[PATCH v8 00/12] Enable i915 perf stream for Haswell OA unit

[PATCH v8 00/12] Enable i915 perf stream for Haswell OA unit

[Robert Bragg]

Rebased on nightly, and updated as per review from Matt and Chris

The first patch from Chris adds an i915_gem_context_pin_legacy() utility that
I'm depending on now - though it doesn't really form part of the i915-perf
series proper. I'm assuming Chris plans to send a version of this to the list
himself with a proper commit message.

- Robert

Chris Wilson (1):
  ctx-pin placeholder from chris

Robert Bragg (11):
  drm/i915: Add i915 perf infrastructure
  drm/i915: rename OACONTROL GEN7_OACONTROL
  drm/i915: return EACCES for check_cmd() failures
  drm/i915: don't whitelist oacontrol in cmd parser
  drm/i915: Add 'render basic' Haswell OA unit config
  drm/i915: Enable i915 perf stream for Haswell OA unit
  drm/i915: advertise available metrics via sysfs
  drm/i915: Add dev.i915.perf_stream_paranoid sysctl option
  drm/i915: add oa_event_min_timer_exponent sysctl
  drm/i915: Add more Haswell OA metric sets
  drm/i915: Add a kerneldoc summary for i915_perf.c

 drivers/gpu/drm/i915/Makefile           |    4 +
 drivers/gpu/drm/i915/gvt/handlers.c     |    2 +-
 drivers/gpu/drm/i915/i915_cmd_parser.c  |   45 +-
 drivers/gpu/drm/i915/i915_drv.c         |    9 +
 drivers/gpu/drm/i915/i915_drv.h         |  157 +++
 drivers/gpu/drm/i915/i915_gem_context.c |   34 +-
 drivers/gpu/drm/i915/i915_oa_hsw.c      |  752 ++++++++++++++
 drivers/gpu/drm/i915/i915_oa_hsw.h      |   38 +
 drivers/gpu/drm/i915/i915_perf.c        | 1726 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h         |  340 +++++-
 include/uapi/drm/i915_drm.h             |  134 +++
 11 files changed, 3190 insertions(+), 51 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/i915_oa_hsw.c
 create mode 100644 drivers/gpu/drm/i915/i915_oa_hsw.h
 create mode 100644 drivers/gpu/drm/i915/i915_perf.c

-- 
2.10.1

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[PATCH v8 01/12] ctx-pin placeholder from chris

[Robert Bragg]

From: Chris Wilson <chris@chris-wilson.co.uk>

---
 drivers/gpu/drm/i915/i915_drv.h         |  1 +
 drivers/gpu/drm/i915/i915_gem_context.c | 34 ++++++++++++++++++++++-----------
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 55afb66..5a260db 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3437,6 +3437,7 @@ struct drm_i915_gem_object *
 i915_gem_alloc_context_obj(struct drm_device *dev, size_t size);
 struct i915_gem_context *
 i915_gem_context_create_gvt(struct drm_device *dev);
+struct i915_vma *i915_gem_context_pin_legacy(struct i915_gem_context *ctx);
 
 static inline struct i915_gem_context *
 i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 5dca32a..a620e15b 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -751,12 +751,31 @@ needs_pd_load_post(struct i915_hw_ppgtt *ppgtt,
 	return false;
 }
 
+struct i915_vma *i915_gem_context_pin_legacy(struct i915_gem_context *ctx)
+{
+	struct i915_vma *vma = ctx->engine[RCS].state;
+	int ret;
+
+	/* Clear this page out of any CPU caches for coherent swap-in/out. */
+	if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
+		ret = i915_gem_object_set_to_gtt_domain(vma->obj, false);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	ret = i915_vma_pin(vma, 0, ctx->ggtt_alignment, PIN_GLOBAL);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return vma;
+}
+
 static int do_rcs_switch(struct drm_i915_gem_request *req)
 {
 	struct i915_gem_context *to = req->ctx;
 	struct intel_engine_cs *engine = req->engine;
 	struct i915_hw_ppgtt *ppgtt = to->ppgtt ?: req->i915->mm.aliasing_ppgtt;
-	struct i915_vma *vma = to->engine[RCS].state;
+	struct i915_vma *vma;
 	struct i915_gem_context *from;
 	u32 hw_flags;
 	int ret, i;
@@ -764,17 +783,10 @@ static int do_rcs_switch(struct drm_i915_gem_request *req)
 	if (skip_rcs_switch(ppgtt, engine, to))
 		return 0;
 
-	/* Clear this page out of any CPU caches for coherent swap-in/out. */
-	if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
-		ret = i915_gem_object_set_to_gtt_domain(vma->obj, false);
-		if (ret)
-			return ret;
-	}
-
 	/* Trying to pin first makes error handling easier. */
-	ret = i915_vma_pin(vma, 0, to->ggtt_alignment, PIN_GLOBAL);
-	if (ret)
-		return ret;
+	vma = i915_gem_context_pin_legacy(to);
+	if (IS_ERR(vma))
+		return PTR_ERR(vma);
 
 	/*
 	 * Pin can switch back to the default context if we end up calling into
-- 
2.10.1

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[PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[Robert Bragg]

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: Robert Bragg <robert@sixbynine.org>
---
 drivers/gpu/drm/i915/Makefile    |   3 +
 drivers/gpu/drm/i915/i915_drv.c  |   4 +
 drivers/gpu/drm/i915/i915_drv.h  |  91 ++++++++
 drivers/gpu/drm/i915/i915_perf.c | 443 +++++++++++++++++++++++++++++++++++++++
 include/uapi/drm/i915_drm.h      |  67 ++++++
 5 files changed, 608 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/i915_perf.c

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 6123400..8d4e25f 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -113,6 +113,9 @@ 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
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index af3559d..685c96e 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -836,6 +836,8 @@ 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_workqueues:
@@ -849,6 +851,7 @@ 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);
 }
@@ -2556,6 +2559,7 @@ 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 = {
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5a260db..7a65c0b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1767,6 +1767,84 @@ 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;
 
@@ -2069,6 +2147,12 @@ 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 *);
@@ -3482,6 +3566,9 @@ 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,
@@ -3607,6 +3694,10 @@ 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);
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
new file mode 100644
index 0000000..c45cf92
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -0,0 +1,443 @@
+/*
+ * 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;
+	}
+
+	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;
+}
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 03725fe..98cd493 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/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.
@@ -1222,6 +1224,71 @@ 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
-- 
2.10.1

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[PATCH v8 03/12] drm/i915: rename OACONTROL GEN7_OACONTROL

[Robert Bragg]

OACONTROL changes quite a bit for gen8, with some bits split out into a
per-context OACTXCONTROL register. Rename now before adding more gen7 OA
registers

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/gvt/handlers.c    | 2 +-
 drivers/gpu/drm/i915/i915_cmd_parser.c | 4 ++--
 drivers/gpu/drm/i915/i915_reg.h        | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
index 9ab1f95..4527cb7 100644
--- a/drivers/gpu/drm/i915/gvt/handlers.c
+++ b/drivers/gpu/drm/i915/gvt/handlers.c
@@ -2177,7 +2177,7 @@ static int init_generic_mmio_info(struct intel_gvt *gvt)
 	MMIO_DFH(0x1217c, D_ALL, F_CMD_ACCESS, NULL, NULL);
 
 	MMIO_F(0x2290, 8, 0, 0, 0, D_HSW_PLUS, NULL, NULL);
-	MMIO_D(OACONTROL, D_HSW);
+	MMIO_D(GEN7_OACONTROL, D_HSW);
 	MMIO_D(0x2b00, D_BDW_PLUS);
 	MMIO_D(0x2360, D_BDW_PLUS);
 	MMIO_F(0x5200, 32, 0, 0, 0, D_ALL, NULL, NULL);
diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index f191d7b..fe34470 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -450,7 +450,7 @@ static const struct drm_i915_reg_descriptor gen7_render_regs[] = {
 	REG64(PS_INVOCATION_COUNT),
 	REG64(PS_DEPTH_COUNT),
 	REG64_IDX(RING_TIMESTAMP, RENDER_RING_BASE),
-	REG32(OACONTROL), /* Only allowed for LRI and SRM. See below. */
+	REG32(GEN7_OACONTROL), /* Only allowed for LRI and SRM. See below. */
 	REG64(MI_PREDICATE_SRC0),
 	REG64(MI_PREDICATE_SRC1),
 	REG32(GEN7_3DPRIM_END_OFFSET),
@@ -1108,7 +1108,7 @@ static bool check_cmd(const struct intel_engine_cs *engine,
 			 * to the register. Hence, limit OACONTROL writes to
 			 * only MI_LOAD_REGISTER_IMM commands.
 			 */
-			if (reg_addr == i915_mmio_reg_offset(OACONTROL)) {
+			if (reg_addr == i915_mmio_reg_offset(GEN7_OACONTROL)) {
 				if (desc->cmd.value == MI_LOAD_REGISTER_MEM) {
 					DRM_DEBUG_DRIVER("CMD: Rejected LRM to OACONTROL\n");
 					return false;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 542e570..59628d5 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -615,7 +615,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define HSW_CS_GPR(n)                   _MMIO(0x2600 + (n) * 8)
 #define HSW_CS_GPR_UDW(n)               _MMIO(0x2600 + (n) * 8 + 4)
 
-#define OACONTROL _MMIO(0x2360)
+#define GEN7_OACONTROL _MMIO(0x2360)
 
 #define _GEN7_PIPEA_DE_LOAD_SL	0x70068
 #define _GEN7_PIPEB_DE_LOAD_SL	0x71068
-- 
2.10.1

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[PATCH v8 04/12] drm/i915: return EACCES for check_cmd() failures

[Robert Bragg]

check_cmd() is checking whether a command adheres to certain
restrictions that ensure it's safe to execute within a privileged batch
buffer. Returning false implies a privilege problem, not that the
command is invalid.

The distinction makes the difference between allowing the buffer to be
executed as an unprivileged batch buffer or returning an EINVAL error to
userspace without executing anything.

In a case where userspace may want to test whether it can successfully
write to a register that needs privileges the distinction may be
important and an EINVAL error may be considered fatal.

In particular this is currently true for Mesa, which includes a test for
whether OACONTROL can be written too, but Mesa treats any error when
flushing a batch buffer as fatal, calling exit(1).

As it is currently Mesa can gracefully handle a failure to write to
OACONTROL if the command parser is disabled, but if we were to remove
OACONTROL from the parser's whitelist then the returned EINVAL would
break Mesa applications as they attempt an OACONTROL write.

This bumps the command parser version from 7 to 8, as the change is
visible to userspace.

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_cmd_parser.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index fe34470..c45dd83 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -1272,7 +1272,7 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
 
 		if (!check_cmd(engine, desc, cmd, length, is_master,
 			       &oacontrol_set)) {
-			ret = -EINVAL;
+			ret = -EACCES;
 			break;
 		}
 
@@ -1333,6 +1333,9 @@ int i915_cmd_parser_get_version(struct drm_i915_private *dev_priv)
 	 * 5. GPGPU dispatch compute indirect registers.
 	 * 6. TIMESTAMP register and Haswell CS GPR registers
 	 * 7. Allow MI_LOAD_REGISTER_REG between whitelisted registers.
+	 * 8. Don't report cmd_check() failures as EINVAL errors to userspace;
+	 *    rely on the HW to NOOP disallowed commands as it would without
+	 *    the parser enabled.
 	 */
-	return 7;
+	return 8;
 }
-- 
2.10.1

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[PATCH v8 05/12] drm/i915: don't whitelist oacontrol in cmd parser

[Robert Bragg]

Being able to program OACONTROL from a non-privileged batch buffer is
not sufficient to be able to configure the OA unit. This was originally
allowed to help enable Mesa to expose OA counters via the
INTEL_performance_query extension, but the current implementation based
on programming OACONTROL via a batch buffer isn't able to report useable
data without a more complete OA unit configuration. Mesa handles the
possibility that writes to OACONTROL may not be allowed and so only
advertises the extension after explicitly testing that a write to
OACONTROL succeeds. Based on this; removing OACONTROL from the whitelist
should be ok for userspace.

Removing this simplifies adding a new kernel api for configuring the OA
unit without needing to consider the possibility that userspace might
trample on OACONTROL state which we'd like to start managing within
the kernel instead. In particular running any Mesa based GL application
currently results in clearing OACONTROL when initializing which would
disable the capturing of metrics.

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_cmd_parser.c | 38 ++--------------------------------
 1 file changed, 2 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index c45dd83..5152d6f 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -450,7 +450,6 @@ static const struct drm_i915_reg_descriptor gen7_render_regs[] = {
 	REG64(PS_INVOCATION_COUNT),
 	REG64(PS_DEPTH_COUNT),
 	REG64_IDX(RING_TIMESTAMP, RENDER_RING_BASE),
-	REG32(GEN7_OACONTROL), /* Only allowed for LRI and SRM. See below. */
 	REG64(MI_PREDICATE_SRC0),
 	REG64(MI_PREDICATE_SRC1),
 	REG32(GEN7_3DPRIM_END_OFFSET),
@@ -1060,8 +1059,7 @@ bool intel_engine_needs_cmd_parser(struct intel_engine_cs *engine)
 static bool check_cmd(const struct intel_engine_cs *engine,
 		      const struct drm_i915_cmd_descriptor *desc,
 		      const u32 *cmd, u32 length,
-		      const bool is_master,
-		      bool *oacontrol_set)
+		      const bool is_master)
 {
 	if (desc->flags & CMD_DESC_SKIP)
 		return true;
@@ -1099,31 +1097,6 @@ static bool check_cmd(const struct intel_engine_cs *engine,
 			}
 
 			/*
-			 * OACONTROL requires some special handling for
-			 * writes. We want to make sure that any batch which
-			 * enables OA also disables it before the end of the
-			 * batch. The goal is to prevent one process from
-			 * snooping on the perf data from another process. To do
-			 * that, we need to check the value that will be written
-			 * to the register. Hence, limit OACONTROL writes to
-			 * only MI_LOAD_REGISTER_IMM commands.
-			 */
-			if (reg_addr == i915_mmio_reg_offset(GEN7_OACONTROL)) {
-				if (desc->cmd.value == MI_LOAD_REGISTER_MEM) {
-					DRM_DEBUG_DRIVER("CMD: Rejected LRM to OACONTROL\n");
-					return false;
-				}
-
-				if (desc->cmd.value == MI_LOAD_REGISTER_REG) {
-					DRM_DEBUG_DRIVER("CMD: Rejected LRR to OACONTROL\n");
-					return false;
-				}
-
-				if (desc->cmd.value == MI_LOAD_REGISTER_IMM(1))
-					*oacontrol_set = (cmd[offset + 1] != 0);
-			}
-
-			/*
 			 * Check the value written to the register against the
 			 * allowed mask/value pair given in the whitelist entry.
 			 */
@@ -1214,7 +1187,6 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
 	u32 *cmd, *batch_end;
 	struct drm_i915_cmd_descriptor default_desc = noop_desc;
 	const struct drm_i915_cmd_descriptor *desc = &default_desc;
-	bool oacontrol_set = false; /* OACONTROL tracking. See check_cmd() */
 	bool needs_clflush_after = false;
 	int ret = 0;
 
@@ -1270,8 +1242,7 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
 			break;
 		}
 
-		if (!check_cmd(engine, desc, cmd, length, is_master,
-			       &oacontrol_set)) {
+		if (!check_cmd(engine, desc, cmd, length, is_master)) {
 			ret = -EACCES;
 			break;
 		}
@@ -1279,11 +1250,6 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
 		cmd += length;
 	}
 
-	if (oacontrol_set) {
-		DRM_DEBUG_DRIVER("CMD: batch set OACONTROL but did not clear it\n");
-		ret = -EINVAL;
-	}
-
 	if (cmd >= batch_end) {
 		DRM_DEBUG_DRIVER("CMD: Got to the end of the buffer w/o a BBE cmd!\n");
 		ret = -EINVAL;
-- 
2.10.1

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[PATCH v8 06/12] drm/i915: Add 'render basic' Haswell OA unit config

[Robert Bragg]

Adds a static OA unit, MUX + B Counter configuration for basic render
metrics on Haswell. This is auto generated from an XML
description of metric sets, currently maintained in gputop, ref:

  https://github.com/rib/gputop
  > gputop-data/oa-*.xml
  > scripts/i915-perf-kernelgen.py

  $ make -C gputop-data -f Makefile.xml SYSFS=0 WHITELIST=RenderBasic

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/Makefile      |   3 +-
 drivers/gpu/drm/i915/i915_drv.h    |  14 ++++
 drivers/gpu/drm/i915/i915_oa_hsw.c | 144 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_oa_hsw.h |  34 +++++++++
 4 files changed, 194 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/i915/i915_oa_hsw.c
 create mode 100644 drivers/gpu/drm/i915/i915_oa_hsw.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 8d4e25f..ac0c3ad 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -114,7 +114,8 @@ i915-$(CONFIG_DRM_I915_CAPTURE_ERROR) += i915_gpu_error.o
 i915-y += i915_vgpu.o
 
 # perf code
-i915-y += i915_perf.o
+i915-y += i915_perf.o \
+	  i915_oa_hsw.o
 
 ifeq ($(CONFIG_DRM_I915_GVT),y)
 i915-y += intel_gvt.o
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 7a65c0b..f22adc4 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1767,6 +1767,11 @@ struct intel_wm_config {
 	bool sprites_scaled;
 };
 
+struct i915_oa_reg {
+	i915_reg_t addr;
+	u32 value;
+};
+
 struct i915_perf_stream;
 
 struct i915_perf_stream_ops {
@@ -2151,6 +2156,15 @@ struct drm_i915_private {
 		bool initialized;
 		struct mutex lock;
 		struct list_head streams;
+
+		struct {
+			u32 metrics_set;
+
+			const struct i915_oa_reg *mux_regs;
+			int mux_regs_len;
+			const struct i915_oa_reg *b_counter_regs;
+			int b_counter_regs_len;
+		} oa;
 	} perf;
 
 	/* Abstract the submission mechanism (legacy ringbuffer or execlists) away */
diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.c b/drivers/gpu/drm/i915/i915_oa_hsw.c
new file mode 100644
index 0000000..8906380
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_oa_hsw.c
@@ -0,0 +1,144 @@
+/*
+ * Autogenerated file, DO NOT EDIT manually!
+ *
+ * Copyright (c) 2015 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.
+ *
+ */
+
+#include "i915_drv.h"
+#include "i915_oa_hsw.h"
+
+enum metric_set_id {
+	METRIC_SET_ID_RENDER_BASIC = 1,
+};
+
+int i915_oa_n_builtin_metric_sets_hsw = 1;
+
+static const struct i915_oa_reg b_counter_config_render_basic[] = {
+	{ _MMIO(0x2724), 0x00800000 },
+	{ _MMIO(0x2720), 0x00000000 },
+	{ _MMIO(0x2714), 0x00800000 },
+	{ _MMIO(0x2710), 0x00000000 },
+};
+
+static const struct i915_oa_reg mux_config_render_basic[] = {
+	{ _MMIO(0x253a4), 0x01600000 },
+	{ _MMIO(0x25440), 0x00100000 },
+	{ _MMIO(0x25128), 0x00000000 },
+	{ _MMIO(0x2691c), 0x00000800 },
+	{ _MMIO(0x26aa0), 0x01500000 },
+	{ _MMIO(0x26b9c), 0x00006000 },
+	{ _MMIO(0x2791c), 0x00000800 },
+	{ _MMIO(0x27aa0), 0x01500000 },
+	{ _MMIO(0x27b9c), 0x00006000 },
+	{ _MMIO(0x2641c), 0x00000400 },
+	{ _MMIO(0x25380), 0x00000010 },
+	{ _MMIO(0x2538c), 0x00000000 },
+	{ _MMIO(0x25384), 0x0800aaaa },
+	{ _MMIO(0x25400), 0x00000004 },
+	{ _MMIO(0x2540c), 0x06029000 },
+	{ _MMIO(0x25410), 0x00000002 },
+	{ _MMIO(0x25404), 0x5c30ffff },
+	{ _MMIO(0x25100), 0x00000016 },
+	{ _MMIO(0x25110), 0x00000400 },
+	{ _MMIO(0x25104), 0x00000000 },
+	{ _MMIO(0x26804), 0x00001211 },
+	{ _MMIO(0x26884), 0x00000100 },
+	{ _MMIO(0x26900), 0x00000002 },
+	{ _MMIO(0x26908), 0x00700000 },
+	{ _MMIO(0x26904), 0x00000000 },
+	{ _MMIO(0x26984), 0x00001022 },
+	{ _MMIO(0x26a04), 0x00000011 },
+	{ _MMIO(0x26a80), 0x00000006 },
+	{ _MMIO(0x26a88), 0x00000c02 },
+	{ _MMIO(0x26a84), 0x00000000 },
+	{ _MMIO(0x26b04), 0x00001000 },
+	{ _MMIO(0x26b80), 0x00000002 },
+	{ _MMIO(0x26b8c), 0x00000007 },
+	{ _MMIO(0x26b84), 0x00000000 },
+	{ _MMIO(0x27804), 0x00004844 },
+	{ _MMIO(0x27884), 0x00000400 },
+	{ _MMIO(0x27900), 0x00000002 },
+	{ _MMIO(0x27908), 0x0e000000 },
+	{ _MMIO(0x27904), 0x00000000 },
+	{ _MMIO(0x27984), 0x00004088 },
+	{ _MMIO(0x27a04), 0x00000044 },
+	{ _MMIO(0x27a80), 0x00000006 },
+	{ _MMIO(0x27a88), 0x00018040 },
+	{ _MMIO(0x27a84), 0x00000000 },
+	{ _MMIO(0x27b04), 0x00004000 },
+	{ _MMIO(0x27b80), 0x00000002 },
+	{ _MMIO(0x27b8c), 0x000000e0 },
+	{ _MMIO(0x27b84), 0x00000000 },
+	{ _MMIO(0x26104), 0x00002222 },
+	{ _MMIO(0x26184), 0x0c006666 },
+	{ _MMIO(0x26284), 0x04000000 },
+	{ _MMIO(0x26304), 0x04000000 },
+	{ _MMIO(0x26400), 0x00000002 },
+	{ _MMIO(0x26410), 0x000000a0 },
+	{ _MMIO(0x26404), 0x00000000 },
+	{ _MMIO(0x25420), 0x04108020 },
+	{ _MMIO(0x25424), 0x1284a420 },
+	{ _MMIO(0x2541c), 0x00000000 },
+	{ _MMIO(0x25428), 0x00042049 },
+};
+
+static const struct i915_oa_reg *
+get_render_basic_mux_config(struct drm_i915_private *dev_priv,
+			    int *len)
+{
+	*len = ARRAY_SIZE(mux_config_render_basic);
+	return mux_config_render_basic;
+}
+
+int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv)
+{
+	dev_priv->perf.oa.mux_regs = NULL;
+	dev_priv->perf.oa.mux_regs_len = 0;
+	dev_priv->perf.oa.b_counter_regs = NULL;
+	dev_priv->perf.oa.b_counter_regs_len = 0;
+
+	switch (dev_priv->perf.oa.metrics_set) {
+	case METRIC_SET_ID_RENDER_BASIC:
+		dev_priv->perf.oa.mux_regs =
+			get_render_basic_mux_config(dev_priv,
+						    &dev_priv->perf.oa.mux_regs_len);
+		if (!dev_priv->perf.oa.mux_regs) {
+			DRM_DEBUG_DRIVER("No suitable MUX config for \"RENDER_BASIC\" metric set");
+
+			/* EINVAL because *_register_sysfs already checked this
+			 * and so it wouldn't have been advertised so userspace and
+			 * so shouldn't have been requested
+			 */
+			return -EINVAL;
+		}
+
+		dev_priv->perf.oa.b_counter_regs =
+			b_counter_config_render_basic;
+		dev_priv->perf.oa.b_counter_regs_len =
+			ARRAY_SIZE(b_counter_config_render_basic);
+
+		return 0;
+	default:
+		return -ENODEV;
+	}
+}
diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.h b/drivers/gpu/drm/i915/i915_oa_hsw.h
new file mode 100644
index 0000000..b618a1f
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_oa_hsw.h
@@ -0,0 +1,34 @@
+/*
+ * Autogenerated file, DO NOT EDIT manually!
+ *
+ * Copyright (c) 2015 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.
+ *
+ */
+
+#ifndef __I915_OA_HSW_H__
+#define __I915_OA_HSW_H__
+
+extern int i915_oa_n_builtin_metric_sets_hsw;
+
+extern int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv);
+
+#endif
-- 
2.10.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

[PATCH v8 07/12] drm/i915: Enable i915 perf stream for Haswell OA unit

[Robert Bragg]

Gen graphics hardware can be set up to periodically write snapshots of
performance counters into a circular buffer via its Observation
Architecture and this patch exposes that capability to userspace via the
i915 perf interface.

v2:
   Make sure to initialize ->specific_ctx_id when opening, without
   relying on _pin_notify hook, in case ctx already pinned.
v3:
   Revert back to pinning ctx upfront when opening stream, removing
   need to hook in to pinning and to update OACONTROL on the fly.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Robert Bragg <robert@sixbynine.org>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h  |   66 ++-
 drivers/gpu/drm/i915/i915_perf.c | 1036 +++++++++++++++++++++++++++++++++++++-
 drivers/gpu/drm/i915/i915_reg.h  |  338 +++++++++++++
 include/uapi/drm/i915_drm.h      |   71 ++-
 4 files changed, 1482 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f22adc4..dd2b4d3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1767,6 +1767,11 @@ struct intel_wm_config {
 	bool sprites_scaled;
 };
 
+struct i915_oa_format {
+	u32 format;
+	int size;
+};
+
 struct i915_oa_reg {
 	i915_reg_t addr;
 	u32 value;
@@ -1787,11 +1792,6 @@ struct i915_perf_stream_ops {
 	 */
 	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
 	 */
@@ -1801,9 +1801,7 @@ struct i915_perf_stream_ops {
 
 	/* 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).
+	 * wait queue that would be passed to poll_wait().
 	 */
 	int (*wait_unlocked)(struct i915_perf_stream *stream);
 
@@ -1843,11 +1841,28 @@ struct i915_perf_stream {
 	struct list_head link;
 
 	u32 sample_flags;
+	int sample_size;
 
 	struct i915_gem_context *ctx;
 	bool enabled;
 
-	struct i915_perf_stream_ops *ops;
+	const struct i915_perf_stream_ops *ops;
+};
+
+struct i915_oa_ops {
+	void (*init_oa_buffer)(struct drm_i915_private *dev_priv);
+	int (*enable_metric_set)(struct drm_i915_private *dev_priv);
+	void (*disable_metric_set)(struct drm_i915_private *dev_priv);
+	void (*oa_enable)(struct drm_i915_private *dev_priv);
+	void (*oa_disable)(struct drm_i915_private *dev_priv);
+	void (*update_oacontrol)(struct drm_i915_private *dev_priv);
+	void (*update_hw_ctx_id_locked)(struct drm_i915_private *dev_priv,
+					u32 ctx_id);
+	int (*read)(struct i915_perf_stream *stream,
+		    char __user *buf,
+		    size_t count,
+		    size_t *offset);
+	bool (*oa_buffer_is_empty)(struct drm_i915_private *dev_priv);
 };
 
 struct drm_i915_private {
@@ -2154,16 +2169,47 @@ struct drm_i915_private {
 
 	struct {
 		bool initialized;
+
 		struct mutex lock;
 		struct list_head streams;
 
+		spinlock_t hook_lock;
+
 		struct {
-			u32 metrics_set;
+			struct i915_perf_stream *exclusive_stream;
+
+			u32 specific_ctx_id;
+			struct i915_vma *pinned_rcs_vma;
+
+			struct hrtimer poll_check_timer;
+			wait_queue_head_t poll_wq;
+			bool pollin;
+
+			bool periodic;
+			int period_exponent;
+			int timestamp_frequency;
+
+			int tail_margin;
+
+			int metrics_set;
 
 			const struct i915_oa_reg *mux_regs;
 			int mux_regs_len;
 			const struct i915_oa_reg *b_counter_regs;
 			int b_counter_regs_len;
+
+			struct {
+				struct i915_vma *vma;
+				u8 *vaddr;
+				int format;
+				int format_size;
+			} oa_buffer;
+
+			u32 gen7_latched_oastatus1;
+
+			struct i915_oa_ops ops;
+			const struct i915_oa_format *oa_formats;
+			int n_builtin_sets;
 		} oa;
 	} perf;
 
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index c45cf92..8b9cf0d 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -25,16 +25,899 @@
  */
 
