Re: [RFC] CXL/ACPI: Remove overlapping Soft Reserved regions before adding CFMW resources

[Gregory Price]

On Fri, Jul 11, 2025 at 05:34:27AM +0000, Zhijian Li (Fujitsu) wrote:
> 
> 
> On 11/07/2025 05:15, Nathan Fontenot wrote:
> In this case(with your V4 patch), we would see:
> ```
> 5d0000000-6cfffffff : CXL Window 0
>    5d0000000-6cfffffff : region0
> ```
> Actually, it cannot be consumed by the hmem/dax_hmem neither.
> 
> This made me realize that my current idea ignores the case of CXL_ACPI=y && CXL_REGION=n. I quickly tested it(I will take a deeper look later):
> 
> After the OS boots, we can see this resource. Can anyone tell me how to create the corresponding dax_region? Because I tried using dax create-device without success.
> ```
> 5d0000000-6cfffffff : CXL Window 0
>    5d0000000-6cfffffff : Soft Reserved
> ```
> 

with CXL_REGION=n you cannot create the dax region.

region0 --creates-> dax_region0 --creates-> dax0

all you've done here by setting CXL_REGION=N is break the probe chain
but otherwise successfully attributed the memory to the CXL driver.

~Gregory