Seclusive Cache Hierarchy for Mitigating Cross-Core Cache and Coherence Directory Attacks

Vishal Gupta, Vinod Ganesan, Biswabandan Panda

Abstract: Cross-core cache attacks glean sensitive data by exploiting the fundamental interference at the shared resources like the last-level cache (LLC) and coherence directories. Complete non-interference will make cross-core cache attacks unsuccessful. To this end, we propose a seclusive cache hierarchy with zero storage overhead and a marginal increase in on-chip traffic, that provides non-interference by employing cache-privatization on demand. Upon a cross-core eviction by an attacker core at the LLC, the block is back-filled into the private cache of the victim core. Our back-fill strategy mitigates cross-core conflict based LLC and coherence directory-based attacks. We show the efficacy of the seclusive cache hierarchy by comparing it with existing cache hierarchies.