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Confidential virtual machines (CVM) use trusted hardware to encrypt data being processed in memory to prevent unauthorized access. Applications can be migrated to CVM without changes, i.e., lift and shift, to handle sensitive workloads securely in public clouds. AMD Secure Encrypted Virtualization (SEV) is one of the prominent technologies that provides hardware support for CVM. In this paper, we investigate various system operations, including CPU, memory, and disk and network I/O, to understand the performance overheads of SEV-supported CVMs. Our findings indicate that memory and I/O-intensive workloads can incur significant overhead. We then study the performance implications of running unmodified database applications, specifically Cock-roachDB, on CVMs by examining typical data access patterns of OLTP and OLAP workloads. A notable performance overhead of up to 18% is observed for TPC-C workload running on multinode database clusters, and an overhead of up to 13% is observed for TPC-H workload running on single-node database instances. The non-negligible overhead suggests the potential and necessity for database optimizations with respect to CVM, particularly for time-sensitive workloads. We offer a glimpse of the effect that CVM overhead can have in query planning using a simple join query: the optimal join algorithm becomes suboptimal on CVM, along with discussion of potential optimizations for reducing CVM overhead in the realm of database applications.
Qiu et al. (Thu,) studied this question.