| In the embedded domain,mixed-criticality systems have received widespread attention,and how to run multiple partitions with different criticality and certification assurance levels on the same physical computing platform has become a research focus in the industry.Hypervisor virtualization technology is widely used in mixed-criticality systems and can provide strong temporal and spatial isolation for multiple virtual machines(VMs),allowing multiple VMs to execute concurrently on the same physical platform.Among them,Hypervisors using a static partitioning architecture can statically partition the system resources on the physical platform into multiple resource partitions to avoid the resource contention and resource scheduling problems between the VMs.However,existing Hypervisors that adopt a static partitioning architecture have more virtual machine traps caused by physical interrupts and large interrupt latency overhead,which hinders the real-time performance and stability of VMs.To mitigate the above issues,the thesis researches and designs a realtime Hypervisor prototype named Bao-SK,which is suitable for mixedcriticality systems in the embedded domain.While providing basic virtualization services,this thesis proposes a new interrupt delivery mechanism,namely physical interrupt pass-through mechanism,which forwards physical interrupts directly to VMs for processing without causing any virtual machine traps due to physical interrupts.Moreover,this thesis also designs a virtual machine communication mechanism for BaoSK,responsible for providing communication services for the mutual cooperation of different critical level tasks.In order to verify the feasibility and effectiveness of the proposed techniques,we conducted a comprehensive experimental evaluation of Bao-SK.The experimental results show that Bao-SK can reduce the number of virtual machine traps and reduce interrupt latency by about 5.2 times compared to Bao.At the same time,I/O read and write performance also improved by approximately 8%.Compared with the Linux native system,Bao-SK introdues about 1%real-time overhead for VMs,and less than 3%CPU and memory performance overhead. |
