[PATCH 5/9] drm/xe/guc: Add configfs support for guc_log_level

[Stuart Summers <stuart.summers@intel.com>]

Allow the GuC log level to be selected per-device via configfs in
addition to the existing 'guc_log_level' module parameter. The configfs
attribute lives under the new 'debug' configfs subdirectory:

  /sys/kernel/config/xe/<bdf>/debug/guc_log_level

When the configfs attribute is set to a valid level (0-5), it overrides
the module parameter for that device. The default value is -1
(XE_GUC_LOG_LEVEL_UNSET), which means 'unset' and falls back to the
'guc_log_level' module parameter, ensuring existing users that rely
solely on the module parameter are unaffected by this change.

The module parameter implementation itself is untouched.

Note that the expectation is a user will only set the log level when
CONFIG_DRM_XE_DEBUG is set.

Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Assisted-by: Copilot:claude-sonnet-4.6,claude-opus-4.7,claude-sonnet-5
---
 drivers/gpu/drm/xe/xe_configfs.c       |  2 +
 drivers/gpu/drm/xe/xe_configfs_debug.c | 82 ++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_configfs_debug.h |  7 +++
 drivers/gpu/drm/xe/xe_configfs_types.h |  1 +
 drivers/gpu/drm/xe/xe_defaults.h       |  3 +
 drivers/gpu/drm/xe/xe_guc_log.c        |  3 +-
 6 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index 111aacce8a84..ea09d5f9e925 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -100,6 +100,7 @@ const struct xe_config_device xe_configfs_device_defaults = {
 	.debug = {
 		.engines_allowed = U64_MAX,
 		.gt_types_allowed = U64_MAX,
+		.guc_log_level = XE_GUC_LOG_LEVEL_UNSET,
 		.enable_multi_queue = true,
 		.enable_psmi = false,
 		.survivability_mode = false,
@@ -418,6 +419,7 @@ static void dump_custom_dev_config(struct pci_dev *pdev,
 #if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
 	PRI_CUSTOM_ATTR("%llx", debug.engines_allowed);
 	PRI_CUSTOM_ATTR("%llx", debug.gt_types_allowed);
+	PRI_CUSTOM_ATTR("%d", debug.guc_log_level);
 	PRI_CUSTOM_ATTR("%d", debug.enable_multi_queue);
 	PRI_CUSTOM_ATTR("%d", debug.enable_psmi);
 	PRI_CUSTOM_ATTR("%d", debug.survivability_mode);
diff --git a/drivers/gpu/drm/xe/xe_configfs_debug.c b/drivers/gpu/drm/xe/xe_configfs_debug.c
index 5420e4751b58..1d95b4acca9c 100644
--- a/drivers/gpu/drm/xe/xe_configfs_debug.c
+++ b/drivers/gpu/drm/xe/xe_configfs_debug.c
@@ -17,6 +17,7 @@
 #include "xe_configfs_debug.h"
 #include "xe_configfs_types.h"
 #include "xe_gt_types.h"
+#include "xe_guc_log.h"
 #include "xe_hw_engine_types.h"
 #include "xe_pci_types.h"
 
@@ -44,6 +45,7 @@
  *	        ├── ctx_restore_post_bb
  *	        ├── engines_allowed
  *	        ├── gt_types_allowed
+ *	        ├── guc_log_level
  *	        ├── enable_multi_queue
  *	        ├── enable_psmi
  *	        └── survivability_mode
@@ -167,6 +169,27 @@
  *
  *	# echo '' > /sys/kernel/config/xe/0000:03:00.0/debug/gt_types_allowed
  *
+ * GuC log level:
+ * --------------
+ *
+ * Set the GuC firmware logging verbosity for this device. Accepted values
+ * match the ``guc_log_level`` module parameter:
+ *
+ *   - 0: disable
+ *   - 1: normal (non-verbose)
+ *   - 2..%GUC_LOG_LEVEL_MAX: verbose levels
+ *
+ * Example::
+ *
+ *	# echo 3 > /sys/kernel/config/xe/0000:03:00.0/debug/guc_log_level
+ *
+ * The default value is %XE_GUC_LOG_LEVEL_UNSET (-1), which means the value
+ * of the ``guc_log_level`` module parameter is used. Any value greater
+ * than -1 written to this attribute overrides the module parameter for
+ * this device.
+ *
+ * This attribute can only be set before binding to the device.
+ *
  * Enable multi-queue
  * ------------------
  *
@@ -752,6 +775,63 @@ static ssize_t gt_types_allowed_store(struct config_item *item, const char *page
 	return len;
 }
 
