cxl memory's space can't access

[cwk]

I'm using qemu to build cxl device simulation environment. When using ndctl's cxl command I can find the below output:
[ { "memdev":"mem0", "pmem_size":536870912, "serial":0, "host":"0000:0d:00.0" } ]

But I don't know how to access this cxl space.
I can only find cxl file in /dev/cxl.
Does libcxl provide any API to access cxl address space such as mmap function?

[Vishal Verma]

@cwk08 Yes there are a few steps before you can use this space. In case of pmem space (persistent memory) as you show in your example, the support is available today - see the cxl create-region command - you'd use this to create a pmem region, that would show up as an nvdimm region. This would allow you to have (create / modify) nvdimm namespaces using ndctl create-namespace.

Similar support for volatile space on a CXL memdev is currently being developed. Some patches for enabling this in the kernel have been posted here:
https://lore.kernel.org/linux-cxl/[e-mail]/

I believe a QEMU implementation for volatile capacity is in progress too, and I'll be posting libcxl / cxl-cli patches to plumb this through shortly as well.

[cwk]

Thanks for your reply. After creating namespace by ndctl, I can find pmem file in /dev path now , and it is able to be mounted on file system.