drm/i915: Add i915 perf infrastructure

Adds base i915 perf infrastructure for Gen performance metrics.

This adds a DRM_IOCTL_I915_PERF_OPEN ioctl that takes an array of uint64
properties to configure a stream of metrics and returns a new fd usable
with standard VFS system calls including read() to read typed and sized
records; ioctl() to enable or disable capture and poll() to wait for
data.

A stream is opened something like:

  uint64_t properties[] = {
      /* Single context sampling */
      DRM_I915_PERF_PROP_CTX_HANDLE,        ctx_handle,

      /* Include OA reports in samples */
      DRM_I915_PERF_PROP_SAMPLE_OA,         true,

      /* OA unit configuration */
      DRM_I915_PERF_PROP_OA_METRICS_SET,    metrics_set_id,
      DRM_I915_PERF_PROP_OA_FORMAT,         report_format,
      DRM_I915_PERF_PROP_OA_EXPONENT,       period_exponent,
   };
   struct drm_i915_perf_open_param parm = {
      .flags = I915_PERF_FLAG_FD_CLOEXEC |
               I915_PERF_FLAG_FD_NONBLOCK |
               I915_PERF_FLAG_DISABLED,
      .properties_ptr = (uint64_t)properties,
      .num_properties = sizeof(properties) / 16,
   };
   int fd = drmIoctl(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param);

Records read all start with a common { type, size } header with
DRM_I915_PERF_RECORD_SAMPLE being of most interest. Sample records
contain an extensible number of fields and it's the
DRM_I915_PERF_PROP_SAMPLE_xyz properties given when opening that
determine what's included in every sample.

No specific streams are supported yet so any attempt to open a stream
will return an error.

v2:
    use i915_gem_context_get() - Chris Wilson
v3:
    update read() interface to avoid passing state struct - Chris Wilson
    fix some rebase fallout, with i915-perf init/deinit
v4:
    s/DRM_IORW/DRM_IOW/ - Emil Velikov
Signed-off-by: NRobert Bragg <robert@sixbynine.org>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NSourab Gupta <sourab.gupta@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161107194957.3385-2-robert@sixbynine.org

drivers/gpu/drm/i915/Makefile

@@ -117,6 +117,9 @@ i915-$(CONFIG_DRM_I915_CAPTURE_ERROR) += i915_gpu_error.o
 # virtual gpu code
 i915-y += i915_vgpu.o
 
+# perf code
+i915-y += i915_perf.o
+
 ifeq ($(CONFIG_DRM_I915_GVT),y)
 i915-y += intel_gvt.o
 include $(src)/gvt/Makefile

drivers/gpu/drm/i915/i915_drv.c

@@ -848,6 +848,8 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
 
 	intel_detect_preproduction_hw(dev_priv);
 
+	i915_perf_init(dev_priv);
+
 	return 0;
 
 err_gvt:
@@ -863,6 +865,7 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv,
  */
 static void i915_driver_cleanup_early(struct drm_i915_private *dev_priv)
 {
+	i915_perf_fini(dev_priv);
 	i915_gem_load_cleanup(&dev_priv->drm);
 	i915_workqueues_cleanup(dev_priv);
 }
@@ -2565,6 +2568,7 @@ static const struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I915_GEM_USERPTR, i915_gem_userptr_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_GETPARAM, i915_gem_context_getparam_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_SETPARAM, i915_gem_context_setparam_ioctl, DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_PERF_OPEN, i915_perf_open_ioctl, DRM_RENDER_ALLOW),
 };
 
 static struct drm_driver driver = {

drivers/gpu/drm/i915/i915_drv.h

@@ -1797,6 +1797,84 @@ struct intel_wm_config {
 	bool sprites_scaled;
 };
 
