Research And Implementation Of Multiple Embeded Operating System Based On The Full Virtualizaiton Technique

With the development of the embedded industry,the embedded system involves more application scenarios than before,which makes the embedded systems that only support a single application scenario no longer meet the needs of users.This leads to the fact that the design of embedded systems become more and more complex,therefore,an urgent need is that we need some new solutions to integrate these different application subsystems.In addition,there are often many applications which have different needs of security in the embedded systems;the integration of applications must ensure data security and safety of applications which has high security requirements.Finally,many legacy software are not portable or difficult to migrate to the new platform,so these issues must be considered while doing applications integration at the same time.Using the full virtualization technology in the embedded system allow you to virtualize multiple partitions on a single hardware platform,each partition can run a separate operating system,so the common OS And RTOS can run in a single platform,virtualization technology can also emulate legacy hardware to feed the need of legacy software,which makes the real-time,non-real-time and legacy software can be integrated in the same platform,and also satisfied the data isolation needs of applications in different security levels.Compared with existing virtualization products,embedded virtualization products are more concerned about whether the products can meet the real-time requirements of real-time tasks.There are many open source hypervisor with complete device virtualization and multi-core support suiting for embedded environments,but they can not meet the hard real-time requirements.By studying the existing Hypervisor which is suitable for embedded platform,This thesis choose Xen as the target and study its virtualization implementation,especially the VCPU scheduling process of Xen,and then analyzes the impact of hypervisor on real-time,finally,introduces a new VCPU scheduling algorithm and improves the process of Xen interrupt handling to enhance the real-time performance of Xen.Based on the above,this thesis port RTEMS to the Xen platform and add support for paravirtualization devices.At the end of this thesis,the real-time performance of RTOS which runs in experimental prototype system has been tested from the response time of task and interrupt,and the results show that the average response delay time of RTOS which runs in experimental prototype system is lower than the scheme that RTOS runs in Xen,and the worst response delay time is lower than the others significantly,the experimental prototype system has better real-time performance than the other scheme,such as Xen with Credit,Credit2 and RTDS scheduler.