From 5b7451fdd703dc582aac102bc4052b9bea501dfe Mon Sep 17 00:00:00 2001
From: Michal Wajdeczko <michal.wajdeczko@intel.com>
Date: Wed, 1 Oct 2025 01:35:21 +0200
Subject: [PATCH] drm/xe/pf: Expose VF control operations over debugfs
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To allow the user to control the activity of individual VFs,
expose basic VF control operations (pause, resume, stop, reset)
over the debugfs as write-only files:

  /sys/kernel/debug/dri/BDF/sriov/
  ├── vf1
  │   ├── pause
  │   ├── reset
  │   ├── resume
  │   ├── stop
  │   :
  ├── vf2
  :   :

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://lore.kernel.org/r/20250930233525.201263-4-michal.wajdeczko@intel.com
---
 drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c | 93 ++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
index 2ab0b1f4818ad..97636ed86fb8b 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_debugfs.c
@@ -8,13 +8,41 @@
 
 #include "xe_device.h"
 #include "xe_device_types.h"
+#include "xe_pm.h"
 #include "xe_sriov_pf.h"
+#include "xe_sriov_pf_control.h"
 #include "xe_sriov_pf_debugfs.h"
 #include "xe_sriov_pf_helpers.h"
 #include "xe_sriov_pf_service.h"
 #include "xe_sriov_printk.h"
 #include "xe_tile_sriov_pf_debugfs.h"
 
+/*
+ *      /sys/kernel/debug/dri/BDF/
+ *      ├── sriov		# d_inode->i_private = (xe_device*)
+ *      │   ├── pf		# d_inode->i_private = (xe_device*)
+ *      │   ├── vf1		# d_inode->i_private = VFID(1)
+ *      :   :
+ *      │   ├── vfN		# d_inode->i_private = VFID(N)
+ */
+
+static void *extract_priv(struct dentry *d)
+{
+	return d->d_inode->i_private;
+}
+
+static struct xe_device *extract_xe(struct dentry *d)
+{
+	return extract_priv(d->d_parent);
+}
+
+static unsigned int extract_vfid(struct dentry *d)
+{
+	void *p = extract_priv(d);
+
+	return p == extract_xe(d) ? PFID : (uintptr_t)p;
+}
+
 static int simple_show(struct seq_file *m, void *data)
 {
 	struct drm_printer p = drm_seq_file_printer(m);
@@ -39,6 +67,70 @@ static void pf_populate_pf(struct xe_device *xe, struct dentry *pfdent)
 	drm_debugfs_create_files(debugfs_list, ARRAY_SIZE(debugfs_list), pfdent, minor);
 }
 
+/*
+ *      /sys/kernel/debug/dri/BDF/
+ *      ├── sriov
+ *      │   ├── vf1
+ *      │   │   ├── pause
+ *      │   │   ├── reset
+ *      │   │   ├── resume
+ *      │   │   ├── stop
+ *      │   │   :
+ *      │   ├── vf2
+ *      │   │   ├── ...
+ */
+
+static ssize_t from_file_write_to_vf_call(struct file *file, const char __user *userbuf,
+					  size_t count, loff_t *ppos,
+					  int (*call)(struct xe_device *, unsigned int))
+{
+	struct dentry *dent = file_dentry(file)->d_parent;
+	struct xe_device *xe = extract_xe(dent);
+	unsigned int vfid = extract_vfid(dent);
+	bool yes;
+	int ret;
+
+	if (*ppos)
+		return -EINVAL;
+	ret = kstrtobool_from_user(userbuf, count, &yes);
+	if (ret < 0)
+		return ret;
+	if (yes) {
+		xe_pm_runtime_get(xe);
+		ret = call(xe, vfid);
+		xe_pm_runtime_put(xe);
+	}
+	if (ret < 0)
+		return ret;
+	return count;
+}
+
+#define DEFINE_VF_CONTROL_ATTRIBUTE(OP)						\
+static int OP##_show(struct seq_file *s, void *unused)				\
+{										\
+	return 0;								\
+}										\
+static ssize_t OP##_write(struct file *file, const char __user *userbuf,	\
+			  size_t count, loff_t *ppos)				\
+{										\
+	return from_file_write_to_vf_call(file, userbuf, count, ppos,		\
+					  xe_sriov_pf_control_##OP);		\
+}										\
+DEFINE_SHOW_STORE_ATTRIBUTE(OP)
+
+DEFINE_VF_CONTROL_ATTRIBUTE(pause_vf);
+DEFINE_VF_CONTROL_ATTRIBUTE(resume_vf);
+DEFINE_VF_CONTROL_ATTRIBUTE(stop_vf);
+DEFINE_VF_CONTROL_ATTRIBUTE(reset_vf);
+
+static void pf_populate_vf(struct xe_device *xe, struct dentry *vfdent)
+{
+	debugfs_create_file("pause", 0200, vfdent, xe, &pause_vf_fops);
+	debugfs_create_file("resume", 0200, vfdent, xe, &resume_vf_fops);
+	debugfs_create_file("stop", 0200, vfdent, xe, &stop_vf_fops);
+	debugfs_create_file("reset", 0200, vfdent, xe, &reset_vf_fops);
+}
+
 static void pf_populate_with_tiles(struct xe_device *xe, struct dentry *dent, unsigned int vfid)
 {
 	struct xe_tile *tile;
@@ -103,6 +195,7 @@ void xe_sriov_pf_debugfs_register(struct xe_device *xe, struct dentry *root)
 			return;
 		vfdent->d_inode->i_private = (void *)(uintptr_t)VFID(n);
 
+		pf_populate_vf(xe, vfdent);
 		pf_populate_with_tiles(xe, vfdent, VFID(n));
 	}
 }
-- 
2.47.3