+struct i915_perf_stream;
+
+struct i915_perf_stream_ops {
+	/* Enables the collection of HW samples, either in response to
+	 * I915_PERF_IOCTL_ENABLE or implicitly called when stream is
+	 * opened without I915_PERF_FLAG_DISABLED.
+	 */
+	void (*enable)(struct i915_perf_stream *stream);
+
+	/* Disables the collection of HW samples, either in response to
+	 * I915_PERF_IOCTL_DISABLE or implicitly called before
+	 * destroying the stream.
+	 */
+	void (*disable)(struct i915_perf_stream *stream);
+
+	/* Return: true if any i915 perf records are ready to read()
+	 * for this stream.
+	 */
+	bool (*can_read)(struct i915_perf_stream *stream);
+
+	/* Call poll_wait, passing a wait queue that will be woken
+	 * once there is something ready to read() for the stream
+	 */
+	void (*poll_wait)(struct i915_perf_stream *stream,
+			  struct file *file,
+			  poll_table *wait);
+
+	/* For handling a blocking read, wait until there is something
+	 * to ready to read() for the stream. E.g. wait on the same
+	 * wait queue that would be passed to poll_wait() until
+	 * ->can_read() returns true (if its safe to call ->can_read()
+	 * without the i915 perf lock held).
+	 */
+	int (*wait_unlocked)(struct i915_perf_stream *stream);
+
+	/* read - Copy buffered metrics as records to userspace
+	 * @buf: the userspace, destination buffer
+	 * @count: the number of bytes to copy, requested by userspace
+	 * @offset: zero at the start of the read, updated as the read
+	 *          proceeds, it represents how many bytes have been
+	 *          copied so far and the buffer offset for copying the
+	 *          next record.
+	 *
+	 * Copy as many buffered i915 perf samples and records for
+	 * this stream to userspace as will fit in the given buffer.
+	 *
+	 * Only write complete records; returning -ENOSPC if there
+	 * isn't room for a complete record.
+	 *
+	 * Return any error condition that results in a short read
+	 * such as -ENOSPC or -EFAULT, even though these may be
+	 * squashed before returning to userspace.
+	 */
+	int (*read)(struct i915_perf_stream *stream,
+		    char __user *buf,
+		    size_t count,
+		    size_t *offset);
+
+	/* Cleanup any stream specific resources.
+	 *
+	 * The stream will always be disabled before this is called.
+	 */
+	void (*destroy)(struct i915_perf_stream *stream);
+};
+
+struct i915_perf_stream {
+	struct drm_i915_private *dev_priv;
+
+	struct list_head link;
+
+	u32 sample_flags;
+
+	struct i915_gem_context *ctx;
+	bool enabled;
+
+	struct i915_perf_stream_ops *ops;
+};
+
 struct drm_i915_private {
 	struct drm_device drm;
 
@@ -2092,6 +2170,12 @@ struct drm_i915_private {
 
 	struct i915_runtime_pm pm;
 
+	struct {
+		bool initialized;
+		struct mutex lock;
+		struct list_head streams;
+	} perf;
+
 	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
 	struct {
 		void (*resume)(struct drm_i915_private *);
@@ -3253,6 +3337,9 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, void *data,
 				       struct drm_file *file);
 
+int i915_perf_open_ioctl(struct drm_device *dev, void *data,
+			 struct drm_file *file);
+
 /* i915_gem_evict.c */
 int __must_check i915_gem_evict_something(struct i915_address_space *vm,
 					  u64 min_size, u64 alignment,
@@ -3383,6 +3470,10 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
 			    u32 batch_len,
 			    bool is_master);
 