 #include <linux/anon_inodes.h>
+#include <linux/sizes.h>
 
 #include "i915_drv.h"
+#include "i915_oa_hsw.h"
+
+/* HW requires this to be a power of two, between 128k and 16M, though driver
+ * is currently generally designed assuming the largest 16M size is used such
+ * that the overflow cases are unlikely in normal operation.
+ */
+#define OA_BUFFER_SIZE		SZ_16M
+
+#define OA_TAKEN(tail, head)	((tail - head) & (OA_BUFFER_SIZE - 1))
+
+/* There's a HW race condition between OA unit tail pointer register updates and
+ * writes to memory whereby the tail pointer can sometimes get ahead of what's
+ * been written out to the OA buffer so far.
+ *
+ * Although this can be observed explicitly by checking for a zeroed report-id
+ * field in tail reports, it seems preferable to account for this earlier e.g.
+ * as part of the _oa_buffer_is_empty checks to minimize -EAGAIN polling cycles
+ * in this situation.
+ *
+ * To give time for the most recent reports to land before they may be copied to
+ * userspace, the driver operates as if the tail pointer effectively lags behind
+ * the HW tail pointer by 'tail_margin' bytes. The margin in bytes is calculated
+ * based on this constant in nanoseconds, the current OA sampling exponent
+ * and current report size.
+ *
+ * There is also a fallback check while reading to simply skip over reports with
+ * a zeroed report-id.
+ */
+#define OA_TAIL_MARGIN_NSEC	100000ULL
+
+/* frequency for checking whether the OA unit has written new reports to the
+ * circular OA buffer...
+ */
+#define POLL_FREQUENCY 200
+#define POLL_PERIOD (NSEC_PER_SEC / POLL_FREQUENCY)
+
+/* The maximum exponent the hardware accepts is 63 (essentially it selects one
+ * of the 64bit timestamp bits to trigger reports from) but there's currently
+ * no known use case for sampling as infrequently as once per 47 thousand years.
+ *
+ * Since the timestamps included in OA reports are only 32bits it seems
+ * reasonable to limit the OA exponent where it's still possible to account for
+ * overflow in OA report timestamps.
+ */
+#define OA_EXPONENT_MAX 31
+
+#define INVALID_CTX_ID 0xffffffff
+
+
+/* XXX: beware if future OA HW adds new report formats that the current
+ * code assumes all reports have a power-of-two size and ~(size - 1) can
+ * be used as a mask to align the OA tail pointer.
+ */
+static struct i915_oa_format hsw_oa_formats[I915_OA_FORMAT_MAX] = {
+	[I915_OA_FORMAT_A13]	    = { 0, 64 },
+	[I915_OA_FORMAT_A29]	    = { 1, 128 },
+	[I915_OA_FORMAT_A13_B8_C8]  = { 2, 128 },
+	/* A29_B8_C8 Disallowed as 192 bytes doesn't factor into buffer size */
+	[I915_OA_FORMAT_B4_C8]	    = { 4, 64 },
+	[I915_OA_FORMAT_A45_B8_C8]  = { 5, 256 },
+	[I915_OA_FORMAT_B4_C8_A16]  = { 6, 128 },
+	[I915_OA_FORMAT_C4_B8]	    = { 7, 64 },
+};
+
+#define SAMPLE_OA_REPORT      (1<<0)
 
 struct perf_open_properties {
 	u32 sample_flags;
 
 	u64 single_context:1;
 	u64 ctx_handle;
+
+	/* OA sampling state */
+	int metrics_set;
+	int oa_format;
+	bool oa_periodic;
+	int oa_period_exponent;
+};
+
+/* NB: This is either called via fops or the poll check hrtimer (atomic ctx)
+ *
+ * It's safe to read OA config state here unlocked, assuming that this is only
+ * called while the stream is enabled, while the global OA configuration can't
+ * be modified.
+ *
+ * Note: we don't lock around the head/tail reads even though there's the slim
+ * possibility of read() fop errors forcing a re-init of the OA buffer
+ * pointers.  A race here could result in a false positive !empty status which
+ * is acceptable.
+ */
+static bool gen7_oa_buffer_is_empty_fop_unlocked(struct drm_i915_private *dev_priv)
+{
+	int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+	u32 oastatus2 = I915_READ(GEN7_OASTATUS2);
+	u32 oastatus1 = I915_READ(GEN7_OASTATUS1);
+	u32 head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
+	u32 tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
+
+	return OA_TAKEN(tail, head) <
+		dev_priv->perf.oa.tail_margin + report_size;
+}
+
+/**
+ * Appends a status record to a userspace read() buffer.
+ */
+static int append_oa_status(struct i915_perf_stream *stream,
+			    char __user *buf,
+			    size_t count,
+			    size_t *offset,
+			    enum drm_i915_perf_record_type type)
+{
+	struct drm_i915_perf_record_header header = { type, 0, sizeof(header) };
+
+	if ((count - *offset) < header.size)
+		return -ENOSPC;
+
+	if (copy_to_user(buf + *offset, &header, sizeof(header)))
+		return -EFAULT;
+
+	(*offset) += header.size;
+
+	return 0;
+}
+
+/**
+ * Copies single OA report into userspace read() buffer.
+ */
+static int append_oa_sample(struct i915_perf_stream *stream,
+			    char __user *buf,
+			    size_t count,
+			    size_t *offset,
+			    const u8 *report)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+	struct drm_i915_perf_record_header header;
+	u32 sample_flags = stream->sample_flags;
+
+	header.type = DRM_I915_PERF_RECORD_SAMPLE;
+	header.pad = 0;
+	header.size = stream->sample_size;
+
+	if ((count - *offset) < header.size)
+		return -ENOSPC;
+
+	buf += *offset;
+	if (copy_to_user(buf, &header, sizeof(header)))
+		return -EFAULT;
+	buf += sizeof(header);
+
+	if (sample_flags & SAMPLE_OA_REPORT) {
+		if (copy_to_user(buf, report, report_size))
+			return -EFAULT;
+	}
+
+	(*offset) += header.size;
+
+	return 0;
+}
+
+/**
+ * Copies all buffered OA reports into userspace read() buffer.
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @offset: (inout): the current position for writing into @buf
+ * @head_ptr: (inout): the current oa buffer cpu read position
+ * @tail_ptr: the current oa buffer gpu write position
+ *
+ * Returns 0 on success, negative error code on failure.
+ *
+ * Notably any error condition resulting in a short read (-ENOSPC or
+ * -EFAULT) will be returned even though one or more records may
+ * have been successfully copied. In this case it's up to the caller
+ * to decide if the error should be squashed before returning to
+ * userspace.
+ *
+ * Note: reports are consumed from the head, and appended to the
+ * tail, so the head chases the tail?... If you think that's mad
+ * and back-to-front you're not alone, but this follows the
+ * Gen PRM naming convention.
+ */
+static int gen7_append_oa_reports(struct i915_perf_stream *stream,
+				  char __user *buf,
+				  size_t count,
+				  size_t *offset,
+				  u32 *head_ptr,
+				  u32 tail)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+	u8 *oa_buf_base = dev_priv->perf.oa.oa_buffer.vaddr;
+	int tail_margin = dev_priv->perf.oa.tail_margin;
+	u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
+	u32 mask = (OA_BUFFER_SIZE - 1);
+	u32 head;
+	u32 taken;
+	int ret = 0;
+
+
+	if (WARN_ON(!stream->enabled))
+		return -EIO;
+
+	head = *head_ptr - gtt_offset;
+	tail -= gtt_offset;
+
+	/* The OA unit is expected to wrap the tail pointer according to the OA
+	 * buffer size and since we should never write a misaligned head
+	 * pointer we don't expect to read one back either...
+	 */
+	if (tail > OA_BUFFER_SIZE || head > OA_BUFFER_SIZE ||
+	    head % report_size) {
+		DRM_ERROR("Inconsistent OA buffer pointer (head = %u, tail = %u): force restart",
+			  head, tail);
+		dev_priv->perf.oa.ops.oa_disable(dev_priv);
+		dev_priv->perf.oa.ops.oa_enable(dev_priv);
+		*head_ptr = I915_READ(GEN7_OASTATUS2) &
+			GEN7_OASTATUS2_HEAD_MASK;
+		return -EIO;
+	}
+
+
+	/* The tail pointer increases in 64 byte increments, not in report_size
+	 * steps...
+	 */
+	tail &= ~(report_size - 1);
+
+	/* Move the tail pointer back by the current tail_margin to account for
+	 * the possibility that the latest reports may not have really landed
+	 * in memory yet...
+	 */
+
+	if (OA_TAKEN(tail, head) < report_size + tail_margin)
+		return -EAGAIN;
+
+	tail -= tail_margin;
+	tail &= mask;
+
+	for (/* none */;
+	     (taken = OA_TAKEN(tail, head));
+	     head = (head + report_size) & mask) {
+		u8 *report = oa_buf_base + head;
+		u32 *report32 = (void *)report;
+
+		/* All the report sizes factor neatly into the buffer
+		 * size so we never expect to see a report split
+		 * between the beginning and end of the buffer.
+		 *
+		 * Given the initial alignment check a misalignment
+		 * here would imply a driver bug that would result
+		 * in an overrun.
+		 */
+		if (WARN_ON((OA_BUFFER_SIZE - head) < report_size)) {
+			DRM_ERROR("Spurious OA head ptr: non-integral report offset\n");
+			break;
+		}
+
+		/* The report-ID field for periodic samples includes
+		 * some undocumented flags related to what triggered
+		 * the report and is never expected to be zero so we
+		 * can check that the report isn't invalid before
+		 * copying it to userspace...
+		 */
+		if (report32[0] == 0) {
+			DRM_ERROR("Skipping spurious, invalid OA report\n");
+			continue;
+		}
+
+		ret = append_oa_sample(stream, buf, count, offset, report);
+		if (ret)
+			break;
+
+		/* The above report-id field sanity check is based on
+		 * the assumption that the OA buffer is initially
+		 * zeroed and we reset the field after copying so the
+		 * check is still meaningful once old reports start
+		 * being overwritten.
+		 */
+		report32[0] = 0;
+	}
+
+	*head_ptr = gtt_offset + head;
+
+	return ret;
+}
+
+static int gen7_oa_read(struct i915_perf_stream *stream,
+			char __user *buf,
+			size_t count,
+			size_t *offset)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+	u32 oastatus2;
+	u32 oastatus1;
+	u32 head;
+	u32 tail;
+	int ret;
+
+	if (WARN_ON(!dev_priv->perf.oa.oa_buffer.vaddr))
+		return -EIO;
+
+	oastatus2 = I915_READ(GEN7_OASTATUS2);
+	oastatus1 = I915_READ(GEN7_OASTATUS1);
+
+	head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
+	tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
+
+	/* XXX: On Haswell we don't have a safe way to clear oastatus1
+	 * bits while the OA unit is enabled (while the tail pointer
+	 * may be updated asynchronously) so we ignore status bits
+	 * that have already been reported to userspace.
+	 */
+	oastatus1 &= ~dev_priv->perf.oa.gen7_latched_oastatus1;
+
+	/* We treat OABUFFER_OVERFLOW as a significant error:
+	 *
+	 * - The status can be interpreted to mean that the buffer is
+	 *   currently full (with a higher precedence than OA_TAKEN()
+	 *   which will start to report a near-empty buffer after an
+	 *   overflow) but it's awkward that we can't clear the status
+	 *   on Haswell, so without a reset we won't be able to catch
+	 *   the state again.
+	 *
+	 * - Since it also implies the HW has started overwriting old
+	 *   reports it may also affect our sanity checks for invalid
+	 *   reports when copying to userspace that assume new reports
+	 *   are being written to cleared memory.
+	 *
+	 * - In the future we may want to introduce a flight recorder
+	 *   mode where the driver will automatically maintain a safe
+	 *   guard band between head/tail, avoiding this overflow
+	 *   condition, but we avoid the added driver complexity for
+	 *   now.
+	 */
+	if (unlikely(oastatus1 & GEN7_OASTATUS1_OABUFFER_OVERFLOW)) {
+		ret = append_oa_status(stream, buf, count, offset,
+				       DRM_I915_PERF_RECORD_OA_BUFFER_LOST);
+		if (ret)
+			return ret;
+
+		DRM_ERROR("OA buffer overflow: force restart");
+
+		dev_priv->perf.oa.ops.oa_disable(dev_priv);
+		dev_priv->perf.oa.ops.oa_enable(dev_priv);
+
+		oastatus2 = I915_READ(GEN7_OASTATUS2);
+		oastatus1 = I915_READ(GEN7_OASTATUS1);
+
+		head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
+		tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
+	}
+
+	if (unlikely(oastatus1 & GEN7_OASTATUS1_REPORT_LOST)) {
+		ret = append_oa_status(stream, buf, count, offset,
+				       DRM_I915_PERF_RECORD_OA_REPORT_LOST);
+		if (ret)
+			return ret;
+		dev_priv->perf.oa.gen7_latched_oastatus1 |=
+			GEN7_OASTATUS1_REPORT_LOST;
+	}
+
+	ret = gen7_append_oa_reports(stream, buf, count, offset,
+				     &head, tail);
+
+	/* All the report sizes are a power of two and the
+	 * head should always be incremented by some multiple
+	 * of the report size.
+	 *
+	 * A warning here, but notably if we later read back a
+	 * misaligned pointer we will treat that as a bug since
+	 * it could lead to a buffer overrun.
+	 */
+	WARN_ONCE(head & (report_size - 1),
+		  "i915: Writing misaligned OA head pointer");
+
+	/* Note: we update the head pointer here even if an error
+	 * was returned since the error may represent a short read
+	 * where some some reports were successfully copied.
+	 */
+	I915_WRITE(GEN7_OASTATUS2,
+		   ((head & GEN7_OASTATUS2_HEAD_MASK) |
+		    OA_MEM_SELECT_GGTT));
+
+	return ret;
+}
+
+static int i915_oa_wait_unlocked(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	/* We would wait indefinitly if periodic sampling is not enabled */
+	if (!dev_priv->perf.oa.periodic)
+		return -EIO;
+
+	/* Note: the oa_buffer_is_empty() condition is ok to run unlocked as it
+	 * just performs mmio reads of the OA buffer head + tail pointers and
+	 * it's assumed we're handling some operation that implies the stream
+	 * can't be destroyed until completion (such as a read()) that ensures
+	 * the device + OA buffer can't disappear
+	 */
+	return wait_event_interruptible(dev_priv->perf.oa.poll_wq,
+					!dev_priv->perf.oa.ops.oa_buffer_is_empty(dev_priv));
+}
+
+static void i915_oa_poll_wait(struct i915_perf_stream *stream,
+			      struct file *file,
+			      poll_table *wait)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	poll_wait(file, &dev_priv->perf.oa.poll_wq, wait);
+}
+
+static int i915_oa_read(struct i915_perf_stream *stream,
+			char __user *buf,
+			size_t count,
+			size_t *offset)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	return dev_priv->perf.oa.ops.read(stream, buf, count, offset);
+}
+
+/* Determine the render context hw id, and ensure it remains fixed for the
+ * lifetime of the stream. This ensures that we don't have to worry about
+ * updating the context ID in OACONTROL on the fly.
+ */
+static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	struct i915_vma *vma;
+	int ret;
+
+	ret = i915_mutex_lock_interruptible(&dev_priv->drm);
+	if (ret)
+		return ret;
+
+	/* As the ID is the gtt offset of the context's vma we pin
+	 * the vma to ensure the ID remains fixed.
+	 *
+	 * NB: implied RCS engine...
+	 */
+	vma = i915_gem_context_pin_legacy(stream->ctx);
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto unlock;
+	}
+
+	dev_priv->perf.oa.pinned_rcs_vma = vma;
+
+	/* Explicitly track the ID (instead of calling i915_ggtt_offset()
+	 * on the fly) considering the difference with gen8+ and
+	 * execlists
+	 */
+	dev_priv->perf.oa.specific_ctx_id = i915_ggtt_offset(vma);
+
+unlock:
+	mutex_unlock(&dev_priv->drm.struct_mutex);
+
+	return ret;
+}
+
+static void oa_put_render_ctx_id(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	mutex_lock(&dev_priv->drm.struct_mutex);
+
+	i915_vma_unpin(dev_priv->perf.oa.pinned_rcs_vma);
+	dev_priv->perf.oa.pinned_rcs_vma = NULL;
+
+	dev_priv->perf.oa.specific_ctx_id = INVALID_CTX_ID;
+
+	mutex_unlock(&dev_priv->drm.struct_mutex);
+}
+
+static void
+free_oa_buffer(struct drm_i915_private *i915)
+{
+	mutex_lock(&i915->drm.struct_mutex);
+
+	i915_gem_object_unpin_map(i915->perf.oa.oa_buffer.vma->obj);
+	i915_vma_unpin(i915->perf.oa.oa_buffer.vma);
+	i915_gem_object_put(i915->perf.oa.oa_buffer.vma->obj);
+
+	i915->perf.oa.oa_buffer.vma = NULL;
+	i915->perf.oa.oa_buffer.vaddr = NULL;
+
+	mutex_unlock(&i915->drm.struct_mutex);
+}
+
+static void i915_oa_stream_destroy(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	BUG_ON(stream != dev_priv->perf.oa.exclusive_stream);
+
+	dev_priv->perf.oa.ops.disable_metric_set(dev_priv);
+
+	free_oa_buffer(dev_priv);
+
+	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+	intel_runtime_pm_put(dev_priv);
+
+	if (stream->ctx)
+		oa_put_render_ctx_id(stream);
+
+	dev_priv->perf.oa.exclusive_stream = NULL;
+}
+
+static void gen7_init_oa_buffer(struct drm_i915_private *dev_priv)
+{
+	u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
+
+	/* Pre-DevBDW: OABUFFER must be set with counters off,
+	 * before OASTATUS1, but after OASTATUS2
+	 */
+	I915_WRITE(GEN7_OASTATUS2, gtt_offset | OA_MEM_SELECT_GGTT); /* head */
+	I915_WRITE(GEN7_OABUFFER, gtt_offset);
+	I915_WRITE(GEN7_OASTATUS1, gtt_offset | OABUFFER_SIZE_16M); /* tail */
+
+	/* On Haswell we have to track which OASTATUS1 flags we've
+	 * already seen since they can't be cleared while periodic
+	 * sampling is enabled.
+	 */
+	dev_priv->perf.oa.gen7_latched_oastatus1 = 0;
+
+	/* NB: although the OA buffer will initially be allocated
+	 * zeroed via shmfs (and so this memset is redundant when
+	 * first allocating), we may re-init the OA buffer, either
+	 * when re-enabling a stream or in error/reset paths.
+	 *
+	 * The reason we clear the buffer for each re-init is for the
+	 * sanity check in gen7_append_oa_reports() that looks at the
+	 * report-id field to make sure it's non-zero which relies on
+	 * the assumption that new reports are being written to zeroed
+	 * memory...
+	 */
+	memset(dev_priv->perf.oa.oa_buffer.vaddr, 0, OA_BUFFER_SIZE);
+
+	/* Maybe make ->pollin per-stream state if we support multiple
+	 * concurrent streams in the future.
+	 */
+	dev_priv->perf.oa.pollin = false;
+}
+
+static int alloc_oa_buffer(struct drm_i915_private *dev_priv)
+{
+	struct drm_i915_gem_object *bo;
+	struct i915_vma *vma;
+	int ret;
+
+	if (WARN_ON(dev_priv->perf.oa.oa_buffer.vma))
+		return -ENODEV;
+
+	ret = i915_mutex_lock_interruptible(&dev_priv->drm);
+	if (ret)
+		return ret;
+
+	BUILD_BUG_ON_NOT_POWER_OF_2(OA_BUFFER_SIZE);
+	BUILD_BUG_ON(OA_BUFFER_SIZE < SZ_128K || OA_BUFFER_SIZE > SZ_16M);
+
+	bo = i915_gem_object_create(&dev_priv->drm, OA_BUFFER_SIZE);
+	if (IS_ERR(bo)) {
+		DRM_ERROR("Failed to allocate OA buffer\n");
+		ret = PTR_ERR(bo);
+		goto unlock;
+	}
+
+	ret = i915_gem_object_set_cache_level(bo, I915_CACHE_LLC);
+	if (ret)
+		goto err_unref;
+
+	/* PreHSW required 512K alignment, HSW requires 16M */
+	vma = i915_gem_object_ggtt_pin(bo, NULL, 0, SZ_16M, 0);
+	if (IS_ERR(vma)) {
+		ret = PTR_ERR(vma);
+		goto err_unref;
+	}
+	dev_priv->perf.oa.oa_buffer.vma = vma;
+
+	dev_priv->perf.oa.oa_buffer.vaddr =
+		i915_gem_object_pin_map(bo, I915_MAP_WB);
+	if (IS_ERR(dev_priv->perf.oa.oa_buffer.vaddr)) {
+		ret = PTR_ERR(dev_priv->perf.oa.oa_buffer.vaddr);
+		goto err_unpin;
+	}
+
+	dev_priv->perf.oa.ops.init_oa_buffer(dev_priv);
+
+	DRM_DEBUG_DRIVER("OA Buffer initialized, gtt offset = 0x%x, vaddr = %p",
+			 i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma),
+			 dev_priv->perf.oa.oa_buffer.vaddr);
+
+	goto unlock;
+
+err_unpin:
+	__i915_vma_unpin(vma);
+
+err_unref:
+	i915_gem_object_put(bo);
+
+	dev_priv->perf.oa.oa_buffer.vaddr = NULL;
+	dev_priv->perf.oa.oa_buffer.vma = NULL;
+
+unlock:
+	mutex_unlock(&dev_priv->drm.struct_mutex);
+	return ret;
+}
+
+static void config_oa_regs(struct drm_i915_private *dev_priv,
+			   const struct i915_oa_reg *regs,
+			   int n_regs)
+{
+	int i;
+
+	for (i = 0; i < n_regs; i++) {
+		const struct i915_oa_reg *reg = regs + i;
+
+		I915_WRITE(reg->addr, reg->value);
+	}
+}
+
+static int hsw_enable_metric_set(struct drm_i915_private *dev_priv)
+{
+	int ret = i915_oa_select_metric_set_hsw(dev_priv);
+
+	if (ret)
+		return ret;
+
+	I915_WRITE(GDT_CHICKEN_BITS, (I915_READ(GDT_CHICKEN_BITS) |
+				      GT_NOA_ENABLE));
+
+	/* PRM:
+	 *
+	 * OA unit is using “crclk” for its functionality. When trunk
+	 * level clock gating takes place, OA clock would be gated,
+	 * unable to count the events from non-render clock domain.
+	 * Render clock gating must be disabled when OA is enabled to
+	 * count the events from non-render domain. Unit level clock
+	 * gating for RCS should also be disabled.
+	 */
+	I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) &
+				    ~GEN7_DOP_CLOCK_GATE_ENABLE));
+	I915_WRITE(GEN6_UCGCTL1, (I915_READ(GEN6_UCGCTL1) |
+				  GEN6_CSUNIT_CLOCK_GATE_DISABLE));
+
+	config_oa_regs(dev_priv, dev_priv->perf.oa.mux_regs,
+		       dev_priv->perf.oa.mux_regs_len);
+
+	/* It apparently takes a fairly long time for a new MUX
+	 * configuration to be be applied after these register writes.
+	 * This delay duration was derived empirically based on the
+	 * render_basic config but hopefully it covers the maximum
+	 * configuration latency.
+	 *
+	 * As a fallback, the checks in _append_oa_reports() to skip
+	 * invalid OA reports do also seem to work to discard reports
+	 * generated before this config has completed - albeit not
+	 * silently.
+	 *
+	 * Unfortunately this is essentially a magic number, since we
+	 * don't currently know of a reliable mechanism for predicting
+	 * how long the MUX config will take to apply and besides
+	 * seeing invalid reports we don't know of a reliable way to
+	 * explicitly check that the MUX config has landed.
+	 *
+	 * It's even possible we've miss characterized the underlying
+	 * problem - it just seems like the simplest explanation why
+	 * a delay at this location would mitigate any invalid reports.
+	 */
+	usleep_range(15000, 20000);
+
+	config_oa_regs(dev_priv, dev_priv->perf.oa.b_counter_regs,
+		       dev_priv->perf.oa.b_counter_regs_len);
+
+	return 0;
+}
+
+static void hsw_disable_metric_set(struct drm_i915_private *dev_priv)
+{
+	I915_WRITE(GEN6_UCGCTL1, (I915_READ(GEN6_UCGCTL1) &
+				  ~GEN6_CSUNIT_CLOCK_GATE_DISABLE));
+	I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) |
+				    GEN7_DOP_CLOCK_GATE_ENABLE));
+
+	I915_WRITE(GDT_CHICKEN_BITS, (I915_READ(GDT_CHICKEN_BITS) &
+				      ~GT_NOA_ENABLE));
+}
+
+static void gen7_update_oacontrol_locked(struct drm_i915_private *dev_priv)
+{
+	assert_spin_locked(&dev_priv->perf.hook_lock);
+
+	if (dev_priv->perf.oa.exclusive_stream->enabled) {
+		struct i915_gem_context *ctx =
+			dev_priv->perf.oa.exclusive_stream->ctx;
+		u32 ctx_id = dev_priv->perf.oa.specific_ctx_id;
+
+		bool periodic = dev_priv->perf.oa.periodic;
+		u32 period_exponent = dev_priv->perf.oa.period_exponent;
+		u32 report_format = dev_priv->perf.oa.oa_buffer.format;
+
+		I915_WRITE(GEN7_OACONTROL,
+			   (ctx_id & GEN7_OACONTROL_CTX_MASK) |
+			   (period_exponent <<
+			    GEN7_OACONTROL_TIMER_PERIOD_SHIFT) |
+			   (periodic ? GEN7_OACONTROL_TIMER_ENABLE : 0) |
+			   (report_format << GEN7_OACONTROL_FORMAT_SHIFT) |
+			   (ctx ? GEN7_OACONTROL_PER_CTX_ENABLE : 0) |
+			   GEN7_OACONTROL_ENABLE);
+	} else
+		I915_WRITE(GEN7_OACONTROL, 0);
+}
+
+static void gen7_oa_enable(struct drm_i915_private *dev_priv)
+{
+	unsigned long flags;
+
+	/* Reset buf pointers so we don't forward reports from before now.
+	 *
+	 * Think carefully if considering trying to avoid this, since it
+	 * also ensures status flags and the buffer itself are cleared
+	 * in error paths, and we have checks for invalid reports based
+	 * on the assumption that certain fields are written to zeroed
+	 * memory which this helps maintains.
+	 */
+	gen7_init_oa_buffer(dev_priv);
+
+	spin_lock_irqsave(&dev_priv->perf.hook_lock, flags);
+	gen7_update_oacontrol_locked(dev_priv);
+	spin_unlock_irqrestore(&dev_priv->perf.hook_lock, flags);
+}
+
+static void i915_oa_stream_enable(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	dev_priv->perf.oa.ops.oa_enable(dev_priv);
+
+	if (dev_priv->perf.oa.periodic)
+		hrtimer_start(&dev_priv->perf.oa.poll_check_timer,
+			      ns_to_ktime(POLL_PERIOD),
+			      HRTIMER_MODE_REL_PINNED);
+}
+
+static void gen7_oa_disable(struct drm_i915_private *dev_priv)
+{
+	I915_WRITE(GEN7_OACONTROL, 0);
+}
+
+static void i915_oa_stream_disable(struct i915_perf_stream *stream)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+
+	dev_priv->perf.oa.ops.oa_disable(dev_priv);
+
+	if (dev_priv->perf.oa.periodic)
+		hrtimer_cancel(&dev_priv->perf.oa.poll_check_timer);
+}
+
+static u64 oa_exponent_to_ns(struct drm_i915_private *dev_priv, int exponent)
+{
+	return 1000000000ULL * (2ULL << exponent) /
+		dev_priv->perf.oa.timestamp_frequency;
+}
+
+static const struct i915_perf_stream_ops i915_oa_stream_ops = {
+	.destroy = i915_oa_stream_destroy,
+	.enable = i915_oa_stream_enable,
+	.disable = i915_oa_stream_disable,
+	.wait_unlocked = i915_oa_wait_unlocked,
+	.poll_wait = i915_oa_poll_wait,
+	.read = i915_oa_read,
 };
 
