mkdaxfs fails with uncached-minus mode error (kernel only supports write-back for CXL device) #7
Description
I attempted to mount the physical address of a CXL device using mkdaxfs, but encountered an error. The error details are as follows:
The CXL device is configured as a Device-DAX device. The physical address range of the DAX device is:
The dmesg output is as follows:
By analyzing the dmesg logs and cross-referencing the source code, I identified the root cause of the failure when using mkdaxfs to mount the physical address of a DAX device:
The uncached-minus memory mode is not supported by the DAX device's underlying memory hardware and kernel rules. The kernel can only allocate the write-back mode, but mkdaxfs explicitly requests the unsupported uncached-minus mode in strict mode, which triggers the error.
Could you provide guidance on how to resolve this error? Does mkdaxfs support CXL devices? @congwang-mk