Re: [PATCH v2 3/5] cxl: Introduce 'struct cxl_dpa_partition' and 'struct cxl_range_info'

[Dan Williams <dan.j.williams@intel.com>]

Alejandro Lucero Palau wrote:
> 
> On 1/22/25 08:59, Dan Williams wrote:
> > The pending efforts to add CXL Accelerator (type-2) device [1], and
> > Dynamic Capacity (DCD) support [2], tripped on the
> > no-longer-fit-for-purpose design in the CXL subsystem for tracking
> > device-physical-address (DPA) metadata. Trip hazards include:
> >
> > - CXL Memory Devices need to consider a PMEM partition, but Accelerator
> >    devices with CXL.mem likely do not in the common case.
> >
> > - CXL Memory Devices enumerate DPA through Memory Device mailbox
> >    commands like Partition Info, Accelerators devices do not.
> 
> 
> Forgot to mention this one. Mailbox is optional for accelerators.
> 
> 
> So maybe "but this way is optional for accelerators, implying 
> accel-driver defined/hardcoded enumeration".

That's what "Accelerators do not" means. I.e. that setting up the DPA
layout needs to be refactored into infrastructure that can be shared
with drivers that will not use a mailbox for this purpose.

[..scrolls to end to see if any additional comments..]