CXL 2.0 Support Steps Closer To The Mainline Linux Kernel

So far for the virtual CES this week there hasn't been any big CXL 2.0 announcements since the Compute Express Link 2.0 specification was finalized back in November, but the Linux kernel support for this CPU-to-device interconnect continues coming together and will be hopefully mainlined in a coming release.

Back in November the CXL 2.0 spec was published and immediately following that Intel began posting Linux support patches for implementing the specification with an initial focus on type-3 memory devices as memory expanders for RAM or persistent memory.

This initial CXL 2.0 enablement is being done in part through emulation with there also being patches against QEMU for testing. Ben Widawsky of Intel who has been leading the effort sent out the third round of patches on Monday for CXL 2.0 support in the Linux kernel and still focusing on the initial "type-3" memory device support.

This first round of CXL 2.0 patches for 2021 bring many low-level improvements to the code, various fixes, more data being exposed via sysfs, and greater documentation.

The work is still in-progress and thus might not land for Linux 5.12 this spring but at least is progressing and presumably should comfortably be merged this year. The newest patches for those interested in this new industry interconnect standard can find them on the LKML.

Among the main backers of Compute Express Link are Intel, AMD, Dell EMC, HPE, Google, Facebook, Microsoft, and many others. This year we'll hopefully be hearing more about CXL 2.0 devices with this latest specification building off the physical PCI Express 5.0 standard.