drm/xe/pf: Prepare sysfs for SR-IOV admin attributes

We already have some SR-IOV specific knobs exposed as debugfs
files to allow low level tuning of the SR-IOV configurations,
but those files are mainly for the use by the developers and
debugfs might not be available on the production builds.

Start building dedicated sysfs sub-tree under xe device, where
in upcoming patches we will add selected attributes that will
help provision and manage PF and all VFs:

  /sys/bus/pci/drivers/xe/BDF/
  ├── sriov_admin/
      ├── pf/
      ├── vf1/
      ├── vf2/
      :
      └── vfN/

Add all required data types and helper macros that will be used
by upcoming patches to define actual attributes.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patch.msgid.link/20251030222348.186658-2-michal.wajdeczko@intel.com

drivers/gpu/drm/xe/Makefile

@@ -178,6 +178,7 @@ xe-$(CONFIG_PCI_IOV) += \
 	xe_sriov_pf_debugfs.o \
 	xe_sriov_pf_provision.o \
 	xe_sriov_pf_service.o \
+	xe_sriov_pf_sysfs.o \
 	xe_tile_sriov_pf_debugfs.o
 
 # include helpers for tests even when XE is built-in

drivers/gpu/drm/xe/xe_sriov_pf.c

@@ -16,6 +16,7 @@
 #include "xe_sriov_pf.h"
 #include "xe_sriov_pf_helpers.h"
 #include "xe_sriov_pf_service.h"
+#include "xe_sriov_pf_sysfs.h"
 #include "xe_sriov_printk.h"
 
 static unsigned int wanted_max_vfs(struct xe_device *xe)
@@ -128,6 +129,10 @@ int xe_sriov_pf_init_late(struct xe_device *xe)
 			return err;
 	}
 
