[PATCH v24 04/11] cxl: Prepare memdev creation for type2

alejandro.lucero-palau
2026-03-23T11:32:09Z

From: Alejandro Lucero <alucerop@amd.com>

Current cxl core is relying on a CXL_DEVTYPE_CLASSMEM type device when
creating a memdev leading to problems when obtaining cxl_memdev_state
references from a CXL_DEVTYPE_DEVMEM type.

Modify check for obtaining cxl_memdev_state adding CXL_DEVTYPE_DEVMEM
support.

Make devm_cxl_add_memdev accessible from an accel driver.

Signed-off-by: Alejandro Lucero <alucerop@amd.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/cxl/core/memdev.c | 15 +++++++++++--
drivers/cxl/cxlmem.h | 6 ------
drivers/cxl/mem.c | 45 +++++++++++++++++++++++++++++----------
include/cxl/cxl.h | 6 ++++++
4 files changed, 53 insertions(+), 19 deletions(-)

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 166ec6b7d041..759b43364ed7 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -7,6 +7,7 @@
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/pci.h>
+#include <cxl/cxl.h>
#include <cxlmem.h>
#include "trace.h"
#include "core.h"
@@ -576,9 +577,16 @@ static const struct device_type cxl_memdev_type = {
.groups = cxl_memdev_attribute_groups,
};

+static const struct device_type cxl_accel_memdev_type = {
+ .name = "cxl_accel_memdev",
+ .release = cxl_memdev_release,
+ .devnode = cxl_memdev_devnode,
+};
+
bool is_cxl_memdev(const struct device *dev)
{
- return dev->type == &cxl_memdev_type;
+ return (dev->type == &cxl_memdev_type ||
+ dev->type == &cxl_accel_memdev_type);
}
EXPORT_SYMBOL_NS_GPL(is_cxl_memdev, "CXL");

@@ -773,7 +781,10 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
dev->parent = cxlds->dev;
dev->bus = &cxl_bus_type;
dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
- dev->type = &cxl_memdev_type;
+ if (cxlds->type == CXL_DEVTYPE_DEVMEM)
+ dev->type = &cxl_accel_memdev_type;
+ else
+ dev->type = &cxl_memdev_type;
device_set_pm_not_required(dev);
INIT_WORK(&cxlmd->detach_work, detach_memdev);

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 281546de426e..c98db6f18aa2 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -34,10 +34,6 @@
(FIELD_GET(CXLMDEV_RESET_NEEDED_MASK, status) != \
CXLMDEV_RESET_NEEDED_NOT)

-struct cxl_memdev_attach {
- int (*probe)(struct cxl_memdev *cxlmd);
-};
-
/**
* struct cxl_memdev - CXL bus object representing a Type-3 Memory Device
* @dev: driver core device object
@@ -103,8 +99,6 @@ static inline bool is_cxl_endpoint(struct cxl_port *port)

struct cxl_memdev *__devm_cxl_add_memdev(struct cxl_dev_state *cxlds,
const struct cxl_memdev_attach *attach);
-struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds,
- const struct cxl_memdev_attach *attach);
int devm_cxl_sanitize_setup_notifier(struct device *host,
struct cxl_memdev *cxlmd);
struct cxl_memdev_state;
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index fcffe24dcb42..ff858318091f 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -65,6 +65,26 @@ static int cxl_debugfs_poison_clear(void *data, u64 dpa)
DEFINE_DEBUGFS_ATTRIBUTE(cxl_poison_clear_fops, NULL,
cxl_debugfs_poison_clear, "%llx\n");

+static void cxl_memdev_poison_enable(struct cxl_memdev_state *mds,
+ struct cxl_memdev *cxlmd,
+ struct dentry *dentry)
+{
+ /*
+ * Avoid poison debugfs for DEVMEM aka accelerators as they rely on
+ * cxl_memdev_state.
+ */
+ if (!mds)
+ return;
+
+ if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
+ debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
+ &cxl_poison_inject_fops);
+
+ if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
+ debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
+ &cxl_poison_clear_fops);
+}
+
static int cxl_mem_probe(struct device *dev)
{
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
@@ -92,12 +112,7 @@ static int cxl_mem_probe(struct device *dev)
dentry = cxl_debugfs_create_dir(dev_name(dev));
debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show);

- if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
- debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
- &cxl_poison_inject_fops);
- if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
- debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
- &cxl_poison_clear_fops);
+ cxl_memdev_poison_enable(mds, cxlmd, dentry);

rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
if (rc)
@@ -206,16 +221,24 @@ static ssize_t trigger_poison_list_store(struct device *dev,
}
static DEVICE_ATTR_WO(trigger_poison_list);

-static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
+static bool cxl_poison_attr_visible(struct kobject *kobj, struct attribute *a)
{
struct device *dev = kobj_to_dev(kobj);
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);

- if (a == &dev_attr_trigger_poison_list.attr)
- if (!test_bit(CXL_POISON_ENABLED_LIST,
- mds->poison.enabled_cmds))
- return 0;
+ if (!mds ||
+ !test_bit(CXL_POISON_ENABLED_LIST, mds->poison.enabled_cmds))
+ return false;
+
+ return true;
+}
+
+static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+ if (a == &dev_attr_trigger_poison_list.attr &&
+ !cxl_poison_attr_visible(kobj, a))
+ return 0;

return a->mode;
}
diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
index 1346771edc4e..10a9b8fa2f6b 100644
--- a/include/cxl/cxl.h
+++ b/include/cxl/cxl.h
@@ -149,6 +149,10 @@ struct cxl_dpa_partition {

#define CXL_NR_PARTITIONS_MAX 2

+struct cxl_memdev_attach {
+ int (*probe)(struct cxl_memdev *cxlmd);
+};
+
/**
* struct cxl_dev_state - The driver device state
*
@@ -225,4 +229,6 @@ struct cxl_dev_state *_devm_cxl_dev_state_create(struct device *dev,
})

int cxl_set_capacity(struct cxl_dev_state *cxlds, u64 capacity);
+struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds,
+ const struct cxl_memdev_attach *attach);
#endif /* __CXL_CXL_H__ */
--
2.34.1