The Performance Impact Of Intel's Register File Data Sampling "RFDS" Mitigation

Earlier this week on Patch Tuesday was the disclosure by Intel of the Register File Data Sampling (RFDS) vulnerability and mitigation via updated CPU microcode and a kernel patch. RFDS is around malicious user-space software potentially being able to infer stale register values from kernel space. Register File Data Sampling affects recent Intel Atom / E-core bearing processors including the latest Raptor Lake Refresh processors. In this article are some initial benchmarks of the RFDS performance impact under Linux when using the Core i9 14900K processor.