Hardware Virtualization

A widely used technique for securing computer systems is to execute programs inside protection domains that enforce established security policies. These containers, often referred to as sandboxes, come in a variety of forms. Although current sandboxing techniques have individual strengths, they also have limitations that reduce the scope of their applicability. In this paper, we give a detailed analysis of the options available to designers of sandboxing mechanisms. As we discuss the tradeoffs of various design choices, we present a sandboxing facility that combines the strengths of a wide variety of design alternatives. Our design provides a set of simple yet powerful primitives that serve as a flexible, general-purpose framework for confining untrusted programs. As we present our work, we compare and contrast it with the work of others and give preliminary results.

Virtualization has experienced a dramatic expansion recently and today is ubiquitous in modern IT industry since it provides numerous benefits to companies and individual users. It increases efficiency, flexibility and scalability of IT equipment by enabling different software-based environments on a single physical hardware. Each virtual machine is a separate instance that is completely independent and separated from the computer hardware and it runs on emulated hardware. Emulated hardware is managed by virtualization tool that provides lower resources when compared to physical hardware. This paper presents a performance evaluation of three different virtual machines run by three recent versions of Windows operating system, namely Windows 7 TM Professional, Windows 8.1 TM Professional and Windows 10 TM Professional, on a host computer system run by Linux Ubuntu. Performance measurement results show that Window 7 is the most suitable virtual operating system since it obtains the best performance when run on a Linux host.

Virtualization has experienced a dramatic expansion recently and today is ubiquitous in modern IT industry since it provides numerous benefits to companies and individual users. It increases efficiency, flexibility and scalability of IT equipment by enabling different software-based environments on a single physical hardware. Each virtual machine is a separate instance that is completely independent and separated from the computer hardware and it runs on emulated hardware. Emulated hardware is managed by virtualization tool that provides lower resources when compared to physical hardware. This paper presents a performance evaluation of three different virtual machines run by three recent versions of Windows operating system, namely Windows 7 TM Professional, Windows 8.1 TM Professional and Windows 10 TM Professional, on a host computer system run by Linux Ubuntu. Performance measurement results show that Window 7 is the most suitable virtual operating system since it obtains the best performance when run on a Linux host.

Data and information needs for large organizations rely heavily on information technology infrastructure support. One of the necessary supporting components is the availability of a sufficient number of servers to increase data center. The huge costs required to increase the number of server units. Virtualization technology can be the perfect solution to resolve these problems. However, due to the high cost of a license, causing an open source-based virtualization used as the main option, namely Proxmox. The application virtualization based Proxmox, can maximize the use of resources, because the function of 3 units of physical servers can be enabled simultaneously on 1 physical server unit. The presence of live migration feature of Proxmox, allowing to move a virtual machine from one physical server to another physical server when maintenance underway. This change can take place without stopping services running on virtual machine.

Server virtualization technology has experienced significant development so that more and more industries are adopting this technology. By using server virtualization, the industry can make savings in purchasing new servers and maintenance because virtualization allows one server to run with multiple operating systems at once. The high level of use of virtualization raises a gap for the occurrence of computer crimes involving virtualization. When computer crimes occur on virtualization, it is necessary to conduct digital forensic investigations to find useful clues in solving crime cases. Therefore, in this study a digital forensic investigation was conducted on Proxmox server virtualization by acquiring the entire storage virtualization media and carrying out checks on the results of the acquisition. Based on the investigation carried out, the acquisition technique by acquiring the entire storage media on Proxmox cannot be used because the structure of the evidence files and folder...

Machine Monitor (VMM) is a piece of software which facilitates hardware Virtualization. Software based Virtualization technologies encompass consid-erable instruction overhead. We have implemented a purely hardware-assisted VMM for x86 architec-ture on AMD Secure ...

Virtualization has gained astonishing popularity in recent decades. It is applied in several application domains, including mainframes, personal computers, data centers, and embedded systems. While the benefits of virtualization are no longer to be demonstrated, it often comes at the price of performance degradation compared to native execution. In this work, we conduct a comparative study on the performance outcome of VMWare, KVM, and Docker against compute-intensive, IO-intensive, and system benchmarks. The experiments reveal that containers are the way-to-go for the fast execution of applications. It also shows that VMWare and KVM perform similarly on most of the benchmarks.

Virtualization has become popular (again) as a means of consolidating multiple operating systems (OSes) onto a smaller set of hardware resources. The roles of OSes in such environments have changed. Whereas normally an OS provides balance between the demands of application and hardware support, in the world of virtualization it can be beneficial to split these roles. One OS may support a particular application set and use other OSes to interact with physical hardware. The hypervisor, or virtualization layer, provides communication facilities for the inter-OS communication needed to support such a deployment model.

This report delves into the extensive research conducted on cloud migration and its implications in modern technology, specifically focusing on the migration to Amazon Web Services (AWS). As an expert in IT infrastructure management and DevOps practices, I explore the detailed processes of both simple and complex cloud migrations, highlighting the strategies for migrating virtual machines, Active Directory, file servers, and SQL servers to the AWS cloud platform. Through in-depth analysis and real-world examples, this report sheds light on the evolving landscape of cloud computing, emphasizing the critical role AWS plays in enabling efficient, scalable, and secure infrastructure transitions. The findings provide valuable insights into the significance of cloud migration in today's technological advancements, demonstrating how organizations can optimize their infrastructure through thoughtful planning and execution.

