CSR: Medium: Dynamic Binary Translation for a Retargetable and Behaviorally-Accurate Cross-Architecture Whole System Virtual Machine

该项目致力于提高整个系统虚拟化的性能、适用性和可靠性。整个系统虚拟化是一种方法，它允许一种类型的计算机上的完整软件集像在不同类型的计算机上运行的单个程序一样运行，而不需要在二进制(机器代码)级别进行任何更改。特别是，它允许软件在来自不同供应商的不同机器之间迁移，在大型数据中心进行不同的系统升级，或者在移动设备和更强大的服务器之间迁移，以实现更好的电源管理、系统可靠性和整体性能增强。整个系统的虚拟化在软件开发和系统安全等其他应用中也很重要，动态二进制翻译是本项目研究的关键使能技术。使用动态二进制翻译，来自一台机器的二进制形式的机器指令被翻译成具有不同指令集体系结构的另一台机器的指令，因此软件可以在真实或虚拟机器上的不同平台上无缝运行。该项目将产生一个原型，在基于ARM的客户端和基于Intel x86的服务器的客户端-服务器环境中，使用开源软件QEMU作为前端，LLVM作为后端。这个原型将提供一个试验台来研究动态二进制翻译的几个重要问题，动态二进制翻译支持多核平台上的多线程代码的全系统虚拟化。该项目解决了从研究发现到应用的几个技术挑战。第一个是提高翻译后的多线程代码的性能，并减少在二进制翻译期间产生的开销，特别是在客户端-服务器环境中。它还解决了与在具有不同内存一致性模型的机器之间迁移二进制代码相关的挑战，并解决了验证已翻译代码的正确性的挑战。

This project focuses on improving the performance, applicability and reliability of whole system virtualization. Whole system virtualization is an approach that allows the complete set of software from one kind of computer to run as if it were a single program on a different kind of computer without any change at the binary (machine code) level. In particular, it allows software to migrate among different machines from different vendors with different system upgrades in large data centers, or between mobile devices and more powerful servers to allow better power management, system reliability and overall performance enhancement. Whole system virtualization is also important in other applications such as software development and system security.Dynamic binary translation is the key enabling technology studied in this project. With dynamic binary translation, machine instructions in their binary form from one machine are translated to instructions for another machine with a different instruction set architecture, so software can run seamlessly across different platforms on either real or virtual machines. The project will result in a prototype using the open-source software QEMU as its front-end and LLVM as its back-end in a client-server environment with ARM-based clients and Intel x86-based servers. This prototype will provide a test bed to study several issues important to dynamic binary translation that supports whole system virtualization of multi-threaded codes on multi-core platforms. This project addresses several technology challenges as it goes from research discovery toward application. The first is to improve the performance of the translated multi-threaded code and to reduce the overheads incurred during the binary translation, in particular in a client-server environment. It also addresses the challenges related to migrating binary codes across machines with different memory consistency models, and addresses challenges to verifying the correctness of the translated code.