+static int i915_oa_stream_init(struct i915_perf_stream *stream,
+			       struct drm_i915_perf_open_param *param,
+			       struct perf_open_properties *props)
+{
+	struct drm_i915_private *dev_priv = stream->dev_priv;
+	int format_size;
+	int ret;
+
+	if (!(props->sample_flags & SAMPLE_OA_REPORT)) {
+		DRM_ERROR("Only OA report sampling supported\n");
+		return -EINVAL;
+	}
+
+	if (!dev_priv->perf.oa.ops.init_oa_buffer) {
+		DRM_ERROR("OA unit not supported\n");
+		return -ENODEV;
+	}
+
+	/* To avoid the complexity of having to accurately filter
+	 * counter reports and marshal to the appropriate client
+	 * we currently only allow exclusive access
+	 */
+	if (dev_priv->perf.oa.exclusive_stream) {
+		DRM_ERROR("OA unit already in use\n");
+		return -EBUSY;
+	}
+
+	if (!props->metrics_set) {
+		DRM_ERROR("OA metric set not specified\n");
+		return -EINVAL;
+	}
+
+	if (!props->oa_format) {
+		DRM_ERROR("OA report format not specified\n");
+		return -EINVAL;
+	}
+
+	stream->sample_size = sizeof(struct drm_i915_perf_record_header);
+
+	format_size = dev_priv->perf.oa.oa_formats[props->oa_format].size;
+
+	stream->sample_flags |= SAMPLE_OA_REPORT;
+	stream->sample_size += format_size;
+
+	dev_priv->perf.oa.oa_buffer.format_size = format_size;
+	if (WARN_ON(dev_priv->perf.oa.oa_buffer.format_size == 0))
+		return -EINVAL;
+
+	dev_priv->perf.oa.oa_buffer.format =
+		dev_priv->perf.oa.oa_formats[props->oa_format].format;
+
+	dev_priv->perf.oa.metrics_set = props->metrics_set;
+
+	dev_priv->perf.oa.periodic = props->oa_periodic;
+	if (dev_priv->perf.oa.periodic) {
+		u64 period_ns = oa_exponent_to_ns(dev_priv,
+						  props->oa_period_exponent);
+
+		dev_priv->perf.oa.period_exponent = props->oa_period_exponent;
+
+		/* See comment for OA_TAIL_MARGIN_NSEC for details
+		 * about this tail_margin...
+		 */
+		dev_priv->perf.oa.tail_margin =
+			((OA_TAIL_MARGIN_NSEC / period_ns) + 1) * format_size;
+	}
+
+	if (stream->ctx) {
+		ret = oa_get_render_ctx_id(stream);
+		if (ret)
+			return ret;
+	}
+
+	ret = alloc_oa_buffer(dev_priv);
+	if (ret)
+		goto err_oa_buf_alloc;
+
+	/* PRM - observability performance counters:
+	 *
+	 *   OACONTROL, performance counter enable, note:
+	 *
+	 *   "When this bit is set, in order to have coherent counts,
+	 *   RC6 power state and trunk clock gating must be disabled.
+	 *   This can be achieved by programming MMIO registers as
+	 *   0xA094=0 and 0xA090[31]=1"
+	 *
+	 *   In our case we are expecting that taking pm + FORCEWAKE
+	 *   references will effectively disable RC6.
+	 */
+	intel_runtime_pm_get(dev_priv);
+	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+
+	ret = dev_priv->perf.oa.ops.enable_metric_set(dev_priv);
+	if (ret)
+		goto err_enable;
+
+	stream->ops = &i915_oa_stream_ops;
+
+	dev_priv->perf.oa.exclusive_stream = stream;
+
+	return 0;
+
+err_enable:
+	intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+	intel_runtime_pm_put(dev_priv);
+	free_oa_buffer(dev_priv);
+
+err_oa_buf_alloc:
+	if (stream->ctx)
+		oa_put_render_ctx_id(stream);
+
+	return ret;
+}
+
 static ssize_t i915_perf_read_locked(struct i915_perf_stream *stream,
 				     struct file *file,
 				     char __user *buf,
@@ -78,8 +961,20 @@ static ssize_t i915_perf_read(struct file *file,
 	struct drm_i915_private *dev_priv = stream->dev_priv;
 	ssize_t ret;
 
+	/* To ensure it's handled consistently we simply treat all reads of a
+	 * disabled stream as an error. In particular it might otherwise lead
+	 * to a deadlock for blocking file descriptors...
+	 */
+	if (!stream->enabled)
+		return -EIO;
+
 	if (!(file->f_flags & O_NONBLOCK)) {
-		/* Allow false positives from stream->ops->wait_unlocked.
+		/* There's the small chance of false positives from
+		 * stream->ops->wait_unlocked.
+		 *
+		 * E.g. with single context filtering since we only wait until
+		 * oabuffer has >= 1 report we don't immediately know whether
+		 * any reports really belong to the current context
 		 */
 		do {
 			ret = stream->ops->wait_unlocked(stream);
@@ -97,21 +992,51 @@ static ssize_t i915_perf_read(struct file *file,
 		mutex_unlock(&dev_priv->perf.lock);
 	}
 
+	if (ret >= 0) {
+		/* Maybe make ->pollin per-stream state if we support multiple
+		 * concurrent streams in the future.
+		 */
+		dev_priv->perf.oa.pollin = false;
+	}
+
 	return ret;
 }
 
-static unsigned int i915_perf_poll_locked(struct i915_perf_stream *stream,
+static enum hrtimer_restart oa_poll_check_timer_cb(struct hrtimer *hrtimer)
+{
+	struct drm_i915_private *dev_priv =
+		container_of(hrtimer, typeof(*dev_priv),
+			     perf.oa.poll_check_timer);
+
+	if (!dev_priv->perf.oa.ops.oa_buffer_is_empty(dev_priv)) {
+		dev_priv->perf.oa.pollin = true;
+		wake_up(&dev_priv->perf.oa.poll_wq);
+	}
+
+	hrtimer_forward_now(hrtimer, ns_to_ktime(POLL_PERIOD));
+
+	return HRTIMER_RESTART;
+}
+
+static unsigned int i915_perf_poll_locked(struct drm_i915_private *dev_priv,
+					  struct i915_perf_stream *stream,
 					  struct file *file,
 					  poll_table *wait)
 {
-	unsigned int streams = 0;
+	unsigned int events = 0;
 
 	stream->ops->poll_wait(stream, file, wait);
 
-	if (stream->ops->can_read(stream))
-		streams |= POLLIN;
+	/* Note: we don't explicitly check whether there's something to read
+	 * here since this path may be very hot depending on what else
+	 * userspace is polling, or on the timeout in use. We rely solely on
+	 * the hrtimer/oa_poll_check_timer_cb to notify us when there are
+	 * samples to read.
+	 */
+	if (dev_priv->perf.oa.pollin)
+		events |= POLLIN;
 
-	return streams;
+	return events;
 }
 
 static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
@@ -121,7 +1046,7 @@ static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
 	int ret;
 
 	mutex_lock(&dev_priv->perf.lock);
-	ret = i915_perf_poll_locked(stream, file, wait);
+	ret = i915_perf_poll_locked(dev_priv, stream, file, wait);
 	mutex_unlock(&dev_priv->perf.lock);
 
 	return ret;
@@ -285,18 +1210,21 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
 		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.
+	ret = i915_oa_stream_init(stream, param, props);
+	if (ret)
+		goto err_alloc;
+
+	/* we avoid simply assigning stream->sample_flags = props->sample_flags
+	 * to have _stream_init check the combination of sample flags more
+	 * thoroughly, but still this is the expected result at this point.
 	 */
-	DRM_ERROR("Unsupported i915 perf stream configuration\n");
-	ret = -EINVAL;
-	goto err_alloc;
+	if (WARN_ON(stream->sample_flags != props->sample_flags)) {
+		ret = -ENODEV;
+		goto err_alloc;
+	}
 
 	list_add(&stream->link, &dev_priv->perf.streams);
 
@@ -376,6 +1304,56 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv,
 			props->single_context = 1;
 			props->ctx_handle = value;
 			break;
+		case DRM_I915_PERF_PROP_SAMPLE_OA:
+			props->sample_flags |= SAMPLE_OA_REPORT;
+			break;
+		case DRM_I915_PERF_PROP_OA_METRICS_SET:
+			if (value == 0 ||
+			    value > dev_priv->perf.oa.n_builtin_sets) {
+				DRM_ERROR("Unknown OA metric set ID");
+				return -EINVAL;
+			}
+			props->metrics_set = value;
+			break;
+		case DRM_I915_PERF_PROP_OA_FORMAT:
+			if (value == 0 || value >= I915_OA_FORMAT_MAX) {
+				DRM_ERROR("Invalid OA report format\n");
+				return -EINVAL;
+			}
+			if (!dev_priv->perf.oa.oa_formats[value].size) {
+				DRM_ERROR("Invalid OA report format\n");
+				return -EINVAL;
+			}
+			props->oa_format = value;
+			break;
+		case DRM_I915_PERF_PROP_OA_EXPONENT:
+			if (value > OA_EXPONENT_MAX) {
+				DRM_ERROR("OA timer exponent too high (> %u)\n",
+					  OA_EXPONENT_MAX);
+				return -EINVAL;
+			}
+
+			/* NB: The exponent represents a period as follows:
+			 *
+			 *   80ns * 2^(period_exponent + 1)
+			 *
+			 * Theoretically we can program the OA unit to sample
+			 * every 160ns but don't allow that by default unless
+			 * root.
+			 *
+			 * Referring to perf's
+			 * kernel.perf_event_max_sample_rate for a precedent
+			 * (100000 by default); with an OA exponent of 6 we get
+			 * a period of 10.240 microseconds -just under 100000Hz
+			 */
+			if (value < 6 && !capable(CAP_SYS_ADMIN)) {
+				DRM_ERROR("Minimum OA sampling exponent is 6 without root privileges\n");
+				return -EACCES;
+			}
+
+			props->oa_periodic = true;
+			props->oa_period_exponent = value;
+			break;
 		default:
 			MISSING_CASE(id);
 			DRM_ERROR("Unknown i915 perf property ID");
@@ -426,8 +1404,33 @@ int i915_perf_open_ioctl(struct drm_device *dev, void *data,
 
 void i915_perf_init(struct drm_i915_private *dev_priv)
 {
+	if (!IS_HASWELL(dev_priv))
+		return;
+
+	hrtimer_init(&dev_priv->perf.oa.poll_check_timer,
+		     CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	dev_priv->perf.oa.poll_check_timer.function = oa_poll_check_timer_cb;
+	init_waitqueue_head(&dev_priv->perf.oa.poll_wq);
+
 	INIT_LIST_HEAD(&dev_priv->perf.streams);
 	mutex_init(&dev_priv->perf.lock);
+	spin_lock_init(&dev_priv->perf.hook_lock);
+
+	dev_priv->perf.oa.ops.init_oa_buffer = gen7_init_oa_buffer;
+	dev_priv->perf.oa.ops.enable_metric_set = hsw_enable_metric_set;
+	dev_priv->perf.oa.ops.disable_metric_set = hsw_disable_metric_set;
+	dev_priv->perf.oa.ops.oa_enable = gen7_oa_enable;
+	dev_priv->perf.oa.ops.oa_disable = gen7_oa_disable;
+	dev_priv->perf.oa.ops.read = gen7_oa_read;
+	dev_priv->perf.oa.ops.oa_buffer_is_empty =
+		gen7_oa_buffer_is_empty_fop_unlocked;
+
+	dev_priv->perf.oa.timestamp_frequency = 12500000;
+
+	dev_priv->perf.oa.oa_formats = hsw_oa_formats;
+
+	dev_priv->perf.oa.n_builtin_sets =
+		i915_oa_n_builtin_metric_sets_hsw;
 
 	dev_priv->perf.initialized = true;
 }
@@ -437,7 +1440,6 @@ void i915_perf_fini(struct drm_i915_private *dev_priv)
 	if (!dev_priv->perf.initialized)
 		return;
 
-	/* Currently nothing to clean up */
-
+	memset(&dev_priv->perf.oa.ops, 0, sizeof(dev_priv->perf.oa.ops));
 	dev_priv->perf.initialized = false;
 }
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 59628d5..6e3b435 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -616,6 +616,343 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
 #define HSW_CS_GPR_UDW(n)               _MMIO(0x2600 + (n) * 8 + 4)
 
 #define GEN7_OACONTROL _MMIO(0x2360)
+#define  GEN7_OACONTROL_CTX_MASK	    0xFFFFF000
+#define  GEN7_OACONTROL_TIMER_PERIOD_MASK   0x3F
+#define  GEN7_OACONTROL_TIMER_PERIOD_SHIFT  6
+#define  GEN7_OACONTROL_TIMER_ENABLE	    (1<<5)
+#define  GEN7_OACONTROL_FORMAT_A13	    (0<<2)
+#define  GEN7_OACONTROL_FORMAT_A29	    (1<<2)
+#define  GEN7_OACONTROL_FORMAT_A13_B8_C8    (2<<2)
+#define  GEN7_OACONTROL_FORMAT_A29_B8_C8    (3<<2)
+#define  GEN7_OACONTROL_FORMAT_B4_C8	    (4<<2)
+#define  GEN7_OACONTROL_FORMAT_A45_B8_C8    (5<<2)
+#define  GEN7_OACONTROL_FORMAT_B4_C8_A16    (6<<2)
+#define  GEN7_OACONTROL_FORMAT_C4_B8	    (7<<2)
+#define  GEN7_OACONTROL_FORMAT_SHIFT	    2
+#define  GEN7_OACONTROL_PER_CTX_ENABLE	    (1<<1)
+#define  GEN7_OACONTROL_ENABLE		    (1<<0)
+
+#define GEN8_OACTXID _MMIO(0x2364)
+
+#define GEN8_OACONTROL _MMIO(0x2B00)
+#define  GEN8_OA_REPORT_FORMAT_A12	    (0<<2)
+#define  GEN8_OA_REPORT_FORMAT_A12_B8_C8    (2<<2)
+#define  GEN8_OA_REPORT_FORMAT_A36_B8_C8    (5<<2)
+#define  GEN8_OA_REPORT_FORMAT_C4_B8	    (7<<2)
+#define  GEN8_OA_REPORT_FORMAT_SHIFT	    2
+#define  GEN8_OA_SPECIFIC_CONTEXT_ENABLE    (1<<1)
+#define  GEN8_OA_COUNTER_ENABLE             (1<<0)
+
+#define GEN8_OACTXCONTROL _MMIO(0x2360)
+#define  GEN8_OA_TIMER_PERIOD_MASK	    0x3F
+#define  GEN8_OA_TIMER_PERIOD_SHIFT	    2
+#define  GEN8_OA_TIMER_ENABLE		    (1<<1)
+#define  GEN8_OA_COUNTER_RESUME		    (1<<0)
+
+#define GEN7_OABUFFER _MMIO(0x23B0) /* R/W */
+#define  GEN7_OABUFFER_OVERRUN_DISABLE	    (1<<3)
+#define  GEN7_OABUFFER_EDGE_TRIGGER	    (1<<2)
+#define  GEN7_OABUFFER_STOP_RESUME_ENABLE   (1<<1)
+#define  GEN7_OABUFFER_RESUME		    (1<<0)
+
+#define GEN8_OABUFFER _MMIO(0x2b14)
+
+#define GEN7_OASTATUS1 _MMIO(0x2364)
+#define  GEN7_OASTATUS1_TAIL_MASK	    0xffffffc0
+#define  GEN7_OASTATUS1_COUNTER_OVERFLOW    (1<<2)
+#define  GEN7_OASTATUS1_OABUFFER_OVERFLOW   (1<<1)
+#define  GEN7_OASTATUS1_REPORT_LOST	    (1<<0)
+
+#define GEN7_OASTATUS2 _MMIO(0x2368)
+#define GEN7_OASTATUS2_HEAD_MASK    0xffffffc0
+
+#define GEN8_OASTATUS _MMIO(0x2b08)
+#define  GEN8_OASTATUS_OVERRUN_STATUS	    (1<<3)
+#define  GEN8_OASTATUS_COUNTER_OVERFLOW     (1<<2)
+#define  GEN8_OASTATUS_OABUFFER_OVERFLOW    (1<<1)
+#define  GEN8_OASTATUS_REPORT_LOST	    (1<<0)
+
+#define GEN8_OAHEADPTR _MMIO(0x2B0C)
+#define GEN8_OATAILPTR _MMIO(0x2B10)
+
+#define OABUFFER_SIZE_128K  (0<<3)
+#define OABUFFER_SIZE_256K  (1<<3)
+#define OABUFFER_SIZE_512K  (2<<3)
+#define OABUFFER_SIZE_1M    (3<<3)
+#define OABUFFER_SIZE_2M    (4<<3)
+#define OABUFFER_SIZE_4M    (5<<3)
+#define OABUFFER_SIZE_8M    (6<<3)
+#define OABUFFER_SIZE_16M   (7<<3)
+
+#define OA_MEM_SELECT_GGTT  (1<<0)
+
+#define EU_PERF_CNTL0	    _MMIO(0xe458)
+
+#define GDT_CHICKEN_BITS    _MMIO(0x9840)
+#define GT_NOA_ENABLE	    0x00000080
+
+/*
+ * OA Boolean state
+ */
+
+#define OAREPORTTRIG1 _MMIO(0x2740)
+#define OAREPORTTRIG1_THRESHOLD_MASK 0xffff
+#define OAREPORTTRIG1_EDGE_LEVEL_TRIGER_SELECT_MASK 0xffff0000 /* 0=level */
+
+#define OAREPORTTRIG2 _MMIO(0x2744)
+#define OAREPORTTRIG2_INVERT_A_0  (1<<0)
+#define OAREPORTTRIG2_INVERT_A_1  (1<<1)
+#define OAREPORTTRIG2_INVERT_A_2  (1<<2)
+#define OAREPORTTRIG2_INVERT_A_3  (1<<3)
+#define OAREPORTTRIG2_INVERT_A_4  (1<<4)
+#define OAREPORTTRIG2_INVERT_A_5  (1<<5)
+#define OAREPORTTRIG2_INVERT_A_6  (1<<6)
+#define OAREPORTTRIG2_INVERT_A_7  (1<<7)
+#define OAREPORTTRIG2_INVERT_A_8  (1<<8)
+#define OAREPORTTRIG2_INVERT_A_9  (1<<9)
+#define OAREPORTTRIG2_INVERT_A_10 (1<<10)
+#define OAREPORTTRIG2_INVERT_A_11 (1<<11)
+#define OAREPORTTRIG2_INVERT_A_12 (1<<12)
+#define OAREPORTTRIG2_INVERT_A_13 (1<<13)
+#define OAREPORTTRIG2_INVERT_A_14 (1<<14)
+#define OAREPORTTRIG2_INVERT_A_15 (1<<15)
+#define OAREPORTTRIG2_INVERT_B_0  (1<<16)
+#define OAREPORTTRIG2_INVERT_B_1  (1<<17)
+#define OAREPORTTRIG2_INVERT_B_2  (1<<18)
+#define OAREPORTTRIG2_INVERT_B_3  (1<<19)
+#define OAREPORTTRIG2_INVERT_C_0  (1<<20)
+#define OAREPORTTRIG2_INVERT_C_1  (1<<21)
+#define OAREPORTTRIG2_INVERT_D_0  (1<<22)
+#define OAREPORTTRIG2_THRESHOLD_ENABLE	    (1<<23)
+#define OAREPORTTRIG2_REPORT_TRIGGER_ENABLE (1<<31)
+
+#define OAREPORTTRIG3 _MMIO(0x2748)
+#define OAREPORTTRIG3_NOA_SELECT_MASK	    0xf
+#define OAREPORTTRIG3_NOA_SELECT_8_SHIFT    0
+#define OAREPORTTRIG3_NOA_SELECT_9_SHIFT    4
+#define OAREPORTTRIG3_NOA_SELECT_10_SHIFT   8
+#define OAREPORTTRIG3_NOA_SELECT_11_SHIFT   12
+#define OAREPORTTRIG3_NOA_SELECT_12_SHIFT   16
+#define OAREPORTTRIG3_NOA_SELECT_13_SHIFT   20
+#define OAREPORTTRIG3_NOA_SELECT_14_SHIFT   24
+#define OAREPORTTRIG3_NOA_SELECT_15_SHIFT   28
+
+#define OAREPORTTRIG4 _MMIO(0x274c)
+#define OAREPORTTRIG4_NOA_SELECT_MASK	    0xf
+#define OAREPORTTRIG4_NOA_SELECT_0_SHIFT    0
+#define OAREPORTTRIG4_NOA_SELECT_1_SHIFT    4
+#define OAREPORTTRIG4_NOA_SELECT_2_SHIFT    8
+#define OAREPORTTRIG4_NOA_SELECT_3_SHIFT    12
+#define OAREPORTTRIG4_NOA_SELECT_4_SHIFT    16
+#define OAREPORTTRIG4_NOA_SELECT_5_SHIFT    20
+#define OAREPORTTRIG4_NOA_SELECT_6_SHIFT    24
+#define OAREPORTTRIG4_NOA_SELECT_7_SHIFT    28
+
+#define OAREPORTTRIG5 _MMIO(0x2750)
+#define OAREPORTTRIG5_THRESHOLD_MASK 0xffff
+#define OAREPORTTRIG5_EDGE_LEVEL_TRIGER_SELECT_MASK 0xffff0000 /* 0=level */
+
+#define OAREPORTTRIG6 _MMIO(0x2754)
+#define OAREPORTTRIG6_INVERT_A_0  (1<<0)
+#define OAREPORTTRIG6_INVERT_A_1  (1<<1)
+#define OAREPORTTRIG6_INVERT_A_2  (1<<2)
+#define OAREPORTTRIG6_INVERT_A_3  (1<<3)
+#define OAREPORTTRIG6_INVERT_A_4  (1<<4)
+#define OAREPORTTRIG6_INVERT_A_5  (1<<5)
+#define OAREPORTTRIG6_INVERT_A_6  (1<<6)
+#define OAREPORTTRIG6_INVERT_A_7  (1<<7)
+#define OAREPORTTRIG6_INVERT_A_8  (1<<8)
+#define OAREPORTTRIG6_INVERT_A_9  (1<<9)
+#define OAREPORTTRIG6_INVERT_A_10 (1<<10)
+#define OAREPORTTRIG6_INVERT_A_11 (1<<11)
+#define OAREPORTTRIG6_INVERT_A_12 (1<<12)
+#define OAREPORTTRIG6_INVERT_A_13 (1<<13)
+#define OAREPORTTRIG6_INVERT_A_14 (1<<14)
+#define OAREPORTTRIG6_INVERT_A_15 (1<<15)
+#define OAREPORTTRIG6_INVERT_B_0  (1<<16)
+#define OAREPORTTRIG6_INVERT_B_1  (1<<17)
+#define OAREPORTTRIG6_INVERT_B_2  (1<<18)
+#define OAREPORTTRIG6_INVERT_B_3  (1<<19)
+#define OAREPORTTRIG6_INVERT_C_0  (1<<20)
+#define OAREPORTTRIG6_INVERT_C_1  (1<<21)
+#define OAREPORTTRIG6_INVERT_D_0  (1<<22)
+#define OAREPORTTRIG6_THRESHOLD_ENABLE	    (1<<23)
+#define OAREPORTTRIG6_REPORT_TRIGGER_ENABLE (1<<31)
+
+#define OAREPORTTRIG7 _MMIO(0x2758)
+#define OAREPORTTRIG7_NOA_SELECT_MASK	    0xf
+#define OAREPORTTRIG7_NOA_SELECT_8_SHIFT    0
+#define OAREPORTTRIG7_NOA_SELECT_9_SHIFT    4
+#define OAREPORTTRIG7_NOA_SELECT_10_SHIFT   8
+#define OAREPORTTRIG7_NOA_SELECT_11_SHIFT   12
+#define OAREPORTTRIG7_NOA_SELECT_12_SHIFT   16
+#define OAREPORTTRIG7_NOA_SELECT_13_SHIFT   20
+#define OAREPORTTRIG7_NOA_SELECT_14_SHIFT   24
+#define OAREPORTTRIG7_NOA_SELECT_15_SHIFT   28
+
+#define OAREPORTTRIG8 _MMIO(0x275c)
+#define OAREPORTTRIG8_NOA_SELECT_MASK	    0xf
+#define OAREPORTTRIG8_NOA_SELECT_0_SHIFT    0
+#define OAREPORTTRIG8_NOA_SELECT_1_SHIFT    4
+#define OAREPORTTRIG8_NOA_SELECT_2_SHIFT    8
+#define OAREPORTTRIG8_NOA_SELECT_3_SHIFT    12
+#define OAREPORTTRIG8_NOA_SELECT_4_SHIFT    16
+#define OAREPORTTRIG8_NOA_SELECT_5_SHIFT    20
+#define OAREPORTTRIG8_NOA_SELECT_6_SHIFT    24
+#define OAREPORTTRIG8_NOA_SELECT_7_SHIFT    28
+
+#define OASTARTTRIG1 _MMIO(0x2710)
+#define OASTARTTRIG1_THRESHOLD_COUNT_MASK_MBZ 0xffff0000
+#define OASTARTTRIG1_THRESHOLD_MASK	      0xffff
+
+#define OASTARTTRIG2 _MMIO(0x2714)
+#define OASTARTTRIG2_INVERT_A_0 (1<<0)
+#define OASTARTTRIG2_INVERT_A_1 (1<<1)
+#define OASTARTTRIG2_INVERT_A_2 (1<<2)
+#define OASTARTTRIG2_INVERT_A_3 (1<<3)
+#define OASTARTTRIG2_INVERT_A_4 (1<<4)
+#define OASTARTTRIG2_INVERT_A_5 (1<<5)
+#define OASTARTTRIG2_INVERT_A_6 (1<<6)
+#define OASTARTTRIG2_INVERT_A_7 (1<<7)
+#define OASTARTTRIG2_INVERT_A_8 (1<<8)
+#define OASTARTTRIG2_INVERT_A_9 (1<<9)
+#define OASTARTTRIG2_INVERT_A_10 (1<<10)
+#define OASTARTTRIG2_INVERT_A_11 (1<<11)
+#define OASTARTTRIG2_INVERT_A_12 (1<<12)
+#define OASTARTTRIG2_INVERT_A_13 (1<<13)
+#define OASTARTTRIG2_INVERT_A_14 (1<<14)
+#define OASTARTTRIG2_INVERT_A_15 (1<<15)
+#define OASTARTTRIG2_INVERT_B_0 (1<<16)
+#define OASTARTTRIG2_INVERT_B_1 (1<<17)
+#define OASTARTTRIG2_INVERT_B_2 (1<<18)
+#define OASTARTTRIG2_INVERT_B_3 (1<<19)
+#define OASTARTTRIG2_INVERT_C_0 (1<<20)
+#define OASTARTTRIG2_INVERT_C_1 (1<<21)
+#define OASTARTTRIG2_INVERT_D_0 (1<<22)
+#define OASTARTTRIG2_THRESHOLD_ENABLE	    (1<<23)
+#define OASTARTTRIG2_START_TRIG_FLAG_MBZ    (1<<24)
+#define OASTARTTRIG2_EVENT_SELECT_0  (1<<28)
+#define OASTARTTRIG2_EVENT_SELECT_1  (1<<29)
+#define OASTARTTRIG2_EVENT_SELECT_2  (1<<30)
+#define OASTARTTRIG2_EVENT_SELECT_3  (1<<31)
+
+#define OASTARTTRIG3 _MMIO(0x2718)
+#define OASTARTTRIG3_NOA_SELECT_MASK	   0xf
+#define OASTARTTRIG3_NOA_SELECT_8_SHIFT    0
+#define OASTARTTRIG3_NOA_SELECT_9_SHIFT    4
+#define OASTARTTRIG3_NOA_SELECT_10_SHIFT   8
+#define OASTARTTRIG3_NOA_SELECT_11_SHIFT   12
+#define OASTARTTRIG3_NOA_SELECT_12_SHIFT   16
+#define OASTARTTRIG3_NOA_SELECT_13_SHIFT   20
+#define OASTARTTRIG3_NOA_SELECT_14_SHIFT   24
+#define OASTARTTRIG3_NOA_SELECT_15_SHIFT   28
+
+#define OASTARTTRIG4 _MMIO(0x271c)
+#define OASTARTTRIG4_NOA_SELECT_MASK	    0xf
+#define OASTARTTRIG4_NOA_SELECT_0_SHIFT    0
+#define OASTARTTRIG4_NOA_SELECT_1_SHIFT    4
+#define OASTARTTRIG4_NOA_SELECT_2_SHIFT    8
+#define OASTARTTRIG4_NOA_SELECT_3_SHIFT    12
+#define OASTARTTRIG4_NOA_SELECT_4_SHIFT    16
+#define OASTARTTRIG4_NOA_SELECT_5_SHIFT    20
+#define OASTARTTRIG4_NOA_SELECT_6_SHIFT    24
+#define OASTARTTRIG4_NOA_SELECT_7_SHIFT    28
+
+#define OASTARTTRIG5 _MMIO(0x2720)
+#define OASTARTTRIG5_THRESHOLD_COUNT_MASK_MBZ 0xffff0000
+#define OASTARTTRIG5_THRESHOLD_MASK	      0xffff
+
+#define OASTARTTRIG6 _MMIO(0x2724)
+#define OASTARTTRIG6_INVERT_A_0 (1<<0)
+#define OASTARTTRIG6_INVERT_A_1 (1<<1)
+#define OASTARTTRIG6_INVERT_A_2 (1<<2)
+#define OASTARTTRIG6_INVERT_A_3 (1<<3)
+#define OASTARTTRIG6_INVERT_A_4 (1<<4)
+#define OASTARTTRIG6_INVERT_A_5 (1<<5)
+#define OASTARTTRIG6_INVERT_A_6 (1<<6)
+#define OASTARTTRIG6_INVERT_A_7 (1<<7)
+#define OASTARTTRIG6_INVERT_A_8 (1<<8)
+#define OASTARTTRIG6_INVERT_A_9 (1<<9)
+#define OASTARTTRIG6_INVERT_A_10 (1<<10)
+#define OASTARTTRIG6_INVERT_A_11 (1<<11)
+#define OASTARTTRIG6_INVERT_A_12 (1<<12)
+#define OASTARTTRIG6_INVERT_A_13 (1<<13)
+#define OASTARTTRIG6_INVERT_A_14 (1<<14)
+#define OASTARTTRIG6_INVERT_A_15 (1<<15)
+#define OASTARTTRIG6_INVERT_B_0 (1<<16)
+#define OASTARTTRIG6_INVERT_B_1 (1<<17)
+#define OASTARTTRIG6_INVERT_B_2 (1<<18)
+#define OASTARTTRIG6_INVERT_B_3 (1<<19)
+#define OASTARTTRIG6_INVERT_C_0 (1<<20)
+#define OASTARTTRIG6_INVERT_C_1 (1<<21)
+#define OASTARTTRIG6_INVERT_D_0 (1<<22)
+#define OASTARTTRIG6_THRESHOLD_ENABLE	    (1<<23)
+#define OASTARTTRIG6_START_TRIG_FLAG_MBZ    (1<<24)
+#define OASTARTTRIG6_EVENT_SELECT_4  (1<<28)
+#define OASTARTTRIG6_EVENT_SELECT_5  (1<<29)
+#define OASTARTTRIG6_EVENT_SELECT_6  (1<<30)
+#define OASTARTTRIG6_EVENT_SELECT_7  (1<<31)
+
+#define OASTARTTRIG7 _MMIO(0x2728)
+#define OASTARTTRIG7_NOA_SELECT_MASK	   0xf
+#define OASTARTTRIG7_NOA_SELECT_8_SHIFT    0
+#define OASTARTTRIG7_NOA_SELECT_9_SHIFT    4
+#define OASTARTTRIG7_NOA_SELECT_10_SHIFT   8
+#define OASTARTTRIG7_NOA_SELECT_11_SHIFT   12
+#define OASTARTTRIG7_NOA_SELECT_12_SHIFT   16
+#define OASTARTTRIG7_NOA_SELECT_13_SHIFT   20
+#define OASTARTTRIG7_NOA_SELECT_14_SHIFT   24
+#define OASTARTTRIG7_NOA_SELECT_15_SHIFT   28
+
+#define OASTARTTRIG8 _MMIO(0x272c)
+#define OASTARTTRIG8_NOA_SELECT_MASK	   0xf
+#define OASTARTTRIG8_NOA_SELECT_0_SHIFT    0
+#define OASTARTTRIG8_NOA_SELECT_1_SHIFT    4
+#define OASTARTTRIG8_NOA_SELECT_2_SHIFT    8
+#define OASTARTTRIG8_NOA_SELECT_3_SHIFT    12
+#define OASTARTTRIG8_NOA_SELECT_4_SHIFT    16
+#define OASTARTTRIG8_NOA_SELECT_5_SHIFT    20
+#define OASTARTTRIG8_NOA_SELECT_6_SHIFT    24
+#define OASTARTTRIG8_NOA_SELECT_7_SHIFT    28
+
+/* CECX_0 */
+#define OACEC_COMPARE_LESS_OR_EQUAL	6
+#define OACEC_COMPARE_NOT_EQUAL		5
+#define OACEC_COMPARE_LESS_THAN		4
+#define OACEC_COMPARE_GREATER_OR_EQUAL	3
+#define OACEC_COMPARE_EQUAL		2
+#define OACEC_COMPARE_GREATER_THAN	1
+#define OACEC_COMPARE_ANY_EQUAL		0
+
+#define OACEC_COMPARE_VALUE_MASK    0xffff
+#define OACEC_COMPARE_VALUE_SHIFT   3
+
+#define OACEC_SELECT_NOA	(0<<19)
+#define OACEC_SELECT_PREV	(1<<19)
+#define OACEC_SELECT_BOOLEAN	(2<<19)
+
+/* CECX_1 */
+#define OACEC_MASK_MASK		    0xffff
+#define OACEC_CONSIDERATIONS_MASK   0xffff
+#define OACEC_CONSIDERATIONS_SHIFT  16
+
+#define OACEC0_0 _MMIO(0x2770)
+#define OACEC0_1 _MMIO(0x2774)
+#define OACEC1_0 _MMIO(0x2778)
+#define OACEC1_1 _MMIO(0x277c)
+#define OACEC2_0 _MMIO(0x2780)
+#define OACEC2_1 _MMIO(0x2784)
+#define OACEC3_0 _MMIO(0x2788)
+#define OACEC3_1 _MMIO(0x278c)
+#define OACEC4_0 _MMIO(0x2790)
+#define OACEC4_1 _MMIO(0x2794)
+#define OACEC5_0 _MMIO(0x2798)
+#define OACEC5_1 _MMIO(0x279c)
+#define OACEC6_0 _MMIO(0x27a0)
+#define OACEC6_1 _MMIO(0x27a4)
+#define OACEC7_0 _MMIO(0x27a8)
+#define OACEC7_1 _MMIO(0x27ac)
+
 
