虛擬化技術在大型電腦及個人電腦上的應用以十分成熟，因此我們可在同一硬體上執行多個作業系統，是現今雲端運算中很常使用到的技術。而在嵌入式硬體上，早期因為硬體設備較差，處理器運算能力較差、記憶體較小 … 等等因素，導致在這部份的發展一直受到限制，隨著嵌入式硬體的運算能力提昇、智慧型手機的出現，將嵌入式硬體的使用推進至一個新的境界。更進一步ARM也提出了要進入伺服器市場的遠景，訂定了新一代ARM處理器規格。在此種種因素下，虛擬化技術得到了實現的可能性，同時也變得越來越重要。在ARM推出硬體輔助的平台之前，我們在原有的Linux KVM架構上，提供了ARM系列處理器的支援，以實現在嵌入式平台上運行多個作業系統的可能性，我們將此成果命名為ARMvisor。而在這當中I/O的效能對整個系統運作佔了不少的影響，從周邊裝置如網路卡、記憶卡等，到中斷控制器、間隔定時器，皆為I/O虛擬化所需要負責的部份。在這篇論文中我們將討論如何去做這部份的虛擬化，以及要如何將它針對效能進行最佳化。此外也會使用一些系統及I/O方面的檢測程式，去評估此作法的成效。

System Virtualization is getting mature in servers and personal computers, so we can run multiple operating systems on the same hardware at the same time by leverage the benefit of Virtualization. It is used commonly in cloud computing technology. However, there are some restrictions in embedded systems, such as worse computing power, less memory, and so on. Nowadays, the computing power of embedded processor becomes more powerful. In addition, ARM Company also plans to provide processor for server usage, and design a new specification of processor in advance. Therefore, the virtualization technology becomes more important and possible in embedded systems. We purpose an approach to implement system virtualization for ARM based on Linux module KVM, before ARM provides hardware-assistance platform. We named this approach ARMvisor. We find out the performance of I/O virtualization plays an important role. There are many devices may have an influence, such as network communication, block device access, interrupt controller … etc. We use Virtio and in-kernel-irqchip to improve the performance. In the thesis, we will also use some system benchmark (e.g., LMBench), and I/O benchmark (e.g., iperf) to evaluate the performance of ARMvisor.

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