This research paper explores the distinctions between 32-bit and 64-bit operating systems, focusing on their advantages, limitations, and appropriate use cases.
By analysing their
- architecture,
- memory management,
- performance, and
- compatibility,
this research paper provides a comprehensive guide for users, developers, and organizations in selecting the right operating system for their needs. 

The transition from 32-bit to 64-bit operating systems represents a pivotal shift in the evolution of computing technology. This paper explores the architectural differences between the two, focusing on how these distinctions influence memory management, processing capabilities, and overall system performance.
A 32-bit operating system, limited to addressing a maximum of 4 GB of RAM, is suitable for lightweight and legacy applications, offering resource efficiency and compatibility with older hardware. However, it struggles to meet the demands of modern, memory-intensive tasks.
In contrast, 64-bit operating systems, with their ability to handle vast memory spaces and perform advanced calculations more efficiently, are designed to support contemporary applications such as high-definition gaming, scientific simulations, and complex data processing.
The benefits of 64-bit systems extend beyond raw performance, including enhanced security features like better implementation of Address Space Layout Randomization (ASLR) and support for larger file systems.
Despite these advantages, 64-bit systems pose challenges in compatibility with legacy software and demand more resources, making them less ideal for low-power or embedded systems.

This paper examines the trade-offs between the two architectures, highlighting real-world use cases and scenarios where one may be preferred over the other.
It also considers future trends, including the declining relevance of 32-bit systems and the growing dominance of 64-bit environments in personal, enterprise, and industrial computing.
By delving into these aspects, the paper aims to provide a comprehensive guide to understanding

Recent growth in the processing and memory resources of mobile devices has fueled research within the field of mobile virtualization. Mobile virtualization enables multiple persona on a single mobile device by hosting heterogeneous operating systems (OSs) concurrently. However, adding a virtualization layer to resource-constrained mobile devices with real-time requirements can lead to intolerable performance overheads. Hardware virtualization extensions that support efficient virtualization have been incorporated in recent mobile processors. Prior to hardware virtualization extensions, virtualization techniques that are enabled by performance prohibitive and resource consuming software were adopted for mobile devices. Moreover, mobile virtualization solutions lack standard procedures for device component sharing and interfacing between multiple OSSs. The objective of this article is to survey software- and hardware-based mobile virtualization techniques in light of the recent advanc...

A major obstacle to virtualizing HPC workloads is a concern about the performance loss due to virtualization. We will demonstrate that new features significantly enhance the performance and scalability of virtualized HPC workloads on VMware's virtualization platform. Specifically, we will discuss VMware's ESXi Server performance for virtual machines with up to 64 virtual CPUs as well as support for exposing virtual NUMA topology to guest operating systems, enabling the operating system and applications to make intelligent NUMA aware decisions about memory allocation and process/thread placement. NUMA support is especially important for large VMs which necessarily span host NUMA nodes on all modern hardware. We will show how the virtual NUMA topology is chosen to closely match physical host topology, while preserving the now expected virtualization benefits of portability and load balancing. We show that the benefit of exposing the virtual NUMA topology can lead to performance gains of up to 167%. Overall, we will show close to native performance on applications from SPEC MPI V2.0 and SPEC OMP V3.2 benchmarks virtualized on our prototype VMware's ESXi Server.

The users of today's operating systems demand high reliability and security. However, faults introduced outside of the core operating system by buggy and malicious device drivers can significantly impact these dependability attributes. To help improve driver isolation, we propose an approach that utilizes the latest hardware virtualization support to efficiently sandbox each device driver in its own minimal Virtual Machine (VM) so that the kernel is protected from faults in these drivers. We present our implementation of a low-overhead virtual-machine based framework which allows reuse of existing drivers. We have constructed a prototype to demonstrate that it is feasible to utilize existing hardware virtualization techniques to allow device drivers in a VM to communicate with devices directly without frequent hardware traps into the Virtual Machine Monitor (VMM). We have implemented a prototype parallel port driver which interacts through iKernel to communicate with a physical LED device.

A recent trend in x86 virtualization products from Microsoft, VMware, and XenSource has been the reliance on hardware virtualization features found in current 64-bit microprocessors. Hardware virtualization allows for direct execution of guest code and potentially simplifies the implementation of a Virtual Machine Monitor (or "hypervisor") 1. Until recently, hypervisors on the PC platform have relied on a variety of techniques ranging from the slow but simple approach of pure interpretation, the memory intensive approach of dynamic recompilation of guest code into translated code cache, to a hardware assisted technique known as "ring compression" which relies on the host MMU for hardware memory protection. These techniques traditionally either deliver poor performance 2 , or are not portable. This makes most virtualization products unsuitable for use on cell phones, on ultra-mobile notebooks such as ASUS EEE or OLPC XO, on game consoles such as Xbox 360 or Sony Playstation 3, or on older Windows 98/2000/XP class PCs. This paper describes ongoing research into the design of portable virtual machines which can be written in C or C++, have reasonable performance characteristics, could be hosted on PowerPC, ARM, and legacy x86 based systems, and provide practical backward compatibility and security features not possible with hardware based virtualization.

