The latest Compute Express Link ( [1]CXL ) feature work being pursued for the mainline Linux kernel is a driver to create CXL block devices for storage. On Monday a "request for comments" patch series sent out the initial code for setting up CXL shared memory to be used as Linux block devices.

The CXL Block Device (CBD) is summed up in the RFC patch series as:

"As shared memory is supported in CXL3.0 spec, we can transfer data via CXL shared memory. CBD means CXL block device, it use CXL shared memory to transfer command and data to access block device in different host."

CBD works similarly to network block devices but leveraging CXL shared memory rather than network traffic.

Right now the CBD code is in its early stage of development and it will be a while before CXL 3.0 hardware is found out in the wild at scale, but nevertheless an interesting endeavor. Those wanting to learn more can see the [2]RFC patch series from Dongsheng Yang.



[1] https://www.phoronix.com/search/CXL

[2] https://lore.kernel.org/lkml/20240422071606.52637-1-dongsheng.yang@easystack.cn/