drm/xe/configfs: Add sriov.admin_only_pf attribute

Instead of relying on fixed relation to the display probe flag,
add configfs attribute to allow an administrator to configure
desired PF operation mode in a more flexible way.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patch.msgid.link/20260121214218.2817-6-michal.wajdeczko@intel.com

4 files changed, 69 insertions, 1 deletions

diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index 5a54ca67d3dc..d8c3fbe81aa6 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -264,6 +264,7 @@ struct xe_config_group_device {
 		bool enable_psmi;
 		struct {
 			unsigned int max_vfs;
+			bool admin_only_pf;
 		} sriov;
 	} config;
 
@@ -282,6 +283,7 @@ static const struct xe_config_device device_defaults = {
 	.enable_psmi = false,
 	.sriov = {
 		.max_vfs = XE_DEFAULT_MAX_VFS,
+		.admin_only_pf = XE_DEFAULT_ADMIN_ONLY_PF,
 	},
 };
 
@@ -897,10 +899,40 @@ static ssize_t sriov_max_vfs_store(struct config_item *item, const char *page, s
 	return len;
 }
 
+static ssize_t sriov_admin_only_pf_show(struct config_item *item, char *page)
+{
+	struct xe_config_group_device *dev = to_xe_config_group_device(item->ci_parent);
+
+	guard(mutex)(&dev->lock);
+
+	return sprintf(page, "%s\n", str_yes_no(dev->config.sriov.admin_only_pf));
+}
+
+static ssize_t sriov_admin_only_pf_store(struct config_item *item, const char *page, size_t len)
+{
+	struct xe_config_group_device *dev = to_xe_config_group_device(item->ci_parent);
+	bool admin_only_pf;
+	int ret;
+
+	guard(mutex)(&dev->lock);
+
+	if (is_bound(dev))
+		return -EBUSY;
+
+	ret = kstrtobool(page, &admin_only_pf);
+	if (ret)
+		return ret;
+
+	dev->config.sriov.admin_only_pf = admin_only_pf;
+	return len;
+}
+
 CONFIGFS_ATTR(sriov_, max_vfs);
+CONFIGFS_ATTR(sriov_, admin_only_pf);
 
 static struct configfs_attribute *xe_config_sriov_attrs[] = {
 	&sriov_attr_max_vfs,
+	&sriov_attr_admin_only_pf,
 	NULL,
 };
 
@@ -911,6 +943,8 @@ static bool xe_config_sriov_is_visible(struct config_item *item,
 
 	if (attr == &sriov_attr_max_vfs && dev->mode != XE_SRIOV_MODE_PF)
 		return false;
+	if (attr == &sriov_attr_admin_only_pf && dev->mode != XE_SRIOV_MODE_PF)
+		return false;
 
 	return true;
 }
@@ -1064,6 +1098,7 @@ static void dump_custom_dev_config(struct pci_dev *pdev,
 	PRI_CUSTOM_ATTR("%llx", engines_allowed);
 	PRI_CUSTOM_ATTR("%d", enable_psmi);
 	PRI_CUSTOM_ATTR("%d", survivability_mode);
+	PRI_CUSTOM_ATTR("%u", sriov.admin_only_pf);
 
 #undef PRI_CUSTOM_ATTR
 }
@@ -1243,6 +1278,32 @@ u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev,
 
 #ifdef CONFIG_PCI_IOV
 /**
+ * xe_configfs_admin_only_pf() - Get PF's operational mode.
+ * @pdev: the &pci_dev device
+ *
+ * Find the configfs group that belongs to the PCI device and return a flag
+ * whether the PF driver should be dedicated for VFs management only.
+ *
+ * If configfs group is not present, use driver's default value.
+ *
+ * Return: true if PF driver is dedicated for VFs administration only.
+ */
+bool xe_configfs_admin_only_pf(struct pci_dev *pdev)
+{
+	struct xe_config_group_device *dev = find_xe_config_group_device(pdev);
+	bool admin_only_pf;
+
+	if (!dev)
+		return XE_DEFAULT_ADMIN_ONLY_PF;
+
+	scoped_guard(mutex, &dev->lock)
+		admin_only_pf = dev->config.sriov.admin_only_pf;
+
+	config_group_put(&dev->group);
+
+	return admin_only_pf;
+}
+/**
  * xe_configfs_get_max_vfs() - Get number of VFs that could be managed
  * @pdev: the &pci_dev device
  *
diff --git a/drivers/gpu/drm/xe/xe_configfs.h b/drivers/gpu/drm/xe/xe_configfs.h
index e0a555b871b3..487531269511 100644
--- a/drivers/gpu/drm/xe/xe_configfs.h
+++ b/drivers/gpu/drm/xe/xe_configfs.h
@@ -8,6 +8,7 @@
 #include <linux/limits.h>
 #include <linux/types.h>
 
+#include "xe_defaults.h"
 #include "xe_hw_engine_types.h"
 #include "xe_module.h"
 
@@ -28,6 +29,7 @@ u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev, enum xe_engine_cla
 					const u32 **cs);
 #ifdef CONFIG_PCI_IOV
 unsigned int xe_configfs_get_max_vfs(struct pci_dev *pdev);
+bool xe_configfs_admin_only_pf(struct pci_dev *pdev);
 #endif
 #else
 static inline int xe_configfs_init(void) { return 0; }
@@ -47,6 +49,10 @@ static inline unsigned int xe_configfs_get_max_vfs(struct pci_dev *pdev)
 {
 	return xe_modparam.max_vfs;
 }
+static inline bool xe_configfs_admin_only_pf(struct pci_dev *pdev)
+{
+	return XE_DEFAULT_ADMIN_ONLY_PF;
+}
 #endif
 #endif
 
diff --git a/drivers/gpu/drm/xe/xe_defaults.h b/drivers/gpu/drm/xe/xe_defaults.h
index 9183d05b96e1..5d5d41d067c5 100644
--- a/drivers/gpu/drm/xe/xe_defaults.h
+++ b/drivers/gpu/drm/xe/xe_defaults.h
@@ -18,6 +18,7 @@
 #define XE_DEFAULT_FORCE_PROBE			CONFIG_DRM_XE_FORCE_PROBE
 #define XE_DEFAULT_MAX_VFS			~0
 #define XE_DEFAULT_MAX_VFS_STR			"unlimited"
+#define XE_DEFAULT_ADMIN_ONLY_PF		false
 #define XE_DEFAULT_WEDGED_MODE			XE_WEDGED_MODE_UPON_CRITICAL_ERROR
 #define XE_DEFAULT_WEDGED_MODE_STR		"upon-critical-error"
 #define XE_DEFAULT_SVM_NOTIFIER_SIZE		512
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf.c b/drivers/gpu/drm/xe/xe_sriov_pf.c
index 919f176a19eb..47a6e0fd66e0 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf.c
+++ b/drivers/gpu/drm/xe/xe_sriov_pf.c
@@ -22,7 +22,7 @@
 
 static bool wanted_admin_only(struct xe_device *xe)
 {
-	return !xe->info.probe_display;
+	return xe_configfs_admin_only_pf(to_pci_dev(xe->drm.dev));
 }
 
 static unsigned int wanted_max_vfs(struct xe_device *xe)