A recent trend in x86 virtualization products from Microsoft, VMware, and XenSource has been the reliance on hardware virtualization features found in current 64-bit microprocessors. Hardware virtualization allows for direct execution of guest code and potentially simplifies the implementation of a Virtual Machine Monitor (or "hypervisor") 1 . Until recently, hypervisors on the PC platform have relied on a variety of techniques ranging from the slow but simple approach of pure interpretation, the memory intensive approach of dynamic recompilation of guest code into translated code cache, to a hardware assisted technique known as "ring compression" which relies on the host MMU for hardware memory protection. These techniques traditionally either deliver poor performance 2

IT service providers employ server virtualization as a basic building block of their platforms to increase the cost effectiveness. The economic benefits from server virtualization come from higher resource utilization, reduced maintenance and operational costs including energy consumption. However, those benefits require efficient assignments of virtual servers or jobs to a limited number of physical hosts. The primary measures of evaluating efficiency of an assignment are that all the system resources are utilized effectively and the performance of each virtual machine is consistent with the desired performance bounds. While satisfying such SLA/performance bounds is essential for many classes of applications, the interference among the virtual machines makes such assurance admittedly difficult. This is primarily due to the complexity of estimating the completion time of jobs on assigned virtual servers. In this paper, we present a mathematical model for estimating the processing time of jobs in shared virtual servers by treating it as a conventional job scheduling problem. Given a job set, its total processing time is the fundamental objective function for a class of optimization problems, commonly known as job scheduling problems. The classical model that assumes the total processing time as the sum of individual processing times, unfortunately does not capture the multiple-resource contention to process a job. A job needs several resources such as processing cores and memory on the physical platform, hence the resource contention does not exhibit the simple classical behavior. In this work, we establish a general quantitative model for the total processing time for machines with multiple resources. A job is characterized by vector valued loading statistics and the total processing time of a job set is given by a quadratic function of those loading vectors. We validate the model with actual measurements of applications running times on a Xen-based virtualized infrastructure. The experimental results indicate that the proposed model is effective in capturing the resource contention in a virtualized platform. The average error rate of the estimated running time with synthetic workloads is 10.7% for identical jobs and 6.0% for heterogeneous jobs, and is within 6% with realistic workloads.

Monte Carlo simulations are a powerful tool used in various scientific and engineering domains for modeling and understanding complex systems through probabilistic analysis. As computational demands increase, there is a growing need to accelerate these simulations using modern technologies. This paper presents a comparative analysis of two widely used technologies-Celery, a distributed task queue, and Docker, a containerization platform-for accelerating Monte Carlo simulations. We evaluate these tools based on performance, scalability, ease of use, and integration into existing workflows. Celery provides an efficient framework for distributing tasks across multiple processors or machines, enhancing parallelism and reducing computation time. Docker, on the other hand, offers a lightweight and portable solution for deploying simulations in isolated environments, ensuring consistent performance across different systems. Our study highlights the strengths and limitations of each approach and offers insights into their optimal use cases. Results indicate that while Celery excels in task distribution and parallel execution, Docker provides significant advantages in environment management and reproducibility. By leveraging the complementary features of Celery and Docker, users can achieve substantial improvements in simulation speed and reliability. This paper concludes with recommendations for selecting the appropriate technology based on specific simulation requirements and computational resources.

* This paper proposes ViMo that is a micro virtual machine monitor for ARM mobile systems, which enables to run multiple OSes on single mobile system at the same time. ViMo does not require any modification or compilation of OS, so that time and cost developing a virtualized mobile system can be reduced. Isolation of each virtual machine is another major feature of ViMo and it prevents the other virtual machines from the malfunctions of contaminated virtual machine.

Using a dedicated server for one operating system that only requires resources that are not too large is a waste. The remaining resources may be greater than the resources used, so that remaining resources will be wasted. On the other hand, a server with one operating system will preclude the use by the different operating system. The author suggests a method for the problem. The method offered is the use of a virtual machine that is also called virtual private servers (VPS). With virtual machine, a server machine can be equipped with multiple operating systems, so that existing resources can be optimized. VPS bridges the gap between shared web hosting services from dedicated server service, giving customers the freedom from other VPS services in the realm of software, but with a lower expenditure than dedicated servers. Using server virtualization makes more efficient use of resources. Resources remaining unused by a single operating system can be used by other operating systems. Virtualization also allows backup mechanisms for virtual machine.

Software is a set of instructions, data, or programs used to operate a computer and execute specific tasks. In simpler terms, it tells a computer how to function. It Is a generic term used to refer to applications, scripts, and programs that run on devices such as PCs, mobile phones, tablets, and other smart devices. Important Goals of Software Testing: Detecting bugs as soon as feasible in any situation. Avoiding errors in a projects and product's final versions. Inspect to see whether the customer requirements criterion has been satisfied. Last but not least, the primary purpose of testing is to gauge the project and product level of quality. The main goal of software testing is to detect bugs as early as possible and ensure that the software is bug-free. Software development involves inherent risks that can impact project success. The key components of software: Functionality, Reliability, Efficiency. Software development risks are potential events or conditions that can hinder the successful implementation of a software project. These risks may lead to delays, cost overruns, or subpar end products. Software has numerous advantages, but it also comes with several disadvantages and potential risks. In terms of methodology, a theoretical approach was used as the research technique for this study which involves doing a review of various publications, research papers, and studies published on this topic, but it focuses more on primary sources of information. The results display that software engineering is speedily becoming a powerful tool with enormous potential to advance academic work, and it is already being used in a variety of ways.

