DIFUZZRTL
ToolDIFUZZRTL is a processor fuzzing tool characterized by the MorFuzz paper as a state-of-the-art processor fuzzer. In that paper, MorFuzz reports 4.4× higher coverage than DifuzzRTL and discusses prior processor fuzzers as commonly using reference-model-based state comparison to identify mismatches.
First seen 5/24/2026
Last seen 6/9/2026
Evidence 71 chunks
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WIKI
DIFUZZRTL
DIFUZZRTL is a processor fuzzing tool. The MorFuzz paper refers to it as the "state-of-the-art processor fuzzer" when reporting coverage comparisons against MorFuzz.
Role in processor-fuzzing research
NEIGHBORHOOD
43 nodes · 55 edgesgraph · DiFuzzRTL · depth=1
RELATIONSHIPS
50 connectionsProcessorFuzz is compared against DIFUZZRTL in terms of bug-finding speed.
Instiller is experimentally compared against DiFuzzRTL, showing improvements in coverage, mismatch detection, and instruction length.
MorFuzz is compared against DifuzzRTL in terms of coverage and performance.
DIFUZZRTL implements register coverage as its coverage metric.
DIFUZZRTL adapts CGF to capture FSM state transitions during RTL simulation.
DIFUZZRTL implements differential fuzzing by comparing RTL simulation results with ISA golden model results.
DifuzzRTL uses control register coverage as its hardware coverage matrix.
DIFUZZRTL runs RTL simulation alongside ISA simulation for differential testing.
DIFUZZRTL evaluates the OpenRISC Mor1kx Cappuccino as one of its real-world CPU RTL targets.
DIFUZZRTL is compared against RFuzz, the state-of-the-art RTL fuzzer, showing 40x faster execution and 6.4x faster state exploration.
DIFUZZRTL uses differential testing to detect bugs in processors.
DIFUZZRTL relies on RTL simulation to evaluate test inputs.
DIFUZZRTL evaluates the RISC-V BOOM Core as one of its real-world CPU RTL targets.
DIFUZZRTL's paper mentions speculative execution vulnerabilities as motivation for CPU RTL fuzzing.
DIFUZZRTL monitors FSM state transitions via register coverage.
DIFUZZRTL monitors the remainder register in the MulDiv module as part of its register coverage.
DIFUZZRTL was used to evaluate the BOOM Core processor.
DiFuzzRTL is a state-of-the-art RTL fuzzer used as a baseline for comparison.
DIFUZZRTL provides an open-source mutation engine that ProcessorFuzz also uses.
DIFUZZRTL implements the register coverage metric for hardware fuzzing guidance.
DIFUZZRTL implements CGF adapted for processor hardware fuzzing.
DIFUZZRTL monitors registers controlling multiplexer selection signals as its coverage metric.
DIFUZZRTL is evaluated on the RISC-V Rocket Core processor.
DIFUZZRTL is evaluated on the BOOM processor.
DIFUZZRTL monitors registers that control multiplexer selection signals as coverage metric
DifuzzRTL is a processor fuzzing tool.
DIFUZZRTL implements register-coverage guided fuzzing as its core coverage metric for RTL fuzzing.
DIFUZZRTL implements cycle-sensitive register coverage as a key feature of its coverage metric.
DIFUZZRTL implements asynchronous interrupt handling to manage interrupt events in RTL simulation.
DIFUZZRTL uses backward data-flow analysis to identify control registers in RTL designs.
DIFUZZRTL implements per-instruction mutation to generate valid instruction sequences for fuzzing.
DIFUZZRTL introduces SimInput as a new unified CPU input format for fuzzing.
DIFUZZRTL uses SimInput as input to both ISA and RTL simulators.
DIFUZZRTL uses control registers as the basis for its register-coverage metric.
DIFUZZRTL uses an ISA-level golden model to compare against RTL simulation results for bug detection.
DIFUZZRTL cross-checks execution results from ISA and RTL simulations to identify bugs.
DIFUZZRTL generates input stimuli for RTL simulation based on SimInput.
DIFUZZRTL uses a pseudo interrupt controller in both ISA and RTL simulations.
DIFUZZRTL evaluates the RISC-V Rocket Core as one of its real-world CPU RTL targets.
DIFUZZRTL runs ISA simulation in parallel with RTL simulation for differential testing.
DIFUZZRTL considers SoC design when fuzzing CPU RTL designs, while providing a more direct input approach.
The paper evaluates INSTILLER against DiFuzzRTL as a state-of-the-art baseline.
Dongup Kwon is one of the authors of the DIFUZZRTL paper.
DIFUZZRTL uses TileLink protocol as part of its unified CPU input format.
Eunjin Baek is one of the authors of the DIFUZZRTL paper.
DIFUZZRTL supports FPGA emulation as a testing environment via FireSim.
Jaewon Hur is one of the authors of the DIFUZZRTL paper.
DIFUZZRTL uses a pseudo memory unit in RTL simulation to serve memory requests.
DIFUZZRTL uses stimuli generation to produce formatted inputs for CPU RTL designs.
DIFUZZRTL uses drop-in-replacement designs to support various CPU RTLs.
LINKED ENTITIES
8 linksProcessorFuzz COMPARES_WITH Extracted graph relationship
register coverage IMPLEMENTS Extracted graph relationship
Coverage-based Greybox Fuzzing IMPLEMENTS Extracted graph relationship
differential testing IMPLEMENTS Extracted graph relationship
Finite State Machine USES Extracted graph relationship
remainder register USES Extracted graph relationship
BOOM Core EVALUATES Extracted graph relationship
MorFuzz COMPARES_WITH The evidence reports MorFuzz coverage results relative to DifuzzRTL, stating that MorFuzz achieves 4.4× higher coverage than the state-of-the-art processor fuzzer DifuzzRTL.
CITATIONS
4 sources4 citations — click to collapse
[1] DIFUZZRTL is characterized as a state-of-the-art processor fuzzer in the MorFuzz paper. MorFuzz: Fuzzing Processor via Runtime Instruction Morphing enhanced Synchronizable Co-simulation
[2] MorFuzz reports achieving 4.4× higher coverage than DifuzzRTL and 1.6× higher coverage than riscv-dv. MorFuzz: Fuzzing Processor via Runtime Instruction Morphing enhanced Synchronizable Co-simulation
[3] Prior processor fuzzers are described as commonly using a reference model, comparing processor state with reference-model state, and treating mismatches as bugs. MorFuzz: Fuzzing Processor via Runtime Instruction Morphing enhanced Synchronizable Co-simulation
[4] The MorFuzz paper notes that implementation differences between software reference models and hardware can cause false positives that misguide fuzzers and inhibit coverage of deep processor states. MorFuzz: Fuzzing Processor via Runtime Instruction Morphing enhanced Synchronizable Co-simulation