MgX: Near-Zero Overhead Memory Protection with an Application to Secure DNN Acceleration

In this paper, we propose MgX, a near-zero overhead memory protection scheme for hardware accelerators. MgX minimizes the performance overhead of off-chip memory encryption and integrity verification by exploiting the application-specific aspect of accelerators. Accelerators tend to explicitly manage data movement between on-chip and off-chip memory, typically at an object granularity that is much larger than cache lines. Exploiting these accelerator-specific characteristics, MgX generates version numbers used in memory encryption and integrity verification only using on-chip state without storing them in memory, and also customizes the granularity of the memory protection to match the granularity used by the accelerator. To demonstrate the applicability of MgX, we present an in-depth study of MgX for deep neural network (DNN) and also describe implementations for H.264 video decoding and genome alignment. Experimental results show that applying MgX has less than 1% performance overhead for both DNN inference and training on state-of-the-art DNN architectures.