Energy consumption is a primary concern for datacenters' management. Numerous datacenters are relying on virtualization, as it provides flexible resource management means such as virtual machine (VM) checkpoint/restart, migration and consolidation. However, one of the main hindrances to server consolidation is physical memory. In nowadays cloud, memory is generally statically allocated to VMs and wasted if not used. Techniques (such as ballooning) were introduced for dynamically reclaiming memory from VMs, such that only the needed memory is provisioned to each VM. However, the challenge is to precisely monitor the needed memory, i.e., the working set of each VM. In this paper, we thoroughly review the main techniques that were proposed for monitoring the working set of VMs. Additionally, we have implemented the main techniques in the Xen hypervisor and we have defined different metrics in order to evaluate their efficiency. Based on the evaluation results, we propose Badis, a s...

Numerous systems have been designed which use virtualization to subdivide the ample resources of a modern computer. Some require specialized hardware, or cannot support commodity operating systems. Some target 100% binary compatibility at the expense of performance. Others sacrifice security or functionality for speed. Few offer resource isolation or performance guarantees; most provide only best-effort provisioning, risking denial of service. This paper presents Xen, an x86 virtual machine monitor which allows multiple commodity operating systems to share conventional hardware in a safe and resource managed fashion, but without sacrificing either performance or functionality. This is achieved by providing an idealized virtual machine abstraction to which operating systems such as Linux, BSD and Windows XP, can be ported with minimal effort. Our design is targeted at hosting up to 100 virtual machine instances simultaneously on a modern server. The virtualization approach taken by Xen is extremely efficient: we allow operating systems such as Linux and Windows XP to be hosted simultaneously for a negligible performance overhead-at most a few percent compared with the unvirtualized case. We considerably outperform competing commercial and freely available solutions in a range of microbenchmarks and system-wide tests.

Data centres have evolved over the past few years into an essential part of contemporary business operations. However, data centres consume a significant amount of energy and generate substantial amounts of carbon emissions, which has led to growing concerns regarding their impact on the environment. Green data centres have emerged as a solution to these concerns, with virtualization technology being one of the most effective strategies to reduce energy usage. The paper analyses the effectiveness of data centre virtualization in reducing energy usage in a green data centre by analysing the requirements for achieving scalability and high availability in data centre solutions. It then evaluates the concepts, techniques, and technologies used within the design and implementation of a green data centre, with a specific focus on virtualization. The research explores the potential benefits and challenges of virtualization in green data centres, such as reduced energy consumption, improved server utilization. Also critically assesses emerging data centre technologies and their applicability to virtualization in green data centres. It examines usefulness of virtualization in green data centres, as well as the promise of future technologies like softwaredefined networking (SDN), network function virtualization (NFV), and containerization.

VirtuaLinux is a meta-distribution that enables a standard Linux distribution to support robust physical and virtualized clusters. VirtuaLinux helps in avoiding the "single point of failure" effect by means of a combination of architectural strategies, including the transparent support for disk-less and master-less cluster configuration. VirtuaLinux supports the creation and management of Virtual Clusters in seamless way: VirtuaLinux Virtual Cluster Manager enables the system administrator to create, save, restore Xenbased Virtual Clusters, and to map and dynamically re-map them onto the nodes of the physical cluster. In this paper we introduce and discuss VirtuaLinux virtualization architecture, features, and tools, and in particular, the novel disk abstraction layer, which permits the fast and space-efficient creation of Virtual Clusters.

Server virtualization technology has experienced significant development so that more and more industries are adopting this technology. By using server virtualization, the industry can make savings in purchasing new servers and maintenance because virtualization allows one server to run with multiple operating systems at once. The high level of use of virtualization raises a gap for the occurrence of computer crimes involving virtualization. When computer crimes occur on virtualization, it is necessary to conduct digital forensic investigations to find useful clues in solving crime cases. Therefore, in this study a digital forensic investigation was conducted on Proxmox server virtualization by acquiring the entire storage virtualization media and carrying out checks on the results of the acquisition. Based on the investigation carried out, the acquisition technique by acquiring the entire storage media on Proxmox cannot be used because the structure of the evidence files and folder...

Virtualization technology is important for servers that compose cloud data centers. The current trend is to consolidate servers to manage them easily and reduce hardware and power consumption in data centers. However, performance degradation is inherent to virtualization technology and is caused by the hypervisor and overhead due to the consolidation of several virtual servers inside a physical server. Several ways exist to virtualize a server; these methods are based mainly on virtual machines and containers. In this paper, we propose a general method to estimate the value of the consolidation overhead classes, regardless of the virtualization platform, server characteristics and workload type. We conducted several experiments in different scenarios to illustrate the usefulness of the proposed method. The results show the applicability of the proposed method and indicate that these inherent overheads are not negligible in many cases depending on, first, the type of hypervisor and, second, the hardware resources features of the physical server.

