/dev/cxl directory is not created with linux kernel 6.3 and over

[yongchen65]

I have a CXL device installed on a system with Linux kernel 6.2.9. I was able to see /dev/cxl directory after system booted up. But after l updated my system with the latest Linux kernel 6.5.4, the /dev/cxl directory is no longer seen. I tried different Linux kernels (eg 6.4.x 6.3.x etc), but still couldn't see /dev/cxl directory. was there any configuration settings I was missing with the new kernels?

[1hhYangGe]

I have meet the same question, with a CXL Type3 device plugged into the server. I can see it with lspci and numactl , but not with cxl-cli in kernel 6.7.5.
I can see /dev/dax0.0 in my system, but can't see /dev/cxl , in kernel 6.7.5; And both of these can been seen in kernel 5.14. I guess maybe some kernel parameter is wrong, But I'm not good at this, can someone help us?

My kernel configuration :

CONFIG_EFI_SOFT_RESERVE=y

CONFIG_X86_PMEM_LEGACY=m
CONFIG_ZONE_DEVICE=y
CONFIG_LIBNVDIMM=m
CONFIG_BLK_DEV_PMEM=m
CONFIG_BTT=y
CONFIG_NVDIMM_PFN=y
CONFIG_NVDIMM_DAX=y
CONFIG_DEV_DAX_PMEM=m
CONFIG_ENCRYPTED_KEYS=y
CONFIG_NVDIMM_SECURITY_TEST=y

CONFIG_STRICT_DEVMEM=n
CONFIG_IO_STRICT_DEVMEM=n   <== I want to mmap my cxl memory

CONFIG_CXL_BUS=m
CONFIG_CXL_PCI=m
CONFIG_CXL_ACPI=m
CONFIG_CXL_PMEM=m
CONFIG_CXL_MEM=m
CONFIG_CXL_PORT=m
CONFIG_CXL_REGION=y
CONFIG_CXL_REGION_INVALIDATION_TEST=y
CONFIG_DEV_DAX_CXL=m

$ cat /proc/cmdline
BOOT_IMAGE=(hd0,gpt2)/vmlinuz-6.7.56.7.5-001.el9.x86_64 root=/dev/mapper/cs-root ro crashkernel=1G-4G:192M,4G-64G:256M,64G-:512M resume=/dev/mapper/cs-swap rd.lvm.lv=cs/root rd.lvm.lv=cs/swap rhgb quiet

[FuHaoTHU]

It seems that kernel object file (cxl*.ko) was not loaded automatically, use insmod to insert them or recompile the kernel with CONFIG_CXL_*=y may help you to solve this.