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Xen Project Membership Spotlight: Citrix

The Xen Project is comprised of a diverse set of member companies and contributors that are committed to the growth and success of the Xen Project Hypervisor. The Xen Project Hypervisor is a staple technology for server and cloud vendors, and is gaining traction in the embedded, security and automotive space. This blog series highlights the companies contributing to the changes and growth being made to the Xen Project, and how the Xen Project technology bolsters their business.


Name: James Bulpin
Title: Senior Director, Technology
Company: Citrix

When did you join the Xen Project and why/how is your organizations involved?
Citrix was a founding member of the Xen Project and, through the work of XenSource, which was acquired by Citrix in 2007, has been active in the open-source Xen Project hypervisor since 2005. Personally I’ve been involved with Xen since its very early days as a research project in the early 2000s.

Citrix is a significant contributor to, consumer of, and leader in the Xen Project. The Xen Project hypervisor forms the core of our XenServer platform, which has widespread use as a free platform for general purpose server virtualization, a commercial server virtualization and cloud hosting platform, a technology component in other Citrix products, and the platform of choice for Citrix’s flagship application and desktop delivery solutions. We see the Xen Project hypervisor as a powerful, flexible and secure foundation on top of which a wide variety of products, solutions and services can be built.

How does your involvement benefit your company?
A hypervisor is a complex entity, requiring deep knowledge of many areas of technology in order to implement successfully; it requires deep knowledge of CPU virtualization instructions, interrupt and exception handling, efficient resource management (such as CPU scheduling), a wide variety of I/O virtualization mechanisms, multiple mechanisms to boot virtual machines, multiple security boundaries, and so on. By collaborating with other vendors who share our need for an efficient, flexible hypervisor, and with vendors whose technology can be enabled through the hypervisor, we are able to achieve far more than any one of us could on our own. Ultimately this allows us to bring a very sophisticated solution to our customers at a low cost.

How does the Xen Project’s technology help your business?
In addition to the Xen Project hypervisor and other components being a core part of our commercial products, Xen Project has enabled rapid multi-vendor innovation that helps us to get ahead of the competition and helps our customers solve their problems. The open-source nature of the hypervisor removes barriers to collaboration and accelerates innovation. In recent years this has allowed Citrix and its partners to be first to market with innovative solutions such as virtualized GPUs with NVIDIA and Intel, VM introspection with BitDefender, and hypervisor live patching built in collaboration with Oracle, Amazon and others.

What are some of the major changes you see with virtualization and the transition to cloud native computing?
Over time we expect to see virtualization creeping up the stack. Hypervisors and the CPU virtualization instructions they rely upon virtualize at the lowest layers; PaaS and cloud-native services are effectively performing virtualization further up the stack (e.g. a Linux container virtualizes the kernel, and a “lambda” type function virtualizes a language runtime environment).

Although we’ve seen FUD that argues that these high levels of virtualization render the lower levels obsolete, in reality the different layers of virtualization bring different values to an overall cloud computing platform. We see that cloud platforms will evolve to use multiple virtualization techniques, albeit in a more integrated fashion than we see today. For example we anticipate that platforms providing container or PaaS services will actually rely on hypervisor techniques and CPU virtualization instructions to provide a strong security boundary (particularly in a multi-tenant context) at the bottom, and use container technology, software sandboxing and other lightweight virtualization techniques on top. Such as solution will likely have a very tight integration between the layers to minimize overhead. The small, flexible, and efficient structure of the Xen Project hypervisor makes it an attractive technology to embed in a system like this.

What advice would you give someone considering joining the Xen Project?
Although many members will join with a particular goal in mind, such as adding functionality to the hypervisor to enable their own products/technology, I would recommend looking beyond that and considering how to best leverage the opportunity to collaborate with the other members. For example, adding a mechanism to Xen to enable the use of a particular piece of hardware is valuable in its own right, however using the Project to collaborate with a vendor that can exploit that mechanism and that piece of hardware and take it to a broader customer base could end up providing an ever better return on investment. I would also encourage new joiners to get involved in code and design review of other members’ contributions. This is a great way to quickly learn about Xen, helps improve the code, and fuels the necessary “give and take” model that an open source project needs to operate successfully.