 #define _GEN7_PIPEA_DE_LOAD_SL	0x70068
 #define _GEN7_PIPEB_DE_LOAD_SL	0x71068
@@ -6993,6 +7330,7 @@ enum {
 # define GEN6_RCCUNIT_CLOCK_GATE_DISABLE		(1 << 11)
 
 #define GEN6_UCGCTL3				_MMIO(0x9408)
+# define GEN6_OACSUNIT_CLOCK_GATE_DISABLE		(1 << 20)
 
 #define GEN7_UCGCTL4				_MMIO(0x940c)
 #define  GEN7_L3BANK2X_CLOCK_GATE_DISABLE	(1<<25)
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 98cd493..82d6239 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1224,6 +1224,18 @@ struct drm_i915_gem_context_param {
 	__u64 value;
 };
 
+enum drm_i915_oa_format {
+	I915_OA_FORMAT_A13 = 1,
+	I915_OA_FORMAT_A29,
+	I915_OA_FORMAT_A13_B8_C8,
+	I915_OA_FORMAT_B4_C8,
+	I915_OA_FORMAT_A45_B8_C8,
+	I915_OA_FORMAT_B4_C8_A16,
+	I915_OA_FORMAT_C4_B8,
+
+	I915_OA_FORMAT_MAX	    /* non-ABI */
+};
+
 enum drm_i915_perf_property_id {
 	/**
 	 * Open the stream for a specific context handle (as used with
@@ -1232,6 +1244,32 @@ enum drm_i915_perf_property_id {
 	 */
 	DRM_I915_PERF_PROP_CTX_HANDLE = 1,
 
+	/**
+	 * A value of 1 requests the inclusion of raw OA unit reports as
+	 * part of stream samples.
+	 */
+	DRM_I915_PERF_PROP_SAMPLE_OA,
+
+	/**
+	 * The value specifies which set of OA unit metrics should be
+	 * be configured, defining the contents of any OA unit reports.
+	 */
+	DRM_I915_PERF_PROP_OA_METRICS_SET,
+
+	/**
+	 * The value specifies the size and layout of OA unit reports.
+	 */
+	DRM_I915_PERF_PROP_OA_FORMAT,
+
+	/**
+	 * Specifying this property implicitly requests periodic OA unit
+	 * sampling and (at least on Haswell) the sampling frequency is derived
+	 * from this exponent as follows:
+	 *
+	 *   80ns * 2^(period_exponent + 1)
+	 */
+	DRM_I915_PERF_PROP_OA_EXPONENT,
+
 	DRM_I915_PERF_PROP_MAX /* non-ABI */
 };
 
@@ -1251,7 +1289,23 @@ struct drm_i915_perf_open_param {
 	__u64 __user properties_ptr;
 };
 
+/**
+ * Enable data capture for a stream that was either opened in a disabled state
+ * via I915_PERF_FLAG_DISABLED or was later disabled via
+ * I915_PERF_IOCTL_DISABLE.
+ *
+ * It is intended to be cheaper to disable and enable a stream than it may be
+ * to close and re-open a stream with the same configuration.
+ *
+ * It's undefined whether any pending data for the stream will be lost.
+ */
 #define I915_PERF_IOCTL_ENABLE	_IO('i', 0x0)
+
+/**
+ * Disable data capture for a stream.
+ *
+ * It is an error to try and read a stream that is disabled.
+ */
 #define I915_PERF_IOCTL_DISABLE	_IO('i', 0x1)
 
 /**
@@ -1275,17 +1329,30 @@ enum drm_i915_perf_record_type {
 	 * 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
+	 * affect on the ordering of data within a sample. The order is
 	 * documented here.
 	 *
 	 * struct {
 	 *     struct drm_i915_perf_record_header header;
 	 *
-	 *     TODO: itemize extensible sample data here
+	 *     { u32 oa_report[]; } && DRM_I915_PERF_PROP_SAMPLE_OA
 	 * };
 	 */
 	DRM_I915_PERF_RECORD_SAMPLE = 1,
 
+	/*
+	 * Indicates that one or more OA reports were not written by the
+	 * hardware. This can happen for example if an MI_REPORT_PERF_COUNT
+	 * command collides with periodic sampling - which would be more likely
+	 * at higher sampling frequencies.
+	 */
+	DRM_I915_PERF_RECORD_OA_REPORT_LOST = 2,
+
+	/**
+	 * An error occurred that resulted in all pending OA reports being lost.
+	 */
+	DRM_I915_PERF_RECORD_OA_BUFFER_LOST = 3,
+
 	DRM_I915_PERF_RECORD_MAX /* non-ABI */
 };
 
-- 
2.10.1

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[PATCH v8 08/12] drm/i915: advertise available metrics via sysfs

[Robert Bragg]

Each metric set is given a sysfs entry like:

/sys/class/drm/card0/metrics/<guid>/id

This allows userspace to enumerate the specific sets that are available
for the current system. The 'id' file contains an unsigned integer that
can be used to open the associated metric set via
DRM_IOCTL_I915_PERF_OPEN. The <guid> is a globally unique ID for a
specific OA unit register configuration that can be reliably used by
userspace as a key to lookup corresponding counter meta data and
normalization equations.

The guid registry is currently maintained as part of gputop along with
the XML metric set descriptions and code generation scripts, ref:

 https://github.com/rib/gputop
 > gputop-data/guids.xml
 > scripts/update-guids.py
 > gputop-data/oa-*.xml
 > scripts/i915-perf-kernelgen.py

 $ make -C gputop-data -f Makefile.xml SYSFS=1 WHITELIST=RenderBasic

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c    |  5 ++++
 drivers/gpu/drm/i915/i915_drv.h    |  4 +++
 drivers/gpu/drm/i915/i915_oa_hsw.c | 51 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_oa_hsw.h |  4 +++
 drivers/gpu/drm/i915/i915_perf.c   | 52 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 116 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 685c96e..29bc83b 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1116,6 +1116,9 @@ static void i915_driver_register(struct drm_i915_private *dev_priv)
 		i915_debugfs_register(dev_priv);
 		i915_guc_register(dev_priv);
 		i915_setup_sysfs(dev_priv);
+
+		/* Depends on sysfs having been initialized */
+		i915_perf_register(dev_priv);
 	} else
 		DRM_ERROR("Failed to register driver for userspace access!\n");
 
@@ -1152,6 +1155,8 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv)
 	acpi_video_unregister();
 	intel_opregion_unregister(dev_priv);
 
+	i915_perf_unregister(dev_priv);
+
 	i915_teardown_sysfs(dev_priv);
 	i915_guc_unregister(dev_priv);
 	i915_debugfs_unregister(dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index dd2b4d3..01438fb 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2170,6 +2170,8 @@ struct drm_i915_private {
 	struct {
 		bool initialized;
 
+		struct kobject *metrics_kobj;
+
 		struct mutex lock;
 		struct list_head streams;
 
@@ -3757,6 +3759,8 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine,
 /* 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);
+extern void i915_perf_register(struct drm_i915_private *dev_priv);
+extern void i915_perf_unregister(struct drm_i915_private *dev_priv);
 
 /* i915_suspend.c */
 extern int i915_save_state(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.c b/drivers/gpu/drm/i915/i915_oa_hsw.c
index 8906380..6af25cf 100644
--- a/drivers/gpu/drm/i915/i915_oa_hsw.c
+++ b/drivers/gpu/drm/i915/i915_oa_hsw.c
@@ -24,6 +24,8 @@
  *
  */
 
+#include <linux/sysfs.h>
+
 #include "i915_drv.h"
 #include "i915_oa_hsw.h"
 
@@ -142,3 +144,52 @@ int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv)
 		return -ENODEV;
 	}
 }
+
+static ssize_t
+show_render_basic_id(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", METRIC_SET_ID_RENDER_BASIC);
+}
+
+static struct device_attribute dev_attr_render_basic_id = {
+	.attr = { .name = "id", .mode = 0444 },
+	.show = show_render_basic_id,
+	.store = NULL,
+};
+
+static struct attribute *attrs_render_basic[] = {
+	&dev_attr_render_basic_id.attr,
+	NULL,
+};
+
+static struct attribute_group group_render_basic = {
+	.name = "403d8832-1a27-4aa6-a64e-f5389ce7b212",
+	.attrs =  attrs_render_basic,
+};
+
+int
+i915_perf_register_sysfs_hsw(struct drm_i915_private *dev_priv)
+{
+	int mux_len;
+	int ret = 0;
+
+	if (get_render_basic_mux_config(dev_priv, &mux_len)) {
+		ret = sysfs_create_group(dev_priv->perf.metrics_kobj, &group_render_basic);
+		if (ret)
+			goto error_render_basic;
+	}
+
+	return 0;
+
+error_render_basic:
+	return ret;
+}
+
+void
+i915_perf_unregister_sysfs_hsw(struct drm_i915_private *dev_priv)
+{
+	int mux_len;
+
+	if (get_render_basic_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_render_basic);
+}
diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.h b/drivers/gpu/drm/i915/i915_oa_hsw.h
index b618a1f..429a229 100644
--- a/drivers/gpu/drm/i915/i915_oa_hsw.h
+++ b/drivers/gpu/drm/i915/i915_oa_hsw.h
@@ -31,4 +31,8 @@ extern int i915_oa_n_builtin_metric_sets_hsw;
 
 extern int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv);
 
+extern int i915_perf_register_sysfs_hsw(struct drm_i915_private *dev_priv);
+
+extern void i915_perf_unregister_sysfs_hsw(struct drm_i915_private *dev_priv);
+
 #endif
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 8b9cf0d..8d07c41 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -812,6 +812,15 @@ static int i915_oa_stream_init(struct i915_perf_stream *stream,
 	int format_size;
 	int ret;
 
+	/* If the sysfs metrics/ directory wasn't registered for some
+	 * reason then don't let userspace try their luck with config
+	 * IDs
+	 */
+	if (!dev_priv->perf.metrics_kobj) {
+		DRM_ERROR("OA metrics weren't advertised via sysfs\n");
+		return -EINVAL;
+	}
+
 	if (!(props->sample_flags & SAMPLE_OA_REPORT)) {
 		DRM_ERROR("Only OA report sampling supported\n");
 		return -EINVAL;
@@ -1402,6 +1411,49 @@ int i915_perf_open_ioctl(struct drm_device *dev, void *data,
 	return ret;
 }
 
+void i915_perf_register(struct drm_i915_private *dev_priv)
+{
+	if (!IS_HASWELL(dev_priv))
+		return;
+
+	if (!dev_priv->perf.initialized)
+		return;
+
+	/* To be sure we're synchronized with an attempted
+	 * i915_perf_open_ioctl(); considering that we register after
+	 * being exposed to userspace.
+	 */
+	mutex_lock(&dev_priv->perf.lock);
+
+	dev_priv->perf.metrics_kobj =
+		kobject_create_and_add("metrics",
+				       &dev_priv->drm.primary->kdev->kobj);
+	if (!dev_priv->perf.metrics_kobj)
+		goto exit;
+
+	if (i915_perf_register_sysfs_hsw(dev_priv)) {
+		kobject_put(dev_priv->perf.metrics_kobj);
+		dev_priv->perf.metrics_kobj = NULL;
+	}
+
+exit:
+	mutex_unlock(&dev_priv->perf.lock);
+}
+
+void i915_perf_unregister(struct drm_i915_private *dev_priv)
+{
+	if (!IS_HASWELL(dev_priv))
+		return;
+
+	if (!dev_priv->perf.metrics_kobj)
+		return;
+
+	i915_perf_unregister_sysfs_hsw(dev_priv);
+
+	kobject_put(dev_priv->perf.metrics_kobj);
+	dev_priv->perf.metrics_kobj = NULL;
+}
+
 void i915_perf_init(struct drm_i915_private *dev_priv)
 {
 	if (!IS_HASWELL(dev_priv))
-- 
2.10.1

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https://lists.freedesktop.org/mailman/listinfo/intel-gfx

[PATCH v8 09/12] drm/i915: Add dev.i915.perf_stream_paranoid sysctl option

[Robert Bragg]

Consistent with the kernel.perf_event_paranoid sysctl option that can
allow non-root users to access system wide cpu metrics, this can
optionally allow non-root users to access system wide OA counter metrics
from Gen graphics hardware.

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h  |  1 +
 drivers/gpu/drm/i915/i915_perf.c | 50 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 01438fb..a138f86 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2171,6 +2171,7 @@ struct drm_i915_private {
 		bool initialized;
 
 		struct kobject *metrics_kobj;
+		struct ctl_table_header *sysctl_header;
 
 		struct mutex lock;
 		struct list_head streams;
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 8d07c41..4e42073 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -64,6 +64,11 @@
 #define POLL_FREQUENCY 200
 #define POLL_PERIOD (NSEC_PER_SEC / POLL_FREQUENCY)
 
+/* for sysctl proc_dointvec_minmax of dev.i915.perf_stream_paranoid */
+static int zero;
+static int one = 1;
+static u32 i915_perf_stream_paranoid = true;
+
 /* The maximum exponent the hardware accepts is 63 (essentially it selects one
  * of the 64bit timestamp bits to trigger reports from) but there's currently
  * no known use case for sampling as infrequently as once per 47 thousand years.
@@ -1207,7 +1212,13 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
 		}
 	}
 
-	if (!specific_ctx && !capable(CAP_SYS_ADMIN)) {
+	/* Similar to perf's kernel.perf_paranoid_cpu sysctl option
+	 * we check a dev.i915.perf_stream_paranoid sysctl option
+	 * to determine if it's ok to access system wide OA counters
+	 * without CAP_SYS_ADMIN privileges.
+	 */
+	if (!specific_ctx &&
+	    i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
 		DRM_ERROR("Insufficient privileges to open system-wide i915 perf stream\n");
 		ret = -EACCES;
 		goto err_ctx;
@@ -1454,6 +1465,39 @@ void i915_perf_unregister(struct drm_i915_private *dev_priv)
 	dev_priv->perf.metrics_kobj = NULL;
 }
 
+static struct ctl_table oa_table[] = {
+	{
+	 .procname = "perf_stream_paranoid",
+	 .data = &i915_perf_stream_paranoid,
+	 .maxlen = sizeof(i915_perf_stream_paranoid),
+	 .mode = 0644,
+	 .proc_handler = proc_dointvec_minmax,
+	 .extra1 = &zero,
+	 .extra2 = &one,
+	 },
+	{}
+};
+
+static struct ctl_table i915_root[] = {
+	{
+	 .procname = "i915",
+	 .maxlen = 0,
+	 .mode = 0555,
+	 .child = oa_table,
+	 },
+	{}
+};
+
+static struct ctl_table dev_root[] = {
+	{
+	 .procname = "dev",
+	 .maxlen = 0,
+	 .mode = 0555,
+	 .child = i915_root,
+	 },
+	{}
+};
+
 void i915_perf_init(struct drm_i915_private *dev_priv)
 {
 	if (!IS_HASWELL(dev_priv))
@@ -1484,6 +1528,8 @@ void i915_perf_init(struct drm_i915_private *dev_priv)
 	dev_priv->perf.oa.n_builtin_sets =
 		i915_oa_n_builtin_metric_sets_hsw;
 
+	dev_priv->perf.sysctl_header = register_sysctl_table(dev_root);
+
 	dev_priv->perf.initialized = true;
 }
 
@@ -1492,6 +1538,8 @@ void i915_perf_fini(struct drm_i915_private *dev_priv)
 	if (!dev_priv->perf.initialized)
 		return;
 
+	unregister_sysctl_table(dev_priv->perf.sysctl_header);
+
 	memset(&dev_priv->perf.oa.ops, 0, sizeof(dev_priv->perf.oa.ops));
 	dev_priv->perf.initialized = false;
 }
-- 
2.10.1

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[PATCH v8 10/12] drm/i915: add oa_event_min_timer_exponent sysctl

[Robert Bragg]

The minimal sampling period is now configurable via a
dev.i915.oa_min_timer_exponent sysctl parameter.

Following the precedent set by perf, the default is the minimum that
won't (on its own) exceed the default kernel.perf_event_max_sample_rate
default of 100000 samples/s.

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_perf.c | 42 ++++++++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index 4e42073..e3c6f51 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -82,6 +82,22 @@ static u32 i915_perf_stream_paranoid = true;
 #define INVALID_CTX_ID 0xffffffff
 
 
+/* for sysctl proc_dointvec_minmax of i915_oa_min_timer_exponent */
+static int oa_exponent_max = OA_EXPONENT_MAX;
+
+/* Theoretically we can program the OA unit to sample every 160ns but don't
+ * allow that by default unless root...
+ *
+ * The period is derived from the exponent as:
+ *
+ *   period = 80ns * 2^(exponent + 1)
+ *
+ * Referring to perf's kernel.perf_event_max_sample_rate for a precedent
+ * (100000 by default); with an OA exponent of 6 we get a period of 10.240
+ * microseconds - just under 100000Hz
+ */
+static u32 i915_oa_min_timer_exponent = 6;
+
 /* XXX: beware if future OA HW adds new report formats that the current
  * code assumes all reports have a power-of-two size and ~(size - 1) can
  * be used as a mask to align the OA tail pointer.
@@ -1353,21 +1369,14 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv,
 				return -EINVAL;
 			}
 
-			/* NB: The exponent represents a period as follows:
-			 *
-			 *   80ns * 2^(period_exponent + 1)
-			 *
-			 * Theoretically we can program the OA unit to sample
+			/* Theoretically we can program the OA unit to sample
 			 * every 160ns but don't allow that by default unless
 			 * root.
-			 *
-			 * Referring to perf's
-			 * kernel.perf_event_max_sample_rate for a precedent
-			 * (100000 by default); with an OA exponent of 6 we get
-			 * a period of 10.240 microseconds -just under 100000Hz
 			 */
-			if (value < 6 && !capable(CAP_SYS_ADMIN)) {
-				DRM_ERROR("Minimum OA sampling exponent is 6 without root privileges\n");
+			if (value < i915_oa_min_timer_exponent &&
+			    !capable(CAP_SYS_ADMIN)) {
+				DRM_ERROR("Minimum OA sampling exponent (sysctl dev.i915.oa_min_timer_exponent) is %u without root privileges\n",
+					  i915_oa_min_timer_exponent);
 				return -EACCES;
 			}
 
@@ -1475,6 +1484,15 @@ static struct ctl_table oa_table[] = {
 	 .extra1 = &zero,
 	 .extra2 = &one,
 	 },
+	{
+	 .procname = "oa_min_timer_exponent",
+	 .data = &i915_oa_min_timer_exponent,
+	 .maxlen = sizeof(i915_oa_min_timer_exponent),
+	 .mode = 0644,
+	 .proc_handler = proc_dointvec_minmax,
+	 .extra1 = &zero,
+	 .extra2 = &oa_exponent_max,
+	 },
 	{}
 };
 
-- 
2.10.1

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[PATCH v8 11/12] drm/i915: Add more Haswell OA metric sets

[Robert Bragg]

This adds 'compute', 'compute extended', 'memory reads', 'memory writes'
and 'sampler balance' metric sets for Haswell.

The code is auto generated from an XML description of metric sets,
currently maintained in gputop, ref:

 https://github.com/rib/gputop
 > gputop-data/oa-*.xml
 > scripts/i915-perf-kernelgen.py

 $ make -C gputop-data -f Makefile.xml

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_oa_hsw.c | 559 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 558 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.c b/drivers/gpu/drm/i915/i915_oa_hsw.c
index 6af25cf..4ddf756 100644
--- a/drivers/gpu/drm/i915/i915_oa_hsw.c
+++ b/drivers/gpu/drm/i915/i915_oa_hsw.c
@@ -31,9 +31,14 @@
 
 enum metric_set_id {
 	METRIC_SET_ID_RENDER_BASIC = 1,
+	METRIC_SET_ID_COMPUTE_BASIC,
+	METRIC_SET_ID_COMPUTE_EXTENDED,
+	METRIC_SET_ID_MEMORY_READS,
+	METRIC_SET_ID_MEMORY_WRITES,
+	METRIC_SET_ID_SAMPLER_BALANCE,
 };
 
-int i915_oa_n_builtin_metric_sets_hsw = 1;
+int i915_oa_n_builtin_metric_sets_hsw = 6;
 
 static const struct i915_oa_reg b_counter_config_render_basic[] = {
 	{ _MMIO(0x2724), 0x00800000 },
@@ -112,6 +117,298 @@ get_render_basic_mux_config(struct drm_i915_private *dev_priv,
 	return mux_config_render_basic;
 }
 