Presently, the uses of virtualization technologies are increased very frequently. This increases the IT agility, flexibility, and scalability. There is a layer of virtualization between the guest OS and physical hardware. This paper analyze the performance of virtualization technology with comparitive analysis. Our experiment showed that KVM gives the best performance as compared to XEN. This paper suggests best-suited hypervisors for aimed application.

Presently, the uses of virtualization technologies are increased very frequently. This increases the IT agility, flexibility, and scalability. There is a layer of virtualization between the guest OS and physical hardware. This paper analyze the performance of virtualization technology with comparitive analysis. Our experiment showed that KVM gives the best performance as compared to XEN. This paper suggests best-suited hypervisors for aimed application.

In this study, the technical performance of virtualization and containerization is examined. Analyze the starting times of virtual machines (VMs) in cloud environments, a critical performance characteristic. Three researchers have thoroughly researched the context of virtualization and containerization technologies using various suggested methods, each revealing the specific benefits and drawbacks of these tactics. These studies emphasize the importance of carefully weighing the advantages and disadvantages of virtualization and containerization technologies in light of the particular application requirements and larger organizational goals. This study has laid a solid foundation for adopting technology by thoroughly investigating the complex interactions between various technologies and their related effects. The research contributions aim to provide academics, practitioners, and organizations with the knowledge necessary to make wise technical decisions that will enable them to accomplish their goals as the technological landscape continues to change.

Malicious software is rampant on the Internet and costs billions of dollars each year. Safe and thorough analysis of malware is key to protecting vulnerable systems and cleaning those that have already been infected. Most current state-of-the-art analysis platforms run alongside the malware, increasing their detectability. This reduces the value of analysis because some malware is known to behave differently when being analyzed. Virtualization offers a compelling platform for malware analysis, with strong isolation and the ability to save and restore guest state. Current virtual machine monitors (VMMs), however, are not designed for malware analysis. Due to their complexity, they often fail to provide transparency and even expose vulnerabilities which could be exploited by the malware running inside guest system. We propose a lightweight VMM (namely MAVMM) that is designed specially for a single job: malware analysis. MAVMM does not implement unnecessary virtualization features commonly found in general purpose hypervisors, including virtual device emulation. We take advantage of hardware virtualization support to make MAVMM more simple, secure and transparent. In this paper, we describe the design and implementation of MAVMM, and the features that we can extract from programs running inside the guest OS. We evaluate our platform in three aspects: functionality, detectability and performance. We show that our system can extract useful information from malicious software, and that it is not susceptible to known virtualization detection techniques.

Dalam membangun sebuah program melalui virtualisasi, pengembang biasanya menjalankan virtualisasi pada server sehingga proses pembuatan program dapat berjalan pada berbagai platform maupun konfigurasi hardware. Masalah yang dihadapi dengan virtualisasi adalah perlunya menyiapkan satu sistem operasi secara utuh, termasuk berbagai aplikasi yang dibawa sistem tersebut. Bisa dibayangkan dengan banyaknya virtualisasi yang berjalan di sebuah server akan memberatkan sistem tersebut. Docker adalah salah satu platform yang dibangun berdasarkan teknologi container. Docker merupakan sebuah project open-source yang menyediakan platform terbuka untuk developer maupun sysadmin untuk dapat membangun, mengemas dan menjalankan aplikasi dimanapun sebagai sebuah wadah (container) yang ringan. Hasil yang didapatkan pada penelitian yang dilakukan adalah sebuah aplikasi web dimana dalam mengimplementasikan teknik virtualisasi server menggunakan Docker untuk keperluan deployment aplikasi berhasil dilakukan. Aplikasi yang digunakan merupakan aplikasi jual beli yang tersimpan pada Server Docker dimana kedua Client berhasil menggunakan aplikasi tersebut di platform berbeda yaitu Windows 7 dan Windows 8 tanpa mengalami kendala sedikit pun.

Virtualization is a framework or methodology that is used to divide the resources of a computer into multiple execution environments by applying concepts or technologies storage virtualization, client virtualization, and server virtualization are different ways to achieve virtualization. Our goal in this paper is to implement server virtualization with attacks and threats with possible solutions. Server virtualization is best suitable for dividing a server into a multiple virtual servers via software such as VMware and Hyper V. This method is used to increase the resource utilization by performing the same. In this each virtual server act and look like a physical server by increasing the capacity of every single physical machine (Kuche et al. in Int J Comput Netw Wireless Mobile Commun (IJCNWMC) 4:5-10 (2014), [1] with problems like efficient resource management, more downtime and privacy and security of data are associated with server virtualization. The problem is unauthorized users are accessing the access of machine/server in VMware platform. This can be done by proposing model named object level permission model to provide security by assigning permissions and roles as per level.