What excites you most about the future of Xen?
Xen has already proven itself in a number of diverse use-cases including traditional server virtualization, large-scale cloud computing, and client virtualization. I’m excited to see Xen, as a reusable technology component, grow in new use-cases such as edge computing, automotive, aviation and aerospace. Xen’s flexibility, small footprint, and OS independence make it a good fit in these growing sectors.


A Brief Introduction to the Xen Project and Virtualization from Mohsen Mostafa Jokar

Mohsen Mostafa Jokar is a Linux administrator who works at the newspaper Hamshahri as a network and virtualization administrator. His interest in virtualization goes back to when he was at school and saw a Microsoft Virtual PC for the first time. He installed it on a PC with 256 MB of RAM and used it to virtualize Windows 98 and DOS.

Beyond Linux and virtualization, Mohsen is also familiar with Fedora Core, Knoppix, RedHat, bochs, Qemu, Xen, Citrix XenServer and VMWare ESXi.

He recently wrote an introductory book on Xen called “Hello Xen Project,” which is now available via this wiki. It provides a brief history of virtualization and the Xen Project, dom(s) and grub, using the Xen Project, and having fun with Xen. He hopes that more Xen users and experts will share their expertise and knowledge about this strong, stable and reliable virtualization platform through this wikipedia page.

A celebration of Xen Project 4.9 and the wiki book.

A celebration of Xen Project 4.9 and the wiki book.

In addition to his fascination with virtualization, Mohsen is a translator and an author. He has translated and written books for beginners and professional users that focus on virtualization, security and Linux. A few books that he has worked on as a technical reviewer include “Elixir in Action,” “Learn Git in a Month of Lunches,” “Mesos in Action” and “Reverse Engineering for Beginners.”

Automotive, Security and the Future of the Xen Project at The Xen Project Developer and Design Summit

The Xen Developer and Design Summit schedule is now live! This conference combines the formats of the Xen Project Developer Summits with the Xen Project Hackathons. If you are part of the Xen Project’s community of developers and power users, come join us in Budapest, Hungary, July 11 – 13 for this must-attend event!


The conference will cover many different topic areas including community, embedded/automotive, performance, tooling, hardware, security and more. The format will include traditional panels and presentation, as well as design and problem solving sessions.

Design and problem solving session proposals will be accepted until July 7. This is a great way to meet other developers face-to-face to:

  • Discuss and advance the design and architecture of future functionality
  • Coordinate and plan upcoming features
  • Discuss and share best practices and ideas on how to improve community collaboration
  • Hear interactive sessions covering lessons learned from contributors, users and vendor

Submit your design and problem solving ideas here.

Keynotes this year are coming from Lars Kurth, Xen Project Chairperson and Director of Open Source Solutions at Citrix; Oleksandr Andrushchenko, Lead Software Engineer at EPAM Systems; Stefano Stabellini, Virtualization Architect at Aporeto; and Wei Liu, Senior Software Engineer at Citrix.

Here’s a small sampling of other speaking sessions during the conference:


  • Dedicated Secure Domain as an Approach for Certification of Automotive Sector Solutions from Iurii Mykhalskyi of GlobalLogic
  • Harmony of CPU Scheduling Between RT Guest OS and Rich Guest OS in Automotive Virtualization from Sangyun Lee of LG Electronics


  • Hypervisor-Based Security: Bringing Virtualized Exceptions Into the Game from Mihai Dontu of Bitdefender
  • Uniprof: Transparent Unikernel Performance Profiling and Debugging from Florian Schmidt of NEC

Future of Xen

  • Intel GVT-g: From Production to Upstream from Zhi Wang of Intel
  • Recent and Ongoing Xen Related Work in the Linux Kernel from Jürgen Groß of SUSE

General Hypervisor

  • Bring up PCI Passthrough on ARM from Julien Grall of ARM
  • EFI Secure Boot, Shim and Xen: Current Status of Developments from Daniel Kiper of Oracle

You can view the entire schedule here. Early bird specials for tickets (price is $250) are available until May 31st.

