基于Xen的自下而上调用的设计与实现

The Design and Implement of Xen-Based Upcall

针对虚拟机监视器(virtual machine monitor,VMM)与上层客户虚拟机(Guest-VM)之间的语义鸿沟(semantic gap)问题,该文提出了一种自下而上的调用方式,该方法使得VMM能够同步调用客户机的已有功能来获取客户机语义信息,为在客户虚拟机地址空间之外的监控机制带来便利。在Xen半虚拟化环境下,实现了自下而上的同步调用方式,有效地解决了语义重构所需的重复定义和实现问题。实验表明,该方法能使VMM有效地调用客户机的已有功能为自己服务,使VMM能准确地获取上层虚拟机操作系统的信息。

In order to solve the semantic gap problem between virtual machine monitor （VMM） and guest virtual machine （VM）, an up-call mechanism is proposed, with which the service request is launched by VMM, and the guest-VM is responsible to provide response to the request from VMM. This makes it possible for VMM to synchronously call guest-VM services to get guest semantic information, bringing convenience for monitor agents constructed out of guest-VM address space to get guest information exactly. The up-call mechanism implemented as a synchronous communication channel is able to make up the problem of duplicate definitions and implementations inside VMM brought by semantic reconstruction. A prototype system on the para-virtualization platform of Xen is implemented. The result shows that the method proposed in this paper is able to help VMM to call guest functions to get guest services and semantic information instantly.