+	err = xe_sriov_pf_sysfs_init(xe);
+	if (err)
+		return err;
+
 	return 0;
 }
 

drivers/gpu/drm/xe/xe_sriov_pf_sysfs.c

@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
+
+#include <drm/drm_managed.h>
+
+#include "xe_assert.h"
+#include "xe_sriov.h"
+#include "xe_sriov_pf_helpers.h"
+#include "xe_sriov_pf_sysfs.h"
+#include "xe_sriov_printk.h"
+
+/*
+ * /sys/bus/pci/drivers/xe/BDF/
+ * :
+ * ├── sriov_admin/
+ *     ├── ...
+ *     ├── pf/
+ *     │   ├── ...
+ *     │   └── ...
+ *     ├── vf1/
+ *     │   ├── ...
+ *     │   └── ...
+ *     ├── vf2/
+ *     :
+ *     └── vfN/
+ */
+
+struct xe_sriov_kobj {
+	struct kobject base;
+	struct xe_device *xe;
+	unsigned int vfid;
+};
+#define to_xe_sriov_kobj(p) container_of_const((p), struct xe_sriov_kobj, base)
+
+struct xe_sriov_dev_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct xe_device *xe, char *buf);
+	ssize_t (*store)(struct xe_device *xe, const char *buf, size_t count);
+};
+#define to_xe_sriov_dev_attr(p) container_of_const((p), struct xe_sriov_dev_attr, attr)
+
+#define XE_SRIOV_DEV_ATTR(NAME) \
+struct xe_sriov_dev_attr xe_sriov_dev_attr_##NAME = \
+	__ATTR(NAME, 0644, xe_sriov_dev_attr_##NAME##_show, xe_sriov_dev_attr_##NAME##_store)
+
+#define XE_SRIOV_DEV_ATTR_RO(NAME) \
+struct xe_sriov_dev_attr xe_sriov_dev_attr_##NAME = \
+	__ATTR(NAME, 0444, xe_sriov_dev_attr_##NAME##_show, NULL)
+
+#define XE_SRIOV_DEV_ATTR_WO(NAME) \
+struct xe_sriov_dev_attr xe_sriov_dev_attr_##NAME = \
+	__ATTR(NAME, 0200, NULL, xe_sriov_dev_attr_##NAME##_store)
+
+struct xe_sriov_vf_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct xe_device *xe, unsigned int vfid, char *buf);
+	ssize_t (*store)(struct xe_device *xe, unsigned int vfid, const char *buf, size_t count);
+};
+#define to_xe_sriov_vf_attr(p) container_of_const((p), struct xe_sriov_vf_attr, attr)
+
+#define XE_SRIOV_VF_ATTR(NAME) \
+struct xe_sriov_vf_attr xe_sriov_vf_attr_##NAME = \
+	__ATTR(NAME, 0644, xe_sriov_vf_attr_##NAME##_show, xe_sriov_vf_attr_##NAME##_store)
+
+#define XE_SRIOV_VF_ATTR_RO(NAME) \
+struct xe_sriov_vf_attr xe_sriov_vf_attr_##NAME = \
+	__ATTR(NAME, 0444, xe_sriov_vf_attr_##NAME##_show, NULL)
+
+#define XE_SRIOV_VF_ATTR_WO(NAME) \
+struct xe_sriov_vf_attr xe_sriov_vf_attr_##NAME = \
+	__ATTR(NAME, 0200, NULL, xe_sriov_vf_attr_##NAME##_store)
+
+/* device level attributes go here */
+
+static const struct attribute_group *xe_sriov_dev_attr_groups[] = {
+	NULL
+};
+
+/* and VF-level attributes go here */
+
+static const struct attribute_group *xe_sriov_vf_attr_groups[] = {
+	NULL
+};
+
+/* no user serviceable parts below */
+
+static struct kobject *create_xe_sriov_kobj(struct xe_device *xe, unsigned int vfid)
+{
+	struct xe_sriov_kobj *vkobj;
+
+	xe_sriov_pf_assert_vfid(xe, vfid);
+
+	vkobj = kzalloc(sizeof(*vkobj), GFP_KERNEL);
+	if (!vkobj)
+		return NULL;
+
+	vkobj->xe = xe;
+	vkobj->vfid = vfid;
+	return &vkobj->base;
+}
+
+static void release_xe_sriov_kobj(struct kobject *kobj)
+{
+	struct xe_sriov_kobj *vkobj = to_xe_sriov_kobj(kobj);
+
+	kfree(vkobj);
+}
+
+static ssize_t xe_sriov_dev_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct xe_sriov_dev_attr *vattr  = to_xe_sriov_dev_attr(attr);
+	struct xe_sriov_kobj *vkobj = to_xe_sriov_kobj(kobj);
+	struct xe_device *xe = vkobj->xe;
+
+	if (!vattr->show)
+		return -EPERM;
+
+	return vattr->show(xe, buf);
+}
+
+static ssize_t xe_sriov_dev_attr_store(struct kobject *kobj, struct attribute *attr,
+				       const char *buf, size_t count)
+{
+	struct xe_sriov_dev_attr *vattr = to_xe_sriov_dev_attr(attr);
+	struct xe_sriov_kobj *vkobj = to_xe_sriov_kobj(kobj);
+	struct xe_device *xe = vkobj->xe;
+
+	if (!vattr->store)
+		return -EPERM;
+
+	return vattr->store(xe, buf, count);
+}
+
+static ssize_t xe_sriov_vf_attr_show(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct xe_sriov_vf_attr *vattr = to_xe_sriov_vf_attr(attr);
+	struct xe_sriov_kobj *vkobj = to_xe_sriov_kobj(kobj);
+	struct xe_device *xe = vkobj->xe;
+	unsigned int vfid = vkobj->vfid;
+
+	xe_sriov_pf_assert_vfid(xe, vfid);
+
+	if (!vattr->show)
+		return -EPERM;
+
+	return vattr->show(xe, vfid, buf);
+}
+
+static ssize_t xe_sriov_vf_attr_store(struct kobject *kobj, struct attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct xe_sriov_vf_attr *vattr = to_xe_sriov_vf_attr(attr);
+	struct xe_sriov_kobj *vkobj = to_xe_sriov_kobj(kobj);
+	struct xe_device *xe = vkobj->xe;
+	unsigned int vfid = vkobj->vfid;
+
+	xe_sriov_pf_assert_vfid(xe, vfid);
+
+	if (!vattr->store)
+		return -EPERM;
+
+	return vattr->store(xe, vfid, buf, count);
+}
+
+static const struct sysfs_ops xe_sriov_dev_sysfs_ops = {
+	.show = xe_sriov_dev_attr_show,
+	.store = xe_sriov_dev_attr_store,
+};
+
+static const struct sysfs_ops xe_sriov_vf_sysfs_ops = {
+	.show = xe_sriov_vf_attr_show,
+	.store = xe_sriov_vf_attr_store,
+};
+
+static const struct kobj_type xe_sriov_dev_ktype = {
+	.release = release_xe_sriov_kobj,
+	.sysfs_ops = &xe_sriov_dev_sysfs_ops,
+	.default_groups = xe_sriov_dev_attr_groups,
+};
+
+static const struct kobj_type xe_sriov_vf_ktype = {
+	.release = release_xe_sriov_kobj,
+	.sysfs_ops = &xe_sriov_vf_sysfs_ops,
+	.default_groups = xe_sriov_vf_attr_groups,
+};
+
+static int pf_sysfs_error(struct xe_device *xe, int err, const char *what)
+{
+	if (IS_ENABLED(CONFIG_DRM_XE_DEBUG))
+		xe_sriov_dbg(xe, "Failed to setup sysfs %s (%pe)\n", what, ERR_PTR(err));
+	return err;
+}
+
+static void action_put_kobject(void *arg)
+{
+	struct kobject *kobj = arg;
+
+	kobject_put(kobj);
+}
+
+static int pf_setup_root(struct xe_device *xe)
+{
+	struct kobject *parent = &xe->drm.dev->kobj;
+	struct kobject *root;
+	int err;
+
+	root = create_xe_sriov_kobj(xe, PFID);
+	if (!root)
+		return pf_sysfs_error(xe, -ENOMEM, "root obj");
+
+	err = devm_add_action_or_reset(xe->drm.dev, action_put_kobject, root);
+	if (err)
+		return pf_sysfs_error(xe, err, "root action");
+
+	err = kobject_init_and_add(root, &xe_sriov_dev_ktype, parent, "sriov_admin");
+	if (err)
+		return pf_sysfs_error(xe, err, "root init");
+
+	xe_assert(xe, IS_SRIOV_PF(xe));
+	xe_assert(xe, !xe->sriov.pf.sysfs.root);
+	xe->sriov.pf.sysfs.root = root;
+	return 0;
+}
+
+static int pf_setup_tree(struct xe_device *xe)
+{
+	unsigned int totalvfs = xe_sriov_pf_get_totalvfs(xe);
+	struct kobject *root, *kobj;
+	unsigned int n;
+	int err;
+
+	xe_assert(xe, IS_SRIOV_PF(xe));
+	root = xe->sriov.pf.sysfs.root;
+
+	for (n = 0; n <= totalvfs; n++) {
+		kobj = create_xe_sriov_kobj(xe, VFID(n));
+		if (!kobj)
+			return pf_sysfs_error(xe, -ENOMEM, "tree obj");
+
+		err = devm_add_action_or_reset(xe->drm.dev, action_put_kobject, root);
+		if (err)
+			return pf_sysfs_error(xe, err, "tree action");
+
+		if (n)
+			err = kobject_init_and_add(kobj, &xe_sriov_vf_ktype,
+						   root, "vf%u", n);
+		else
+			err = kobject_init_and_add(kobj, &xe_sriov_vf_ktype,
+						   root, "pf");
+		if (err)
+			return pf_sysfs_error(xe, err, "tree init");
+
+		xe_assert(xe, !xe->sriov.pf.vfs[n].kobj);
+		xe->sriov.pf.vfs[n].kobj = kobj;
+	}
+
+	return 0;
+}
+
+/**
+ * xe_sriov_pf_sysfs_init() - Setup PF's SR-IOV sysfs tree.
+ * @xe: the PF &xe_device to setup sysfs
+ *
+ * This function will create additional nodes that will represent PF and VFs
+ * devices, each populated with SR-IOV Xe specific attributes.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_sriov_pf_sysfs_init(struct xe_device *xe)
+{
+	int err;
+
+	err = pf_setup_root(xe);
+	if (err)
+		return err;
+
+	err = pf_setup_tree(xe);
+	if (err)
+		return err;
+
+	return 0;
+}

