Re: [PATCH v5 6/7] dax/hmem, cxl: Defer and resolve ownership of Soft Reserved memory ranges

[dan.j.williams]

Alejandro Lucero Palau wrote:
[..]
> I will take a look at this presentation, but I think there could be 
> another option where accelerators information is obtained during pci 
> enumeration by the kernel and using this information by this 
> functionality skipping those ranges allocated to them. Forcing them to 
> be compiled with the kernel would go against what distributions 
> currently and widely do with initramfs. Not sure if some current "early" 
> stubs could be used for this though but the information needs to be 
> recollected before this code does the checks.

The simple path is "do not use EFI_MEMORY_SP for accelerator memory".
However, if the accelerator wants to publish memory as EFI_MEMORY_SP
then it needs to coordinate with the kernel's default behavior somehow.
That means expanding the list of drivers that dax_hmem needs to await
before it can make a determination, or teaching dax_hmem to look for a
secondary indication that it should never fall back to the default
behavior.

Talk to your AMD peers Paul and Rajneesh about their needs. I took it on
faith that the use case was required.