+/* i915_perf.c */
+extern void i915_perf_init(struct drm_i915_private *dev_priv);
+extern void i915_perf_fini(struct drm_i915_private *dev_priv);
+
 /* i915_suspend.c */
 extern int i915_save_state(struct drm_device *dev);
 extern int i915_restore_state(struct drm_device *dev);

drivers/gpu/drm/i915/i915_perf.c

+/*
+ * Copyright © 2015-2016 Intel Corporation
+ *
+ * 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.
+ *
+ * Authors:
+ *   Robert Bragg <robert@sixbynine.org>
+ */
+
+#include <linux/anon_inodes.h>
+
+#include "i915_drv.h"
+
+struct perf_open_properties {
+	u32 sample_flags;
+
+	u64 single_context:1;
+	u64 ctx_handle;
+};
+
+static ssize_t i915_perf_read_locked(struct i915_perf_stream *stream,
+				     struct file *file,
+				     char __user *buf,
+				     size_t count,
+				     loff_t *ppos)
+{
+	/* Note we keep the offset (aka bytes read) separate from any
+	 * error status so that the final check for whether we return
+	 * the bytes read with a higher precedence than any error (see
+	 * comment below) doesn't need to be handled/duplicated in
+	 * stream->ops->read() implementations.
+	 */
+	size_t offset = 0;
+	int ret = stream->ops->read(stream, buf, count, &offset);
+
+	/* If we've successfully copied any data then reporting that
+	 * takes precedence over any internal error status, so the
+	 * data isn't lost.
+	 *
+	 * For example ret will be -ENOSPC whenever there is more
+	 * buffered data than can be copied to userspace, but that's
+	 * only interesting if we weren't able to copy some data
+	 * because it implies the userspace buffer is too small to
+	 * receive a single record (and we never split records).
+	 *
+	 * Another case with ret == -EFAULT is more of a grey area
+	 * since it would seem like bad form for userspace to ask us
+	 * to overrun its buffer, but the user knows best:
+	 *
+	 *   http://yarchive.net/comp/linux/partial_reads_writes.html
+	 */
+	return offset ?: (ret ?: -EAGAIN);
+}
+
+static ssize_t i915_perf_read(struct file *file,
+			      char __user *buf,
+			      size_t count,
+			      loff_t *ppos)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	ssize_t ret;
+
+	if (!(file->f_flags & O_NONBLOCK)) {
+		/* Allow false positives from stream->ops->wait_unlocked.
+		 */
+		do {
+			ret = stream->ops->wait_unlocked(stream);
+			if (ret)
+				return ret;
+
+			mutex_lock(&dev_priv->perf.lock);
+			ret = i915_perf_read_locked(stream, file,
+						    buf, count, ppos);
+			mutex_unlock(&dev_priv->perf.lock);
+		} while (ret == -EAGAIN);
+	} else {
+		mutex_lock(&dev_priv->perf.lock);
+		ret = i915_perf_read_locked(stream, file, buf, count, ppos);
+		mutex_unlock(&dev_priv->perf.lock);
+	}
+
+	return ret;
+}
+
+static unsigned int i915_perf_poll_locked(struct i915_perf_stream *stream,
+					  struct file *file,
+					  poll_table *wait)
+{
+	unsigned int streams = 0;
+
+	stream->ops->poll_wait(stream, file, wait);
+
+	if (stream->ops->can_read(stream))
+		streams |= POLLIN;
+
+	return streams;
+}
+
+static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	int ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_poll_locked(stream, file, wait);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+static void i915_perf_enable_locked(struct i915_perf_stream *stream)
+{
+	if (stream->enabled)
+		return;
+
+	/* Allow stream->ops->enable() to refer to this */
+	stream->enabled = true;
+
+	if (stream->ops->enable)
+		stream->ops->enable(stream);
+}
+
+static void i915_perf_disable_locked(struct i915_perf_stream *stream)
+{
+	if (!stream->enabled)
+		return;
+
+	/* Allow stream->ops->disable() to refer to this */
+	stream->enabled = false;
