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Compositional Verification of a Baby Virtual Memory Manager

  • Alexander Vaynberg
  • Zhong Shao
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7679)

Abstract

A virtual memory manager (VMM) is a part of an operating system that provides the rest of the kernel with an abstract model of memory. Although small in size, it involves complicated and interdependent invariants that make monolithic verification of the VMM and the kernel running on top of it difficult. In this paper, we make the observation that a VMM is constructed in layers: physical page allocation, page table drivers, address space API, etc., each layer providing an abstraction that the next layer utilizes. We use this layering to simplify the verification of individual modules of VMM and then to link them together by composing a series of small refinements. The compositional verification also supports function calls from less abstract layers into more abstract ones, allowing us to simplify the verification of initialization functions as well. To facilitate such compositional verification, we develop a framework that assists in creation of verification systems for each layer and refinements between the layers. Using this framework, we have produced a certification of BabyVMM, a small VMM designed for simplified hardware. The same proof also shows that a certified kernel using BabyVMM’s virtual memory abstraction can be refined following a similar sequence of refinements, and can then be safely linked with BabyVMM. Both the verification framework and the entire certification of BabyVMM have been mechanized in the Coq Proof Assistant.

Keywords

Memory Model Operational Semantic Address Space Physical Memory Separation Logic 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Alexander Vaynberg
    • 1
  • Zhong Shao
    • 1
  1. 1.Yale UniversityUSA

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