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cxl: Export QTG ids from CFMWS to sysfs as qos_class attribute

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Export the QoS Throttling Group ID from the CXL Fixed Memory Window
Structure (CFMWS) under the root decoder sysfs attributes as qos_class.

CXL rev3.0 9.17.1.3 CXL Fixed Memory Window Structure (CFMWS)

cxl cli will use this id to match with the _DSM retrieved id for a
hot-plugged CXL memory device DPA memory range to make sure that the
DPA range is under the right CFMWS window.

Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/169713681699.2205276.14475306324720093079.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dave Jiang 2023-10-12 11:53:37 -07:00 committed by Dan Williams
parent 178e1ea6a6
commit 529c0a4404
4 changed files with 32 additions and 0 deletions
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15
Documentation/ABI/testing/sysfs-bus-cxl
View File

@ -369,6 +369,21 @@ Description:
provided it is currently idle / not bound to a driver.
What: /sys/bus/cxl/devices/decoderX.Y/qos_class
Date: May, 2023
KernelVersion: v6.5
Contact: linux-cxl@vger.kernel.org
Description:
(RO) For CXL host platforms that support "QoS Telemmetry" this
root-decoder-only attribute conveys a platform specific cookie
that identifies a QoS performance class for the CXL Window.
This class-id can be compared against a similar "qos_class"
published for each memory-type that an endpoint supports. While
it is not required that endpoints map their local memory-class
to a matching platform class, mismatches are not recommended and
there are platform specific side-effects that may result.
What: /sys/bus/cxl/devices/regionZ/uuid
Date: May, 2022
KernelVersion: v6.0

3
drivers/cxl/acpi.c
View File

@ -289,6 +289,9 @@ static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
}
}
}
cxlrd->qos_class = cfmws->qtg_id;
rc = cxl_decoder_add(cxld, target_map);
err_xormap:
if (rc)

11
drivers/cxl/core/port.c
View File

@ -278,6 +278,15 @@ static ssize_t interleave_ways_show(struct device *dev,
static DEVICE_ATTR_RO(interleave_ways);
static ssize_t qos_class_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
return sysfs_emit(buf, "%d\n", cxlrd->qos_class);
}
static DEVICE_ATTR_RO(qos_class);
static struct attribute *cxl_decoder_base_attrs[] = {
&dev_attr_start.attr,
&dev_attr_size.attr,
@ -297,6 +306,7 @@ static struct attribute *cxl_decoder_root_attrs[] = {
&dev_attr_cap_type2.attr,
&dev_attr_cap_type3.attr,
&dev_attr_target_list.attr,
&dev_attr_qos_class.attr,
SET_CXL_REGION_ATTR(create_pmem_region)
SET_CXL_REGION_ATTR(create_ram_region)
SET_CXL_REGION_ATTR(delete_region)
@ -1691,6 +1701,7 @@ struct cxl_root_decoder *cxl_root_decoder_alloc(struct cxl_port *port,
}
atomic_set(&cxlrd->region_id, rc);
cxlrd->qos_class = CXL_QOS_CLASS_INVALID;
return cxlrd;
}
EXPORT_SYMBOL_NS_GPL(cxl_root_decoder_alloc, CXL);

3
drivers/cxl/cxl.h
View File

@ -321,6 +321,7 @@ enum cxl_decoder_type {
*/
#define CXL_DECODER_MAX_INTERLEAVE 16
#define CXL_QOS_CLASS_INVALID -1
/**
* struct cxl_decoder - Common CXL HDM Decoder Attributes
@ -432,6 +433,7 @@ typedef struct cxl_dport *(*cxl_calc_hb_fn)(struct cxl_root_decoder *cxlrd,
* @calc_hb: which host bridge covers the n'th position by granularity
* @platform_data: platform specific configuration data
* @range_lock: sync region autodiscovery by address range
* @qos_class: QoS performance class cookie
* @cxlsd: base cxl switch decoder
*/
struct cxl_root_decoder {
@ -440,6 +442,7 @@ struct cxl_root_decoder {
cxl_calc_hb_fn calc_hb;
void *platform_data;
struct mutex range_lock;
int qos_class;
struct cxl_switch_decoder cxlsd;
};