+
+	if (stream->ops->disable)
+		stream->ops->disable(stream);
+}
+
+static long i915_perf_ioctl_locked(struct i915_perf_stream *stream,
+				   unsigned int cmd,
+				   unsigned long arg)
+{
+	switch (cmd) {
+	case I915_PERF_IOCTL_ENABLE:
+		i915_perf_enable_locked(stream);
+		return 0;
+	case I915_PERF_IOCTL_DISABLE:
+		i915_perf_disable_locked(stream);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static long i915_perf_ioctl(struct file *file,
+			    unsigned int cmd,
+			    unsigned long arg)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	long ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_ioctl_locked(stream, cmd, arg);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+static void i915_perf_destroy_locked(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	if (stream->enabled)
+		i915_perf_disable_locked(stream);
+
+	if (stream->ops->destroy)
+		stream->ops->destroy(stream);
+
+	list_del(&stream->link);
+
+	if (stream->ctx) {
+		mutex_lock(&dev_priv->drm.struct_mutex);
+		i915_gem_context_put(stream->ctx);
+		mutex_unlock(&dev_priv->drm.struct_mutex);
+	}
+
+	kfree(stream);
+}
+
+static int i915_perf_release(struct inode *inode, struct file *file)
+{
+	struct i915_perf_stream *stream = file->private_data;
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	mutex_lock(&dev_priv->perf.lock);
+	i915_perf_destroy_locked(stream);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return 0;
+}
+
+
+static const struct file_operations fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.release	= i915_perf_release,
+	.poll		= i915_perf_poll,
+	.read		= i915_perf_read,
+	.unlocked_ioctl	= i915_perf_ioctl,
+};
+
+
+static struct i915_gem_context *
+lookup_context(struct drm_i915_private *dev_priv,
+	       struct drm_i915_file_private *file_priv,
+	       u32 ctx_user_handle)
+{
+	struct i915_gem_context *ctx;
+	int ret;
+
+	ret = i915_mutex_lock_interruptible(&dev_priv->drm);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ctx = i915_gem_context_lookup(file_priv, ctx_user_handle);
+	if (!IS_ERR(ctx))
+		i915_gem_context_get(ctx);
+
+	mutex_unlock(&dev_priv->drm.struct_mutex);
+
+	return ctx;
+}
+
+static int
+i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
+			    struct drm_i915_perf_open_param *param,
+			    struct perf_open_properties *props,
+			    struct drm_file *file)
+{
+	struct i915_gem_context *specific_ctx = NULL;
+	struct i915_perf_stream *stream = NULL;
+	unsigned long f_flags = 0;
+	int stream_fd;
+	int ret;
+
+	if (props->single_context) {
+		u32 ctx_handle = props->ctx_handle;
+		struct drm_i915_file_private *file_priv = file->driver_priv;
+
+		specific_ctx = lookup_context(dev_priv, file_priv, ctx_handle);
+		if (IS_ERR(specific_ctx)) {
+			ret = PTR_ERR(specific_ctx);
+			if (ret != -EINTR)
+				DRM_ERROR("Failed to look up context with ID %u for opening perf stream\n",
+					  ctx_handle);
+			goto err;
+		}
+	}
+
+	if (!specific_ctx && !capable(CAP_SYS_ADMIN)) {
+		DRM_ERROR("Insufficient privileges to open system-wide i915 perf stream\n");
+		ret = -EACCES;
+		goto err_ctx;
+	}
+
+	stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+	if (!stream) {
+		ret = -ENOMEM;
+		goto err_ctx;
+	}
+
+	stream->sample_flags = props->sample_flags;
+	stream->dev_priv = dev_priv;
+	stream->ctx = specific_ctx;
+
+	/*
+	 * TODO: support sampling something
+	 *
+	 * For now this is as far as we can go.
+	 */
+	DRM_ERROR("Unsupported i915 perf stream configuration\n");
+	ret = -EINVAL;
+	goto err_alloc;
+
+	list_add(&stream->link, &dev_priv->perf.streams);
+
+	if (param->flags & I915_PERF_FLAG_FD_CLOEXEC)
+		f_flags |= O_CLOEXEC;
