Xen hypervisor quadruples its possible core count for version 4.19

The Xen Project has delivered a new cut of its open source hypervisor.

Version 4.19 debuted on Thursday, billed as "a significant milestone in enhancing performance, security, and versatility."

The performance claim rests on changes such as an increase in the maximum number of CPUs Xen can be built for - from 4095 to 16383.

Security has been improved by crushing 13 bugs identified in past advisories, and adoption of more MISRA-C rules - guidelines on secure software development from the Motor Industry Software Reliability Association. If it seems odd that an open source hypervisor like Xen cares about auto industry software standards, know that embedded systems are among the project's prime targets - and consider what happens if buggy software means a driver can't apply the brakes when they're needed.

Versatility is addressed with further support for PVH - a tech Xen added in 2018. It enables a lightweight guest that isn't as bound to a software interface with the hypervisor as a paravirtualized environment, but doesn't need to mimic bare metal like a hardware virtual machine.

Xen Project community manager Kelly Choi rated the release "a significant achievement for the Xen community, bringing crucial enhancements across all supported architectures." She singled out the x2APIC driver for x86 and dynamic node programming for Arm as exemplifying "our focus on meeting the evolving needs of our users, and underscores our dedication to advancing virtualization technology with a robust, reliable and open source hypervisor."

The Project had another win last week after one of its biggest backers, French FOSS outfit Vates, announced it had contributed an HPE Moonshot chassis packing 40 servers to serve as test infrastructure for the project's code.

Two weeks before that, the Project warned that its colo provider had advised it of an unexpected and imminent closure - creating uncertainty about how developers could test Xen's wares and how to fund a replacement.

Vates's hardware donation appears to have sorted that out in the nick of time.

The French concern also signalled its intention to stage more physical events for the Xen community, and suggested enhanced collaboration between the Project and the academic community could be the basis for some gabfests. Indeed, Vates has already organized one such confab: a January 2025 event that will see Vates, the University of Grenoble Alps (UGA) and the Grenoble Computer Science Lab (LIG) talk Xen.

"They are providing a prestigious venue along with the involvement of PhDs, researchers, and students," wrote Vates CEO and founder Olivier Lambert. "This partnership achieves multiple goals: hosting the event in a distinguished location and attracting fresh talent to the Xen Project." ®