+static const struct i915_oa_reg b_counter_config_compute_basic[] = {
+	{ _MMIO(0x2710), 0x00000000 },
+	{ _MMIO(0x2714), 0x00800000 },
+	{ _MMIO(0x2718), 0xaaaaaaaa },
+	{ _MMIO(0x271c), 0xaaaaaaaa },
+	{ _MMIO(0x2720), 0x00000000 },
+	{ _MMIO(0x2724), 0x00800000 },
+	{ _MMIO(0x2728), 0xaaaaaaaa },
+	{ _MMIO(0x272c), 0xaaaaaaaa },
+	{ _MMIO(0x2740), 0x00000000 },
+	{ _MMIO(0x2744), 0x00000000 },
+	{ _MMIO(0x2748), 0x00000000 },
+	{ _MMIO(0x274c), 0x00000000 },
+	{ _MMIO(0x2750), 0x00000000 },
+	{ _MMIO(0x2754), 0x00000000 },
+	{ _MMIO(0x2758), 0x00000000 },
+	{ _MMIO(0x275c), 0x00000000 },
+	{ _MMIO(0x236c), 0x00000000 },
+};
+
+static const struct i915_oa_reg mux_config_compute_basic[] = {
+	{ _MMIO(0x253a4), 0x00000000 },
+	{ _MMIO(0x2681c), 0x01f00800 },
+	{ _MMIO(0x26820), 0x00001000 },
+	{ _MMIO(0x2781c), 0x01f00800 },
+	{ _MMIO(0x26520), 0x00000007 },
+	{ _MMIO(0x265a0), 0x00000007 },
+	{ _MMIO(0x25380), 0x00000010 },
+	{ _MMIO(0x2538c), 0x00300000 },
+	{ _MMIO(0x25384), 0xaa8aaaaa },
+	{ _MMIO(0x25404), 0xffffffff },
+	{ _MMIO(0x26800), 0x00004202 },
+	{ _MMIO(0x26808), 0x00605817 },
+	{ _MMIO(0x2680c), 0x10001005 },
+	{ _MMIO(0x26804), 0x00000000 },
+	{ _MMIO(0x27800), 0x00000102 },
+	{ _MMIO(0x27808), 0x0c0701e0 },
+	{ _MMIO(0x2780c), 0x000200a0 },
+	{ _MMIO(0x27804), 0x00000000 },
+	{ _MMIO(0x26484), 0x44000000 },
+	{ _MMIO(0x26704), 0x44000000 },
+	{ _MMIO(0x26500), 0x00000006 },
+	{ _MMIO(0x26510), 0x00000001 },
+	{ _MMIO(0x26504), 0x88000000 },
+	{ _MMIO(0x26580), 0x00000006 },
+	{ _MMIO(0x26590), 0x00000020 },
+	{ _MMIO(0x26584), 0x00000000 },
+	{ _MMIO(0x26104), 0x55822222 },
+	{ _MMIO(0x26184), 0xaa866666 },
+	{ _MMIO(0x25420), 0x08320c83 },
+	{ _MMIO(0x25424), 0x06820c83 },
+	{ _MMIO(0x2541c), 0x00000000 },
+	{ _MMIO(0x25428), 0x00000c03 },
+};
+
+static const struct i915_oa_reg *
+get_compute_basic_mux_config(struct drm_i915_private *dev_priv,
+			     int *len)
+{
+	*len = ARRAY_SIZE(mux_config_compute_basic);
+	return mux_config_compute_basic;
+}
+
+static const struct i915_oa_reg b_counter_config_compute_extended[] = {
+	{ _MMIO(0x2724), 0xf0800000 },
+	{ _MMIO(0x2720), 0x00000000 },
+	{ _MMIO(0x2714), 0xf0800000 },
+	{ _MMIO(0x2710), 0x00000000 },
+	{ _MMIO(0x2770), 0x0007fe2a },
+	{ _MMIO(0x2774), 0x0000ff00 },
+	{ _MMIO(0x2778), 0x0007fe6a },
+	{ _MMIO(0x277c), 0x0000ff00 },
+	{ _MMIO(0x2780), 0x0007fe92 },
+	{ _MMIO(0x2784), 0x0000ff00 },
+	{ _MMIO(0x2788), 0x0007fea2 },
+	{ _MMIO(0x278c), 0x0000ff00 },
+	{ _MMIO(0x2790), 0x0007fe32 },
+	{ _MMIO(0x2794), 0x0000ff00 },
+	{ _MMIO(0x2798), 0x0007fe9a },
+	{ _MMIO(0x279c), 0x0000ff00 },
+	{ _MMIO(0x27a0), 0x0007ff23 },
+	{ _MMIO(0x27a4), 0x0000ff00 },
+	{ _MMIO(0x27a8), 0x0007fff3 },
+	{ _MMIO(0x27ac), 0x0000fffe },
+};
+
+static const struct i915_oa_reg mux_config_compute_extended[] = {
+	{ _MMIO(0x2681c), 0x3eb00800 },
+	{ _MMIO(0x26820), 0x00900000 },
+	{ _MMIO(0x25384), 0x02aaaaaa },
+	{ _MMIO(0x25404), 0x03ffffff },
+	{ _MMIO(0x26800), 0x00142284 },
+	{ _MMIO(0x26808), 0x0e629062 },
+	{ _MMIO(0x2680c), 0x3f6f55cb },
+	{ _MMIO(0x26810), 0x00000014 },
+	{ _MMIO(0x26804), 0x00000000 },
+	{ _MMIO(0x26104), 0x02aaaaaa },
+	{ _MMIO(0x26184), 0x02aaaaaa },
+	{ _MMIO(0x25420), 0x00000000 },
+	{ _MMIO(0x25424), 0x00000000 },
+	{ _MMIO(0x2541c), 0x00000000 },
+	{ _MMIO(0x25428), 0x00000000 },
+};
+
+static const struct i915_oa_reg *
+get_compute_extended_mux_config(struct drm_i915_private *dev_priv,
+				int *len)
+{
+	*len = ARRAY_SIZE(mux_config_compute_extended);
+	return mux_config_compute_extended;
+}
+
+static const struct i915_oa_reg b_counter_config_memory_reads[] = {
+	{ _MMIO(0x2724), 0xf0800000 },
+	{ _MMIO(0x2720), 0x00000000 },
+	{ _MMIO(0x2714), 0xf0800000 },
+	{ _MMIO(0x2710), 0x00000000 },
+	{ _MMIO(0x274c), 0x76543298 },
+	{ _MMIO(0x2748), 0x98989898 },
+	{ _MMIO(0x2744), 0x000000e4 },
+	{ _MMIO(0x2740), 0x00000000 },
+	{ _MMIO(0x275c), 0x98a98a98 },
+	{ _MMIO(0x2758), 0x88888888 },
+	{ _MMIO(0x2754), 0x000c5500 },
+	{ _MMIO(0x2750), 0x00000000 },
+	{ _MMIO(0x2770), 0x0007f81a },
+	{ _MMIO(0x2774), 0x0000fc00 },
+	{ _MMIO(0x2778), 0x0007f82a },
+	{ _MMIO(0x277c), 0x0000fc00 },
+	{ _MMIO(0x2780), 0x0007f872 },
+	{ _MMIO(0x2784), 0x0000fc00 },
+	{ _MMIO(0x2788), 0x0007f8ba },
+	{ _MMIO(0x278c), 0x0000fc00 },
+	{ _MMIO(0x2790), 0x0007f87a },
+	{ _MMIO(0x2794), 0x0000fc00 },
+	{ _MMIO(0x2798), 0x0007f8ea },
+	{ _MMIO(0x279c), 0x0000fc00 },
+	{ _MMIO(0x27a0), 0x0007f8e2 },
+	{ _MMIO(0x27a4), 0x0000fc00 },
+	{ _MMIO(0x27a8), 0x0007f8f2 },
+	{ _MMIO(0x27ac), 0x0000fc00 },
+};
+
+static const struct i915_oa_reg mux_config_memory_reads[] = {
+	{ _MMIO(0x253a4), 0x34300000 },
+	{ _MMIO(0x25440), 0x2d800000 },
+	{ _MMIO(0x25444), 0x00000008 },
+	{ _MMIO(0x25128), 0x0e600000 },
+	{ _MMIO(0x25380), 0x00000450 },
+	{ _MMIO(0x25390), 0x00052c43 },
+	{ _MMIO(0x25384), 0x00000000 },
+	{ _MMIO(0x25400), 0x00006144 },
+	{ _MMIO(0x25408), 0x0a418820 },
+	{ _MMIO(0x2540c), 0x000820e6 },
+	{ _MMIO(0x25404), 0xff500000 },
+	{ _MMIO(0x25100), 0x000005d6 },
+	{ _MMIO(0x2510c), 0x0ef00000 },
+	{ _MMIO(0x25104), 0x00000000 },
+	{ _MMIO(0x25420), 0x02108421 },
+	{ _MMIO(0x25424), 0x00008421 },
+	{ _MMIO(0x2541c), 0x00000000 },
+	{ _MMIO(0x25428), 0x00000000 },
+};
+
+static const struct i915_oa_reg *
+get_memory_reads_mux_config(struct drm_i915_private *dev_priv,
+			    int *len)
+{
+	*len = ARRAY_SIZE(mux_config_memory_reads);
+	return mux_config_memory_reads;
+}
+
+static const struct i915_oa_reg b_counter_config_memory_writes[] = {
+	{ _MMIO(0x2724), 0xf0800000 },
+	{ _MMIO(0x2720), 0x00000000 },
+	{ _MMIO(0x2714), 0xf0800000 },
+	{ _MMIO(0x2710), 0x00000000 },
+	{ _MMIO(0x274c), 0x76543298 },
+	{ _MMIO(0x2748), 0x98989898 },
+	{ _MMIO(0x2744), 0x000000e4 },
+	{ _MMIO(0x2740), 0x00000000 },
+	{ _MMIO(0x275c), 0xbabababa },
+	{ _MMIO(0x2758), 0x88888888 },
+	{ _MMIO(0x2754), 0x000c5500 },
+	{ _MMIO(0x2750), 0x00000000 },
+	{ _MMIO(0x2770), 0x0007f81a },
+	{ _MMIO(0x2774), 0x0000fc00 },
+	{ _MMIO(0x2778), 0x0007f82a },
+	{ _MMIO(0x277c), 0x0000fc00 },
+	{ _MMIO(0x2780), 0x0007f822 },
+	{ _MMIO(0x2784), 0x0000fc00 },
+	{ _MMIO(0x2788), 0x0007f8ba },
+	{ _MMIO(0x278c), 0x0000fc00 },
+	{ _MMIO(0x2790), 0x0007f87a },
+	{ _MMIO(0x2794), 0x0000fc00 },
+	{ _MMIO(0x2798), 0x0007f8ea },
+	{ _MMIO(0x279c), 0x0000fc00 },
+	{ _MMIO(0x27a0), 0x0007f8e2 },
+	{ _MMIO(0x27a4), 0x0000fc00 },
+	{ _MMIO(0x27a8), 0x0007f8f2 },
+	{ _MMIO(0x27ac), 0x0000fc00 },
+};
+
+static const struct i915_oa_reg mux_config_memory_writes[] = {
+	{ _MMIO(0x253a4), 0x34300000 },
+	{ _MMIO(0x25440), 0x01500000 },
+	{ _MMIO(0x25444), 0x00000120 },
+	{ _MMIO(0x25128), 0x0c200000 },
+	{ _MMIO(0x25380), 0x00000450 },
+	{ _MMIO(0x25390), 0x00052c43 },
+	{ _MMIO(0x25384), 0x00000000 },
+	{ _MMIO(0x25400), 0x00007184 },
+	{ _MMIO(0x25408), 0x0a418820 },
+	{ _MMIO(0x2540c), 0x000820e6 },
+	{ _MMIO(0x25404), 0xff500000 },
+	{ _MMIO(0x25100), 0x000005d6 },
+	{ _MMIO(0x2510c), 0x1e700000 },
+	{ _MMIO(0x25104), 0x00000000 },
+	{ _MMIO(0x25420), 0x02108421 },
+	{ _MMIO(0x25424), 0x00008421 },
+	{ _MMIO(0x2541c), 0x00000000 },
+	{ _MMIO(0x25428), 0x00000000 },
+};
+
+static const struct i915_oa_reg *
+get_memory_writes_mux_config(struct drm_i915_private *dev_priv,
+			     int *len)
+{
+	*len = ARRAY_SIZE(mux_config_memory_writes);
+	return mux_config_memory_writes;
+}
+
+static const struct i915_oa_reg b_counter_config_sampler_balance[] = {
+	{ _MMIO(0x2740), 0x00000000 },
+	{ _MMIO(0x2744), 0x00800000 },
+	{ _MMIO(0x2710), 0x00000000 },
+	{ _MMIO(0x2714), 0x00800000 },
+	{ _MMIO(0x2720), 0x00000000 },
+	{ _MMIO(0x2724), 0x00800000 },
+};
+
+static const struct i915_oa_reg mux_config_sampler_balance[] = {
+	{ _MMIO(0x2eb9c), 0x01906400 },
+	{ _MMIO(0x2fb9c), 0x01906400 },
+	{ _MMIO(0x253a4), 0x00000000 },
+	{ _MMIO(0x26b9c), 0x01906400 },
+	{ _MMIO(0x27b9c), 0x01906400 },
+	{ _MMIO(0x27104), 0x00a00000 },
+	{ _MMIO(0x27184), 0x00a50000 },
+	{ _MMIO(0x2e804), 0x00500000 },
+	{ _MMIO(0x2e984), 0x00500000 },
+	{ _MMIO(0x2eb04), 0x00500000 },
+	{ _MMIO(0x2eb80), 0x00000084 },
+	{ _MMIO(0x2eb8c), 0x14200000 },
+	{ _MMIO(0x2eb84), 0x00000000 },
+	{ _MMIO(0x2f804), 0x00050000 },
+	{ _MMIO(0x2f984), 0x00050000 },
+	{ _MMIO(0x2fb04), 0x00050000 },
+	{ _MMIO(0x2fb80), 0x00000084 },
+	{ _MMIO(0x2fb8c), 0x00050800 },
+	{ _MMIO(0x2fb84), 0x00000000 },
+	{ _MMIO(0x25380), 0x00000010 },
+	{ _MMIO(0x2538c), 0x000000c0 },
+	{ _MMIO(0x25384), 0xaa550000 },
+	{ _MMIO(0x25404), 0xffffc000 },
+	{ _MMIO(0x26804), 0x50000000 },
+	{ _MMIO(0x26984), 0x50000000 },
+	{ _MMIO(0x26b04), 0x50000000 },
+	{ _MMIO(0x26b80), 0x00000084 },
+	{ _MMIO(0x26b90), 0x00050800 },
+	{ _MMIO(0x26b84), 0x00000000 },
+	{ _MMIO(0x27804), 0x05000000 },
+	{ _MMIO(0x27984), 0x05000000 },
+	{ _MMIO(0x27b04), 0x05000000 },
+	{ _MMIO(0x27b80), 0x00000084 },
+	{ _MMIO(0x27b90), 0x00000142 },
+	{ _MMIO(0x27b84), 0x00000000 },
+	{ _MMIO(0x26104), 0xa0000000 },
+	{ _MMIO(0x26184), 0xa5000000 },
+	{ _MMIO(0x25424), 0x00008620 },
+	{ _MMIO(0x2541c), 0x00000000 },
+	{ _MMIO(0x25428), 0x0004a54a },
+};
+
+static const struct i915_oa_reg *
+get_sampler_balance_mux_config(struct drm_i915_private *dev_priv,
+			       int *len)
+{
+	*len = ARRAY_SIZE(mux_config_sampler_balance);
+	return mux_config_sampler_balance;
+}
+
 int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv)
 {
 	dev_priv->perf.oa.mux_regs = NULL;
@@ -140,6 +437,106 @@ int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv)
 			ARRAY_SIZE(b_counter_config_render_basic);
 
 		return 0;
+	case METRIC_SET_ID_COMPUTE_BASIC:
+		dev_priv->perf.oa.mux_regs =
+			get_compute_basic_mux_config(dev_priv,
+						     &dev_priv->perf.oa.mux_regs_len);
+		if (!dev_priv->perf.oa.mux_regs) {
+			DRM_DEBUG_DRIVER("No suitable MUX config for \"COMPUTE_BASIC\" metric set");
+
+			/* EINVAL because *_register_sysfs already checked this
+			 * and so it wouldn't have been advertised so userspace and
+			 * so shouldn't have been requested
+			 */
+			return -EINVAL;
+		}
+
+		dev_priv->perf.oa.b_counter_regs =
+			b_counter_config_compute_basic;
+		dev_priv->perf.oa.b_counter_regs_len =
+			ARRAY_SIZE(b_counter_config_compute_basic);
+
+		return 0;
+	case METRIC_SET_ID_COMPUTE_EXTENDED:
+		dev_priv->perf.oa.mux_regs =
+			get_compute_extended_mux_config(dev_priv,
+							&dev_priv->perf.oa.mux_regs_len);
+		if (!dev_priv->perf.oa.mux_regs) {
+			DRM_DEBUG_DRIVER("No suitable MUX config for \"COMPUTE_EXTENDED\" metric set");
+
+			/* EINVAL because *_register_sysfs already checked this
+			 * and so it wouldn't have been advertised so userspace and
+			 * so shouldn't have been requested
+			 */
+			return -EINVAL;
+		}
+
+		dev_priv->perf.oa.b_counter_regs =
+			b_counter_config_compute_extended;
+		dev_priv->perf.oa.b_counter_regs_len =
+			ARRAY_SIZE(b_counter_config_compute_extended);
+
+		return 0;
+	case METRIC_SET_ID_MEMORY_READS:
+		dev_priv->perf.oa.mux_regs =
+			get_memory_reads_mux_config(dev_priv,
+						    &dev_priv->perf.oa.mux_regs_len);
+		if (!dev_priv->perf.oa.mux_regs) {
+			DRM_DEBUG_DRIVER("No suitable MUX config for \"MEMORY_READS\" metric set");
+
+			/* EINVAL because *_register_sysfs already checked this
+			 * and so it wouldn't have been advertised so userspace and
+			 * so shouldn't have been requested
+			 */
+			return -EINVAL;
+		}
+
+		dev_priv->perf.oa.b_counter_regs =
+			b_counter_config_memory_reads;
+		dev_priv->perf.oa.b_counter_regs_len =
+			ARRAY_SIZE(b_counter_config_memory_reads);
+
+		return 0;
+	case METRIC_SET_ID_MEMORY_WRITES:
+		dev_priv->perf.oa.mux_regs =
+			get_memory_writes_mux_config(dev_priv,
+						     &dev_priv->perf.oa.mux_regs_len);
+		if (!dev_priv->perf.oa.mux_regs) {
+			DRM_DEBUG_DRIVER("No suitable MUX config for \"MEMORY_WRITES\" metric set");
+
+			/* EINVAL because *_register_sysfs already checked this
+			 * and so it wouldn't have been advertised so userspace and
+			 * so shouldn't have been requested
+			 */
+			return -EINVAL;
+		}
+
+		dev_priv->perf.oa.b_counter_regs =
+			b_counter_config_memory_writes;
+		dev_priv->perf.oa.b_counter_regs_len =
+			ARRAY_SIZE(b_counter_config_memory_writes);
+
+		return 0;
+	case METRIC_SET_ID_SAMPLER_BALANCE:
+		dev_priv->perf.oa.mux_regs =
+			get_sampler_balance_mux_config(dev_priv,
+						       &dev_priv->perf.oa.mux_regs_len);
+		if (!dev_priv->perf.oa.mux_regs) {
+			DRM_DEBUG_DRIVER("No suitable MUX config for \"SAMPLER_BALANCE\" metric set");
+
+			/* EINVAL because *_register_sysfs already checked this
+			 * and so it wouldn't have been advertised so userspace and
+			 * so shouldn't have been requested
+			 */
+			return -EINVAL;
+		}
+
+		dev_priv->perf.oa.b_counter_regs =
+			b_counter_config_sampler_balance;
+		dev_priv->perf.oa.b_counter_regs_len =
+			ARRAY_SIZE(b_counter_config_sampler_balance);
+
+		return 0;
 	default:
 		return -ENODEV;
 	}
@@ -167,6 +564,116 @@ static struct attribute_group group_render_basic = {
 	.attrs =  attrs_render_basic,
 };
 
+static ssize_t
+show_compute_basic_id(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", METRIC_SET_ID_COMPUTE_BASIC);
+}
+
+static struct device_attribute dev_attr_compute_basic_id = {
+	.attr = { .name = "id", .mode = 0444 },
+	.show = show_compute_basic_id,
+	.store = NULL,
+};
+
+static struct attribute *attrs_compute_basic[] = {
+	&dev_attr_compute_basic_id.attr,
+	NULL,
+};
+
+static struct attribute_group group_compute_basic = {
+	.name = "39ad14bc-2380-45c4-91eb-fbcb3aa7ae7b",
+	.attrs =  attrs_compute_basic,
+};
+
+static ssize_t
+show_compute_extended_id(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", METRIC_SET_ID_COMPUTE_EXTENDED);
+}
+
+static struct device_attribute dev_attr_compute_extended_id = {
+	.attr = { .name = "id", .mode = 0444 },
+	.show = show_compute_extended_id,
+	.store = NULL,
+};
+
+static struct attribute *attrs_compute_extended[] = {
+	&dev_attr_compute_extended_id.attr,
+	NULL,
+};
+
+static struct attribute_group group_compute_extended = {
+	.name = "3865be28-6982-49fe-9494-e4d1b4795413",
+	.attrs =  attrs_compute_extended,
+};
+
+static ssize_t
+show_memory_reads_id(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", METRIC_SET_ID_MEMORY_READS);
+}
+
+static struct device_attribute dev_attr_memory_reads_id = {
+	.attr = { .name = "id", .mode = 0444 },
+	.show = show_memory_reads_id,
+	.store = NULL,
+};
+
+static struct attribute *attrs_memory_reads[] = {
+	&dev_attr_memory_reads_id.attr,
+	NULL,
+};
+
+static struct attribute_group group_memory_reads = {
+	.name = "bb5ed49b-2497-4095-94f6-26ba294db88a",
+	.attrs =  attrs_memory_reads,
+};
+
+static ssize_t
+show_memory_writes_id(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", METRIC_SET_ID_MEMORY_WRITES);
+}
+
+static struct device_attribute dev_attr_memory_writes_id = {
+	.attr = { .name = "id", .mode = 0444 },
+	.show = show_memory_writes_id,
+	.store = NULL,
+};
+
+static struct attribute *attrs_memory_writes[] = {
+	&dev_attr_memory_writes_id.attr,
+	NULL,
+};
+
+static struct attribute_group group_memory_writes = {
+	.name = "3358d639-9b5f-45ab-976d-9b08cbfc6240",
+	.attrs =  attrs_memory_writes,
+};
+
+static ssize_t
+show_sampler_balance_id(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", METRIC_SET_ID_SAMPLER_BALANCE);
+}
+
+static struct device_attribute dev_attr_sampler_balance_id = {
+	.attr = { .name = "id", .mode = 0444 },
+	.show = show_sampler_balance_id,
+	.store = NULL,
+};
+
+static struct attribute *attrs_sampler_balance[] = {
+	&dev_attr_sampler_balance_id.attr,
+	NULL,
+};
+
+static struct attribute_group group_sampler_balance = {
+	.name = "bc274488-b4b6-40c7-90da-b77d7ad16189",
+	.attrs =  attrs_sampler_balance,
+};
+
 int
 i915_perf_register_sysfs_hsw(struct drm_i915_private *dev_priv)
 {
@@ -178,9 +685,49 @@ i915_perf_register_sysfs_hsw(struct drm_i915_private *dev_priv)
 		if (ret)
 			goto error_render_basic;
 	}
+	if (get_compute_basic_mux_config(dev_priv, &mux_len)) {
+		ret = sysfs_create_group(dev_priv->perf.metrics_kobj, &group_compute_basic);
+		if (ret)
+			goto error_compute_basic;
+	}
+	if (get_compute_extended_mux_config(dev_priv, &mux_len)) {
+		ret = sysfs_create_group(dev_priv->perf.metrics_kobj, &group_compute_extended);
+		if (ret)
+			goto error_compute_extended;
+	}
+	if (get_memory_reads_mux_config(dev_priv, &mux_len)) {
+		ret = sysfs_create_group(dev_priv->perf.metrics_kobj, &group_memory_reads);
+		if (ret)
+			goto error_memory_reads;
+	}
+	if (get_memory_writes_mux_config(dev_priv, &mux_len)) {
+		ret = sysfs_create_group(dev_priv->perf.metrics_kobj, &group_memory_writes);
+		if (ret)
+			goto error_memory_writes;
+	}
+	if (get_sampler_balance_mux_config(dev_priv, &mux_len)) {
+		ret = sysfs_create_group(dev_priv->perf.metrics_kobj, &group_sampler_balance);
+		if (ret)
+			goto error_sampler_balance;
+	}
 
 	return 0;
 
+error_sampler_balance:
+	if (get_sampler_balance_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_memory_writes);
+error_memory_writes:
+	if (get_sampler_balance_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_memory_reads);
+error_memory_reads:
+	if (get_sampler_balance_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_compute_extended);
+error_compute_extended:
+	if (get_sampler_balance_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_compute_basic);
+error_compute_basic:
+	if (get_sampler_balance_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_render_basic);
 error_render_basic:
 	return ret;
 }
@@ -192,4 +739,14 @@ i915_perf_unregister_sysfs_hsw(struct drm_i915_private *dev_priv)
 
 	if (get_render_basic_mux_config(dev_priv, &mux_len))
 		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_render_basic);
+	if (get_compute_basic_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_compute_basic);
+	if (get_compute_extended_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_compute_extended);
+	if (get_memory_reads_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_memory_reads);
+	if (get_memory_writes_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_memory_writes);
+	if (get_sampler_balance_mux_config(dev_priv, &mux_len))
+		sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_sampler_balance);
 }
-- 
2.10.1

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[PATCH v8 12/12] drm/i915: Add a kerneldoc summary for i915_perf.c

[Robert Bragg]

In particular this tries to capture for posterity some of the early
challenges we had with using the core perf infrastructure in case we
ever want to revisit adapting perf for device metrics.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_perf.c | 163 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 163 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index e3c6f51..621b3aa 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -24,6 +24,169 @@
  *   Robert Bragg <robert@sixbynine.org>
  */
 
+
+/**
+ * DOC: i915 Perf, streaming API for GPU metrics
+ *
+ * Gen graphics supports a large number of performance counters that can help
+ * driver and application developers understand and optimize their use of the
+ * GPU.
+ *
+ * This i915 perf interface enables userspace to configure and open a file
+ * descriptor representing a stream of GPU metrics which can then be read() as
+ * a stream of sample records.
+ *
+ * The interface is particularly suited to exposing buffered metrics that are
+ * captured by DMA from the GPU, unsynchronized with and unrelated to the CPU.
+ *
+ * Streams representing a single context are accessible to applications with a
+ * corresponding drm file descriptor, such that OpenGL can use the interface
+ * without special privileges. Access to system-wide metrics requires root
+ * privileges by default, unless changed via the dev.i915.perf_event_paranoid
+ * sysctl option.
+ *
+ *
+ * The interface was initially inspired by the core Perf infrastructure but
+ * some notable differences are:
+ *
+ * i915 perf file descriptors represent a "stream" instead of an "event"; where
+ * a perf event primarily corresponds to a single 64bit value, while a stream
+ * might sample sets of tightly-coupled counters, depending on the
+ * configuration.  For example the Gen OA unit isn't designed to support
+ * orthogonal configurations of individual counters; it's configured for a set
+ * of related counters. Samples for an i915 perf stream capturing OA metrics
+ * will include a set of counter values packed in a compact HW specific format.
+ * The OA unit supports a number of different packing formats which can be
+ * selected by the user opening the stream. Perf has support for grouping
+ * events, but each event in the group is configured, validated and
+ * authenticated individually with separate system calls.
+ *
+ * i915 perf stream configurations are provided as an array of u64 (key,value)
+ * pairs, instead of a fixed struct with multiple miscellaneous config members,
+ * interleaved with event-type specific members.
+ *
+ * i915 perf doesn't support exposing metrics via an mmap'd circular buffer.
+ * The supported metrics are being written to memory by the GPU unsynchronized
+ * with the CPU, using HW specific packing formats for counter sets. Sometimes
+ * the constraints on HW configuration require reports to be filtered before it
+ * would be acceptable to expose them to unprivileged applications - to hide
+ * the metrics of other processes/contexts. For these use cases a read() based
+ * interface is a good fit, and provides an opportunity to filter data as it
+ * gets copied from the GPU mapped buffers to userspace buffers.
+ *
+ *
+ * Some notes regarding Linux Perf:
+ * --------------------------------
+ *
+ * The first prototype of this driver was based on the core perf
+ * infrastructure, and while we did make that mostly work, with some changes to
+ * perf, we found we were breaking or working around too many assumptions baked
+ * into perf's currently cpu centric design.
+ *
+ * In the end we didn't see a clear benefit to making perf's implementation and
+ * interface more complex by changing design assumptions while we knew we still
+ * wouldn't be able to use any existing perf based userspace tools.
+ *
+ * Also considering the Gen specific nature of the Observability hardware and
+ * how userspace will sometimes need to combine i915 perf OA metrics with
+ * side-band OA data captured via MI_REPORT_PERF_COUNT commands; we're
+ * expecting the interface to be used by a platform specific userspace such as
+ * OpenGL or tools. This is to say; we aren't inherently missing out on having
+ * a standard vendor/architecture agnostic interface by not using perf.
+ *
+ *
+ * For posterity, in case we might re-visit trying to adapt core perf to be
+ * better suited to exposing i915 metrics these were the main pain points we
+ * hit:
+ *
+ * - The perf based OA PMU driver broke some significant design assumptions:
+ *
+ *   Existing perf pmus are used for profiling work on a cpu and we were
+ *   introducing the idea of _IS_DEVICE pmus with different security
+ *   implications, the need to fake cpu-related data (such as user/kernel
+ *   registers) to fit with perf's current design, and adding _DEVICE records
+ *   as a way to forward device-specific status records.
+ *
+ *   The OA unit writes reports of counters into a circular buffer, without
+ *   involvement from the CPU, making our PMU driver the first of a kind.
+ *
+ *   Given the way we were periodically forward data from the GPU-mapped, OA
+ *   buffer to perf's buffer, those bursts of sample writes looked to perf like
+ *   we were sampling too fast and so we had to subvert its throttling checks.
+ *
+ *   Perf supports groups of counters and allows those to be read via
+ *   transactions internally but transactions currently seem designed to be
+ *   explicitly initiated from the cpu (say in response to a userspace read())
+ *   and while we could pull a report out of the OA buffer we can't
+ *   trigger a report from the cpu on demand.
+ *
+ *   Related to being report based; the OA counters are configured in HW as a
+ *   set while perf generally expects counter configurations to be orthogonal.
+ *   Although counters can be associated with a group leader as they are
+ *   opened, there's no clear precedent for being able to provide group-wide
+ *   configuration attributes (for example we want to let userspace choose the
+ *   OA unit report format used to capture all counters in a set, or specify a
+ *   GPU context to filter metrics on). We avoided using perf's grouping
+ *   feature and forwarded OA reports to userspace via perf's 'raw' sample
+ *   field. This suited our userspace well considering how coupled the counters
+ *   are when dealing with normalizing. It would be inconvenient to split
+ *   counters up into separate events, only to require userspace to recombine
+ *   them. For Mesa it's also convenient to be forwarded raw, periodic reports
+ *   for combining with the side-band raw reports it captures using
+ *   MI_REPORT_PERF_COUNT commands.
+ *
+ *   _ As a side note on perf's grouping feature; there was also some concern
+ *     that using PERF_FORMAT_GROUP as a way to pack together counter values
+ *     would quite drastically inflate our sample sizes, which would likely
+ *     lower the effective sampling resolutions we could use when the available
+ *     memory bandwidth is limited.
+ *
+ *     With the OA unit's report formats, counters are packed together as 32
+ *     or 40bit values, with the largest report size being 256 bytes.
+ *
+ *     PERF_FORMAT_GROUP values are 64bit, but there doesn't appear to be a
+ *     documented ordering to the values, implying PERF_FORMAT_ID must also be
+ *     used to add a 64bit ID before each value; giving 16 bytes per counter.
+ *
+ *   Related to counter orthogonality; we can't time share the OA unit, while
+ *   event scheduling is a central design idea within perf for allowing
+ *   userspace to open + enable more events than can be configured in HW at any
+ *   one time.  The OA unit is not designed to allow re-configuration while in
+ *   use. We can't reconfigure the OA unit without losing internal OA unit
+ *   state which we can't access explicitly to save and restore. Reconfiguring
+ *   the OA unit is also relatively slow, involving ~100 register writes. From
+ *   userspace Mesa also depends on a stable OA configuration when emitting
+ *   MI_REPORT_PERF_COUNT commands and importantly the OA unit can't be
+ *   disabled while there are outstanding MI_RPC commands lest we hang the
+ *   command streamer.
+ *
+ *   The contents of sample records aren't extensible by device drivers (i.e.
+ *   the sample_type bits). As an example; Sourab Gupta had been looking to
+ *   attach GPU timestamps to our OA samples. We were shoehorning OA reports
+ *   into sample records by using the 'raw' field, but it's tricky to pack more
+ *   than one thing into this field because events/core.c currently only lets a
+ *   pmu give a single raw data pointer plus len which will be copied into the
+ *   ring buffer. To include more than the OA report we'd have to copy the
+ *   report into an intermediate larger buffer. I'd been considering allowing a
+ *   vector of data+len values to be specified for copying the raw data, but
+ *   it felt like a kludge to being using the raw field for this purpose.
+ *
+ * - It felt like our perf based PMU was making some technical compromises
+ *   just for the sake of using perf:
+ *
+ *   perf_event_open() requires events to either relate to a pid or a specific
+ *   cpu core, while our device pmu related to neither.  Events opened with a
+ *   pid will be automatically enabled/disabled according to the scheduling of
+ *   that process - so not appropriate for us. When an event is related to a
+ *   cpu id, perf ensures pmu methods will be invoked via an inter process
+ *   interrupt on that core. To avoid invasive changes our userspace opened OA
+ *   perf events for a specific cpu. This was workable but it meant the
+ *   majority of the OA driver ran in atomic context, including all OA report
+ *   forwarding, which wasn't really necessary in our case and seems to make
+ *   our locking requirements somewhat complex as we handled the interaction
+ *   with the rest of the i915 driver.
+ */
+
 #include <linux/anon_inodes.h>
 #include <linux/sizes.h>
 
