On Thu, 27 Jan 2022 16:26:54 -0800
Ben Widawsky <ben.widawsky@xxxxxxxxx> wrote:
> Regions are created as a child of the decoder that encompasses an
> address space with constraints. Regions have a number of attributes that
> must be configured before the region can be activated.
>
> The ABI is not meant to be secure, but is meant to avoid accidental
> races. As a result, a buggy process may create a region by name that was
> allocated by a different process. However, multiple processes which are
> trying not to race with each other shouldn't need special
> synchronization to do so.
>
> // Allocate a new region name
> region=$(cat /sys/bus/cxl/devices/decoder0.0/create_region)
>
> // Create a new region by name
> echo $region > /sys/bus/cxl/devices/decoder0.0/create_region
>
> // Region now exists in sysfs
> stat -t /sys/bus/cxl/devices/decoder0.0/$region
>
> // Delete the region, and name
> echo $region > /sys/bus/cxl/devices/decoder0.0/delete_region
>
> Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
>
One trivial comment below.
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 13fb06849199..b9f0099c1f39 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -221,6 +221,7 @@ enum cxl_decoder_type {
> * @target_type: accelerator vs expander (type2 vs type3) selector
> * @flags: memory type capabilities and locking
> * @target_lock: coordinate coherent reads of the target list
> + * @region_ida: allocator for region ids.
> * @nr_targets: number of elements in @target
> * @target: active ordered target list in current decoder configuration
> */
> @@ -236,6 +237,7 @@ struct cxl_decoder {
> enum cxl_decoder_type target_type;
> unsigned long flags;
> seqlock_t target_lock;
> + struct ida region_ida;
> int nr_targets;
> struct cxl_dport *target[];
> };
> @@ -323,6 +325,13 @@ struct cxl_ep {
> struct list_head list;
> };
>
> +bool is_cxl_region(struct device *dev);
Not in this patch. Looks like it is in patch 4.
> +struct cxl_region *to_cxl_region(struct device *dev);
> +struct cxl_region *cxl_alloc_region(struct cxl_decoder *cxld,
> + int interleave_ways);
> +int cxl_add_region(struct cxl_decoder *cxld, struct cxl_region *cxlr);
> +int cxl_delete_region(struct cxl_decoder *cxld, const char *region);
> +
> static inline bool is_cxl_root(struct cxl_port *port)
> {
> return port->uport == port->dev.parent;