+	if (param->flags & I915_PERF_FLAG_FD_NONBLOCK)
+		f_flags |= O_NONBLOCK;
+
+	stream_fd = anon_inode_getfd("[i915_perf]", &fops, stream, f_flags);
+	if (stream_fd < 0) {
+		ret = stream_fd;
+		goto err_open;
+	}
+
+	if (!(param->flags & I915_PERF_FLAG_DISABLED))
+		i915_perf_enable_locked(stream);
+
+	return stream_fd;
+
+err_open:
+	list_del(&stream->link);
+	if (stream->ops->destroy)
+		stream->ops->destroy(stream);
+err_alloc:
+	kfree(stream);
+err_ctx:
+	if (specific_ctx) {
+		mutex_lock(&dev_priv->drm.struct_mutex);
+		i915_gem_context_put(specific_ctx);
+		mutex_unlock(&dev_priv->drm.struct_mutex);
+	}
+err:
+	return ret;
+}
+
+/* Note we copy the properties from userspace outside of the i915 perf
+ * mutex to avoid an awkward lockdep with mmap_sem.
+ *
+ * Note this function only validates properties in isolation it doesn't
+ * validate that the combination of properties makes sense or that all
+ * properties necessary for a particular kind of stream have been set.
+ */
+static int read_properties_unlocked(struct drm_i915_private *dev_priv,
+				    u64 __user *uprops,
+				    u32 n_props,
+				    struct perf_open_properties *props)
+{
+	u64 __user *uprop = uprops;
+	int i;
+
+	memset(props, 0, sizeof(struct perf_open_properties));
+
+	if (!n_props) {
+		DRM_ERROR("No i915 perf properties given");
+		return -EINVAL;
+	}
+
+	/* Considering that ID = 0 is reserved and assuming that we don't
+	 * (currently) expect any configurations to ever specify duplicate
+	 * values for a particular property ID then the last _PROP_MAX value is
+	 * one greater than the maximum number of properties we expect to get
+	 * from userspace.
+	 */
+	if (n_props >= DRM_I915_PERF_PROP_MAX) {
+		DRM_ERROR("More i915 perf properties specified than exist");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < n_props; i++) {
+		u64 id, value;
+		int ret;
+
+		ret = get_user(id, uprop);
+		if (ret)
+			return ret;
+
+		ret = get_user(value, uprop + 1);
+		if (ret)
+			return ret;
+
+		switch ((enum drm_i915_perf_property_id)id) {
+		case DRM_I915_PERF_PROP_CTX_HANDLE:
+			props->single_context = 1;
+			props->ctx_handle = value;
+			break;
+		default:
+			MISSING_CASE(id);
+			DRM_ERROR("Unknown i915 perf property ID");
+			return -EINVAL;
+		}
+
+		uprop += 2;
+	}
+
+	return 0;
+}
+
+int i915_perf_open_ioctl(struct drm_device *dev, void *data,
+			 struct drm_file *file)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_i915_perf_open_param *param = data;
+	struct perf_open_properties props;
+	u32 known_open_flags;
+	int ret;
+
+	if (!dev_priv->perf.initialized) {
+		DRM_ERROR("i915 perf interface not available for this system");
+		return -ENOTSUPP;
+	}
+
+	known_open_flags = I915_PERF_FLAG_FD_CLOEXEC |
+			   I915_PERF_FLAG_FD_NONBLOCK |
+			   I915_PERF_FLAG_DISABLED;
+	if (param->flags & ~known_open_flags) {
+		DRM_ERROR("Unknown drm_i915_perf_open_param flag\n");
+		return -EINVAL;
+	}
+
+	ret = read_properties_unlocked(dev_priv,
+				       u64_to_user_ptr(param->properties_ptr),
+				       param->num_properties,
+				       &props);
+	if (ret)
+		return ret;
+
+	mutex_lock(&dev_priv->perf.lock);
+	ret = i915_perf_open_ioctl_locked(dev_priv, param, &props, file);
+	mutex_unlock(&dev_priv->perf.lock);
+
+	return ret;
+}
+
+void i915_perf_init(struct drm_i915_private *dev_priv)
+{
+	INIT_LIST_HEAD(&dev_priv->perf.streams);
+	mutex_init(&dev_priv->perf.lock);
+
+	dev_priv->perf.initialized = true;
+}
+
+void i915_perf_fini(struct drm_i915_private *dev_priv)
+{
+	if (!dev_priv->perf.initialized)
+		return;
+
+	/* Currently nothing to clean up */
+
+	dev_priv->perf.initialized = false;
+}

