Re: [PATCH v10 21/26] cxl: allow region creation by type2 drivers

[Simon Horman <horms@kernel.org>]

On Wed, Feb 05, 2025 at 03:19:45PM +0000, alucerop@amd.com wrote:
> From: Alejandro Lucero <alucerop@amd.com>
> 
> Creating a CXL region requires userspace intervention through the cxl
> sysfs files. Type2 support should allow accelerator drivers to create
> such cxl region from kernel code.
> 
> Adding that functionality and integrating it with current support for
> memory expanders.
> 
> Based on https://lore.kernel.org/linux-cxl/168592159835.1948938.1647215579839222774.stgit@dwillia2-xfh.jf.intel.com/
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> Co-developed-by: Dan Williams <dan.j.williams@intel.com>
> Reviewed-by: Zhi Wang <zhiw@nvidia.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  drivers/cxl/core/region.c | 145 ++++++++++++++++++++++++++++++++++----
>  drivers/cxl/cxlmem.h      |   2 +
>  drivers/cxl/port.c        |   5 +-
>  include/cxl/cxl.h         |   4 ++
>  4 files changed, 141 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c

...

> +/**
> + * cxl_create_region - Establish a region given an endpoint decoder
> + * @cxlrd: root decoder to allocate HPA
> + * @cxled: endpoint decoder with reserved DPA capacity

nit: @ways: should be documented here too.

> + *
> + * Returns a fully formed region in the commit state and attached to the
> + * cxl_region driver.
> + */
> +struct cxl_region *cxl_create_region(struct cxl_root_decoder *cxlrd,
> +				     struct cxl_endpoint_decoder *cxled, int ways)

...