GhostMinion: A Strictness-Ordered Cache System for Spectre Mitigation

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Out-of-order speculation, a technique ubiquitous since the early 1990s, remains a fundamental security flaw. Via attacks such as Spectre and Meltdown, an attacker can trick a victim, in an otherwise entirely correct program, into leaking its secrets through the effects of misspeculated execution, in a way that is entirely invisible to the programmer’s model. This has serious implications for application sandboxing and inter-process communication.

Designing efficient mitigations that preserve the performance of out-of-order execution has been a challenge. The speculation-hiding techniques in the literature have been shown to not close such channels comprehensively, allowing adversaries to redesign attacks. Strong, precise guarantees are necessary, but mitigations must achieve high performance to be adopted. We present Strictness Ordering, a new constraint system that shows how we can comprehensively eliminate transient side channel attacks, while still allowing complex speculation and data forwarding between speculative instructions. We then present GhostMinion, a cache modification built using a variety of new techniques designed to provide Strictness Order at only 2.5% overhead.
Original languageEnglish
Title of host publicationProceedings of the 54th Annual IEEE/ACM International Symposium on Microarchitecture (MICRO '54)
PublisherACM Association for Computing Machinery
Number of pages13
Publication statusAccepted/In press - 14 Jul 2021
Event54th IEEE/ACM International Symposium on Microarchitecture - Online, Athens, Greece
Duration: 18 Oct 202122 Oct 2022


Conference54th IEEE/ACM International Symposium on Microarchitecture
Abbreviated titleMICRO 2021
Internet address


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