Browsing Institutt for datateknologi og informatikk by Author "Sakalis, Christos"
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Clearing the Shadows: Recovering Lost Performance for Invisible Speculative Execution through HW/SW Co-Design
Tran, Kim-anh; Sakalis, Christos; Själander, Magnus; Ros, Alberto; Kaxiras, Stefanos; Jimborean, Alexandra (Chapter, 2020)Out-of-order processors heavily rely on speculation to achieve high performance, allowing instructions to bypass other slower instructions in order to fully utilize the processor's resources. Speculatively executed ... -
Delay-on-Squash: Stopping Microarchitectural Replay Attacks in Their Tracks
Sakalis, Christos; Kaxiras, Stefanos; Själander, Hans Magnus (Peer reviewed; Journal article, 2022)MicroScope and other similar microarchitectural replay attacks take advantage of the characteristics of speculative execution to trap the execution of the victim application in a loop, enabling the attacker to amplify a ... -
Do Not Predict – Recompute! How Value Recomputation Can Truly Boost the Performance of Invisible Speculation
Sakalis, Christos; Chowdhury, Zamshed; Wadle, Shayne; Akturk, Ismail; Ros, Alberto; Själander, Magnus; Kaxiras, Stefanos; Karpuzcu, Ulya (Chapter, 2021)Recent architectural approaches that address speculative side-channel attacks aim to prevent software from exposing the microarchitectural state changes of transient execution. The Delay-on-Miss technique is one such ... -
Efficient invisible speculative execution through selective delay and value prediction
Sakalis, Christos; Kaxiras, Stefanos; Ros, Alberto; Jimborean, Alexandra; Själander, Magnus (Journal article; Peer reviewed, 2019)Speculative execution, the base on which modern high-performance general-purpose CPUs are built on, has recently been shown to enable a slew of security attacks. All these attacks are centered around a common set of ... -
Evaluating the Potential Applications of Quaternary Logic for Approximate Computing
Sakalis, Christos; Jimborean, Alexandra; Kaxiras, Stefanos; Själander, Magnus (Journal article, 2019)There exist extensive ongoing research efforts on emerging atomic-scale technologies that have the potential to become an alternative to today’s complementary metal--oxide--semiconductor technologies. A common feature among ... -
Ghost loads: what is the cost of invisible speculation?
Sakalis, Christos; Alipour, Mehdi; Ros, Alberto; Jimborean, Alexandra; Kaxiras, Stefanos; Själander, Magnus (Chapter, 2019)Speculative execution is necessary for achieving high performance on modern general-purpose CPUs but, starting with Spectre and Meltdown, it has also been proven to cause severe security flaws. In case of a misspeculation, ... -
Reorder Buffer Contention: A Forward Speculative Interference Attack for Speculation Invariant Instructions
Aimoniotis, Pavlos; Sakalis, Christos; Själander, Magnus; Kaxiras, Stefanos (Peer reviewed; Journal article, 2021)Speculative side-channel attacks access sensitive data and use transmitters to leak the data during wrong-path execution. Various defenses have been proposed to prevent such information leakage. However, not all speculatively ... -
Seeds of SEED: Preventing Priority Inversion in Instruction Scheduling to Disrupt Speculative Interference
Sakalis, Christos; Själander, Magnus; Kaxiras, Stefanos (Chapter, 2021)Speculative side-channel attacks consist of two parts: The speculative instructions that abuse speculative execution to gain illegal access to sensitive data and the side-channel instructions that leak the sensitive data. ... -
Understanding Selective Delay as a Method for Efficient Secure Speculative Execution
Sakalis, Christos; Kaxiras, Stefanos; Ros, Alberto; Jimborean, Alexandra; Själander, Magnus (Peer reviewed; Journal article, 2020)Since the introduction of Meltdown and Spectre, the research community has been tirelessly working on speculative side-channel attacks and on how to shield computer systems from them. To ensure that a system is protected ... -
WIP: “It’s a Trap!”—How Speculation Invariance Can Be Abused with Forward Speculative Interference
Aimoniotis, Pavlos; Sakalis, Christos; Själander, Magnus; Kaxiras, Stefanos (Chapter, 2021)Side-channel attacks based on speculative execution access sensitive data and use transmitters to leak such data during wrong-path execution. Speculative side-channel defenses have been proposed to prevent such information ...