Composite Enclaves: Towards Disaggregated Trusted Execution

The ever-rising computation demand is forcing the move from CPU to heterogeneous specialized hardware, which readily available across modern datacenters through disaggregated infrastructure. On other hand, trusted execution environments (TEEs), one of most promising recent developments in hardware security, can only protect code confined CPU, limiting TEEs’ potential and applicability a handful applications. We observe that computing base (TCB) fixed at design time, practice leads using untrusted software employ peripherals TEEs. Based on this observation, we propose composite enclaves with configurable TCB, allowing access multiple IO resources. Finally, present two case studies enclaves: i) an FPGA platform based RISC-V Keystone connected emulated sensors, ii) large-scale accelerator. These showcase flexible but small TCB (2.5 KLoC for drivers), low-performance overhead (only around 220 additional cycles context switch), thus demonstrating feasibility our approach showing it work wide range hardware.