-- 
2.10.1

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✗ Fi.CI.BAT: failure for Enable i915 perf stream for Haswell OA unit

[Patchwork]

== Series Details ==

Series: Enable i915 perf stream for Haswell OA unit
URL   : https://patchwork.freedesktop.org/series/14505/
State : failure

== Summary ==

Series 14505v1 Enable i915 perf stream for Haswell OA unit
https://patchwork.freedesktop.org/api/1.0/series/14505/revisions/1/mbox/

Test gem_exec_parse:
        Subgroup basic-rejected:
                pass       -> FAIL       (fi-hsw-4770)
                pass       -> FAIL       (fi-ivb-3770)
                pass       -> FAIL       (fi-hsw-4770r)
                pass       -> FAIL       (fi-byt-j1900)
                pass       -> FAIL       (fi-byt-n2820)
                pass       -> FAIL       (fi-ivb-3520m)

fi-bdw-5557u     total:239  pass:224  dwarn:0   dfail:0   fail:0   skip:15 
fi-bsw-n3050     total:239  pass:199  dwarn:0   dfail:0   fail:0   skip:40 
fi-byt-j1900     total:239  pass:210  dwarn:0   dfail:0   fail:1   skip:28 
fi-byt-n2820     total:239  pass:206  dwarn:0   dfail:0   fail:1   skip:32 
fi-hsw-4770      total:239  pass:218  dwarn:0   dfail:0   fail:1   skip:20 
fi-hsw-4770r     total:239  pass:217  dwarn:0   dfail:0   fail:1   skip:21 
fi-ilk-650       total:239  pass:185  dwarn:0   dfail:0   fail:0   skip:54 
fi-ivb-3520m     total:239  pass:215  dwarn:0   dfail:0   fail:1   skip:23 
fi-ivb-3770      total:239  pass:215  dwarn:0   dfail:0   fail:1   skip:23 
fi-kbl-7200u     total:239  pass:217  dwarn:0   dfail:0   fail:0   skip:22 
fi-skl-6260u     total:239  pass:225  dwarn:0   dfail:0   fail:0   skip:14 
fi-skl-6700hq    total:239  pass:218  dwarn:0   dfail:0   fail:0   skip:21 
fi-skl-6700k     total:239  pass:217  dwarn:1   dfail:0   fail:0   skip:21 
fi-skl-6770hq    total:239  pass:225  dwarn:0   dfail:0   fail:0   skip:14 
fi-snb-2520m     total:239  pass:206  dwarn:0   dfail:0   fail:0   skip:33 
fi-snb-2600      total:239  pass:205  dwarn:0   dfail:0   fail:0   skip:34 

0fb1abf5eac2230894a7352e36022066f88a9b19 drm-intel-nightly: 2016y-10m-27d-14h-09m-00s UTC integration manifest
f03e9f6 drm/i915: Add a kerneldoc summary for i915_perf.c
a56d6aa drm/i915: Add more Haswell OA metric sets
8854d93 drm/i915: add oa_event_min_timer_exponent sysctl
19ef73d drm/i915: Add dev.i915.perf_stream_paranoid sysctl option
a76791c drm/i915: advertise available metrics via sysfs
3b6535e drm/i915: Enable i915 perf stream for Haswell OA unit
d56af59 drm/i915: Add 'render basic' Haswell OA unit config
3ff8cbc drm/i915: don't whitelist oacontrol in cmd parser
7f6bdfe drm/i915: return EACCES for check_cmd() failures
cc335c8 drm/i915: rename OACONTROL GEN7_OACONTROL
270b8e8 drm/i915: Add i915 perf infrastructure
ddb0d86 ctx-pin placeholder from chris

== Logs ==

For more details see: https://intel-gfx-ci.01.org/CI/Patchwork_2843/
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Re: [PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[Matthew Auld]

> +/* 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;
> +       }
> +
> +       if (n_props > DRM_I915_PERF_PROP_MAX) {
Ah but DRM_I915_PERF_PROP_MAX is not a property itself.
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Re: [PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[Robert Bragg]

[-- Attachment #1.1: Type: text/plain, Size: 1373 bytes --]

On Fri, Oct 28, 2016 at 3:27 PM, Matthew Auld <
matthew.william.auld@gmail.com> wrote:

> > +/* 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;
> > +       }
> > +
> > +       if (n_props > DRM_I915_PERF_PROP_MAX) {
> Ah but DRM_I915_PERF_PROP_MAX is not a property itself.
>

I'm not sure I follow what your implied concern is?

This is just a sanity check for the number properties given by userspace,
based on the assumption that there's currently no reason for multiple
values with a particular property id.

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Re: [PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[Matthew Auld]

On 31 October 2016 at 16:27, Robert Bragg <robert@sixbynine.org> wrote:
>
>
> On Fri, Oct 28, 2016 at 3:27 PM, Matthew Auld
> <matthew.william.auld@gmail.com> wrote:
>>
>> > +/* 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;
>> > +       }
>> > +
>> > +       if (n_props > DRM_I915_PERF_PROP_MAX) {
>> Ah but DRM_I915_PERF_PROP_MAX is not a property itself.
>
>
> I'm not sure I follow what your implied concern is?
>
> This is just a sanity check for the number properties given by userspace,
> based on the assumption that there's currently no reason for multiple values
> with a particular property id.
>
All I meant was should it not be n_props >= DRM_I915_PERF_PROP_MAX ?

So with that fixed, or if I'm completely mad:
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
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Re: [PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[Robert Bragg]

[-- Attachment #1.1: Type: text/plain, Size: 3221 bytes --]

On Mon, Oct 31, 2016 at 5:13 PM, Matthew Auld <
matthew.william.auld@gmail.com> wrote:

> On 31 October 2016 at 16:27, Robert Bragg <robert@sixbynine.org> wrote:
> >
> >
> > On Fri, Oct 28, 2016 at 3:27 PM, Matthew Auld
> > <matthew.william.auld@gmail.com> wrote:
> >>
> >> > +/* 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;
> >> > +       }
> >> > +
> >> > +       if (n_props > DRM_I915_PERF_PROP_MAX) {
> >> Ah but DRM_I915_PERF_PROP_MAX is not a property itself.
> >
> >
> > I'm not sure I follow what your implied concern is?
> >
> > This is just a sanity check for the number properties given by userspace,
> > based on the assumption that there's currently no reason for multiple
> values
> > with a particular property id.
> >
> All I meant was should it not be n_props >= DRM_I915_PERF_PROP_MAX ?


> So with that fixed, or if I'm completely mad:
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
>

Ah, I see. Actually tbh I think either is reasonable...

The check is mainly about ruling out the silly large values that could be
given, imposing a upper-bound to the number of properties expected from
userspace. It might help catch userspace giving garbage/undefined data, or
block attempts to get the kernel parsing huge amounts of property data
which should never be necessary for configuring a stream. It doesn't e.g.
stop userspace specifying duplicate property IDs even if they supply less
than the maximum allowed. So even if it allowed say 2x the number of
properties I think it would still pretty much do its job.

I could imagine in the future the same check might become much more fuzzy
if we have a case where userspace might need to legitimately specify the
same property ID multiple times (where the sequential order is relevant).

_PERF_PROP_MAX is the last in the enum whereby we can interpret it as an
upper bound on the number of properties while we don't currently expect to
see property IDs duplicated.

The detail here though is that ID 0 is reserved so _PERF_PROP_MAX is more
like ('the maximum number of properties' + 1) - and so this is what you're
essentially highlighting.

I can change this - maybe with a comment about ID 0 being reserved and
explaining the assumption that property ID duplicates aren't currently
expected

Thanks for the review!

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Re: [PATCH v8 07/12] drm/i915: Enable i915 perf stream for Haswell OA unit

[Matthew Auld]

On 28 October 2016 at 03:14, Robert Bragg <robert@sixbynine.org> wrote:
> Gen graphics hardware can be set up to periodically write snapshots of
> performance counters into a circular buffer via its Observation
> Architecture and this patch exposes that capability to userspace via the
> i915 perf interface.
>
> v2:
>    Make sure to initialize ->specific_ctx_id when opening, without
>    relying on _pin_notify hook, in case ctx already pinned.
> v3:
>    Revert back to pinning ctx upfront when opening stream, removing
>    need to hook in to pinning and to update OACONTROL on the fly.
>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  |   66 ++-
>  drivers/gpu/drm/i915/i915_perf.c | 1036 +++++++++++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/i915_reg.h  |  338 +++++++++++++
>  include/uapi/drm/i915_drm.h      |   71 ++-
>  4 files changed, 1482 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index f22adc4..dd2b4d3 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1767,6 +1767,11 @@ struct intel_wm_config {
>         bool sprites_scaled;
>  };
>
> +struct i915_oa_format {
> +       u32 format;
> +       int size;
> +};
> +
>  struct i915_oa_reg {
>         i915_reg_t addr;
>         u32 value;
> @@ -1787,11 +1792,6 @@ struct i915_perf_stream_ops {
>          */
>         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
>          */
> @@ -1801,9 +1801,7 @@ struct i915_perf_stream_ops {
>
>         /* 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).
> +        * wait queue that would be passed to poll_wait().
>          */
>         int (*wait_unlocked)(struct i915_perf_stream *stream);
>
> @@ -1843,11 +1841,28 @@ struct i915_perf_stream {
>         struct list_head link;
>
>         u32 sample_flags;
> +       int sample_size;
>
>         struct i915_gem_context *ctx;
>         bool enabled;
>
> -       struct i915_perf_stream_ops *ops;
> +       const struct i915_perf_stream_ops *ops;
> +};
> +
> +struct i915_oa_ops {
> +       void (*init_oa_buffer)(struct drm_i915_private *dev_priv);
> +       int (*enable_metric_set)(struct drm_i915_private *dev_priv);
> +       void (*disable_metric_set)(struct drm_i915_private *dev_priv);
> +       void (*oa_enable)(struct drm_i915_private *dev_priv);
> +       void (*oa_disable)(struct drm_i915_private *dev_priv);
> +       void (*update_oacontrol)(struct drm_i915_private *dev_priv);
> +       void (*update_hw_ctx_id_locked)(struct drm_i915_private *dev_priv,
> +                                       u32 ctx_id);
> +       int (*read)(struct i915_perf_stream *stream,
> +                   char __user *buf,
> +                   size_t count,
> +                   size_t *offset);
> +       bool (*oa_buffer_is_empty)(struct drm_i915_private *dev_priv);
>  };
>
>  struct drm_i915_private {
> @@ -2154,16 +2169,47 @@ struct drm_i915_private {
>
>         struct {
>                 bool initialized;
> +
>                 struct mutex lock;
>                 struct list_head streams;
>
> +               spinlock_t hook_lock;
We can get rid of this now, or at least rename it ?

> +
>                 struct {
> -                       u32 metrics_set;
> +                       struct i915_perf_stream *exclusive_stream;
> +
> +                       u32 specific_ctx_id;
> +                       struct i915_vma *pinned_rcs_vma;
> +
> +                       struct hrtimer poll_check_timer;
> +                       wait_queue_head_t poll_wq;
> +                       bool pollin;
> +
> +                       bool periodic;
> +                       int period_exponent;
> +                       int timestamp_frequency;
> +
> +                       int tail_margin;
> +
> +                       int metrics_set;
>
>                         const struct i915_oa_reg *mux_regs;
>                         int mux_regs_len;
>                         const struct i915_oa_reg *b_counter_regs;
>                         int b_counter_regs_len;
> +
> +                       struct {
> +                               struct i915_vma *vma;
> +                               u8 *vaddr;
> +                               int format;
> +                               int format_size;
> +                       } oa_buffer;
> +
> +                       u32 gen7_latched_oastatus1;
> +
> +                       struct i915_oa_ops ops;
> +                       const struct i915_oa_format *oa_formats;
> +                       int n_builtin_sets;
>                 } oa;
>         } perf;
>
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index c45cf92..8b9cf0d 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -25,16 +25,899 @@
>   */
>
>  #include <linux/anon_inodes.h>
> +#include <linux/sizes.h>
>
>  #include "i915_drv.h"
> +#include "i915_oa_hsw.h"
> +
> +/* HW requires this to be a power of two, between 128k and 16M, though driver
> + * is currently generally designed assuming the largest 16M size is used such
> + * that the overflow cases are unlikely in normal operation.
> + */
> +#define OA_BUFFER_SIZE         SZ_16M
> +
> +#define OA_TAKEN(tail, head)   ((tail - head) & (OA_BUFFER_SIZE - 1))
> +
> +/* There's a HW race condition between OA unit tail pointer register updates and
> + * writes to memory whereby the tail pointer can sometimes get ahead of what's
> + * been written out to the OA buffer so far.
> + *
> + * Although this can be observed explicitly by checking for a zeroed report-id
> + * field in tail reports, it seems preferable to account for this earlier e.g.
> + * as part of the _oa_buffer_is_empty checks to minimize -EAGAIN polling cycles
> + * in this situation.
> + *
> + * To give time for the most recent reports to land before they may be copied to
> + * userspace, the driver operates as if the tail pointer effectively lags behind
> + * the HW tail pointer by 'tail_margin' bytes. The margin in bytes is calculated
> + * based on this constant in nanoseconds, the current OA sampling exponent
> + * and current report size.
> + *
> + * There is also a fallback check while reading to simply skip over reports with
> + * a zeroed report-id.
> + */
> +#define OA_TAIL_MARGIN_NSEC    100000ULL
> +
> +/* frequency for checking whether the OA unit has written new reports to the
> + * circular OA buffer...
> + */
> +#define POLL_FREQUENCY 200
> +#define POLL_PERIOD (NSEC_PER_SEC / POLL_FREQUENCY)
> +
> +/* The maximum exponent the hardware accepts is 63 (essentially it selects one
> + * of the 64bit timestamp bits to trigger reports from) but there's currently
> + * no known use case for sampling as infrequently as once per 47 thousand years.
> + *
> + * Since the timestamps included in OA reports are only 32bits it seems
> + * reasonable to limit the OA exponent where it's still possible to account for
> + * overflow in OA report timestamps.
> + */
> +#define OA_EXPONENT_MAX 31
> +
> +#define INVALID_CTX_ID 0xffffffff
> +
> +
> +/* XXX: beware if future OA HW adds new report formats that the current
> + * code assumes all reports have a power-of-two size and ~(size - 1) can
> + * be used as a mask to align the OA tail pointer.
> + */
> +static struct i915_oa_format hsw_oa_formats[I915_OA_FORMAT_MAX] = {
> +       [I915_OA_FORMAT_A13]        = { 0, 64 },
> +       [I915_OA_FORMAT_A29]        = { 1, 128 },
> +       [I915_OA_FORMAT_A13_B8_C8]  = { 2, 128 },
> +       /* A29_B8_C8 Disallowed as 192 bytes doesn't factor into buffer size */
> +       [I915_OA_FORMAT_B4_C8]      = { 4, 64 },
> +       [I915_OA_FORMAT_A45_B8_C8]  = { 5, 256 },
> +       [I915_OA_FORMAT_B4_C8_A16]  = { 6, 128 },
> +       [I915_OA_FORMAT_C4_B8]      = { 7, 64 },
> +};
> +
> +#define SAMPLE_OA_REPORT      (1<<0)
>
>  struct perf_open_properties {
>         u32 sample_flags;
>
>         u64 single_context:1;
>         u64 ctx_handle;
> +
> +       /* OA sampling state */
> +       int metrics_set;
> +       int oa_format;
> +       bool oa_periodic;
> +       int oa_period_exponent;
> +};
> +
> +/* NB: This is either called via fops or the poll check hrtimer (atomic ctx)
> + *
> + * It's safe to read OA config state here unlocked, assuming that this is only
> + * called while the stream is enabled, while the global OA configuration can't
> + * be modified.
> + *
> + * Note: we don't lock around the head/tail reads even though there's the slim
> + * possibility of read() fop errors forcing a re-init of the OA buffer
> + * pointers.  A race here could result in a false positive !empty status which
> + * is acceptable.
> + */
> +static bool gen7_oa_buffer_is_empty_fop_unlocked(struct drm_i915_private *dev_priv)
> +{
> +       int report_size = dev_priv->perf.oa.oa_buffer.format_size;
> +       u32 oastatus2 = I915_READ(GEN7_OASTATUS2);
> +       u32 oastatus1 = I915_READ(GEN7_OASTATUS1);
> +       u32 head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
> +       u32 tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
> +
> +       return OA_TAKEN(tail, head) <
> +               dev_priv->perf.oa.tail_margin + report_size;
> +}
> +
> +/**
> + * Appends a status record to a userspace read() buffer.
> + */
> +static int append_oa_status(struct i915_perf_stream *stream,
> +                           char __user *buf,
> +                           size_t count,
> +                           size_t *offset,
> +                           enum drm_i915_perf_record_type type)
> +{
> +       struct drm_i915_perf_record_header header = { type, 0, sizeof(header) };
> +
> +       if ((count - *offset) < header.size)
> +               return -ENOSPC;
> +
> +       if (copy_to_user(buf + *offset, &header, sizeof(header)))
> +               return -EFAULT;
> +
> +       (*offset) += header.size;
> +
> +       return 0;
> +}
> +
> +/**
> + * Copies single OA report into userspace read() buffer.
> + */
> +static int append_oa_sample(struct i915_perf_stream *stream,
> +                           char __user *buf,
> +                           size_t count,
> +                           size_t *offset,
> +                           const u8 *report)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +       int report_size = dev_priv->perf.oa.oa_buffer.format_size;
> +       struct drm_i915_perf_record_header header;
> +       u32 sample_flags = stream->sample_flags;
> +
> +       header.type = DRM_I915_PERF_RECORD_SAMPLE;
> +       header.pad = 0;
> +       header.size = stream->sample_size;
> +
> +       if ((count - *offset) < header.size)
> +               return -ENOSPC;
> +
> +       buf += *offset;
> +       if (copy_to_user(buf, &header, sizeof(header)))
> +               return -EFAULT;
> +       buf += sizeof(header);
> +
> +       if (sample_flags & SAMPLE_OA_REPORT) {
> +               if (copy_to_user(buf, report, report_size))
> +                       return -EFAULT;
> +       }
> +
> +       (*offset) += header.size;
> +
> +       return 0;
> +}
> +
> +/**
> + * Copies all buffered OA reports into userspace read() buffer.
@stream: something, something...

> + * @buf: destination buffer given by userspace
> + * @count: the number of bytes userspace wants to read
> + * @offset: (inout): the current position for writing into @buf
> + * @head_ptr: (inout): the current oa buffer cpu read position
> + * @tail_ptr: the current oa buffer gpu write position
@tail, or probably change the param to tail_ptr ?

> + *
> + * Returns 0 on success, negative error code on failure.
> + *
> + * Notably any error condition resulting in a short read (-ENOSPC or
> + * -EFAULT) will be returned even though one or more records may
> + * have been successfully copied. In this case it's up to the caller
> + * to decide if the error should be squashed before returning to
> + * userspace.
> + *
> + * Note: reports are consumed from the head, and appended to the
> + * tail, so the head chases the tail?... If you think that's mad
> + * and back-to-front you're not alone, but this follows the
> + * Gen PRM naming convention.
> + */
> +static int gen7_append_oa_reports(struct i915_perf_stream *stream,
> +                                 char __user *buf,
> +                                 size_t count,
> +                                 size_t *offset,
> +                                 u32 *head_ptr,
> +                                 u32 tail)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +       int report_size = dev_priv->perf.oa.oa_buffer.format_size;
> +       u8 *oa_buf_base = dev_priv->perf.oa.oa_buffer.vaddr;
> +       int tail_margin = dev_priv->perf.oa.tail_margin;
> +       u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
> +       u32 mask = (OA_BUFFER_SIZE - 1);
> +       u32 head;
> +       u32 taken;
> +       int ret = 0;
> +
> +
Extra newline.

> +       if (WARN_ON(!stream->enabled))
> +               return -EIO;
> +
> +       head = *head_ptr - gtt_offset;
> +       tail -= gtt_offset;
> +
> +       /* The OA unit is expected to wrap the tail pointer according to the OA
> +        * buffer size and since we should never write a misaligned head
> +        * pointer we don't expect to read one back either...
> +        */
> +       if (tail > OA_BUFFER_SIZE || head > OA_BUFFER_SIZE ||
> +           head % report_size) {
> +               DRM_ERROR("Inconsistent OA buffer pointer (head = %u, tail = %u): force restart",
> +                         head, tail);
Missing a '\n' here for the message.

> +               dev_priv->perf.oa.ops.oa_disable(dev_priv);
> +               dev_priv->perf.oa.ops.oa_enable(dev_priv);
> +               *head_ptr = I915_READ(GEN7_OASTATUS2) &
> +                       GEN7_OASTATUS2_HEAD_MASK;
> +               return -EIO;
> +       }
> +
> +
> +       /* The tail pointer increases in 64 byte increments, not in report_size
> +        * steps...
> +        */
> +       tail &= ~(report_size - 1);
> +
> +       /* Move the tail pointer back by the current tail_margin to account for
> +        * the possibility that the latest reports may not have really landed
> +        * in memory yet...
> +        */
> +
> +       if (OA_TAKEN(tail, head) < report_size + tail_margin)
> +               return -EAGAIN;
> +
> +       tail -= tail_margin;
> +       tail &= mask;
> +
> +       for (/* none */;
> +            (taken = OA_TAKEN(tail, head));
> +            head = (head + report_size) & mask) {
> +               u8 *report = oa_buf_base + head;
> +               u32 *report32 = (void *)report;
> +
> +               /* All the report sizes factor neatly into the buffer
> +                * size so we never expect to see a report split
> +                * between the beginning and end of the buffer.
> +                *
> +                * Given the initial alignment check a misalignment
> +                * here would imply a driver bug that would result
> +                * in an overrun.
> +                */
> +               if (WARN_ON((OA_BUFFER_SIZE - head) < report_size)) {
> +                       DRM_ERROR("Spurious OA head ptr: non-integral report offset\n");
> +                       break;
> +               }
> +
> +               /* The report-ID field for periodic samples includes
> +                * some undocumented flags related to what triggered
> +                * the report and is never expected to be zero so we
> +                * can check that the report isn't invalid before
> +                * copying it to userspace...
> +                */
> +               if (report32[0] == 0) {
> +                       DRM_ERROR("Skipping spurious, invalid OA report\n");
> +                       continue;
> +               }
> +
> +               ret = append_oa_sample(stream, buf, count, offset, report);
> +               if (ret)
> +                       break;
> +
> +               /* The above report-id field sanity check is based on
> +                * the assumption that the OA buffer is initially
> +                * zeroed and we reset the field after copying so the
> +                * check is still meaningful once old reports start
> +                * being overwritten.
> +                */
> +               report32[0] = 0;
> +       }
> +
> +       *head_ptr = gtt_offset + head;
> +
> +       return ret;
> +}
> +
> +static int gen7_oa_read(struct i915_perf_stream *stream,
> +                       char __user *buf,
> +                       size_t count,
> +                       size_t *offset)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +       int report_size = dev_priv->perf.oa.oa_buffer.format_size;
> +       u32 oastatus2;
> +       u32 oastatus1;
> +       u32 head;
> +       u32 tail;
> +       int ret;
> +
> +       if (WARN_ON(!dev_priv->perf.oa.oa_buffer.vaddr))
> +               return -EIO;
> +
> +       oastatus2 = I915_READ(GEN7_OASTATUS2);
> +       oastatus1 = I915_READ(GEN7_OASTATUS1);
> +
> +       head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
> +       tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
> +
> +       /* XXX: On Haswell we don't have a safe way to clear oastatus1
> +        * bits while the OA unit is enabled (while the tail pointer
> +        * may be updated asynchronously) so we ignore status bits
> +        * that have already been reported to userspace.
> +        */
> +       oastatus1 &= ~dev_priv->perf.oa.gen7_latched_oastatus1;
> +
> +       /* We treat OABUFFER_OVERFLOW as a significant error:
> +        *
> +        * - The status can be interpreted to mean that the buffer is
> +        *   currently full (with a higher precedence than OA_TAKEN()
> +        *   which will start to report a near-empty buffer after an
> +        *   overflow) but it's awkward that we can't clear the status
> +        *   on Haswell, so without a reset we won't be able to catch
> +        *   the state again.
> +        *
> +        * - Since it also implies the HW has started overwriting old
> +        *   reports it may also affect our sanity checks for invalid
> +        *   reports when copying to userspace that assume new reports
> +        *   are being written to cleared memory.
> +        *
> +        * - In the future we may want to introduce a flight recorder
> +        *   mode where the driver will automatically maintain a safe
> +        *   guard band between head/tail, avoiding this overflow
> +        *   condition, but we avoid the added driver complexity for
> +        *   now.
> +        */
> +       if (unlikely(oastatus1 & GEN7_OASTATUS1_OABUFFER_OVERFLOW)) {
> +               ret = append_oa_status(stream, buf, count, offset,
> +                                      DRM_I915_PERF_RECORD_OA_BUFFER_LOST);
> +               if (ret)
> +                       return ret;
> +
> +               DRM_ERROR("OA buffer overflow: force restart");
Missing '\n'.

