Spectre attack on XuanTie-C910 and defense mechanism based on PHT refreshing

Over the past few decades, processor performance has been enhanced through continuous optimizations in architecture. Recently, several transient execution attacks, such as Spectre, have been disclosed, leveraging these optimizations to steal sensitive data. In this article, we expose the security vulnerability of the high-performance opensource RISC-V processor, XuanTie-C910, to Spectre attack and present a defense mechanism based on Pattern History Table flushing, which can eliminate such attacks. Under the SPEC2017 benchmark test, the average performance loss is 6%, with a 12.97% increase in LUT usage.