Re: [PATCH] cxl: Add hpa_to_spa to the root decoder callback operations

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Wed, 9 Jul 2025 13:07:46 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> Remove cxl_hpa_to_spa_fn callback from cxl root decoder and add the
> callback function to cxl_decoder_ops. Refactor to group all the root
> decoder callbacks together.
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Question inline about mixture of types of CFMWS entry.

> ---
>  drivers/cxl/acpi.c        |  9 +++++++--
>  drivers/cxl/core/port.c   |  2 +-
>  drivers/cxl/core/region.c | 11 ++++++++---
>  drivers/cxl/cxl.h         | 13 ++++++++-----
>  4 files changed, 24 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> index 48478bc406ee..9f7e2a49dc5a 100644
> --- a/drivers/cxl/acpi.c
> +++ b/drivers/cxl/acpi.c
> @@ -20,6 +20,10 @@ static const guid_t acpi_cxl_qtg_id_guid =
>  	GUID_INIT(0xF365F9A6, 0xA7DE, 0x4071,
>  		  0xA6, 0x6A, 0xB4, 0x0C, 0x0B, 0x4F, 0x8E, 0x52);
>  
> +static u64 cxl_default_hpa_to_spa(struct cxl_root_decoder *cxlrd, u64 hpa)
> +{
> +	return hpa;
> +}
>  
>  static u64 cxl_xor_hpa_to_spa(struct cxl_root_decoder *cxlrd, u64 hpa)
>  {
> @@ -342,8 +346,9 @@ static int cxl_acpi_get_extended_linear_cache_size(struct resource *backing_res,
>  	return hmat_get_extended_linear_cache_size(backing_res, nid, size);
>  }
>  
> -static const struct cxl_rd_ops acpi_rd_ops = {
> +static struct cxl_rd_ops acpi_rd_ops = {
>  	.get_extended_linear_cache_size = cxl_acpi_get_extended_linear_cache_size,
> +	.hpa_to_spa = cxl_default_hpa_to_spa,
>  };
>  
>  DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,
> @@ -425,7 +430,7 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
>  	cxlrd->qos_class = cfmws->qtg_id;
>  
>  	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_XOR)
> -		cxlrd->hpa_to_spa = cxl_xor_hpa_to_spa;
> +		cxlrd->ops->hpa_to_spa = cxl_xor_hpa_to_spa;

What happens if we have a mixture for different CMWS entries?
Some xor, some not.

>  
>  	rc = cxl_decoder_add(cxld, target_map);
>  	if (rc)