> +
> +               dev_priv->perf.oa.ops.oa_disable(dev_priv);
> +               dev_priv->perf.oa.ops.oa_enable(dev_priv);
> +
> +               oastatus2 = I915_READ(GEN7_OASTATUS2);
> +               oastatus1 = I915_READ(GEN7_OASTATUS1);
> +
> +               head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
> +               tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
> +       }
> +
> +       if (unlikely(oastatus1 & GEN7_OASTATUS1_REPORT_LOST)) {
> +               ret = append_oa_status(stream, buf, count, offset,
> +                                      DRM_I915_PERF_RECORD_OA_REPORT_LOST);
> +               if (ret)
> +                       return ret;
> +               dev_priv->perf.oa.gen7_latched_oastatus1 |=
> +                       GEN7_OASTATUS1_REPORT_LOST;
> +       }
> +
> +       ret = gen7_append_oa_reports(stream, buf, count, offset,
> +                                    &head, tail);
> +
> +       /* All the report sizes are a power of two and the
> +        * head should always be incremented by some multiple
> +        * of the report size.
> +        *
> +        * A warning here, but notably if we later read back a
> +        * misaligned pointer we will treat that as a bug since
> +        * it could lead to a buffer overrun.
> +        */
> +       WARN_ONCE(head & (report_size - 1),
> +                 "i915: Writing misaligned OA head pointer");
> +
> +       /* Note: we update the head pointer here even if an error
> +        * was returned since the error may represent a short read
> +        * where some some reports were successfully copied.
> +        */
> +       I915_WRITE(GEN7_OASTATUS2,
> +                  ((head & GEN7_OASTATUS2_HEAD_MASK) |
> +                   OA_MEM_SELECT_GGTT));
> +
> +       return ret;
> +}
> +
> +static int i915_oa_wait_unlocked(struct i915_perf_stream *stream)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +
> +       /* We would wait indefinitly if periodic sampling is not enabled */
indefinitely

> +       if (!dev_priv->perf.oa.periodic)
> +               return -EIO;
> +
> +       /* Note: the oa_buffer_is_empty() condition is ok to run unlocked as it
> +        * just performs mmio reads of the OA buffer head + tail pointers and
> +        * it's assumed we're handling some operation that implies the stream
> +        * can't be destroyed until completion (such as a read()) that ensures
> +        * the device + OA buffer can't disappear
> +        */
> +       return wait_event_interruptible(dev_priv->perf.oa.poll_wq,
> +                                       !dev_priv->perf.oa.ops.oa_buffer_is_empty(dev_priv));
> +}
> +
> +static void i915_oa_poll_wait(struct i915_perf_stream *stream,
> +                             struct file *file,
> +                             poll_table *wait)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +
> +       poll_wait(file, &dev_priv->perf.oa.poll_wq, wait);
> +}
> +
> +static int i915_oa_read(struct i915_perf_stream *stream,
> +                       char __user *buf,
> +                       size_t count,
> +                       size_t *offset)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +
> +       return dev_priv->perf.oa.ops.read(stream, buf, count, offset);
> +}
> +
> +/* Determine the render context hw id, and ensure it remains fixed for the
> + * lifetime of the stream. This ensures that we don't have to worry about
> + * updating the context ID in OACONTROL on the fly.
> + */
> +static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +       struct i915_vma *vma;
> +       int ret;
> +
> +       ret = i915_mutex_lock_interruptible(&dev_priv->drm);
> +       if (ret)
> +               return ret;
> +
> +       /* As the ID is the gtt offset of the context's vma we pin
> +        * the vma to ensure the ID remains fixed.
> +        *
> +        * NB: implied RCS engine...
> +        */
> +       vma = i915_gem_context_pin_legacy(stream->ctx);
In case you missed it https://patchwork.freedesktop.org/patch/119263/

> +       if (IS_ERR(vma)) {
> +               ret = PTR_ERR(vma);
> +               goto unlock;
> +       }
> +
> +       dev_priv->perf.oa.pinned_rcs_vma = vma;
> +
> +       /* Explicitly track the ID (instead of calling i915_ggtt_offset()
> +        * on the fly) considering the difference with gen8+ and
> +        * execlists
> +        */
> +       dev_priv->perf.oa.specific_ctx_id = i915_ggtt_offset(vma);
> +
> +unlock:
> +       mutex_unlock(&dev_priv->drm.struct_mutex);
> +
> +       return ret;
> +}
> +
> +static void oa_put_render_ctx_id(struct i915_perf_stream *stream)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +
> +       mutex_lock(&dev_priv->drm.struct_mutex);
> +
> +       i915_vma_unpin(dev_priv->perf.oa.pinned_rcs_vma);
> +       dev_priv->perf.oa.pinned_rcs_vma = NULL;
> +
> +       dev_priv->perf.oa.specific_ctx_id = INVALID_CTX_ID;
> +
> +       mutex_unlock(&dev_priv->drm.struct_mutex);
> +}
> +
> +static void
> +free_oa_buffer(struct drm_i915_private *i915)
> +{
> +       mutex_lock(&i915->drm.struct_mutex);
> +
> +       i915_gem_object_unpin_map(i915->perf.oa.oa_buffer.vma->obj);
> +       i915_vma_unpin(i915->perf.oa.oa_buffer.vma);
> +       i915_gem_object_put(i915->perf.oa.oa_buffer.vma->obj);
> +
> +       i915->perf.oa.oa_buffer.vma = NULL;
> +       i915->perf.oa.oa_buffer.vaddr = NULL;
> +
> +       mutex_unlock(&i915->drm.struct_mutex);
> +}
> +
> +static void i915_oa_stream_destroy(struct i915_perf_stream *stream)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +
> +       BUG_ON(stream != dev_priv->perf.oa.exclusive_stream);
> +
> +       dev_priv->perf.oa.ops.disable_metric_set(dev_priv);
> +
> +       free_oa_buffer(dev_priv);
> +
> +       intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
> +       intel_runtime_pm_put(dev_priv);
> +
> +       if (stream->ctx)
> +               oa_put_render_ctx_id(stream);
> +
> +       dev_priv->perf.oa.exclusive_stream = NULL;
> +}
> +
> +static void gen7_init_oa_buffer(struct drm_i915_private *dev_priv)
> +{
> +       u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
> +
> +       /* Pre-DevBDW: OABUFFER must be set with counters off,
> +        * before OASTATUS1, but after OASTATUS2
> +        */
> +       I915_WRITE(GEN7_OASTATUS2, gtt_offset | OA_MEM_SELECT_GGTT); /* head */
> +       I915_WRITE(GEN7_OABUFFER, gtt_offset);
> +       I915_WRITE(GEN7_OASTATUS1, gtt_offset | OABUFFER_SIZE_16M); /* tail */
> +
> +       /* On Haswell we have to track which OASTATUS1 flags we've
> +        * already seen since they can't be cleared while periodic
> +        * sampling is enabled.
> +        */
> +       dev_priv->perf.oa.gen7_latched_oastatus1 = 0;
> +
> +       /* NB: although the OA buffer will initially be allocated
> +        * zeroed via shmfs (and so this memset is redundant when
> +        * first allocating), we may re-init the OA buffer, either
> +        * when re-enabling a stream or in error/reset paths.
> +        *
> +        * The reason we clear the buffer for each re-init is for the
> +        * sanity check in gen7_append_oa_reports() that looks at the
> +        * report-id field to make sure it's non-zero which relies on
> +        * the assumption that new reports are being written to zeroed
> +        * memory...
> +        */
> +       memset(dev_priv->perf.oa.oa_buffer.vaddr, 0, OA_BUFFER_SIZE);
> +
> +       /* Maybe make ->pollin per-stream state if we support multiple
> +        * concurrent streams in the future.
> +        */
> +       dev_priv->perf.oa.pollin = false;
> +}
> +
> +static int alloc_oa_buffer(struct drm_i915_private *dev_priv)
> +{
> +       struct drm_i915_gem_object *bo;
> +       struct i915_vma *vma;
> +       int ret;
> +
> +       if (WARN_ON(dev_priv->perf.oa.oa_buffer.vma))
> +               return -ENODEV;
> +
> +       ret = i915_mutex_lock_interruptible(&dev_priv->drm);
> +       if (ret)
> +               return ret;
> +
> +       BUILD_BUG_ON_NOT_POWER_OF_2(OA_BUFFER_SIZE);
> +       BUILD_BUG_ON(OA_BUFFER_SIZE < SZ_128K || OA_BUFFER_SIZE > SZ_16M);
> +
> +       bo = i915_gem_object_create(&dev_priv->drm, OA_BUFFER_SIZE);
> +       if (IS_ERR(bo)) {
> +               DRM_ERROR("Failed to allocate OA buffer\n");
> +               ret = PTR_ERR(bo);
> +               goto unlock;
> +       }
> +
> +       ret = i915_gem_object_set_cache_level(bo, I915_CACHE_LLC);
> +       if (ret)
> +               goto err_unref;
> +
> +       /* PreHSW required 512K alignment, HSW requires 16M */
> +       vma = i915_gem_object_ggtt_pin(bo, NULL, 0, SZ_16M, 0);
> +       if (IS_ERR(vma)) {
> +               ret = PTR_ERR(vma);
> +               goto err_unref;
> +       }
> +       dev_priv->perf.oa.oa_buffer.vma = vma;
> +
> +       dev_priv->perf.oa.oa_buffer.vaddr =
> +               i915_gem_object_pin_map(bo, I915_MAP_WB);
> +       if (IS_ERR(dev_priv->perf.oa.oa_buffer.vaddr)) {
> +               ret = PTR_ERR(dev_priv->perf.oa.oa_buffer.vaddr);
> +               goto err_unpin;
> +       }
> +
> +       dev_priv->perf.oa.ops.init_oa_buffer(dev_priv);
> +
> +       DRM_DEBUG_DRIVER("OA Buffer initialized, gtt offset = 0x%x, vaddr = %p",
> +                        i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma),
> +                        dev_priv->perf.oa.oa_buffer.vaddr);
missing '\n'.

