drm/i915/gvt: Add basic debugfs infrastructure

We need debugfs entry to expose some debug information of gvt and vGPUs.
The first tool will be added is mmio-diff, which help to find the
difference values of host and vGPU mmio. It's useful for platform
enabling.

This patch just add a basic debugfs infrastructure, each vGPU has its own
sub-folder. Two simple attributes are created as a template.
.
├── num_tracked_mmio
├── vgpu1
|   └── active
└── vgpu2
    └── active

Signed-off-by: Changbin Du <changbin.du@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>

Author: Changbin Du

drivers/gpu/drm/i915/gvt/Makefile

@@ -1,7 +1,7 @@
 GVT_DIR := gvt
 GVT_SOURCE := gvt.o aperture_gm.o handlers.o vgpu.o trace_points.o firmware.o \
 	interrupt.o gtt.o cfg_space.o opregion.o mmio.o display.o edid.o \
-	execlist.o scheduler.o sched_policy.o render.o cmd_parser.o
+	execlist.o scheduler.o sched_policy.o render.o cmd_parser.o debugfs.o
 
 ccflags-y				+= -I$(src) -I$(src)/$(GVT_DIR)
 i915-y					+= $(addprefix $(GVT_DIR)/, $(GVT_SOURCE))

drivers/gpu/drm/i915/gvt/debugfs.c

@@ -0,0 +1,97 @@
+/*
+ * Copyright(c) 2011-2017 Intel Corporation. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <linux/debugfs.h>
+#include "i915_drv.h"
+#include "gvt.h"
+
+
+/**
+ * intel_gvt_debugfs_add_vgpu - register debugfs entries for a vGPU
+ * @vgpu: a vGPU
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ */
+int intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu)
+{
+	struct dentry *ent;
+	char name[10] = "";
+
+	sprintf(name, "vgpu%d", vgpu->id);
+	vgpu->debugfs = debugfs_create_dir(name, vgpu->gvt->debugfs_root);
+	if (!vgpu->debugfs)
+		return -ENOMEM;
+
+	ent = debugfs_create_bool("active", 0444, vgpu->debugfs,
+				  &vgpu->active);
+	if (!ent)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * intel_gvt_debugfs_remove_vgpu - remove debugfs entries of a vGPU
+ * @vgpu: a vGPU
+ */
+void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu)
+{
+	debugfs_remove_recursive(vgpu->debugfs);
+	vgpu->debugfs = NULL;
+}
+
+/**
+ * intel_gvt_debugfs_init - register gvt debugfs root entry
+ * @gvt: GVT device
+ *
+ * Returns:
+ * zero on success, negative if failed.
+ */
+int intel_gvt_debugfs_init(struct intel_gvt *gvt)
+{
+	struct drm_minor *minor = gvt->dev_priv->drm.primary;
+	struct dentry *ent;
+
+	gvt->debugfs_root = debugfs_create_dir("gvt", minor->debugfs_root);
+	if (!gvt->debugfs_root) {
+		gvt_err("Cannot create debugfs dir\n");
+		return -ENOMEM;
+	}
+
+	ent = debugfs_create_ulong("num_tracked_mmio", 0444, gvt->debugfs_root,
+				   &gvt->mmio.num_tracked_mmio);
+	if (!ent)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * intel_gvt_debugfs_clean - remove debugfs entries
+ * @gvt: GVT device
+ */
+void intel_gvt_debugfs_clean(struct intel_gvt *gvt)
+{
+	debugfs_remove_recursive(gvt->debugfs_root);
+	gvt->debugfs_root = NULL;
+}

drivers/gpu/drm/i915/gvt/gvt.c

@@ -318,6 +318,7 @@ void intel_gvt_clean_device(struct drm_i915_private *dev_priv)
 	if (WARN_ON(!gvt))
 		return;
 
+	intel_gvt_debugfs_clean(gvt);
 	clean_service_thread(gvt);
 	intel_gvt_clean_cmd_parser(gvt);
 	intel_gvt_clean_sched_policy(gvt);
@@ -441,6 +442,10 @@ int intel_gvt_init_device(struct drm_i915_private *dev_priv)
 	}
 	gvt->idle_vgpu = vgpu;
 
+	ret = intel_gvt_debugfs_init(gvt);
+	if (ret)
+		gvt_err("debugfs registeration failed, go on.\n");
+
 	gvt_dbg_core("gvt device initialization is done\n");
 	dev_priv->gvt = gvt;
 	return 0;

drivers/gpu/drm/i915/gvt/gvt.h

@@ -190,6 +190,8 @@ struct intel_vgpu {
 	struct intel_vgpu_display display;
 	struct intel_vgpu_submission submission;
 
+	struct dentry *debugfs;
+
 #if IS_ENABLED(CONFIG_DRM_I915_GVT_KVMGT)
 	struct {
 		struct mdev_device *mdev;
@@ -253,7 +255,7 @@ struct intel_gvt_mmio {
 	unsigned int num_mmio_block;
 
 	DECLARE_HASHTABLE(mmio_info_table, INTEL_GVT_MMIO_HASH_BITS);
-	unsigned int num_tracked_mmio;
+	unsigned long num_tracked_mmio;
 };
 
 struct intel_gvt_firmware {
@@ -301,6 +303,8 @@ struct intel_gvt {
 	struct task_struct *service_thread;
 	wait_queue_head_t service_thread_wq;
 	unsigned long service_request;
+
+	struct dentry *debugfs_root;
 };
 
 static inline struct intel_gvt *to_gvt(struct drm_i915_private *i915)
@@ -619,6 +623,12 @@ static inline bool intel_gvt_mmio_has_mode_mask(
 	return gvt->mmio.mmio_attribute[offset >> 2] & F_MODE_MASK;
 }
 
+int intel_gvt_debugfs_add_vgpu(struct intel_vgpu *vgpu);
+void intel_gvt_debugfs_remove_vgpu(struct intel_vgpu *vgpu);
+int intel_gvt_debugfs_init(struct intel_gvt *gvt);
+void intel_gvt_debugfs_clean(struct intel_gvt *gvt);
+
+
 #include "trace.h"
 #include "mpt.h"
 

drivers/gpu/drm/i915/gvt/handlers.c

@@ -2928,8 +2928,6 @@ int intel_gvt_setup_mmio_info(struct intel_gvt *gvt)
 	gvt->mmio.mmio_block = mmio_blocks;
 	gvt->mmio.num_mmio_block = ARRAY_SIZE(mmio_blocks);
 
-	gvt_dbg_mmio("traced %u virtual mmio registers\n",
-		     gvt->mmio.num_tracked_mmio);
 	return 0;
 err:
 	intel_gvt_clean_mmio_info(gvt);

drivers/gpu/drm/i915/gvt/vgpu.c

@@ -252,6 +252,7 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)
 
 	WARN(vgpu->active, "vGPU is still active!\n");
 
+	intel_gvt_debugfs_remove_vgpu(vgpu);
 	idr_remove(&gvt->vgpu_idr, vgpu->id);
 	intel_vgpu_clean_sched_policy(vgpu);
 	intel_vgpu_clean_submission(vgpu);
@@ -378,10 +379,16 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
 	if (ret)
 		goto out_clean_submission;
 
+	ret = intel_gvt_debugfs_add_vgpu(vgpu);
+	if (ret)
+		goto out_clean_sched_policy;
+
 	mutex_unlock(&gvt->lock);
 
 	return vgpu;
 
+out_clean_sched_policy:
+	intel_vgpu_clean_sched_policy(vgpu);
 out_clean_submission:
 	intel_vgpu_clean_submission(vgpu);
 out_clean_display: