嵌入式多核环境中分区操作系统关键技术研究

The project will build a prototype of partitioned system with virtualization technology in embedded multicore system. Virtualization technology can abstract physical resources as logical representation, while partitioned system can logically allocate physical resources to implement the temporal and spatial isolation. At present, there are various application requirements, and the hardware resource of embedded multicore system should be utilized efficiently by software to solve the conflict of different requirements. This project will adopt hosted Hypervisor to abstract embedded multicore resources and carry out topology management, in order to reduce hardware complexity introduced by multicore. Para-virtulization will reduce the hardware dependency of applications and enhance the portability. Hypervisor will divide partitions according to application requirements and the Inter-Partition Communication will be implemented by Lock-free mechanism. ARINC 653 specification will be referenced to allocate temporal and spatial resources and partitions and tasks will be scheduled based on period and priority. Therefore, critical services such as real-time tasks can be guaranteed safe and reliable, and non-critical applications also can be satisfied. Finite state machine and formal methods will be used to verify system model for ensuring system correctness and availability. The prototype and technologies proposed by this project will contribute theoretical and technical basis for system software research and development in embedded multicore environment.

本项目基于嵌入式多核系统通过虚拟化技术构建分区操作系统原型。虚拟化技术将物理资源抽象为逻辑表示，分区操作系统则对物理资源进行逻辑分配，实现时间和空间的隔离。当前嵌入式多核系统面对的应用需求日益多样，需要通过软件手段来发挥硬件资源的能力以解决不同需求的矛盾。本项目采用寄宿型Hypervisor对嵌入式多核硬件资源进行抽象和拓扑管理，以控制多核环境引入的硬件复杂性；采用半虚拟化实现降低应用对硬件的依赖性，从而增强可移植性。Hypervisor根据应用需求类型划分分区，实现无锁的分区通信机制，并参照ARINC 653标准分配时间和空间资源，基于周期和优先级对分区和任务进行调度，保证实时任务等关键服务的安全可靠以及非关键应用需求得到满足。采用有限状态机和形式化方法对系统模型进行理论抽象和验证，保证系统的正确性和可用性。本项目提出的系统原型和技术方法将为嵌入式多核环境系统软件研发提供理论和技术基础。

本项目基于嵌入式多核系统通过虚拟化技术构建分区操作系统原型，具有丰富的实际工程价值。本项目针对其中的关键技术问题开展了研究与实现。针对内存管理和可靠性，实现了一种通用且易于操作的内存错误注入工具MEI，以及一种在线内存检测器MEMDOG。针对资源隔离，一方面，实现了容器间的资源硬隔离，消除共用内核带来的不安全因素，从而使容器技术能够应用于安全攸关环境；另一方面，研究了用于端口隔离的自动分配端口方案，给Hypervisor增加了自动按照宿主机的端口分配系统生成端口使用方案的工具。针对分区的调度问题，提出了RCBW（Reservation of CPU Bandwidth，CPU带宽预留）方案。针对分区间通信，对无锁同步机制PWCS进行了研究和验证，并着眼于系统抖动和延时，利用系统固有随机性，设计实现了随机数生成器DDSRNG，以满足安全攸关应用需求。本项目研究成果有望对多核环境系统软件的研发与应用提供理论和技术基础。