drm/i915/gvt: Provide generic page_track infrastructure for write-protected page

This patch provide generic page_track infrastructure for write-protected
guest page. The old page_track logic gets rewrote and now stays in a new
standalone page_track.c. This page track infrastructure can be both used
by vGUC and GTT shadowing.

The important change is that it uses radix tree instead of hash table.
We don't have a predictable number of pages that will be tracked.

Here is some performance data (duration in us) of looking up a element:
Before: (aka. intel_vgpu_find_tracked_page)
 0.091 0.089 0.090 ... 0.093 0.091 0.087 ... 0.292 0.285 0.292 0.291
After: (aka. intel_vgpu_find_page_track)
 0.104 0.105 0.100 0.102 0.102 0.100 ... 0.101 0.101 0.105 0.105

The hash table has good performance at beginning, but turns bad with
more pages being tracked even no 3D applications are running. As
expected, radix tree has stable duration and very quick.

The overall benchmark (tested with Heaven Benchmark) marginally improved
since this is not the bottleneck. What we benefit more from this change
is scalability.

Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gvt/page_track.h b/drivers/gpu/drm/i915/gvt/page_track.h
new file mode 100644
index 000000000000..fa607a71c3c0
--- /dev/null
+++ b/drivers/gpu/drm/i915/gvt/page_track.h
@@ -0,0 +1,56 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef _GVT_PAGE_TRACK_H_
+#define _GVT_PAGE_TRACK_H_
+
+struct intel_vgpu_page_track;
+
+typedef int (*gvt_page_track_handler_t)(
+			struct intel_vgpu_page_track *page_track,
+			u64 gpa, void *data, int bytes);
+
+/* Track record for a write-protected guest page. */
+struct intel_vgpu_page_track {
+	gvt_page_track_handler_t handler;
+	bool tracked;
+	void *priv_data;
+};
+
+struct intel_vgpu_page_track *intel_vgpu_find_page_track(
+		struct intel_vgpu *vgpu, unsigned long gfn);
+
+int intel_vgpu_register_page_track(struct intel_vgpu *vgpu,
+		unsigned long gfn, gvt_page_track_handler_t handler,
+		void *priv);
+void intel_vgpu_unregister_page_track(struct intel_vgpu *vgpu,
+		unsigned long gfn);
+
+int intel_vgpu_enable_page_track(struct intel_vgpu *vgpu, unsigned long gfn);
+int intel_vgpu_disable_page_track(struct intel_vgpu *vgpu, unsigned long gfn);
+
+int intel_vgpu_page_track_handler(struct intel_vgpu *vgpu, u64 gpa,
+		void *data, unsigned int bytes);
+
+#endif