include/uapi/drm/i915_drm.h

@@ -258,6 +258,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_I915_GEM_USERPTR		0x33
 #define DRM_I915_GEM_CONTEXT_GETPARAM	0x34
 #define DRM_I915_GEM_CONTEXT_SETPARAM	0x35
+#define DRM_I915_PERF_OPEN		0x36
 
 #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
 #define DRM_IOCTL_I915_FLUSH		DRM_IO ( DRM_COMMAND_BASE + DRM_I915_FLUSH)
@@ -311,6 +312,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_GEM_USERPTR			DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_USERPTR, struct drm_i915_gem_userptr)
 #define DRM_IOCTL_I915_GEM_CONTEXT_GETPARAM	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_GETPARAM, struct drm_i915_gem_context_param)
 #define DRM_IOCTL_I915_GEM_CONTEXT_SETPARAM	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_SETPARAM, struct drm_i915_gem_context_param)
+#define DRM_IOCTL_I915_PERF_OPEN	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_PERF_OPEN, struct drm_i915_perf_open_param)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -1228,6 +1230,71 @@ struct drm_i915_gem_context_param {
 	__u64 value;
 };
 
+enum drm_i915_perf_property_id {
+	/**
+	 * Open the stream for a specific context handle (as used with
+	 * execbuffer2). A stream opened for a specific context this way
+	 * won't typically require root privileges.
+	 */
+	DRM_I915_PERF_PROP_CTX_HANDLE = 1,
+
+	DRM_I915_PERF_PROP_MAX /* non-ABI */
+};
+
+struct drm_i915_perf_open_param {
+	__u32 flags;
+#define I915_PERF_FLAG_FD_CLOEXEC	(1<<0)
+#define I915_PERF_FLAG_FD_NONBLOCK	(1<<1)
+#define I915_PERF_FLAG_DISABLED		(1<<2)
+
+	/** The number of u64 (id, value) pairs */
+	__u32 num_properties;
+
+	/**
+	 * Pointer to array of u64 (id, value) pairs configuring the stream
+	 * to open.
+	 */
+	__u64 __user properties_ptr;
+};
+
+#define I915_PERF_IOCTL_ENABLE	_IO('i', 0x0)
+#define I915_PERF_IOCTL_DISABLE	_IO('i', 0x1)
+
+/**
+ * Common to all i915 perf records
+ */
+struct drm_i915_perf_record_header {
+	__u32 type;
+	__u16 pad;
+	__u16 size;
+};
+
+enum drm_i915_perf_record_type {
+
+	/**
+	 * Samples are the work horse record type whose contents are extensible
+	 * and defined when opening an i915 perf stream based on the given
+	 * properties.
+	 *
+	 * Boolean properties following the naming convention
+	 * DRM_I915_PERF_SAMPLE_xyz_PROP request the inclusion of 'xyz' data in
+	 * every sample.
+	 *
+	 * The order of these sample properties given by userspace has no
+	 * affect on the ordering of data within a sample. The order will be
+	 * documented here.
+	 *
+	 * struct {
+	 *     struct drm_i915_perf_record_header header;
+	 *
+	 *     TODO: itemize extensible sample data here
+	 * };
+	 */
+	DRM_I915_PERF_RECORD_SAMPLE = 1,
+
+	DRM_I915_PERF_RECORD_MAX /* non-ABI */
+};
+
 #if defined(__cplusplus)
 }
 #endif