+/**
+ * xe_configfs_get_guc_log_level - get configfs guc_log_level setting
+ * @pdev: pci device
+ *
+ * Returns the guc_log_level value configured via configfs. If the configfs
+ * value is negative (the default is %XE_GUC_LOG_LEVEL_UNSET, -1), the value
+ * of the ``guc_log_level`` module parameter is returned instead, allowing
+ * the configfs entry to override the module parameter without affecting
+ * users that rely solely on the module parameter.
+ *
+ * Return: GuC log level to use for this device.
+ */
+int xe_configfs_get_guc_log_level(struct pci_dev *pdev)
+{
+	struct xe_config_group_device *dev = find_device(pdev);
+	int level = xe_modparam.guc_log_level;
+
+	if (!dev)
+		goto out;
+
+	if (dev->config.debug.guc_log_level >= 0)
+		level = dev->config.debug.guc_log_level;
+
+	config_group_put(&dev->group);
+out:
+	return level;
+}
+
+static ssize_t guc_log_level_show(struct config_item *item, char *page)
+{
+	struct xe_config_device *dev = xe_configfs_subgroup_to_device(item);
+
+	return sprintf(page, "%d\n", dev->debug.guc_log_level);
+}
+
+static ssize_t guc_log_level_store(struct config_item *item, const char *page, size_t len)
+{
+	struct xe_config_group_device *dev = xe_configfs_subgroup_to_group_device(item);
+	int val;
+	int ret;
+
+	ret = kstrtoint(page, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val > GUC_LOG_LEVEL_MAX)
+		return -EINVAL;
+
+	guard(mutex)(&dev->lock);
+	if (xe_configfs_is_bound(dev))
+		return -EBUSY;
+
+	dev->config.debug.guc_log_level = val;
+
+	return len;
+}
+
 /**
  * xe_configfs_get_enable_multi_queue - get configfs enable_multi_queue setting
  * @pdev: pci device
@@ -895,6 +975,7 @@ CONFIGFS_ATTR(, ctx_restore_mid_bb);
 CONFIGFS_ATTR(, ctx_restore_post_bb);
 CONFIGFS_ATTR(, engines_allowed);
 CONFIGFS_ATTR(, gt_types_allowed);
+CONFIGFS_ATTR(, guc_log_level);
 CONFIGFS_ATTR(, enable_multi_queue);
 CONFIGFS_ATTR(, enable_psmi);
 CONFIGFS_ATTR(, survivability_mode);
@@ -904,6 +985,7 @@ static struct configfs_attribute *xe_configfs_debug_attrs[] = {
 	&attr_ctx_restore_post_bb,
 	&attr_engines_allowed,
 	&attr_gt_types_allowed,
+	&attr_guc_log_level,
 	&attr_enable_multi_queue,
 	&attr_enable_psmi,
 	&attr_survivability_mode,
diff --git a/drivers/gpu/drm/xe/xe_configfs_debug.h b/drivers/gpu/drm/xe/xe_configfs_debug.h
index 4a027ea2082d..5fe39bb72f00 100644
--- a/drivers/gpu/drm/xe/xe_configfs_debug.h
+++ b/drivers/gpu/drm/xe/xe_configfs_debug.h
@@ -7,7 +7,9 @@
 
