Ned Proves Prescient Again, RISC-V Port to Xen

Posted on Tuesday, Feb 14, 2023 by Ned Bellavance

Featured in this episode of Chaos Lever

Relating to our discussion of RISC-V last week, comes an article from The Register discussing the status of a project to port the Xen hypervisor over to RISC-V.

As they correctly surmise, a successful implementation of RISC-V in the datacenter will require the support of a hypervisor, and running with the open-source ethos of RISC-V, the XCP-ng community is in the process of porting the open source hypervisor to the open source architecture. In fact XCP-ng has been working on such a port since 2021, with a recent post detailing the status of their effort.

The tl;dr or more accurately, too long didn’t understand, is that the main branch can build to the riscv64 architecture, but it only supports minimal functionality and is still in the proof-of-concept stage. Updating Xen to run on RISC-V has exposed some deficiencies in the core code and patches waiting to be merged, and it is the goal of XCP-ng to generalize the core of Xen to be applicable across x86, ARM, and RISC-V.

Beyond the basic build, CI/CD processes for RISC-V have been added to Xen’s GitLab and basic xen_start and early_printk functionality is being integrated. There’s certainly a lot more to do, and if you’re a C developer, they’re looking for help.

With the increased focus on RISC-V, I wouldn’t be surprised to find the cloud vendors lending a helping hand, except for AWS, since we know how they do with open-source projects.