Current hardware and operating system abstractions were conceived at a time when we had minimal security threats, scarce compute and memory resources, and limited numbers of users. These assumptions are not true today. On one hand, attacks such as Spectre and Meltdown have shown that current hardware is plagued by vulnerabilities. On the other hand, new emerging cloud paradigms like microservices and serverless computing have led to the sharing of computing resources among hundreds of users at a time. In this new era of computing, we can no longer afford to build each layer separately. Instead, we have to rethink the synergy between the operating system and hardware from the ground up.

In this talk, I will focus on rethinking the virtual memory abstraction. First, I will introduce Microarchitectural Replay Attacks, a novel family of side-channel attacks that exploit existing virtual memory mechanisms. These attacks leverage the fact that, in modern out-of-order processors, a single dynamic instruction can be forced to execute many times. Then, I will describe Elastic Cuckoo Page Tables, my proposal to rebuild the virtual memory abstraction for parallelism. Finally, I will conclude by describing ongoing and future directions towards redesigning the hardware and the operating system layers.