• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.6
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• pp.385-393
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• 2017

As the use of mobile devices such as smartphones increases, there is growing interest on the benefits of virtualization in embedded systems. Full virtualization has the advantage of running the guest virtual machine without modifying the guest operating system. However, full virtualization suffers slow execution speed due to the cost of context switching between the virtual machines and the virtual machine monitor. In this paper, we propose a translated block and context switching optimization to improve the guest execution speed in the embedded system. As a result, the improved dynamic binary translator is up to 5.95 times faster than the native execution. Performance degradation is less than that of the other virtualization system.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.3
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• pp.145-153
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• 2013

Virtualization technology has been applied in IA-32 based server or desktop systems. Recently it has been applied in ARM based mobile systems. Virtualization technology provides many useful features that are not possible in operating system level such as isolation, interposition, encapsulation and portability. In this research, we implement an ARM based VMM(Virtual Machine Monitor) by using the following techniques. First, we use "emulation" to virtualize the processor. Second, we use "shadow page tables" to virtualize the memory. Finally, we use a simple "pass-through I/O" to virtualize the device. Currently the VMM runs ARM Linux kernel 3.4.4 on a BeagleBoard-xM, and we evaluated the performance of the VMM using lmbench and dhrystone. The result of the evaluation shows that our VMM is slower than Xen on ARM that is implemented using paravirtualization but has good performance among the VMMs using full-virtualization.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.4
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• pp.231-241
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• 2011

Recently, system virtualization has been applied to consumer electronics (CE) such as smart mobile phones. Although multi-core processors have become a viable solution for complex applications of consumer electronics, the issue of utilizing multi-core resources in the virtualization layer has not been researched sufficiently. In this paper, we present a new hypervisor design and implementation for multi-core CE devices. We concretely describe virtualization methods for a multi-core processor and multi-core-related subsystems. We also analyze bottlenecks of network performance in a virtualization environment that supports multimedia applications and propose an efficient virtual interrupt distributor. Our new multi-core hypervisor improves network performance by 5.5 times as compared to a hypervisor without the virtual interrupt distributor.

• Journal of the Korea Society of Computer and Information
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• v.27 no.5
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• pp.11-19
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• 2022

In this paper, we propose a fault tolerant embedded system using memory redundancy on the full-virtualization based virtual machine monitor. The proposed virtual machine monitor first virtualizes main memory of embedded system utilizing efficient shadow page table scheme so that the embedded system runs as a virtual machine on the virtual machine monitor. The virtual machine monitor makes the backup of the embedded system run as another virtual machine by copying memory contents of the embedded system into memory space of backup system according to predefined schedules. When an error occurs in the target virtual machine, the corresponding standby virtual machine takes the role of target virtual machine and continues its operation. Performance evaluation studies show that such backups and switches of virtual machines are performed with minor performance degradation.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.57-64
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• 2009

Recently virtualization has been one of the most popular research topics in system software area. While there already exist many commercial virtualization products for general-purpose computer system, little efforts are made to virtualize embedded system. In this paper, we design and implement a virtual machine monitor which divides each physical hardware resource of a embedded system into logical ones and reorganizes them into many virtual machines, which result in running several real-time operating systems concurrently on a single embedded system. We measure various performance metrics of the virtual machine monitor developed on a real embedded system. The results of the study show that our virtual machine monitor has enough potentiality of its application to real-world embedded systems.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.659-660
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• 2008

Virtualization of operating systems have already been developed and commercialized in the enterprise computing area. As the computing power of the embedded systems is growing, it is regarded that the virtualization is the important research area. The virtualization is typically established by the micro kernel. L4 kernel is the one example of the micro kernel. In this paper, we propose the architecture for virtualization of Linux over the L4 kernel.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.233-239
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• 2015

This paper describes a method that is integrated trace for real-time virtualization environment. This method has solved the problem that the performance trace may not be able to analyze integrated method between heterogeneous operating systems which is consists of real-time operating systems and general-purpose operating system. In order to solve this problem, we have attempted to reuse the performance analysis function in general-purpose operating system, thereby real-time operating systems can be analyzed along with general-operating system. Furthermore, we have implemented a prototype based on ARM Cortex-A15 dual-core processor. By using this integrated trace method, real-time system developers can be improved productivity and reliability of results on real-time virtualization environment.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.12
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• pp.443-448
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• 2014

This paper is a study related to fault tolerant design based on PSTR using virtualization techniques. If the fault tolerant PSTR based on virtualization techniques is implemented the communication performance between primary and shadow will improves and monitoring function is easy to available about activities of primary and shadow. The legacy PSTR model is implemented in its hardware. The primary play a main role and shadow play a switched action when the errors occurrs in the primary. The switched action of shadow make it possible to restart the primary function newly. This paper implements fault tolerant primary-shadow model using virtualization techniques on the embedded environment.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.255-257
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• 2009

Recently, researchers are focusing on the usefulness of microkernels regarding to the virtualization of embedded systems. We ported OKL4 2.1 microkernel on MBA2440 and SMDK6410 that use ARM920T and ARM1176JFZ-S cores respectively. The ported OKL4 2.1 environment will be used to develop various virtualization applications.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.792-797
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• 2015

Effective profiling diagnoses the failure of the system and informs risk. If a failure in the target system occurs, it is impossible to diagnose more than one of the exiting tools. In this respect, monitoring of the system based on virtualization is useful. We present in this paper a monitoring framework that uses the characteristics of hardware virtualization to prevent side-effects from a target guest, and uses dynamic binary instrumentation with instruction-level trapping based on hardware virtualization to achieve efficiency and flexibility. We also present examples of some applications that use this framework. The framework provides tracing of guest kernel function, memory dump, and debugging that uses GDB stub with GDB remote protocol. The experimental evaluation of our prototype shows that the monitoring framework incurs at most 2% write memory performance overhead for end users.