 #include <linux/types.h>
 
+#include "xe_defaults.h"
 #include "xe_hw_engine_types.h"
+#include "xe_module.h"
 
 struct pci_dev;
 struct xe_config_device;
@@ -24,6 +26,7 @@ u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev,
 u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev);
 bool xe_configfs_primary_gt_allowed(struct pci_dev *pdev);
 bool xe_configfs_media_gt_allowed(struct pci_dev *pdev);
+int xe_configfs_get_guc_log_level(struct pci_dev *pdev);
 bool xe_configfs_get_enable_multi_queue(struct pci_dev *pdev);
 bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev);
 bool xe_configfs_get_survivability_mode(struct pci_dev *pdev);
@@ -42,6 +45,10 @@ static inline u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev,
 static inline u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev) { return U64_MAX; }
 static inline bool xe_configfs_primary_gt_allowed(struct pci_dev *pdev) { return true; }
 static inline bool xe_configfs_media_gt_allowed(struct pci_dev *pdev) { return true; }
+static inline int xe_configfs_get_guc_log_level(struct pci_dev *pdev)
+{
+	return xe_modparam.guc_log_level;
+}
 static inline bool xe_configfs_get_enable_multi_queue(struct pci_dev *pdev) { return true; }
 static inline bool xe_configfs_get_psmi_enabled(struct pci_dev *pdev) { return false; }
 static inline bool xe_configfs_get_survivability_mode(struct pci_dev *pdev) { return false; }
diff --git a/drivers/gpu/drm/xe/xe_configfs_types.h b/drivers/gpu/drm/xe/xe_configfs_types.h
index 6e8ba6f85fad..e9460c3de891 100644
--- a/drivers/gpu/drm/xe/xe_configfs_types.h
+++ b/drivers/gpu/drm/xe/xe_configfs_types.h
@@ -38,6 +38,7 @@ struct xe_config_group_device {
 			struct wa_bb ctx_restore_post_bb[XE_ENGINE_CLASS_MAX];
 			u64 engines_allowed;
 			u64 gt_types_allowed;
+			int guc_log_level;
 			bool enable_multi_queue;
 			bool enable_psmi;
 			bool survivability_mode;
diff --git a/drivers/gpu/drm/xe/xe_defaults.h b/drivers/gpu/drm/xe/xe_defaults.h
index c8ae1d5f3d60..df88078e84b8 100644
--- a/drivers/gpu/drm/xe/xe_defaults.h
+++ b/drivers/gpu/drm/xe/xe_defaults.h
@@ -13,6 +13,9 @@
 #define XE_DEFAULT_GUC_LOG_LEVEL		1
 #endif
 
+/* Sentinel value for guc_log_level configfs: not set, fall back to module param */
+#define XE_GUC_LOG_LEVEL_UNSET			-1
+
 #define XE_DEFAULT_PROBE_DISPLAY		IS_ENABLED(CONFIG_DRM_XE_DISPLAY)
 #define XE_DEFAULT_VRAM_BAR_SIZE		0
 #define XE_DEFAULT_FORCE_PROBE			CONFIG_DRM_XE_FORCE_PROBE
diff --git a/drivers/gpu/drm/xe/xe_guc_log.c b/drivers/gpu/drm/xe/xe_guc_log.c
index 538d4df0f7aa..531b9759d520 100644
--- a/drivers/gpu/drm/xe/xe_guc_log.c
+++ b/drivers/gpu/drm/xe/xe_guc_log.c
@@ -13,6 +13,7 @@
 #include "abi/guc_lfd_abi.h"
 #include "regs/xe_guc_regs.h"
 #include "xe_bo.h"
+#include "xe_configfs_debug.h"
 #include "xe_devcoredump.h"
 #include "xe_force_wake.h"
 #include "xe_gt_printk.h"
@@ -637,7 +638,7 @@ int xe_guc_log_init(struct xe_guc_log *log)
 
 	xe_map_memset(xe, &bo->vmap, 0, 0, xe_bo_size(bo));
 	log->bo = bo;
-	log->level = xe_modparam.guc_log_level;
+	log->level = xe_configfs_get_guc_log_level(to_pci_dev(xe->drm.dev));
 
 	return 0;
 }
-- 
2.43.0