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Abstract:
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Both real -time virtualization and recursive virtualization are desirable properties of a virtual machine monitor (or hypervisor ) . Although the prospect for virtualization and even recursive virtualization has become better as the PC hardware becomes faster , the real -time systems community so far has not been able to reap much benefits . This is because no existing virtualization mechanism can properly support the stringent timing requirements needed by real -time systems . It is hard to do real -time virtualization , and it is even harder to do it recursively . In this dissertation , we propose a framework whereby the hypervisor is capable of running real -time guests and participating in recursive virtualization . Such a hypervisor is called a real -time hierarchical hypervisor .
We first look at virtualization of abstract resource types from the real -time systems perspective . Unlike the previous work on recursive real -time partitioning that assumes fully -preemptable resources , we concentrate on other and often more practical types of scheduling constraints , especially the non -preemptive and limited -preemptive ones . Then we consider the current x86 architecture and explore the problems that need to be addressed for real -time recursive virtualization . We drill down on the problem that affects timing properties the most , namely , the recursive forwarding and delivery of interrupts , exceptions and intercepts . We choose the x86 architecture because it is popular and readily available , but it is by no means the only architecture of choice for real -time recursive virtualization . We conclude the research with an architecture -independent discussion on future possibilities in real -time recursive virtualization . |