On Fri, Sep 12, 2025 at 04:45:11PM +0200, Robert Richter wrote:
> There is only support to translate addresses from an endpoint to its
> parent port, but not in the opposite direction from the parent to the
> endpoint. Thus, the endpoint address range cannot be determined and
> setup manually for a given SPA range of a region. If the parent
> implements the ->to_hpa() callback, address translation is
> needed. Then, forbid reprogramming of the decoders and lock them.
>
> Signed-off-by: Robert Richter <rrichter@amd.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
> ---
> drivers/cxl/core/region.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 9fb1e9508213..44ea59252ff0 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3497,6 +3497,16 @@ static int setup_address_translation(struct cxl_endpoint_decoder *cxled,
> return -ENXIO;
> }
>
> + /*
> + * There is only support to translate from the endpoint to its
> + * parent port, but not in the opposite direction from the
> + * parent to the endpoint. Thus, the endpoint address range
> + * cannot be determined and setup manually. If the address range
> + * was translated and modified, forbid reprogramming of the
> + * decoders and lock them.
> + */
> + cxld->flags |= CXL_DECODER_F_LOCK;
> +
> ctx->hpa_range = range;
> ctx->interleave_ways = ways;
> ctx->interleave_granularity = gran;
> --
> 2.39.5
>