Virtualization technology is widely used for sharing the abilities of computer systems by splitting the resources among various virtual PCs. In traditional computer systems, the utilization of hardware is not maximized and the resources are not fully consumed. By using the virtualization technology, the maximum utilization of computer system hardware is possible. Today, many organizations especially educational institutes are adopting virtualization technology to minimize the costs and increase the flexibility, responsiveness, and efficiency. In this paper, we built a virtual educational lab in which we successfully implemented Virtual Desktop Infrastructure (VDI) and created more than 30 virtual desktops. The virtual desktops are created on the Citrix XenServer hypervisor using the Citrix XenDesktop. Finally, we used benchmarking software tool called Login VSI in order to measure the performance of the virtual desktop infrastructure and the XenServer hypervisor. The results have shown that the system performs well with 30 virtual desktops without reaching the saturation point.

On modern processors, hardware-assisted virtualization outperforms binary translation for most workloads. But hardware virtualization has a potential problem: virtualization exits are expensive. While hardware virtualization executes guest instructions at native speed, guest/VMM transitions can sap performance. Hardware designers attacked this problem both by reducing guest/VMM transition costs and by adding architectural extensions such as nested paging support to avoid exits. This paper proposes complementary software techniques for reducing the exit frequency. In the simplest form, our VMM inspects guest code dynamically to detect back-to-back pairs of instructions that both exit. By handling a pair of instructions when the first one exits, we save 50% of the transition costs. Then, we generalize from pairs to clusters of instructions that may include loops and other control flow. We use a binary translator to generate, and cache, custom translations for handling exits. The analysis cost is paid once, when the translation is generated, but amortized over all future executions. Our techniques have been fully implemented and validated in recent versions of VMware products. We show that clusters consistently reduce the number of exits for all examined workloads. When execution is dominated by exit costs, this translates into measurable runtime improvements. Most importantly, clusters enable substantial gains for nested virtual machines, delivering speedups as high as 1.52x. Intuitively, this result stems from the fact that transitions between the inner guest and VMM are extremely costly, as they are implemented in software by the outer VMM.

On modern processors, hardware-assisted virtualization outperforms binary translation for most workloads. But hardware virtualization has a potential problem: virtualization exits are expensive. While hardware virtualization executes guest instructions at native speed, guest/VMM transitions can sap performance. Hardware designers attacked this problem both by reducing guest/VMM transition costs and by adding architectural extensions such as nested paging support to avoid exits. This paper proposes complementary software techniques for reducing the exit frequency. In the simplest form, our VMM inspects guest code dynamically to detect back-to-back pairs of instructions that both exit. By handling a pair of instructions when the first one exits, we save 50% of the transition costs. Then, we generalize from pairs to clusters of instructions that may include loops and other control flow. We use a binary translator to generate, and cache, custom translations for handling exits. The analysis cost is paid once, when the translation is generated, but amortized over all future executions. Our techniques have been fully implemented and validated in recent versions of VMware products. We show that clusters consistently reduce the number of exits for all examined workloads. When execution is dominated by exit costs, this translates into measurable runtime improvements. Most importantly, clusters enable substantial gains for nested virtual machines, delivering speedups as high as 1.52x. Intuitively, this result stems from the fact that transitions between the inner guest and VMM are extremely costly, as they are implemented in software by the outer VMM.

Software Defined Network (SDN) merupakan paradigma baru dalam jaringan komputer yang memisahkan antara dataplane dan control plane. Dengan pemisahan tersebut konfigurasi jaringan akan lebih mudah dilakukan tidak serumit pada jaringan konvensional. Pada penelitian ini dibahas mengenai bagaimana penerapan metode network slicing menggunakan FlowVisor pada jaringan SDN dengan POX sebagai kontrolernya. Network slicing memungkinkan tiap network slices dapat dirancang untuk menjamin tingkat kinerja jaringan yang berbeda. Emulator yang digunakan untuk merancang topologi sekaligus sebagai data plane yaitu Mininet. Hasil dari penelitian ini menunjukkan bahwa FlowVisor mampu melakukaan isolasi flowspace setiap slice pada jaringan SDN berdasarkan TCP port yang dilalui ketika terjadinya komunikasi antar host. Perbandingan jaringan SDN tanpa menggunakan metode network slicing dengan jaringan SDN yang menggunakan metode network slicing menghasilkan nilai yang tidak jauh signifikan, namun lebih bai...

There is a growing interest in virtualisation due to its central role in cloud computing, virtual desktop environments and Green IT. Data centres and cloud computing utilise this technology to run multiple operating systems on one physical server, thus reducing hardware costs. However, vulnerabilities in the hypervisor layer have an impact on any virtual machines running on top, making security an important part of virtualisation. In this paper, we evaluate the security of virtualisation, including detection and escaping the environment. We present a methodology to investigate if a virtual machine can be detected and further compromised, based upon previous research. Finally, this methodology is used to evaluate the security of virtual machines. The methods used to evaluate the security include analysis of known vulnerabilities and fuzzing to test the virtual device drivers on three different platforms: VirtualBox, Hyper-V and VMware ESXI. Our results demonstrate that the attack surface of virtualisation is more prone to vulnerabilities than the hypervisor. Comparing our results with previous studies, each platform withstood IOCTL and random fuzzing, demonstrating that the platforms are more robust and secure than previously found. By building on existing research, the results show that security in the hypervisor has been improved. However, using the proposed methodology in this paper it has been shown that an attacker can easily determine that the machine is a virtual machine, which could be used for further exploitation. Finally, our proposed methodology can be utilised to effectively test the security of a virtualised environment.

