[PATCH V18 09/14] drm/xe/configfs: Add bad_page_reservation attribute

[Tejas Upadhyay <tejas.upadhyay@intel.com>]

Add a new configfs attribute 'bad_page_reservation' to control how bad
VRAM pages are handled:
  0 - Logging only (report in dmesg, no offlining)
  1 - Offlining (default)

The attribute can only be set before binding to the device and defaults
to true (offlining enabled). This gives administrators control over
whether corrupted VRAM pages detected by hardware (e.g., ECC errors)
are actively offlined or only logged.

Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
---
 drivers/gpu/drm/xe/xe_configfs.c | 67 +++++++++++++++++++++++++++++++-
 drivers/gpu/drm/xe/xe_configfs.h |  2 +
 2 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index 052cce962161..80c4c5f66e4c 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -61,7 +61,8 @@
  *	    ├── survivability_mode
  *	    ├── gt_types_allowed
  *	    ├── engines_allowed
- *	    └── enable_psmi
+ *          ├── enable_psmi
+ *          └── bad_page_reservation
  *
  * After configuring the attributes as per next section, the device can be
  * probed with::
@@ -159,6 +160,19 @@
  *
  * This attribute can only be set before binding to the device.
  *
+ * Bad pages reservation:
+ * ---------------------
+ *
+ * Controls how bad VRAM pages are handled:
+ *  0 - Logging only (report in dmesg, no offlining)
+ *  1 - Offlining (default)
+ *
+ *  Example to disable offlining::
+ *
+ *      # echo 0 > /sys/kernel/config/xe/0000:03:00.0/bad_page_reservation
+ *
+ * This attribute can only be set before binding to the device.
+ *
  * Context restore BB
  * ------------------
  *
@@ -275,6 +289,7 @@ struct xe_config_group_device {
 		bool survivability_mode;
 		bool enable_psmi;
 		bool enable_multi_queue;
+		bool bad_page_reservation;
 		struct {
 			unsigned int max_vfs;
 			bool admin_only_pf;
@@ -295,6 +310,7 @@ static const struct xe_config_device device_defaults = {
 	.survivability_mode = false,
 	.enable_psmi = false,
 	.enable_multi_queue = true,
+	.bad_page_reservation = true,
 	.sriov = {
 		.max_vfs = XE_DEFAULT_MAX_VFS,
 		.admin_only_pf = XE_DEFAULT_ADMIN_ONLY_PF,
@@ -616,6 +632,32 @@ static ssize_t enable_multi_queue_store(struct config_item *item, const char *pa
 	return len;
 }
 
+static ssize_t bad_page_reservation_show(struct config_item *item, char *page)
+{
+	struct xe_config_device *dev = to_xe_config_device(item);
+
+	return sprintf(page, "%d\n", dev->bad_page_reservation);
+}
+
+static ssize_t bad_page_reservation_store(struct config_item *item, const char *page, size_t len)
+{
+	struct xe_config_group_device *dev = to_xe_config_group_device(item);
+	bool val;
+	int ret;
+
+	ret = kstrtobool(page, &val);
+	if (ret)
+		return ret;
+
+	guard(mutex)(&dev->lock);
+	if (is_bound(dev))
+		return -EBUSY;
+
+	dev->config.bad_page_reservation = val;
+
+	return len;
+}
+
 static bool wa_bb_read_advance(bool dereference, char **p,
 			       const char *append, size_t len,
 			       size_t *max_size)
@@ -855,6 +897,7 @@ CONFIGFS_ATTR(, ctx_restore_mid_bb);
 CONFIGFS_ATTR(, ctx_restore_post_bb);
 CONFIGFS_ATTR(, enable_multi_queue);
 CONFIGFS_ATTR(, enable_psmi);
+CONFIGFS_ATTR(, bad_page_reservation);
 CONFIGFS_ATTR(, engines_allowed);
 CONFIGFS_ATTR(, gt_types_allowed);
 CONFIGFS_ATTR(, survivability_mode);
@@ -864,6 +907,7 @@ static struct configfs_attribute *xe_config_device_attrs[] = {
 	&attr_ctx_restore_post_bb,
 	&attr_enable_multi_queue,
 	&attr_enable_psmi,
+	&attr_bad_page_reservation,
 	&attr_engines_allowed,
 	&attr_gt_types_allowed,
 	&attr_survivability_mode,
@@ -1142,6 +1186,7 @@ static void dump_custom_dev_config(struct pci_dev *pdev,
 	PRI_CUSTOM_ATTR("%llx", engines_allowed);
 	PRI_CUSTOM_ATTR("%d", enable_multi_queue);
 	PRI_CUSTOM_ATTR("%d", enable_psmi);
+	PRI_CUSTOM_ATTR("%d", bad_page_reservation);
 	PRI_CUSTOM_ATTR("%d", survivability_mode);
 	PRI_CUSTOM_ATTR("%u", sriov.admin_only_pf);
 
@@ -1290,6 +1335,26 @@ bool xe_configfs_get_enable_multi_queue(struct pci_dev *pdev)
 	return ret;
 }
 
+/**
+ * xe_configfs_get_bad_page_reservation - get configfs bad_page_reservation setting
+ * @pdev: pci device
+ *
+ * Return: bad_page_reservation setting in configfs
+ */
+bool xe_configfs_get_bad_page_reservation(struct pci_dev *pdev)
+{
+	struct xe_config_group_device *dev = find_xe_config_group_device(pdev);
+	bool ret;
+
+	if (!dev)
+		return device_defaults.bad_page_reservation;
+
+	ret = dev->config.bad_page_reservation;
+	config_group_put(&dev->group);
+
+	return ret;
+}
+
 /**
  * xe_configfs_get_ctx_restore_mid_bb - get configfs ctx_restore_mid_bb setting
  * @pdev: pci device
diff --git a/drivers/gpu/drm/xe/xe_configfs.h b/drivers/gpu/drm/xe/xe_configfs.h
index 4fbbeafba473..7405cc5f3207 100644
--- a/drivers/gpu/drm/xe/xe_configfs.h
+++ b/drivers/gpu/drm/xe/xe_configfs.h
@@ -24,6 +24,7 @@ bool xe_configfs_media_gt_allowed(struct pci_dev *pdev);
 u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev);
 bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev);
 bool xe_configfs_get_enable_multi_queue(struct pci_dev *pdev);
+bool xe_configfs_get_bad_page_reservation(struct pci_dev *pdev);
 u32 xe_configfs_get_ctx_restore_mid_bb(struct pci_dev *pdev,
 				       enum xe_engine_class class,
 				       const u32 **cs);
@@ -44,6 +45,7 @@ static inline bool xe_configfs_media_gt_allowed(struct pci_dev *pdev) { return t
 static inline u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev) { return U64_MAX; }
 static inline bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev) { return false; }
 static inline bool xe_configfs_get_enable_multi_queue(struct pci_dev *pdev) { return true; }
+static inline bool xe_configfs_get_bad_page_reservation(struct pci_dev *pdev) { return true; }
 static inline u32 xe_configfs_get_ctx_restore_mid_bb(struct pci_dev *pdev,
 						     enum xe_engine_class class,
 						     const u32 **cs) { return 0; }
-- 
2.52.0