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cxl: Add decoders_committed sysfs attribute to cxl_port

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This attribute allows cxl-cli to determine whether there are decoders
committed to a memdev.  This is only a snapshot of the state, and
doesn't offer any protection or serialization against a concurrent
disable-region operation.

Reviewed-by: Jim Harris <jim.harris@samsung.com>
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/169747907439.272156.10261062080830155662.stgit@djiang5-mobl3
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dave Jiang 2023-10-16 10:57:54 -07:00 committed by Dan Williams
parent 458ba8189c
commit 05e37b2138
2 changed files with 40 additions and 0 deletions
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15
Documentation/ABI/testing/sysfs-bus-cxl
View File

@ -178,6 +178,21 @@ Description:
hardware decoder target list.
What: /sys/bus/cxl/devices/portX/decoders_committed
Date: October, 2023
KernelVersion: v6.7
Contact: linux-cxl@vger.kernel.org
Description:
(RO) A memory device is considered active when any of its
decoders are in the "committed" state (See CXL 3.0 8.2.4.19.7
CXL HDM Decoder n Control Register). Hotplug and destructive
operations like "sanitize" are blocked while device is actively
decoding a Host Physical Address range. Note that this number
may be elevated without any regionX objects active or even
enumerated, as this may be due to decoders established by
platform firwmare or a previous kernel (kexec).
What: /sys/bus/cxl/devices/decoderX.Y
Date: June, 2021
KernelVersion: v5.14

25
drivers/cxl/core/port.c
View File

@ -534,8 +534,33 @@ static void cxl_port_release(struct device *dev)
kfree(port);
}
static ssize_t decoders_committed_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct cxl_port *port = to_cxl_port(dev);
int rc;
down_read(&cxl_region_rwsem);
rc = sysfs_emit(buf, "%d\n", cxl_num_decoders_committed(port));
up_read(&cxl_region_rwsem);
return rc;
}
static DEVICE_ATTR_RO(decoders_committed);
static struct attribute *cxl_port_attrs[] = {
&dev_attr_decoders_committed.attr,
NULL,
};
static struct attribute_group cxl_port_attribute_group = {
.attrs = cxl_port_attrs,
};
static const struct attribute_group *cxl_port_attribute_groups[] = {
&cxl_base_attribute_group,
&cxl_port_attribute_group,
NULL,
};