| Popis: |
Recently, FPGA-accelerated cloud has emerged as a new computing environment. The inclusion of FPGAs in the cloud has created new security risks, some of which are due to circuits exercising excessive switching activity. These power-wasting tenants can cause timing faults in the collocated circuits or a denial-of-service attack by resetting the host FPGA. In this work, we present the idea of populating the FPGA with voltage sensors based on ring oscillators, to continuously monitor the core voltage fluctuations across the entire FPGA. To implement the sensors, we do not lock any FPGA resources; instead, we infiltrate the sensors undercover, by taking advantage of the logic and the routing resources unused by the tenants. Additionally, we infiltrate the sensors into the FPGA circuits after their implementation, but before their deployment on the cloud; the tenants are thus neither aware nor affected by our voltage monitoring system. Finally, we devise a novel metric that takes the sensor measurements to quantify the power wasting activity in the FPGA clock regions where the sensors are infiltrated. We use VTR benchmarks and a Xilinx Virtex-7 FPGA to test the feasibility of our approach. Experimental results demonstrate that, using the undercover voltage sensors and our novel metric, one can accurately locate the source of the malicious power-wasting activity. |