drivers/gpu/drm/xe/xe_sriov_pf_sysfs.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#ifndef _XE_SRIOV_PF_SYSFS_H_
+#define _XE_SRIOV_PF_SYSFS_H_
+
+struct xe_device;
+
+int xe_sriov_pf_sysfs_init(struct xe_device *xe);
+
+#endif

drivers/gpu/drm/xe/xe_sriov_pf_types.h

@@ -12,10 +12,15 @@
 #include "xe_sriov_pf_provision_types.h"
 #include "xe_sriov_pf_service_types.h"
 
+struct kobject;
+
 /**
  * struct xe_sriov_metadata - per-VF device level metadata
  */
 struct xe_sriov_metadata {
+	/** @kobj: kobject representing VF in PF's SR-IOV sysfs tree. */
+	struct kobject *kobj;
+
 	/** @version: negotiated VF/PF ABI version */
 	struct xe_sriov_pf_service_version version;
 };
@@ -42,6 +47,12 @@ struct xe_device_pf {
 	/** @service: device level service data. */
 	struct xe_sriov_pf_service service;
 
+	/** @sysfs: device level sysfs data. */
+	struct {
+		/** @sysfs.root: the root kobject for all SR-IOV entries in sysfs. */
+		struct kobject *root;
+	} sysfs;
+
 	/** @vfs: metadata for all VFs. */
 	struct xe_sriov_metadata *vfs;
 };