drm/xe/pf: Allow to save and restore VF config blob from debugfs

For feature enabling and testing purposes, allow to capture and
replace full VF configuration using debugfs blob file, but only
under strict debug config.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240919171528.1451-6-michal.wajdeczko@intel.com

1 files changed, 78 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
index ccbcf6e572d0..91fc42e386d8 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_debugfs.c
@@ -417,6 +417,81 @@ static const struct file_operations guc_state_ops = {
 	.llseek		= default_llseek,
 };
 
+/*
+ *      /sys/kernel/debug/dri/0/
+ *      ├── gt0
+ *      │   ├── vf1
+ *      │   │   ├── config_blob
+ */
+static ssize_t config_blob_read(struct file *file, char __user *buf,
+				size_t count, loff_t *pos)
+{
+	struct dentry *dent = file_dentry(file);
+	struct dentry *parent = dent->d_parent;
+	struct xe_gt *gt = extract_gt(parent);
+	unsigned int vfid = extract_vfid(parent);
+	ssize_t ret;
+	void *tmp;
+
+	ret = xe_gt_sriov_pf_config_save(gt, vfid, NULL, 0);
+	if (!ret)
+		return -ENODATA;
+	if (ret < 0)
+		return ret;
+
+	tmp = kzalloc(ret, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	ret = xe_gt_sriov_pf_config_save(gt, vfid, tmp, ret);
+	if (ret > 0)
+		ret = simple_read_from_buffer(buf, count, pos, tmp, ret);
+
+	kfree(tmp);
+	return ret;
+}
+
+static ssize_t config_blob_write(struct file *file, const char __user *buf,
+				 size_t count, loff_t *pos)
+{
+	struct dentry *dent = file_dentry(file);
+	struct dentry *parent = dent->d_parent;
+	struct xe_gt *gt = extract_gt(parent);
+	unsigned int vfid = extract_vfid(parent);
+	ssize_t ret;
+	void *tmp;
+
+	if (*pos)
+		return -EINVAL;
+
+	if (!count)
+		return -ENODATA;
+
+	if (count > SZ_4K)
+		return -EINVAL;
+
+	tmp = kzalloc(count, GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
+
+	if (copy_from_user(tmp, buf, count)) {
+		ret = -EFAULT;
+	} else {
+		ret = xe_gt_sriov_pf_config_restore(gt, vfid, tmp, count);
+		if (!ret)
+			ret = count;
+	}
+	kfree(tmp);
+	return ret;
+}
+
+static const struct file_operations config_blob_ops = {
+	.owner		= THIS_MODULE,
+	.read		= config_blob_read,
+	.write		= config_blob_write,
+	.llseek		= default_llseek,
+};
+
 /**
  * xe_gt_sriov_pf_debugfs_register - Register SR-IOV PF specific entries in GT debugfs.
  * @gt: the &xe_gt to register
@@ -471,6 +546,9 @@ void xe_gt_sriov_pf_debugfs_register(struct xe_gt *gt, struct dentry *root)
 			debugfs_create_file("guc_state",
 					    IS_ENABLED(CONFIG_DRM_XE_DEBUG_SRIOV) ? 0600 : 0400,
 					    vfdentry, NULL, &guc_state_ops);
+			debugfs_create_file("config_blob",
+					    IS_ENABLED(CONFIG_DRM_XE_DEBUG_SRIOV) ? 0600 : 0400,
+					    vfdentry, NULL, &config_blob_ops);
 		}
 	}
 }