Sensing CPU Voltage Noise Through Electromagnetic Emanations

Measuring and Exploiting Guardbands of Server-Grade ARMv8 CPU Cores and DRAMs

“…Cache viruses were crafted to exploit the underlying microarchitecture and test all levels of the cache hierarchy, while core viruses are being generated by genetic algorithms. To stress the cores, we use dI/dt viruses that cause the CPU power consumption to switch between high and low power at a rate equal to PDN 1 st order resonant frequency [2,8,14]. This causes maximum voltage noise.…”

“…This causes maximum voltage noise. We craft this virus using the approach described in [14]. Such viruses represent a pathogenic worst-case scenario that is unlikely to be encountered in real-life workloads targeting to cause maximum voltage noise, power consumption and error rates.…”

“…Since X-Gene2 does not support fine-grained voltage measurements, voltage noise viruses are crafted using an alternative methodology which is based on sensing high voltage noise through CPU electromagnetic emanations (EM) [14]. To prove the effectiveness of the crafted virus, we use an indirect measurement of voltage noise which is Vmin (minimum operational voltage for a given frequency) [2,8,14].…”

“…Typically, these stress-tests are automatically generated using optimization approaches, such as Genetic Algorithms (GA), guided by direct voltage measurements [2,8]. Since X-Gene2 doesn't support fine-grained voltage measurements, to generate dI/dt viruses, we use an alternative methodology which is based on sensing high voltage noise through CPU electromagnetic emanations (EM) [14]. Essentially, we use GA to craft a loop of instructions that maximizes radiated EM amplitude.…”

“…This is achieved by exploiting architectural and micro-architectural characteristics of the X-Gene2 platform and ARMv8 ISA. Workload variations are also present as different workload cause different voltage noise [2,3,8,14]. To capture these workload variations, we perform a comprehensive characterization using real workloads, including SPEC2006 and NAS benchmark suites in both singleprocess and multi-process setups.…”