Re: [PATCH V2 3/3] cxl/mem: Adjust ram/pmem range to represent DPA ranges

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

On Thu, 17 Jun 2021 15:16:20 -0700
<ira.weiny@intel.com> wrote:

> From: Ira Weiny <ira.weiny@intel.com>
> 
> CXL spec defines the volatile DPA range to be 0 to Volatile memory size.
> It further defines the persistent DPA range to follow directly after the
> end of the Volatile DPA through the persistent memory size.

Reference would be good for anyone sanity checking against the spec. I think it's
Table 176 that says this.

> Essentially
> 
> Volatile DPA range   = [0, Volatile size)
> Persistent DPA range = [Volatile size, Volatile size + Persistent size)
> 
> Adjust the pmem_range start to reflect this and remote the TODO.

remove

> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/cxl/pci.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 341885345b53..a1fd7923dfb9 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -1635,8 +1635,9 @@ static int cxl_mem_create_range_info(struct cxl_mem *cxlm)
>  	if (cxlm->partition_align_bytes == 0) {
>  		cxlm->ram_range.start = 0;
>  		cxlm->ram_range.end = cxlm->volatile_only_bytes - 1;
> -		cxlm->pmem_range.start = 0;
> -		cxlm->pmem_range.end = cxlm->persistent_only_bytes - 1;
> +		cxlm->pmem_range.start = cxlm->volatile_only_bytes;
> +		cxlm->pmem_range.end = cxlm->volatile_only_bytes +
> +					cxlm->persistent_only_bytes - 1;
>  		return 0;
>  	}
>  
> @@ -1660,15 +1661,12 @@ static int cxl_mem_create_range_info(struct cxl_mem *cxlm)
>  			cxlm->next_volatile_bytes,
>  			cxlm->next_persistent_bytes);
>  
> -	/*
> -	 * TODO: enumerate DPA map, as 'ram' and 'pmem' do not alias.
> -	 * For now, only the capacity is exported in sysfs
> -	 */
>  	cxlm->ram_range.start = 0;
>  	cxlm->ram_range.end = cxlm->active_volatile_bytes - 1;
>  
> -	cxlm->pmem_range.start = 0;
> -	cxlm->pmem_range.end = cxlm->active_persistent_bytes - 1;
> +	cxlm->pmem_range.start = cxlm->active_volatile_bytes;
> +	cxlm->pmem_range.end = cxlm->active_volatile_bytes +
> +				cxlm->active_persistent_bytes - 1;
>  
>  	return 0;
>  }