differential testing uses → 85% 2e
HiFuzz uses differential testing against Spike as the reference model to detect bugs.
Hierarchical Reinforcement Learning implements → 100% 2e
HiFuzz implements a hierarchical reinforcement learning framework with a two-level agent hierarchy.
Hardware fuzzing implements → 100% 2e
HiFuzz is a hardware fuzzing tool targeting CPU verification.
Constructive Test Generation implements → 95% 2e
HiFuzz uses constructive generation to assemble programs instruction by instruction rather than mutating seeds.
Coverage-guided Fuzzing implements → 90% 2e
HiFuzz uses coverage feedback to guide the reinforcement learning agents toward better test generation.
Program Agent uses → 100% 2e
HiFuzz uses a Program Agent as the high-level planner for global test program structure.
Basic Block Agent uses → 100% 2e
HiFuzz uses a Basic Block Agent as the low-level executor for instruction filling.
Semantic-Aware Basic Block Encoder uses → 100% 2e
HiFuzz integrates a Semantic-Aware Basic Block Encoder to provide intrinsic novelty feedback.
Adaptive Coverage Reward Mechanism uses → 100% 2e
HiFuzz uses an Adaptive Coverage Reward Mechanism to balance module-level exploration.
Intrinsic Novelty Reward uses → 100% 2e
HiFuzz uses an intrinsic novelty reward derived from the BB encoder embeddings to provide dense feedback.
line coverage evaluates → 90% 2e
HiFuzz measures line coverage on Rocket using Verilator.
toggle coverage evaluates → 90% 2e
HiFuzz measures toggle coverage on Rocket using Verilator.
Program Agent ← part of 100% 2e
The Program Agent is a component of the HiFuzz dual-agent architecture.
Basic Block Agent ← part of 100% 2e
The Basic Block Agent is a component of the HiFuzz dual-agent architecture.
Semantic-Aware Basic Block Encoder ← part of 100% 2e
The Semantic-Aware BB Encoder is a feedback component of HiFuzz.
Adaptive Coverage Reward Mechanism ← part of 100% 2e
The ACRM is a feedback component of HiFuzz for balanced module-level coverage.
RISC-V uses → 100% 2e
HiFuzz generates RISC-V programs to fuzz RISC-V processor cores.
spike uses → 100% 2e
HiFuzz uses Spike as the reference model for differential testing on RISC-V cores.
ISA Pre-Simulation uses → 90% 2e
HiFuzz uses an ISA pre-simulation step to validate generated programs before RTL simulation.
Rocket Core evaluates → 100% 2e
HiFuzz is evaluated on the Rocket Core as one of three RISC-V targets.
BOOM core evaluates → 100% 2e
HiFuzz is evaluated on the BOOM Core as one of three RISC-V targets.
CVA6 evaluates → 100% 2e
HiFuzz is evaluated on CVA6 as one of three RISC-V targets.
DiFuzzRTL ← compares with 100% 2e
HiFuzz is compared against DifuzzRTL as a baseline fuzzer.
ProcessorFuzz compares with → 100% 2e
HiFuzz is compared against ProcessorFuzz as a baseline fuzzer.
Cascade ← compares with 100% 2e
HiFuzz is compared against Cascade as a baseline fuzzer, outperforming it by 48.9% on control register coverage.
Control Register Coverage evaluates → 100% 2e
HiFuzz is evaluated using control register coverage as its primary metric on Rocket.
Mux Coverage evaluates → 90% 2e
HiFuzz reports MUX coverage on Rocket and BOOM cores.
Hierarchical Configuration uses → 95% 1e
HiFuzz uses a hierarchical configuration mechanism splitting global structure from per-BB content.
Verilator uses → 100% 1e
HiFuzz is implemented on top of Verilator for RTL simulation.
Hierarchical Configuration ← part of 90% 1e
Hierarchical Configuration is a core mechanism of HiFuzz for splitting global and local program decisions.
CocoTB uses → 100% 1e
HiFuzz is implemented on top of Cocotb for hardware simulation interfacing.
Encarsia evaluates → 90% 1e
HiFuzz is evaluated using the Encarsia benchmark for bug detection.
GenHuzz ← compares with 90% 1e
HiFuzz is structurally compared with GenHuzz as a related generative fuzzer.
The paper introduces HiFuzz as a novel hierarchical reinforcement learning framework for CPU fuzzing.