Xen 4.8 debuts, gives ARM servers vendors a reason to hope

A new version of the Xen Project's hypervisor has emerged blinking into the light.

The Project reckons the best bit of version 4.8 is support for live patching of ARMv8-A CPUs, noting that such silicon is likely to appear in servers. And server users, of course, love anything that avoids operational disruptions. So Xen has made ARM servers just a little more attractive.

The new release has also gained alternative runtime patching for ARM64, technology that the Project says “hypervisor to apply workarounds for erratas affecting the processor and to apply optimizations specific to a CPU.”

There's something for Intel users too: Chipzilla recently extended its virtualisation extensions to AVX-512 and Xen's followed it there.

Another addition is support for the Credit2 scheduler which the Project says “is more scalable and is better at supporting latency sensitive workloads such as VDI, video and sound delivery, as well as unikernel applications” compared to its predecessor. The VDI enhancements understandably make Citrix very happy, as it's big in desktop virtualisation and uses Xen as the basis of its own Xen Server.

Multiprocessor system-on-chips (MPSoCs) are becoming popular in embedded applications because they offer the chance to run multiple operating systems inside one chassis with enough grunt for each to behave nicely. Xen's gone there too, with support for the Xilinx's MPSoCs, thereby giving itself a chance at all manner of embedded and “things” markets in which it's hoped several OSes will run inside one device, but deliver different services.

Debian users can also smile: its developers are working to bring Xen 4.8 to Debian “Stretch”, its next edition.

There's plenty more new stuff listed in the changelog.

Release manager Liu Wei's announcement of the new release says “In this release, we took a security-first approach and spent a lot of energy to improve code quality and harden security. This inevitably slowed down the acceptance of new features a bit, but not enough to not reach meaningful balance between mature security practice and innovation.”

He's being a bit shy because this release is the first made under the Project's new six-monthly release cadence. So the decent crop of new features shows good momentum, while the security-first approach will be welcome as Xen's had more than its fair share of clangers lately.

The Project's name-checked ARM, BitDefender, Bosch, Citrix, Freescale, Intel, Linaro, Oracle, Qualcomm, SUSE, Star Lab, the US National Security Agency, Xilinx, Zentific, and “a number of universities and individuals” for thanks to their contributions to this release. The full acknowledgements page offers details on individual contributions.

What's that? You want the code, not our blathering? Go get it here. ®