Xen on Ampere: A New Era for ARM in the Data Center
ARM based servers are growing in popularity in the data center domain. They bring huge potential for power efficiency and scalability, making them a natural fit for modern data centers. Large scale public cloud providers, like AWS, are already getting on board. Where does virtualization fit into this next wave data center technology? The answer is clear: Xen.
Xen is already compatible with ARM. This is one reason why Xen is such a popular choice with embedded system developers. However, XCP-ng, the enterprise-ready platform built on Xen, still requires additional development to achieve full ARM compatibility. Beyond the Xen hypervisor, XCP-ng includes additional components, like XAPI, that are being actively developed to add full ARM support.
The XCP-ng team were able to get access to some high-powered Ampere servers to see what was possible. Their goal was simple: enabling Xen-based virtualization in enterprise grade ARM-based data centers. While it's still early days for Xen on Ampere, the future looks very bright.
ARM-based servers offer scalable, power-efficient solutions for data centers, and Xen is the key to unlocking their full potential.
This article will explain why this matters, what's the current state, and what's coming next.
Why?
Often when thinking of ARM, mobile devices come to mind. Where a balance of performance and efficiency are paramount. Apple already proved that laptops and desktops are also a great fit for ARM based processors. However, ARM is now making a serious impact in the data center space. AWS has already proven the value of ARM powered servers with their Graviton line of processors. These provide better performance per watt and that leads to cost savings. Now that Ampere is offering high core count CPUs there is a huge potential for ARM in virtualization.
This is where Xen fits in.
Hosting providers, private clouds, and enterprises are all looking for the same thing: to maximize efficiency. Xen is already widely used on ARM, particularly in embedded systems. However, XCP-ng, which includes additional management tools like XAPI, still requires additional development before it can fully power ARM-based data centers. The marriage of Xen's lightweight and secure virtualization and Ampere's power efficiency is a perfect match. The results could be high-density and low-power compute at scale. The holy-grail of data center technologies.
The work isn't just about making Xen compatible with Ampere hardware. It's about expanding the options of virtualization for an ARM-powered future. A future full of possibilities.
Xen’s lightweight, flexible virtualization makes it the ideal choice for ARM-based data centers looking for efficiency and scalability.
Xen on Ampere
The XCP-ng team was able to get their hands on some Ampere Altra-based servers. This opportunity allowed the team to start seeing what Xen could do. The machines were not lightweight concepts. Each server is packed with dual 80-core Altra CPUs running at 3 GHz. In total, delivering 160 cores per system!
But why? The goal for the team was to get Xen to run smoothly on Ampere's ARM powered hardware. This work should help pave the way to a new era of energy-efficient and high-performance virtualization.
Ampere Altra’s high core density makes it an excellent platform for Xen, offering power-efficient, high-performance virtualization.
Ampere’s ambitions go well beyond general-purpose computing. Ampere is also investing in AI-focused chips that are specifically designed to accelerate AI workloads efficiently. Ampere CPUs are particularly compelling for data centers because their AI solutions are designed to provide scalable inference capabilities while remaining power efficient. Learn more about Ampere AI.
Early tests have been promising. Since Xen already runs on ARM, the focus has been on testing its performance and stability on Ampere’s hardware. The team was able to successfully:
- Get Debian Bookworm running as the base OS
- Build and deploy Xen, the xl toolstack, the Linux kernel, and QEMU
- Boot guest VMs and test the core virtualization functionality
Of course the team also encountered some bumps along the way. Issues around ACPI platform errors, PCI related warnings, and memory allocation glitches during initialization were observed. The team is working through the various challenges with help from Ampere engineers.
The current focus is on stability and enabling some core functionalities. Once the initial issues are worked out, full XCP-ng integration will be the goal. This includes improving PCI passthrough, verifying GPU support, and resolving any remaining kernel and ACPI issues.
However, this is not intended to be an academic experiment. It's a crucial step towards bringing enterprise grade Xen virtualization to ARM based data centers. This is extremely important to unlocking the next generation of data-center efficiency and performance.
Existing challenges and next steps
While Xen already runs on ARM, XCP-ng needs additional development to support enterprise deployments. That’s what this project is all about.
Bringing full XCP-ng support to Xen on Ampere's ARM-powered servers is a major step forward for efficient virtualization. Certainly there are still some challenges to resolve to meet this goal. Fortunately, progress is already underway.
A key area of focus is PCI passthrough. This is essential for high performance I/O workloads. GPU support is also an area of concern. Testing is currently underway to determine GPU compatibility. The team is also fine-tuning kernel and ACPI integration. This will ensure smooth operation at scale.
Technical hurdles are part of the adventure and development is already moving forward. With XCP-ng and Ampere engineers working together, these challenges are actively being resolved. This work is bringing Xen on ARM closer to reality. Next steps towards full XCP-ng integration include stabilizing the core system and improving hardware compatibility.
As ARM adoption continues to grow, this work is providing the foundation for a power efficient and high performance future for Xen based virtualization. And that's only the start...
The work happening today lays the foundation for future virtualization on open architectures like RISC-V.
What's next?
Xen on Ampere's ARM powered servers is shaping up to be a huge step forward for Open Source virtualization. The collaboration between the XCP-ng team and Ampere engineers reveals a dedication to this goal. The future of Xen on ARM is going to be more efficient, more scalable, and always open!
📢 Want to Learn More?
Are you as excited as we are about ARM in the data center? Check out the full deep dive on the XCP-ng blog:
Oleksii Kurochko
📡 Follow along as we push the future of virtualization to the next level! Stay tuned for more updates and be sure to join the conversation about Xen on ARM.