A special thank you to our Diamond Sponsor Citrix and Gold sponsors ARM, Intel and Superfluidity. We look forward to seeing you at the event in July, and please stay informed on Xen Project updates by following us on social (Twitter and Facebook) and registering to our xen-announce mailing list.


Q&A with GlobalLogic on the Xen Project and Automotive Virtualization

The Xen Project is commonly used in embedded scenarios due to its security features, light-weight architecture and open source community. These core attributes are now making it more pervasive in the automotive industry, which has similar demands to the embedded industry, especially when it comes to security requirements.

To better understand how the Xen Project is used in the automotive space, we sat down with the folks at GlobalLogic to discuss updates on its Nautilus platform, which uses the Xen Project hypervisor; why they originally chose Xen; how hypervisors generally work in the automotive space; and the company’s upcoming plans with automotive virtualization.

Last year when we talked to GlobalLogic, you mentioned that GPU Virtualization was the next phase of automotive innovation. Where are you at in terms of implementing GPU Virtualization?

We have successfully implemented our Nautilus platform’s GPU virtualization feature for several Tier 1 automotive vendors (located in Japan, the US, and Europe). This was a big win for us and we learned a lot along the way and experienced some major benefits. Mainly, GPU virtualization has eliminated almost all performance degradation during the rendering of heavy 3D graphics scenes, allowing us to create a new level of IVI systems.

Why is the hypervisor important for automotive virtualization and GPU Virtualization in general? Why is Xen Project the hypervisor of choice for you within this space?

The hypervisor allows a significant decrease to the cost of automotive production and reduces the cost of BOM because the functions that were previously executed on different CPUs can be run on separate VMs. At the same time, GPU virtualization is beneficial in the process of 2D/3D graphics rendering. Therefore, the use of hypervisor enables building systems that perform better than their more expensive completely-hardware analogues.

Moreover, there are less processors per board, which leads to higher fail-safety. Essentially, a virtual system divided into a number of small subsystems is cheaper to maintain.

At the dawn of our project, GlobalLogic engineers considered various hypervisors, and finally decided that Xen Project was the most suitable solution because it is open source and has a rich history of application in various fields. Using the Xen Project, lets us concentrate on specific vehicle-related challenges instead of reinventing a virtualization solution.

What are the top three benefits you get from using the Xen hypervisor?

The first benefit that we have experienced is the decreased time to market for the manufacturers. Secondly, our customers get demos for free – if we used a proprietary product, we couldn’t afford this. Finally, it is great to experience the constant support of the global community and the community-driven approach to vulnerability detecting and fixing that we get with the Xen Project.

Were there any challenges with implementing Xen? How did you overcome these challenges?

The main challenges that we had with Xen and GPU virtualization was related to the different based ARM platforms. To overcome this, we developed a bench of drivers and extended the environment around them.

What are the next stages of growth for with automotive virtualization? Any trends that we should watch out for?

GlobalLogic is actively working on the commercialization of the Nautilus platform. We are expanding the GPU feature to a network of customers and vehicle models. At the same time, we are expanding the functionality of virtualization in areas like self-driving, advanced driver assistance systems (ADAS), connected services, safety, etc.

How To Shrink Attack Surfaces with a Hypervisor

A software environment’s attack surface is defined as the sum of points in which an unauthorized user or malicious adversary can enter or extract data. The smaller the attack surface, the better. recently sat down with Doug Goldstein ( or @doug_goldstein) to discuss how companies can use hypervisors to reduce attack surfaces and why the Xen Project hypervisor is a perfect choice for security-first environments. Doug is a principal software engineer at Star Lab, a company focused on providing software protection and integrity solutions for embedded systems.

You can read the full interview here.

Tips and Tricks for Making VM Migration More Secure

A challenge for any cloud installation is the constant tradeoff of availability versus security. In general, the more fluid your cloud system (i.e., making virtualized resources available on demand more quickly and easily), the more your system becomes open to certain cyberattacks. This tradeoff is perhaps most acute during active virtual machine (VM) migration, when a VM is moved from one physical host to another transparently, without disruption of the VM’s operations. Live virtual machine migration is a crucial operation in the day-to-day management of modern cloud environment. recently published an article from John Shackleton of Adventium Labs that focuses on how to recognize and avoid common attacks with VM migration. Read the full article here.