Software analysis, debugging, and reverse engineering have a crucial impact in today's software industry. Efficient and stealthy debuggers are especially relevant for malware analysis. However, existing debugging platforms fail to address a transparent, effective, and high-performance low-level debugger due to their detectable fingerprints, complexity, and implementation restrictions. In this paper, we present HyperDbg, * a new hypervisor-assisted debugger for high-performance and stealthy debugging of user and kernel applications. To accomplish this, HyperDbg relies on state-of-the-art hardware features available in today's CPUs, such as VT-x and Extended Page Table (EPT). In contrast to other widely used existing debuggers, we design HyperDbg using a custom hypervisor, making it independent of OS functionality or API. We propose hardware-based instruction-level emulation and OS-level API hooking via extended page tables to increase the stealthiness. Our results of the dynamic analysis of 10,853 malware samples show that HyperDbg's stealthiness allows debugging on average 22% and 26% more samples than WinDbg and x64dbg, respectively. Moreover, in contrast to existing debuggers, HyperDbg is not detected by any of the 13 tested packers and protectors. We improve the performance over other debuggers by deploying a VMX-compatible script engine, eliminating unnecessary context switches. Our experiment on three concrete debugging scenarios shows that compared to WinDbg as the only kernel debugger, HyperDbg performs step-in, conditional breaks, and syscall recording, 2.98x, 1319x, and 2018x faster, respectively. We finally show real-world applications, such as a 0-day analysis, structure reconstruction for reverse engineering, software performance analysis, and code-coverage analysis. CCS CONCEPTS • Security and privacy → Virtualization and security; Software security engineering; • Software and its engineering → Compilers.

Software analysis, debugging, and reverse engineering have a crucial impact in today’s software industry. Efficient and stealthy debuggers are especially relevant for malware analysis. However, existing debugging platforms fail to address a transparent, effective, and high-performance low-level debugger due to their detectable fingerprints, complexity, and implementation restrictions. In this paper, we present HyperDbg, a new hypervisor-assisted debugger for high-performance and stealthy debugging of user and kernel applications. To accomplish this, HyperDbg relies on state-of-the-art hardware features available in today’s CPUs, such as VT-x and extended page tables. In contrast to other widely used existing debuggers, we design HyperDbg using a custom hypervisor, making it independent of OS functionality or API. We propose hardware-based instruction-level emulation and OS-level API hooking via extended page tables to increase the stealthiness. Our results of the dynamic analysis of...

Malicious software is rampant on the Internet and costs billions of dollars each year. Safe and thorough analysis of malware is key to protecting vulnerable systems and cleaning those that have already been infected. Most current state-of-the-art analysis platforms run alongside the malware, increasing their detectability. This reduces the value of analysis because some malware is known to behave differently when being analyzed. Virtualization offers a compelling platform for malware analysis, with strong isolation and the ability to save and restore guest state. Current virtual machine monitors (VMMs), however, are not designed for malware analysis. Due to their complexity, they often fail to provide transparency and even expose vulnerabilities which could be exploited by the malware running inside guest system. We propose a lightweight VMM (namely MAVMM) that is designed specially for a single job: malware analysis. MAVMM does not implement unnecessary virtualization features commonly found in general purpose hypervisors, including virtual device emulation. We take advantage of hardware virtualization support to make MAVMM more simple, secure and transparent. In this paper, we describe the design and implementation of MAVMM, and the features that we can extract from programs running inside the guest OS. We evaluate our platform in three aspects: functionality, detectability and performance. We show that our system can extract useful information from malicious software, and that it is not susceptible to known virtualization detection techniques.

In recent decades, mixed-criticality systems have been widely adopted to reduce the complexity and development times of real-time critical applications. In these systems, applications run on a separation kernel hypervisor, a software element that controls the execution of the diferent operating systems, providing a virtualized environment and ensuring the necessary spatial and temporal isolation. The guest code can run unmodiied and unaware of the hypervisor or be explicitly modiied to have a tight coupling with the hypervisor. The former is known as full virtualization, while the latter is known as paravirtualization. Full virtualization ofers better compatibility and lexibility than para-virtualization, at the cost of a performance penalty. LEON is a processor family that implements the SPARC V8 architecture and whose use is widespread in the ield of space systems. To the best of our knowledge, all separation kernel hypervisors designed to support the development of mixed-criticality systems for LEON employ para-virtualization, which hinders the adaptation of real-time operating systems. This paper presents the design of a Virtualization Monitor that allows guest real-time operating systems to run virtualized on LEON-based systems without needing to modify their source code. It is designed as a standalone component within a hypervisor and incorporates a set of techniques such as static binary rewriting, automatic code generation, and the use of operating system proiles. To validate the proposed solution, tests and benchmarks have been implemented for three guest systems: RTEMS, FreeRTOS, and Zephyr, analyzing the overhead introduced in certain situations characteristic of real-time applications. Finally, the same benchmarks have been run on AIR, one of the hypervisors that uses para-virtualization. The results obtained show that the use of the proposed techniques allows us to obtain similar results to those obtained using para-virtualization without the need to modify the source code of the guest real-time operating systems. CCS Concepts: • Computer systems organization → Embedded software; Real-time system architecture; • Security and privacy → Virtualization and security.

