A Compute Express Link Memory Device is a CXL component that implements the CXL.mem protocol. It contains some amount of volatile memory, persistent memory, or both. It is enumerated as a PCI device for configuration and passing messages over an MMIO mailbox. Its contribution to the System Physical Address space is handled via HDM (Host Managed Device Memory) decoders that optionally define a device's contribution to an interleaved address range across multiple devices underneath a host-bridge or interleaved across host-bridges.
This section covers the driver infrastructure for a CXL memory device.
drivers/cxl/pci.c
drivers/cxl/pci.c
drivers/cxl/cxl.h
drivers/cxl/cxl.h
drivers/cxl/core/bus.c
include/uapi/linux/cxl_mem.h
include/uapi/linux/cxl_mem.h