Domain Isolation and Access Control in Multi-tenant Cloud FPGAs

While sharing FPGA logic in space and time improves hardware utilization and reduces the overall power consumption in FPGA-accelerated clouds, it also raises security concerns. Accelerators from different tenants running on the same FPGA can be exploited by malicious actors to launch attacks on co-hosted virtual machines, which puts cloud applications and the entire infrastructure at risk. In addition, FPGA-accelerated cloud applications typically rely on a combination of software and hardware components, some of which are provided by non-trusted sources. The software layer executes on CPUs, and the hardware functions run on FPGAs. This type of heterogeneous architecture provides an attack surface that can be exploited by malicious hardware or software processes to breach well-insulated users’ domains. This chapter explores hardware and software infrastructure used to enforce domain isolation and security at the system level in multi-tenant FPGA clouds. The approach we present leverages the Flux Advanced Security Kernel (FLASK) architecture to inherit security policies from software down to hardware accelerators on FPGAs where enforcement mechanisms are implemented. This approach has been prototyped and proven to enforce isolation between co-hosted user domains while incurring minimal communication and power consumption overhead.