Most hypervisors today rely either on (1) full virtualization on high-end hardware (i.e., hardware with virtualization extensions), (2) paravirtualization, or (3) both. These, however, do not fulfill embedded systems' requirements, or require legacy software to be modified. Full virtualization on low-end hardware (i.e., hardware without virtualization extensions), on the other end, has none of those disadvantages. However, it is often claimed that it is not feasible due to an unacceptably high virtualization overhead. We were, nevertheless, unable to find real-world quantitative results supporting those claims. In this paper, performance and footprint measurements from a case study on low-end hardware full virtualization for embedded applications are presented. More specifically, this paper presents: (1) an evaluation of the virtualization overhead in a Linuxbased system as a guest on POK/rodosvisor, a real time operating system for embedded systems featuring low-end hardware full virtualization; (2) a detailed look at the performance of POK/rodosvisor's internal operation, namely, interrupt handlers and context switching; and (3) POK/rodosvisor's footprint for various configurations. To the best of our knowledge, this is the first paper ever to present performance measurements about a Linux-based system as a guest on a hypervisor based on low-end hardware full virtualization, and therefore, targeting a common real-world scenario.

Current HPC system software lacks support for emerging application deployment scenarios that combine one or more simulations with in situ analytics, sometimes called multi-component or multi-enclave applications. This paper presents an initial design study, implementation, and evaluation of mechanisms supporting composite multi-enclave applications in the Hobbes exascale operating system. These mechanisms include virtualization techniques isolating application custom enclaves while using the vendor-supplied host operating system and high-performance inter-VM communication mechanisms. Our initial single-node performance evaluation of these mechanisms on multi-enclave science applications, both real and proxy, demonstrate the ability to support multi-enclave HPC job composition with minimal performance overhead.

The security of virtual machine monitors (VMMs) is a challenging and active field of research. In particular, due to the increasing significance of hardware virtualization in cloud solutions, it is important to clearly understand existing and arising VMM-related threats. Unfortunately, there is still a lot of confusion around this topic as many attacks presented in the past have never been implemented in practice or tested in a realistic scenario. In this paper, we shed light on VM related threats and defences by implementing, testing, and categorizing a wide range of known and unknown attacks based on directly assigned devices. We executed these attacks on an exhaustive set of VMM configurations to determine their potential impact. Our experiments suggest that most of the previously known attacks are ineffective in current VMM setups. We also developed an automatic tool, called PTFuzz, to discover hardware-level problems that affects current VMMs. By using PT-Fuzz, we found several cases of unexpected hardware behaviour, and a major vulnerability on Intel platforms that potentially impacts a large set of machines used in the wild. These vulnerabilities affect unprivileged virtual machines that use a directly assigned device (e.g., network card) and have all the existing hardware protection mechanisms enabled. Such vulnerabilities either allow an attacker to generate a host-side interrupt or hardware faults, violating expected isolation properties. These can cause host software (e.g., VMM) halt as well as they might open the door for practical VMM exploitations. We believe that our study can help cloud providers and researchers to better understand the limitations of their current architectures to provide secure hardware virtualization and prepare for future attacks.

Cloud based E-Learning is one of the booming technologies in Information Technology which brings powerful E-learning products with the help of cloud power. In recent years e-learning has grown into a widely accepted way of learning, and the usage of the global network is inevitable in every education process. Ubiquitous learning integrates wireless, mobile and context awareness technologies in order to detect the situation of the learners and provide more seamless adaptive support beyond formal learning process. In order to support modern pedagogical approaches, as well as a variety of heterogenic learning resources within courses, ubiquitous learning environments need to be based on a powerful IT infrastructure. At the same time, in order to be efficient, ubiquitous learning environments need to be based on learning management systems and integrated into an existing e-learning environment of educational institutions. Cloud technology has numerous advantages over the existing tradit...

A key challenge for supporting elastic behaviour in cloud systems is performant automated (de-)provisioning and scheduling of computing resources. Containers are rapidly replacing Virtual Machines (VMs) as the compute instance of choice in many cloud deployments, due to lower overhead of starting up and terminating containers in comparison to VMs. Performance overheads associated with deploying, terminating and maintaining a container can be significant. We analyse performance of the Kubernetes system and develop a Petri net-based model of resource management within this system. Our model is characterised using data from a Kubernetes deployment, and can be used as a basis to support capacity planning and design of scaleable applications that make use of Kubernetes.

Virtualization has enabled cloud computing to deliver computing capabilities using limited computer hardware. Server virtualization provides capabilities to run multiple virtual machines (VMs) independently in a shared host leading to efficient utilization of server resources. Unfortunately, VMs experience interference from each other as a result of sharing common hardware. The performance interference arises from VMs having to compete for the hypervisor capacity and as a result of resource contention, which happens when resource demands exceed the allocated resources. From this viewpoint, any VM allocation policy needs to take into account VM performance interference before VM placement. Therefore, understanding how to measure performance interference is crucial. In this paper, we propose a simple experimental approach that can be used to measure performance interference in Infrastructure as a Service (IaaS) cloud during VM consolidation.