Intel Begins Sending Out Linux Support Patches For CXL 2.0

Just a day after the CXL 2.0 specification was published, the initial Linux kernel support for this updated Compute Express Link revision was sent out for review.

Longtime open-source Intel Linux developer Ben Widawsky sent out the initial kernel patches for CXL 2.0. The initial focus is on the type-3 memory devices defined by the CXL 2.0 specification that serves as a memory expander for RAM or persistent memory. These initial CXL 2.0 patches are still a work-in-progress but seem to be making good progress given the punctual review process beginning.

Those nine kernel patches so far around the CXL 2.0 memory support amount to just over thirteen hundred lines of new code.

Widawsky also sent out a set of 25 patches to the QEMU developers in working on the CXL 2.0 emulation support. They are leveraging QEMU to move forward on the CXL 2.0 bring-up while awaiting capable hardware and also being an ideal environment for regression testing.

It's good to see the Linux support beginning to form for this industry standard interconnect built off PCI Express. With some luck it won't be far into 2021 before the initial Linux kernel support is present. We'll keep monitoring the work to see as it materializes and goes through further review.

It's also interesting to note Ben Widawsky leading this CXL 2.0 Linux effort. Ben was a longtime contributor to the Intel Linux graphics driver code while back in 2018 began working on improving Intel FreeBSD support and that continued at least through part of 2019. Now he is spending at least part of his time back on Intel Linux efforts given this Compute Express Link enablement work and it being no small task.