Boosting the Bounds of Symbolic QED for Effective Pre-Silicon Verification of Processor Cores
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Existing techniques to ensure functional correctness and hardware trust during pre-silicon verification face severe limitations. In this work, we systematically leverage two key ideas: 1) Symbolic QED, a recent bug detection and localization technique using Bounded Model Checking (BMC); and 2) Symbolic starting states, to present a method that: i) Effectively detects both "difficult" logic bugs and Hardware Trojans, even with long activation sequences where traditional BMC techniques fail; and ii) Does not need skilled manual guidance for writing testbenches, writing design-specific assertions, or debugging spurious counter-examples. Using open-source RISC-V cores, we demonstrate the following: 1. Quick (<5 minutes for an in-order scalar core and <2.5 hours for an out-of-order superscalar core) detection of 100 of logic bug and hardware Trojan scenarios from commercial chips and research literature, and 97.9 100,000 activation instructions taken from random test programs). 2. Quick ( 1 minute) detection of several previously unknown bugs in open-source RISC-V designs.
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