> +
> +       goto unlock;
> +
> +err_unpin:
> +       __i915_vma_unpin(vma);
> +
> +err_unref:
> +       i915_gem_object_put(bo);
> +
> +       dev_priv->perf.oa.oa_buffer.vaddr = NULL;
> +       dev_priv->perf.oa.oa_buffer.vma = NULL;
> +
> +unlock:
> +       mutex_unlock(&dev_priv->drm.struct_mutex);
> +       return ret;
> +}
> +
> +static void config_oa_regs(struct drm_i915_private *dev_priv,
> +                          const struct i915_oa_reg *regs,
> +                          int n_regs)
> +{
> +       int i;
> +
> +       for (i = 0; i < n_regs; i++) {
> +               const struct i915_oa_reg *reg = regs + i;
> +
> +               I915_WRITE(reg->addr, reg->value);
> +       }
> +}
> +
> +static int hsw_enable_metric_set(struct drm_i915_private *dev_priv)
> +{
> +       int ret = i915_oa_select_metric_set_hsw(dev_priv);
> +
> +       if (ret)
> +               return ret;
> +
> +       I915_WRITE(GDT_CHICKEN_BITS, (I915_READ(GDT_CHICKEN_BITS) |
> +                                     GT_NOA_ENABLE));
> +
> +       /* PRM:
> +        *
> +        * OA unit is using “crclk” for its functionality. When trunk
> +        * level clock gating takes place, OA clock would be gated,
> +        * unable to count the events from non-render clock domain.
> +        * Render clock gating must be disabled when OA is enabled to
> +        * count the events from non-render domain. Unit level clock
> +        * gating for RCS should also be disabled.
> +        */
> +       I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) &
> +                                   ~GEN7_DOP_CLOCK_GATE_ENABLE));
> +       I915_WRITE(GEN6_UCGCTL1, (I915_READ(GEN6_UCGCTL1) |
> +                                 GEN6_CSUNIT_CLOCK_GATE_DISABLE));
> +
> +       config_oa_regs(dev_priv, dev_priv->perf.oa.mux_regs,
> +                      dev_priv->perf.oa.mux_regs_len);
> +
> +       /* It apparently takes a fairly long time for a new MUX
> +        * configuration to be be applied after these register writes.
> +        * This delay duration was derived empirically based on the
> +        * render_basic config but hopefully it covers the maximum
> +        * configuration latency.
> +        *
> +        * As a fallback, the checks in _append_oa_reports() to skip
> +        * invalid OA reports do also seem to work to discard reports
> +        * generated before this config has completed - albeit not
> +        * silently.
> +        *
> +        * Unfortunately this is essentially a magic number, since we
> +        * don't currently know of a reliable mechanism for predicting
> +        * how long the MUX config will take to apply and besides
> +        * seeing invalid reports we don't know of a reliable way to
> +        * explicitly check that the MUX config has landed.
> +        *
> +        * It's even possible we've miss characterized the underlying
> +        * problem - it just seems like the simplest explanation why
> +        * a delay at this location would mitigate any invalid reports.
> +        */
> +       usleep_range(15000, 20000);
> +
> +       config_oa_regs(dev_priv, dev_priv->perf.oa.b_counter_regs,
> +                      dev_priv->perf.oa.b_counter_regs_len);
> +
> +       return 0;
> +}
> +
> +static void hsw_disable_metric_set(struct drm_i915_private *dev_priv)
> +{
> +       I915_WRITE(GEN6_UCGCTL1, (I915_READ(GEN6_UCGCTL1) &
> +                                 ~GEN6_CSUNIT_CLOCK_GATE_DISABLE));
> +       I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) |
> +                                   GEN7_DOP_CLOCK_GATE_ENABLE));
> +
> +       I915_WRITE(GDT_CHICKEN_BITS, (I915_READ(GDT_CHICKEN_BITS) &
> +                                     ~GT_NOA_ENABLE));
> +}
> +
> +static void gen7_update_oacontrol_locked(struct drm_i915_private *dev_priv)
> +{
> +       assert_spin_locked(&dev_priv->perf.hook_lock);
> +
> +       if (dev_priv->perf.oa.exclusive_stream->enabled) {
> +               struct i915_gem_context *ctx =
> +                       dev_priv->perf.oa.exclusive_stream->ctx;
> +               u32 ctx_id = dev_priv->perf.oa.specific_ctx_id;
> +
> +               bool periodic = dev_priv->perf.oa.periodic;
> +               u32 period_exponent = dev_priv->perf.oa.period_exponent;
> +               u32 report_format = dev_priv->perf.oa.oa_buffer.format;
> +
> +               I915_WRITE(GEN7_OACONTROL,
> +                          (ctx_id & GEN7_OACONTROL_CTX_MASK) |
> +                          (period_exponent <<
> +                           GEN7_OACONTROL_TIMER_PERIOD_SHIFT) |
> +                          (periodic ? GEN7_OACONTROL_TIMER_ENABLE : 0) |
> +                          (report_format << GEN7_OACONTROL_FORMAT_SHIFT) |
> +                          (ctx ? GEN7_OACONTROL_PER_CTX_ENABLE : 0) |
> +                          GEN7_OACONTROL_ENABLE);
> +       } else
> +               I915_WRITE(GEN7_OACONTROL, 0);
> +}
> +
> +static void gen7_oa_enable(struct drm_i915_private *dev_priv)
> +{
> +       unsigned long flags;
> +
> +       /* Reset buf pointers so we don't forward reports from before now.
> +        *
> +        * Think carefully if considering trying to avoid this, since it
> +        * also ensures status flags and the buffer itself are cleared
> +        * in error paths, and we have checks for invalid reports based
> +        * on the assumption that certain fields are written to zeroed
> +        * memory which this helps maintains.
> +        */
> +       gen7_init_oa_buffer(dev_priv);
> +
> +       spin_lock_irqsave(&dev_priv->perf.hook_lock, flags);
> +       gen7_update_oacontrol_locked(dev_priv);
> +       spin_unlock_irqrestore(&dev_priv->perf.hook_lock, flags);
> +}
> +
> +static void i915_oa_stream_enable(struct i915_perf_stream *stream)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +
> +       dev_priv->perf.oa.ops.oa_enable(dev_priv);
> +
> +       if (dev_priv->perf.oa.periodic)
> +               hrtimer_start(&dev_priv->perf.oa.poll_check_timer,
> +                             ns_to_ktime(POLL_PERIOD),
> +                             HRTIMER_MODE_REL_PINNED);
> +}
> +
> +static void gen7_oa_disable(struct drm_i915_private *dev_priv)
> +{
> +       I915_WRITE(GEN7_OACONTROL, 0);
> +}
> +
> +static void i915_oa_stream_disable(struct i915_perf_stream *stream)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +
> +       dev_priv->perf.oa.ops.oa_disable(dev_priv);
> +
> +       if (dev_priv->perf.oa.periodic)
> +               hrtimer_cancel(&dev_priv->perf.oa.poll_check_timer);
> +}
> +
> +static u64 oa_exponent_to_ns(struct drm_i915_private *dev_priv, int exponent)
> +{
> +       return 1000000000ULL * (2ULL << exponent) /
> +               dev_priv->perf.oa.timestamp_frequency;
> +}
> +
> +static const struct i915_perf_stream_ops i915_oa_stream_ops = {
> +       .destroy = i915_oa_stream_destroy,
> +       .enable = i915_oa_stream_enable,
> +       .disable = i915_oa_stream_disable,
> +       .wait_unlocked = i915_oa_wait_unlocked,
> +       .poll_wait = i915_oa_poll_wait,
> +       .read = i915_oa_read,
>  };
>
> +static int i915_oa_stream_init(struct i915_perf_stream *stream,
> +                              struct drm_i915_perf_open_param *param,
> +                              struct perf_open_properties *props)
> +{
> +       struct drm_i915_private *dev_priv = stream->dev_priv;
> +       int format_size;
> +       int ret;
> +
> +       if (!(props->sample_flags & SAMPLE_OA_REPORT)) {
> +               DRM_ERROR("Only OA report sampling supported\n");
> +               return -EINVAL;
> +       }
> +
> +       if (!dev_priv->perf.oa.ops.init_oa_buffer) {
> +               DRM_ERROR("OA unit not supported\n");
> +               return -ENODEV;
> +       }
> +
> +       /* To avoid the complexity of having to accurately filter
> +        * counter reports and marshal to the appropriate client
> +        * we currently only allow exclusive access
> +        */
> +       if (dev_priv->perf.oa.exclusive_stream) {
> +               DRM_ERROR("OA unit already in use\n");
> +               return -EBUSY;
> +       }
> +
> +       if (!props->metrics_set) {
> +               DRM_ERROR("OA metric set not specified\n");
> +               return -EINVAL;
> +       }
> +
> +       if (!props->oa_format) {
> +               DRM_ERROR("OA report format not specified\n");
> +               return -EINVAL;
> +       }
> +
> +       stream->sample_size = sizeof(struct drm_i915_perf_record_header);
> +
> +       format_size = dev_priv->perf.oa.oa_formats[props->oa_format].size;
> +
> +       stream->sample_flags |= SAMPLE_OA_REPORT;
> +       stream->sample_size += format_size;
> +
> +       dev_priv->perf.oa.oa_buffer.format_size = format_size;
> +       if (WARN_ON(dev_priv->perf.oa.oa_buffer.format_size == 0))
> +               return -EINVAL;
> +
> +       dev_priv->perf.oa.oa_buffer.format =
> +               dev_priv->perf.oa.oa_formats[props->oa_format].format;
> +
> +       dev_priv->perf.oa.metrics_set = props->metrics_set;
> +
> +       dev_priv->perf.oa.periodic = props->oa_periodic;
> +       if (dev_priv->perf.oa.periodic) {
> +               u64 period_ns = oa_exponent_to_ns(dev_priv,
> +                                                 props->oa_period_exponent);
> +
> +               dev_priv->perf.oa.period_exponent = props->oa_period_exponent;
> +
> +               /* See comment for OA_TAIL_MARGIN_NSEC for details
> +                * about this tail_margin...
> +                */
> +               dev_priv->perf.oa.tail_margin =
> +                       ((OA_TAIL_MARGIN_NSEC / period_ns) + 1) * format_size;
> +       }
> +
> +       if (stream->ctx) {
> +               ret = oa_get_render_ctx_id(stream);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       ret = alloc_oa_buffer(dev_priv);
> +       if (ret)
> +               goto err_oa_buf_alloc;
> +
> +       /* PRM - observability performance counters:
> +        *
> +        *   OACONTROL, performance counter enable, note:
> +        *
> +        *   "When this bit is set, in order to have coherent counts,
> +        *   RC6 power state and trunk clock gating must be disabled.
> +        *   This can be achieved by programming MMIO registers as
> +        *   0xA094=0 and 0xA090[31]=1"
> +        *
> +        *   In our case we are expecting that taking pm + FORCEWAKE
> +        *   references will effectively disable RC6.
> +        */
> +       intel_runtime_pm_get(dev_priv);
> +       intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
> +
> +       ret = dev_priv->perf.oa.ops.enable_metric_set(dev_priv);
> +       if (ret)
> +               goto err_enable;
> +
> +       stream->ops = &i915_oa_stream_ops;
> +
> +       dev_priv->perf.oa.exclusive_stream = stream;
> +
> +       return 0;
> +
> +err_enable:
> +       intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
> +       intel_runtime_pm_put(dev_priv);
> +       free_oa_buffer(dev_priv);
> +
> +err_oa_buf_alloc:
> +       if (stream->ctx)
> +               oa_put_render_ctx_id(stream);
> +
> +       return ret;
> +}
> +
>  static ssize_t i915_perf_read_locked(struct i915_perf_stream *stream,
>                                      struct file *file,
>                                      char __user *buf,
> @@ -78,8 +961,20 @@ static ssize_t i915_perf_read(struct file *file,
>         struct drm_i915_private *dev_priv = stream->dev_priv;
>         ssize_t ret;
>
> +       /* To ensure it's handled consistently we simply treat all reads of a
> +        * disabled stream as an error. In particular it might otherwise lead
> +        * to a deadlock for blocking file descriptors...
> +        */
> +       if (!stream->enabled)
> +               return -EIO;
> +
>         if (!(file->f_flags & O_NONBLOCK)) {
> -               /* Allow false positives from stream->ops->wait_unlocked.
> +               /* There's the small chance of false positives from
> +                * stream->ops->wait_unlocked.
> +                *
> +                * E.g. with single context filtering since we only wait until
> +                * oabuffer has >= 1 report we don't immediately know whether
> +                * any reports really belong to the current context
>                  */
>                 do {
>                         ret = stream->ops->wait_unlocked(stream);
> @@ -97,21 +992,51 @@ static ssize_t i915_perf_read(struct file *file,
>                 mutex_unlock(&dev_priv->perf.lock);
>         }
>
> +       if (ret >= 0) {
> +               /* Maybe make ->pollin per-stream state if we support multiple
> +                * concurrent streams in the future.
> +                */
> +               dev_priv->perf.oa.pollin = false;
> +       }
> +
>         return ret;
>  }
>
> -static unsigned int i915_perf_poll_locked(struct i915_perf_stream *stream,
> +static enum hrtimer_restart oa_poll_check_timer_cb(struct hrtimer *hrtimer)
> +{
> +       struct drm_i915_private *dev_priv =
> +               container_of(hrtimer, typeof(*dev_priv),
> +                            perf.oa.poll_check_timer);
> +
> +       if (!dev_priv->perf.oa.ops.oa_buffer_is_empty(dev_priv)) {
> +               dev_priv->perf.oa.pollin = true;
> +               wake_up(&dev_priv->perf.oa.poll_wq);
> +       }
> +
> +       hrtimer_forward_now(hrtimer, ns_to_ktime(POLL_PERIOD));
> +
> +       return HRTIMER_RESTART;
> +}
> +
> +static unsigned int i915_perf_poll_locked(struct drm_i915_private *dev_priv,
> +                                         struct i915_perf_stream *stream,
>                                           struct file *file,
>                                           poll_table *wait)
>  {
> -       unsigned int streams = 0;
> +       unsigned int events = 0;
>
>         stream->ops->poll_wait(stream, file, wait);
>
> -       if (stream->ops->can_read(stream))
> -               streams |= POLLIN;
> +       /* Note: we don't explicitly check whether there's something to read
> +        * here since this path may be very hot depending on what else
> +        * userspace is polling, or on the timeout in use. We rely solely on
> +        * the hrtimer/oa_poll_check_timer_cb to notify us when there are
> +        * samples to read.
> +        */
> +       if (dev_priv->perf.oa.pollin)
> +               events |= POLLIN;
>
> -       return streams;
> +       return events;
>  }
>
>  static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
> @@ -121,7 +1046,7 @@ static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
>         int ret;
>
>         mutex_lock(&dev_priv->perf.lock);
> -       ret = i915_perf_poll_locked(stream, file, wait);
> +       ret = i915_perf_poll_locked(dev_priv, stream, file, wait);
>         mutex_unlock(&dev_priv->perf.lock);
>
>         return ret;
> @@ -285,18 +1210,21 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
>                 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.
> +       ret = i915_oa_stream_init(stream, param, props);
> +       if (ret)
> +               goto err_alloc;
> +
> +       /* we avoid simply assigning stream->sample_flags = props->sample_flags
> +        * to have _stream_init check the combination of sample flags more
> +        * thoroughly, but still this is the expected result at this point.
>          */
> -       DRM_ERROR("Unsupported i915 perf stream configuration\n");
> -       ret = -EINVAL;
> -       goto err_alloc;
> +       if (WARN_ON(stream->sample_flags != props->sample_flags)) {
> +               ret = -ENODEV;
> +               goto err_alloc;
> +       }
>
>         list_add(&stream->link, &dev_priv->perf.streams);
>
> @@ -376,6 +1304,56 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv,
>                         props->single_context = 1;
>                         props->ctx_handle = value;
>                         break;
> +               case DRM_I915_PERF_PROP_SAMPLE_OA:
> +                       props->sample_flags |= SAMPLE_OA_REPORT;
> +                       break;
> +               case DRM_I915_PERF_PROP_OA_METRICS_SET:
> +                       if (value == 0 ||
> +                           value > dev_priv->perf.oa.n_builtin_sets) {
> +                               DRM_ERROR("Unknown OA metric set ID");
> +                               return -EINVAL;
> +                       }
> +                       props->metrics_set = value;
> +                       break;
> +               case DRM_I915_PERF_PROP_OA_FORMAT:
> +                       if (value == 0 || value >= I915_OA_FORMAT_MAX) {
> +                               DRM_ERROR("Invalid OA report format\n");
> +                               return -EINVAL;
> +                       }
> +                       if (!dev_priv->perf.oa.oa_formats[value].size) {
> +                               DRM_ERROR("Invalid OA report format\n");
> +                               return -EINVAL;
> +                       }
> +                       props->oa_format = value;
> +                       break;
> +               case DRM_I915_PERF_PROP_OA_EXPONENT:
> +                       if (value > OA_EXPONENT_MAX) {
> +                               DRM_ERROR("OA timer exponent too high (> %u)\n",
> +                                         OA_EXPONENT_MAX);
> +                               return -EINVAL;
> +                       }
> +
> +                       /* NB: The exponent represents a period as follows:
> +                        *
> +                        *   80ns * 2^(period_exponent + 1)
> +                        *
> +                        * Theoretically we can program the OA unit to sample
> +                        * every 160ns but don't allow that by default unless
> +                        * root.
> +                        *
> +                        * Referring to perf's
> +                        * kernel.perf_event_max_sample_rate for a precedent
> +                        * (100000 by default); with an OA exponent of 6 we get
> +                        * a period of 10.240 microseconds -just under 100000Hz
> +                        */
> +                       if (value < 6 && !capable(CAP_SYS_ADMIN)) {
> +                               DRM_ERROR("Minimum OA sampling exponent is 6 without root privileges\n");
> +                               return -EACCES;
> +                       }
> +
> +                       props->oa_periodic = true;
> +                       props->oa_period_exponent = value;
> +                       break;
>                 default:
>                         MISSING_CASE(id);
>                         DRM_ERROR("Unknown i915 perf property ID");
> @@ -426,8 +1404,33 @@ int i915_perf_open_ioctl(struct drm_device *dev, void *data,
>
>  void i915_perf_init(struct drm_i915_private *dev_priv)
>  {
> +       if (!IS_HASWELL(dev_priv))
> +               return;
> +
> +       hrtimer_init(&dev_priv->perf.oa.poll_check_timer,
> +                    CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> +       dev_priv->perf.oa.poll_check_timer.function = oa_poll_check_timer_cb;
> +       init_waitqueue_head(&dev_priv->perf.oa.poll_wq);
> +
>         INIT_LIST_HEAD(&dev_priv->perf.streams);
>         mutex_init(&dev_priv->perf.lock);
> +       spin_lock_init(&dev_priv->perf.hook_lock);
> +
> +       dev_priv->perf.oa.ops.init_oa_buffer = gen7_init_oa_buffer;
> +       dev_priv->perf.oa.ops.enable_metric_set = hsw_enable_metric_set;
> +       dev_priv->perf.oa.ops.disable_metric_set = hsw_disable_metric_set;
> +       dev_priv->perf.oa.ops.oa_enable = gen7_oa_enable;
> +       dev_priv->perf.oa.ops.oa_disable = gen7_oa_disable;
> +       dev_priv->perf.oa.ops.read = gen7_oa_read;
> +       dev_priv->perf.oa.ops.oa_buffer_is_empty =
> +               gen7_oa_buffer_is_empty_fop_unlocked;
> +
> +       dev_priv->perf.oa.timestamp_frequency = 12500000;
> +
> +       dev_priv->perf.oa.oa_formats = hsw_oa_formats;
> +
> +       dev_priv->perf.oa.n_builtin_sets =
> +               i915_oa_n_builtin_metric_sets_hsw;
>
>         dev_priv->perf.initialized = true;
>  }
> @@ -437,7 +1440,6 @@ void i915_perf_fini(struct drm_i915_private *dev_priv)
>         if (!dev_priv->perf.initialized)
>                 return;
>
> -       /* Currently nothing to clean up */
> -
> +       memset(&dev_priv->perf.oa.ops, 0, sizeof(dev_priv->perf.oa.ops));
>         dev_priv->perf.initialized = false;
>  }
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 59628d5..6e3b435 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -616,6 +616,343 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
>  #define HSW_CS_GPR_UDW(n)               _MMIO(0x2600 + (n) * 8 + 4)
>
>  #define GEN7_OACONTROL _MMIO(0x2360)
> +#define  GEN7_OACONTROL_CTX_MASK           0xFFFFF000
> +#define  GEN7_OACONTROL_TIMER_PERIOD_MASK   0x3F
> +#define  GEN7_OACONTROL_TIMER_PERIOD_SHIFT  6
> +#define  GEN7_OACONTROL_TIMER_ENABLE       (1<<5)
> +#define  GEN7_OACONTROL_FORMAT_A13         (0<<2)
> +#define  GEN7_OACONTROL_FORMAT_A29         (1<<2)
> +#define  GEN7_OACONTROL_FORMAT_A13_B8_C8    (2<<2)
> +#define  GEN7_OACONTROL_FORMAT_A29_B8_C8    (3<<2)
> +#define  GEN7_OACONTROL_FORMAT_B4_C8       (4<<2)
> +#define  GEN7_OACONTROL_FORMAT_A45_B8_C8    (5<<2)
> +#define  GEN7_OACONTROL_FORMAT_B4_C8_A16    (6<<2)
> +#define  GEN7_OACONTROL_FORMAT_C4_B8       (7<<2)
> +#define  GEN7_OACONTROL_FORMAT_SHIFT       2
> +#define  GEN7_OACONTROL_PER_CTX_ENABLE     (1<<1)
> +#define  GEN7_OACONTROL_ENABLE             (1<<0)
> +
> +#define GEN8_OACTXID _MMIO(0x2364)
> +
> +#define GEN8_OACONTROL _MMIO(0x2B00)
> +#define  GEN8_OA_REPORT_FORMAT_A12         (0<<2)
> +#define  GEN8_OA_REPORT_FORMAT_A12_B8_C8    (2<<2)
> +#define  GEN8_OA_REPORT_FORMAT_A36_B8_C8    (5<<2)
> +#define  GEN8_OA_REPORT_FORMAT_C4_B8       (7<<2)
> +#define  GEN8_OA_REPORT_FORMAT_SHIFT       2
> +#define  GEN8_OA_SPECIFIC_CONTEXT_ENABLE    (1<<1)
> +#define  GEN8_OA_COUNTER_ENABLE             (1<<0)
> +
> +#define GEN8_OACTXCONTROL _MMIO(0x2360)
> +#define  GEN8_OA_TIMER_PERIOD_MASK         0x3F
> +#define  GEN8_OA_TIMER_PERIOD_SHIFT        2
> +#define  GEN8_OA_TIMER_ENABLE              (1<<1)
> +#define  GEN8_OA_COUNTER_RESUME                    (1<<0)
> +
> +#define GEN7_OABUFFER _MMIO(0x23B0) /* R/W */
> +#define  GEN7_OABUFFER_OVERRUN_DISABLE     (1<<3)
> +#define  GEN7_OABUFFER_EDGE_TRIGGER        (1<<2)
> +#define  GEN7_OABUFFER_STOP_RESUME_ENABLE   (1<<1)
> +#define  GEN7_OABUFFER_RESUME              (1<<0)
> +
> +#define GEN8_OABUFFER _MMIO(0x2b14)
> +
> +#define GEN7_OASTATUS1 _MMIO(0x2364)
> +#define  GEN7_OASTATUS1_TAIL_MASK          0xffffffc0
> +#define  GEN7_OASTATUS1_COUNTER_OVERFLOW    (1<<2)
> +#define  GEN7_OASTATUS1_OABUFFER_OVERFLOW   (1<<1)
> +#define  GEN7_OASTATUS1_REPORT_LOST        (1<<0)
> +
> +#define GEN7_OASTATUS2 _MMIO(0x2368)
> +#define GEN7_OASTATUS2_HEAD_MASK    0xffffffc0
> +
> +#define GEN8_OASTATUS _MMIO(0x2b08)
> +#define  GEN8_OASTATUS_OVERRUN_STATUS      (1<<3)
> +#define  GEN8_OASTATUS_COUNTER_OVERFLOW     (1<<2)
> +#define  GEN8_OASTATUS_OABUFFER_OVERFLOW    (1<<1)
> +#define  GEN8_OASTATUS_REPORT_LOST         (1<<0)
> +
> +#define GEN8_OAHEADPTR _MMIO(0x2B0C)
> +#define GEN8_OATAILPTR _MMIO(0x2B10)
> +
> +#define OABUFFER_SIZE_128K  (0<<3)
> +#define OABUFFER_SIZE_256K  (1<<3)
> +#define OABUFFER_SIZE_512K  (2<<3)
> +#define OABUFFER_SIZE_1M    (3<<3)
> +#define OABUFFER_SIZE_2M    (4<<3)
> +#define OABUFFER_SIZE_4M    (5<<3)
> +#define OABUFFER_SIZE_8M    (6<<3)
> +#define OABUFFER_SIZE_16M   (7<<3)
> +
> +#define OA_MEM_SELECT_GGTT  (1<<0)
> +
> +#define EU_PERF_CNTL0      _MMIO(0xe458)
> +
> +#define GDT_CHICKEN_BITS    _MMIO(0x9840)
> +#define GT_NOA_ENABLE      0x00000080
> +
> +/*
> + * OA Boolean state
> + */
> +
> +#define OAREPORTTRIG1 _MMIO(0x2740)
> +#define OAREPORTTRIG1_THRESHOLD_MASK 0xffff
> +#define OAREPORTTRIG1_EDGE_LEVEL_TRIGER_SELECT_MASK 0xffff0000 /* 0=level */
> +
> +#define OAREPORTTRIG2 _MMIO(0x2744)
> +#define OAREPORTTRIG2_INVERT_A_0  (1<<0)
> +#define OAREPORTTRIG2_INVERT_A_1  (1<<1)
> +#define OAREPORTTRIG2_INVERT_A_2  (1<<2)
> +#define OAREPORTTRIG2_INVERT_A_3  (1<<3)
> +#define OAREPORTTRIG2_INVERT_A_4  (1<<4)
> +#define OAREPORTTRIG2_INVERT_A_5  (1<<5)
> +#define OAREPORTTRIG2_INVERT_A_6  (1<<6)
> +#define OAREPORTTRIG2_INVERT_A_7  (1<<7)
> +#define OAREPORTTRIG2_INVERT_A_8  (1<<8)
> +#define OAREPORTTRIG2_INVERT_A_9  (1<<9)
> +#define OAREPORTTRIG2_INVERT_A_10 (1<<10)
> +#define OAREPORTTRIG2_INVERT_A_11 (1<<11)
> +#define OAREPORTTRIG2_INVERT_A_12 (1<<12)
> +#define OAREPORTTRIG2_INVERT_A_13 (1<<13)
> +#define OAREPORTTRIG2_INVERT_A_14 (1<<14)
> +#define OAREPORTTRIG2_INVERT_A_15 (1<<15)
> +#define OAREPORTTRIG2_INVERT_B_0  (1<<16)
> +#define OAREPORTTRIG2_INVERT_B_1  (1<<17)
> +#define OAREPORTTRIG2_INVERT_B_2  (1<<18)
> +#define OAREPORTTRIG2_INVERT_B_3  (1<<19)
> +#define OAREPORTTRIG2_INVERT_C_0  (1<<20)
> +#define OAREPORTTRIG2_INVERT_C_1  (1<<21)
> +#define OAREPORTTRIG2_INVERT_D_0  (1<<22)
> +#define OAREPORTTRIG2_THRESHOLD_ENABLE     (1<<23)
> +#define OAREPORTTRIG2_REPORT_TRIGGER_ENABLE (1<<31)
> +
> +#define OAREPORTTRIG3 _MMIO(0x2748)
> +#define OAREPORTTRIG3_NOA_SELECT_MASK      0xf
> +#define OAREPORTTRIG3_NOA_SELECT_8_SHIFT    0
> +#define OAREPORTTRIG3_NOA_SELECT_9_SHIFT    4
> +#define OAREPORTTRIG3_NOA_SELECT_10_SHIFT   8
> +#define OAREPORTTRIG3_NOA_SELECT_11_SHIFT   12
> +#define OAREPORTTRIG3_NOA_SELECT_12_SHIFT   16
> +#define OAREPORTTRIG3_NOA_SELECT_13_SHIFT   20
> +#define OAREPORTTRIG3_NOA_SELECT_14_SHIFT   24
> +#define OAREPORTTRIG3_NOA_SELECT_15_SHIFT   28
> +
> +#define OAREPORTTRIG4 _MMIO(0x274c)
> +#define OAREPORTTRIG4_NOA_SELECT_MASK      0xf
> +#define OAREPORTTRIG4_NOA_SELECT_0_SHIFT    0
> +#define OAREPORTTRIG4_NOA_SELECT_1_SHIFT    4
> +#define OAREPORTTRIG4_NOA_SELECT_2_SHIFT    8
> +#define OAREPORTTRIG4_NOA_SELECT_3_SHIFT    12
> +#define OAREPORTTRIG4_NOA_SELECT_4_SHIFT    16
> +#define OAREPORTTRIG4_NOA_SELECT_5_SHIFT    20
> +#define OAREPORTTRIG4_NOA_SELECT_6_SHIFT    24
> +#define OAREPORTTRIG4_NOA_SELECT_7_SHIFT    28
> +
> +#define OAREPORTTRIG5 _MMIO(0x2750)
> +#define OAREPORTTRIG5_THRESHOLD_MASK 0xffff
> +#define OAREPORTTRIG5_EDGE_LEVEL_TRIGER_SELECT_MASK 0xffff0000 /* 0=level */
> +
> +#define OAREPORTTRIG6 _MMIO(0x2754)
> +#define OAREPORTTRIG6_INVERT_A_0  (1<<0)
> +#define OAREPORTTRIG6_INVERT_A_1  (1<<1)
> +#define OAREPORTTRIG6_INVERT_A_2  (1<<2)
> +#define OAREPORTTRIG6_INVERT_A_3  (1<<3)
> +#define OAREPORTTRIG6_INVERT_A_4  (1<<4)
> +#define OAREPORTTRIG6_INVERT_A_5  (1<<5)
> +#define OAREPORTTRIG6_INVERT_A_6  (1<<6)
> +#define OAREPORTTRIG6_INVERT_A_7  (1<<7)
> +#define OAREPORTTRIG6_INVERT_A_8  (1<<8)
> +#define OAREPORTTRIG6_INVERT_A_9  (1<<9)
> +#define OAREPORTTRIG6_INVERT_A_10 (1<<10)
> +#define OAREPORTTRIG6_INVERT_A_11 (1<<11)
> +#define OAREPORTTRIG6_INVERT_A_12 (1<<12)
> +#define OAREPORTTRIG6_INVERT_A_13 (1<<13)
> +#define OAREPORTTRIG6_INVERT_A_14 (1<<14)
> +#define OAREPORTTRIG6_INVERT_A_15 (1<<15)
> +#define OAREPORTTRIG6_INVERT_B_0  (1<<16)
> +#define OAREPORTTRIG6_INVERT_B_1  (1<<17)
> +#define OAREPORTTRIG6_INVERT_B_2  (1<<18)
> +#define OAREPORTTRIG6_INVERT_B_3  (1<<19)
> +#define OAREPORTTRIG6_INVERT_C_0  (1<<20)
> +#define OAREPORTTRIG6_INVERT_C_1  (1<<21)
> +#define OAREPORTTRIG6_INVERT_D_0  (1<<22)
> +#define OAREPORTTRIG6_THRESHOLD_ENABLE     (1<<23)
> +#define OAREPORTTRIG6_REPORT_TRIGGER_ENABLE (1<<31)
> +
> +#define OAREPORTTRIG7 _MMIO(0x2758)
> +#define OAREPORTTRIG7_NOA_SELECT_MASK      0xf
> +#define OAREPORTTRIG7_NOA_SELECT_8_SHIFT    0
> +#define OAREPORTTRIG7_NOA_SELECT_9_SHIFT    4
> +#define OAREPORTTRIG7_NOA_SELECT_10_SHIFT   8
> +#define OAREPORTTRIG7_NOA_SELECT_11_SHIFT   12
> +#define OAREPORTTRIG7_NOA_SELECT_12_SHIFT   16
> +#define OAREPORTTRIG7_NOA_SELECT_13_SHIFT   20
> +#define OAREPORTTRIG7_NOA_SELECT_14_SHIFT   24
> +#define OAREPORTTRIG7_NOA_SELECT_15_SHIFT   28
> +
> +#define OAREPORTTRIG8 _MMIO(0x275c)
> +#define OAREPORTTRIG8_NOA_SELECT_MASK      0xf
> +#define OAREPORTTRIG8_NOA_SELECT_0_SHIFT    0
> +#define OAREPORTTRIG8_NOA_SELECT_1_SHIFT    4
> +#define OAREPORTTRIG8_NOA_SELECT_2_SHIFT    8
> +#define OAREPORTTRIG8_NOA_SELECT_3_SHIFT    12
> +#define OAREPORTTRIG8_NOA_SELECT_4_SHIFT    16
> +#define OAREPORTTRIG8_NOA_SELECT_5_SHIFT    20
> +#define OAREPORTTRIG8_NOA_SELECT_6_SHIFT    24
> +#define OAREPORTTRIG8_NOA_SELECT_7_SHIFT    28
> +
> +#define OASTARTTRIG1 _MMIO(0x2710)
> +#define OASTARTTRIG1_THRESHOLD_COUNT_MASK_MBZ 0xffff0000
> +#define OASTARTTRIG1_THRESHOLD_MASK          0xffff
> +
> +#define OASTARTTRIG2 _MMIO(0x2714)
> +#define OASTARTTRIG2_INVERT_A_0 (1<<0)
> +#define OASTARTTRIG2_INVERT_A_1 (1<<1)
> +#define OASTARTTRIG2_INVERT_A_2 (1<<2)
> +#define OASTARTTRIG2_INVERT_A_3 (1<<3)
> +#define OASTARTTRIG2_INVERT_A_4 (1<<4)
> +#define OASTARTTRIG2_INVERT_A_5 (1<<5)
> +#define OASTARTTRIG2_INVERT_A_6 (1<<6)
> +#define OASTARTTRIG2_INVERT_A_7 (1<<7)
> +#define OASTARTTRIG2_INVERT_A_8 (1<<8)
> +#define OASTARTTRIG2_INVERT_A_9 (1<<9)
> +#define OASTARTTRIG2_INVERT_A_10 (1<<10)
> +#define OASTARTTRIG2_INVERT_A_11 (1<<11)
> +#define OASTARTTRIG2_INVERT_A_12 (1<<12)
> +#define OASTARTTRIG2_INVERT_A_13 (1<<13)
> +#define OASTARTTRIG2_INVERT_A_14 (1<<14)
> +#define OASTARTTRIG2_INVERT_A_15 (1<<15)
> +#define OASTARTTRIG2_INVERT_B_0 (1<<16)
> +#define OASTARTTRIG2_INVERT_B_1 (1<<17)
> +#define OASTARTTRIG2_INVERT_B_2 (1<<18)
> +#define OASTARTTRIG2_INVERT_B_3 (1<<19)
> +#define OASTARTTRIG2_INVERT_C_0 (1<<20)
> +#define OASTARTTRIG2_INVERT_C_1 (1<<21)
> +#define OASTARTTRIG2_INVERT_D_0 (1<<22)
> +#define OASTARTTRIG2_THRESHOLD_ENABLE      (1<<23)
> +#define OASTARTTRIG2_START_TRIG_FLAG_MBZ    (1<<24)
> +#define OASTARTTRIG2_EVENT_SELECT_0  (1<<28)
> +#define OASTARTTRIG2_EVENT_SELECT_1  (1<<29)
> +#define OASTARTTRIG2_EVENT_SELECT_2  (1<<30)
> +#define OASTARTTRIG2_EVENT_SELECT_3  (1<<31)
> +
> +#define OASTARTTRIG3 _MMIO(0x2718)
> +#define OASTARTTRIG3_NOA_SELECT_MASK      0xf
> +#define OASTARTTRIG3_NOA_SELECT_8_SHIFT    0
> +#define OASTARTTRIG3_NOA_SELECT_9_SHIFT    4
> +#define OASTARTTRIG3_NOA_SELECT_10_SHIFT   8
> +#define OASTARTTRIG3_NOA_SELECT_11_SHIFT   12
> +#define OASTARTTRIG3_NOA_SELECT_12_SHIFT   16
> +#define OASTARTTRIG3_NOA_SELECT_13_SHIFT   20
> +#define OASTARTTRIG3_NOA_SELECT_14_SHIFT   24
> +#define OASTARTTRIG3_NOA_SELECT_15_SHIFT   28
> +
> +#define OASTARTTRIG4 _MMIO(0x271c)
> +#define OASTARTTRIG4_NOA_SELECT_MASK       0xf
> +#define OASTARTTRIG4_NOA_SELECT_0_SHIFT    0
> +#define OASTARTTRIG4_NOA_SELECT_1_SHIFT    4
> +#define OASTARTTRIG4_NOA_SELECT_2_SHIFT    8
> +#define OASTARTTRIG4_NOA_SELECT_3_SHIFT    12
> +#define OASTARTTRIG4_NOA_SELECT_4_SHIFT    16
> +#define OASTARTTRIG4_NOA_SELECT_5_SHIFT    20
> +#define OASTARTTRIG4_NOA_SELECT_6_SHIFT    24
> +#define OASTARTTRIG4_NOA_SELECT_7_SHIFT    28
> +
> +#define OASTARTTRIG5 _MMIO(0x2720)
> +#define OASTARTTRIG5_THRESHOLD_COUNT_MASK_MBZ 0xffff0000
> +#define OASTARTTRIG5_THRESHOLD_MASK          0xffff
> +
> +#define OASTARTTRIG6 _MMIO(0x2724)
> +#define OASTARTTRIG6_INVERT_A_0 (1<<0)
> +#define OASTARTTRIG6_INVERT_A_1 (1<<1)
> +#define OASTARTTRIG6_INVERT_A_2 (1<<2)
> +#define OASTARTTRIG6_INVERT_A_3 (1<<3)
> +#define OASTARTTRIG6_INVERT_A_4 (1<<4)
> +#define OASTARTTRIG6_INVERT_A_5 (1<<5)
> +#define OASTARTTRIG6_INVERT_A_6 (1<<6)
> +#define OASTARTTRIG6_INVERT_A_7 (1<<7)
> +#define OASTARTTRIG6_INVERT_A_8 (1<<8)
> +#define OASTARTTRIG6_INVERT_A_9 (1<<9)
> +#define OASTARTTRIG6_INVERT_A_10 (1<<10)
> +#define OASTARTTRIG6_INVERT_A_11 (1<<11)
> +#define OASTARTTRIG6_INVERT_A_12 (1<<12)
> +#define OASTARTTRIG6_INVERT_A_13 (1<<13)
> +#define OASTARTTRIG6_INVERT_A_14 (1<<14)
> +#define OASTARTTRIG6_INVERT_A_15 (1<<15)
> +#define OASTARTTRIG6_INVERT_B_0 (1<<16)
> +#define OASTARTTRIG6_INVERT_B_1 (1<<17)
> +#define OASTARTTRIG6_INVERT_B_2 (1<<18)
> +#define OASTARTTRIG6_INVERT_B_3 (1<<19)
> +#define OASTARTTRIG6_INVERT_C_0 (1<<20)
> +#define OASTARTTRIG6_INVERT_C_1 (1<<21)
> +#define OASTARTTRIG6_INVERT_D_0 (1<<22)
> +#define OASTARTTRIG6_THRESHOLD_ENABLE      (1<<23)
> +#define OASTARTTRIG6_START_TRIG_FLAG_MBZ    (1<<24)
> +#define OASTARTTRIG6_EVENT_SELECT_4  (1<<28)
> +#define OASTARTTRIG6_EVENT_SELECT_5  (1<<29)
> +#define OASTARTTRIG6_EVENT_SELECT_6  (1<<30)
> +#define OASTARTTRIG6_EVENT_SELECT_7  (1<<31)
> +
> +#define OASTARTTRIG7 _MMIO(0x2728)
> +#define OASTARTTRIG7_NOA_SELECT_MASK      0xf
> +#define OASTARTTRIG7_NOA_SELECT_8_SHIFT    0
> +#define OASTARTTRIG7_NOA_SELECT_9_SHIFT    4
> +#define OASTARTTRIG7_NOA_SELECT_10_SHIFT   8
> +#define OASTARTTRIG7_NOA_SELECT_11_SHIFT   12
> +#define OASTARTTRIG7_NOA_SELECT_12_SHIFT   16
> +#define OASTARTTRIG7_NOA_SELECT_13_SHIFT   20
> +#define OASTARTTRIG7_NOA_SELECT_14_SHIFT   24
> +#define OASTARTTRIG7_NOA_SELECT_15_SHIFT   28
> +
> +#define OASTARTTRIG8 _MMIO(0x272c)
> +#define OASTARTTRIG8_NOA_SELECT_MASK      0xf
> +#define OASTARTTRIG8_NOA_SELECT_0_SHIFT    0
> +#define OASTARTTRIG8_NOA_SELECT_1_SHIFT    4
> +#define OASTARTTRIG8_NOA_SELECT_2_SHIFT    8
> +#define OASTARTTRIG8_NOA_SELECT_3_SHIFT    12
> +#define OASTARTTRIG8_NOA_SELECT_4_SHIFT    16
> +#define OASTARTTRIG8_NOA_SELECT_5_SHIFT    20
> +#define OASTARTTRIG8_NOA_SELECT_6_SHIFT    24
> +#define OASTARTTRIG8_NOA_SELECT_7_SHIFT    28
> +
> +/* CECX_0 */
> +#define OACEC_COMPARE_LESS_OR_EQUAL    6
> +#define OACEC_COMPARE_NOT_EQUAL                5
> +#define OACEC_COMPARE_LESS_THAN                4
> +#define OACEC_COMPARE_GREATER_OR_EQUAL 3
> +#define OACEC_COMPARE_EQUAL            2
> +#define OACEC_COMPARE_GREATER_THAN     1
> +#define OACEC_COMPARE_ANY_EQUAL                0
> +
> +#define OACEC_COMPARE_VALUE_MASK    0xffff
> +#define OACEC_COMPARE_VALUE_SHIFT   3
> +
> +#define OACEC_SELECT_NOA       (0<<19)
> +#define OACEC_SELECT_PREV      (1<<19)
> +#define OACEC_SELECT_BOOLEAN   (2<<19)
> +
> +/* CECX_1 */
> +#define OACEC_MASK_MASK                    0xffff
> +#define OACEC_CONSIDERATIONS_MASK   0xffff
> +#define OACEC_CONSIDERATIONS_SHIFT  16
> +
> +#define OACEC0_0 _MMIO(0x2770)
> +#define OACEC0_1 _MMIO(0x2774)
> +#define OACEC1_0 _MMIO(0x2778)
> +#define OACEC1_1 _MMIO(0x277c)
> +#define OACEC2_0 _MMIO(0x2780)
> +#define OACEC2_1 _MMIO(0x2784)
> +#define OACEC3_0 _MMIO(0x2788)
> +#define OACEC3_1 _MMIO(0x278c)
> +#define OACEC4_0 _MMIO(0x2790)
> +#define OACEC4_1 _MMIO(0x2794)
> +#define OACEC5_0 _MMIO(0x2798)
> +#define OACEC5_1 _MMIO(0x279c)
> +#define OACEC6_0 _MMIO(0x27a0)
> +#define OACEC6_1 _MMIO(0x27a4)
> +#define OACEC7_0 _MMIO(0x27a8)
> +#define OACEC7_1 _MMIO(0x27ac)
> +
>
>  #define _GEN7_PIPEA_DE_LOAD_SL 0x70068
>  #define _GEN7_PIPEB_DE_LOAD_SL 0x71068
> @@ -6993,6 +7330,7 @@ enum {
>  # define GEN6_RCCUNIT_CLOCK_GATE_DISABLE               (1 << 11)
>
>  #define GEN6_UCGCTL3                           _MMIO(0x9408)
> +# define GEN6_OACSUNIT_CLOCK_GATE_DISABLE              (1 << 20)
>
>  #define GEN7_UCGCTL4                           _MMIO(0x940c)
>  #define  GEN7_L3BANK2X_CLOCK_GATE_DISABLE      (1<<25)
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 98cd493..82d6239 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -1224,6 +1224,18 @@ struct drm_i915_gem_context_param {
>         __u64 value;
>  };
>
> +enum drm_i915_oa_format {
> +       I915_OA_FORMAT_A13 = 1,
> +       I915_OA_FORMAT_A29,
> +       I915_OA_FORMAT_A13_B8_C8,
> +       I915_OA_FORMAT_B4_C8,
> +       I915_OA_FORMAT_A45_B8_C8,
> +       I915_OA_FORMAT_B4_C8_A16,
> +       I915_OA_FORMAT_C4_B8,
> +
> +       I915_OA_FORMAT_MAX          /* non-ABI */
> +};
> +
>  enum drm_i915_perf_property_id {
>         /**
>          * Open the stream for a specific context handle (as used with
> @@ -1232,6 +1244,32 @@ enum drm_i915_perf_property_id {
>          */
>         DRM_I915_PERF_PROP_CTX_HANDLE = 1,
>
> +       /**
> +        * A value of 1 requests the inclusion of raw OA unit reports as
> +        * part of stream samples.
> +        */
> +       DRM_I915_PERF_PROP_SAMPLE_OA,
> +
> +       /**
> +        * The value specifies which set of OA unit metrics should be
> +        * be configured, defining the contents of any OA unit reports.
> +        */
> +       DRM_I915_PERF_PROP_OA_METRICS_SET,
> +
> +       /**
> +        * The value specifies the size and layout of OA unit reports.
> +        */
> +       DRM_I915_PERF_PROP_OA_FORMAT,
> +
> +       /**
> +        * Specifying this property implicitly requests periodic OA unit
> +        * sampling and (at least on Haswell) the sampling frequency is derived
> +        * from this exponent as follows:
> +        *
> +        *   80ns * 2^(period_exponent + 1)
> +        */
> +       DRM_I915_PERF_PROP_OA_EXPONENT,
> +
>         DRM_I915_PERF_PROP_MAX /* non-ABI */
>  };
>
> @@ -1251,7 +1289,23 @@ struct drm_i915_perf_open_param {
>         __u64 __user properties_ptr;
>  };
>
> +/**
> + * Enable data capture for a stream that was either opened in a disabled state
> + * via I915_PERF_FLAG_DISABLED or was later disabled via
> + * I915_PERF_IOCTL_DISABLE.
> + *
> + * It is intended to be cheaper to disable and enable a stream than it may be
> + * to close and re-open a stream with the same configuration.
> + *
> + * It's undefined whether any pending data for the stream will be lost.
> + */
>  #define I915_PERF_IOCTL_ENABLE _IO('i', 0x0)
> +
> +/**
> + * Disable data capture for a stream.
> + *
> + * It is an error to try and read a stream that is disabled.
> + */
>  #define I915_PERF_IOCTL_DISABLE        _IO('i', 0x1)
>
>  /**
> @@ -1275,17 +1329,30 @@ enum drm_i915_perf_record_type {
>          * 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
> +        * affect on the ordering of data within a sample. The order is
>          * documented here.
>          *
>          * struct {
>          *     struct drm_i915_perf_record_header header;
>          *
> -        *     TODO: itemize extensible sample data here
> +        *     { u32 oa_report[]; } && DRM_I915_PERF_PROP_SAMPLE_OA
>          * };
>          */
>         DRM_I915_PERF_RECORD_SAMPLE = 1,
>
> +       /*
> +        * Indicates that one or more OA reports were not written by the
> +        * hardware. This can happen for example if an MI_REPORT_PERF_COUNT
> +        * command collides with periodic sampling - which would be more likely
> +        * at higher sampling frequencies.
> +        */
> +       DRM_I915_PERF_RECORD_OA_REPORT_LOST = 2,
> +
> +       /**
> +        * An error occurred that resulted in all pending OA reports being lost.
> +        */
> +       DRM_I915_PERF_RECORD_OA_BUFFER_LOST = 3,
> +
>         DRM_I915_PERF_RECORD_MAX /* non-ABI */
>  };
>
> --
> 2.10.1
>

Otherwise I think we should be good, so assuming you also folded in
all of Chris' comments:
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
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Re: [PATCH v8 11/12] drm/i915: Add more Haswell OA metric sets

[Chris Wilson]

On Fri, Oct 28, 2016 at 03:14:29AM +0100, Robert Bragg wrote:
> This adds 'compute', 'compute extended', 'memory reads', 'memory writes'
> and 'sampler balance' metric sets for Haswell.
> 
> The code is auto generated from an XML description of metric sets,
> currently maintained in gputop, ref:
> 
>  https://github.com/rib/gputop
>  > gputop-data/oa-*.xml
>  > scripts/i915-perf-kernelgen.py
> 
>  $ make -C gputop-data -f Makefile.xml
> 
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_oa_hsw.c | 559 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 558 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.c b/drivers/gpu/drm/i915/i915_oa_hsw.c
> index 6af25cf..4ddf756 100644
> --- a/drivers/gpu/drm/i915/i915_oa_hsw.c
> +++ b/drivers/gpu/drm/i915/i915_oa_hsw.c
> @@ -31,9 +31,14 @@
>  
>  enum metric_set_id {
>  	METRIC_SET_ID_RENDER_BASIC = 1,
> +	METRIC_SET_ID_COMPUTE_BASIC,
> +	METRIC_SET_ID_COMPUTE_EXTENDED,
> +	METRIC_SET_ID_MEMORY_READS,
> +	METRIC_SET_ID_MEMORY_WRITES,
> +	METRIC_SET_ID_SAMPLER_BALANCE,
>  };
>  
> -int i915_oa_n_builtin_metric_sets_hsw = 1;
> +int i915_oa_n_builtin_metric_sets_hsw = 6;
>  
>  static const struct i915_oa_reg b_counter_config_render_basic[] = {
>  	{ _MMIO(0x2724), 0x00800000 },
> @@ -112,6 +117,298 @@ get_render_basic_mux_config(struct drm_i915_private *dev_priv,
>  	return mux_config_render_basic;
>  }
>  
> +static const struct i915_oa_reg b_counter_config_compute_basic[] = {
> +	{ _MMIO(0x2710), 0x00000000 },
> +	{ _MMIO(0x2714), 0x00800000 },
> +	{ _MMIO(0x2718), 0xaaaaaaaa },
> +	{ _MMIO(0x271c), 0xaaaaaaaa },
> +	{ _MMIO(0x2720), 0x00000000 },
> +	{ _MMIO(0x2724), 0x00800000 },
> +	{ _MMIO(0x2728), 0xaaaaaaaa },
> +	{ _MMIO(0x272c), 0xaaaaaaaa },
> +	{ _MMIO(0x2740), 0x00000000 },
> +	{ _MMIO(0x2744), 0x00000000 },
> +	{ _MMIO(0x2748), 0x00000000 },
> +	{ _MMIO(0x274c), 0x00000000 },
> +	{ _MMIO(0x2750), 0x00000000 },
> +	{ _MMIO(0x2754), 0x00000000 },
> +	{ _MMIO(0x2758), 0x00000000 },
> +	{ _MMIO(0x275c), 0x00000000 },
> +	{ _MMIO(0x236c), 0x00000000 },
> +};
> +
> +static const struct i915_oa_reg mux_config_compute_basic[] = {
> +	{ _MMIO(0x253a4), 0x00000000 },
> +	{ _MMIO(0x2681c), 0x01f00800 },
> +	{ _MMIO(0x26820), 0x00001000 },
> +	{ _MMIO(0x2781c), 0x01f00800 },
> +	{ _MMIO(0x26520), 0x00000007 },
> +	{ _MMIO(0x265a0), 0x00000007 },
> +	{ _MMIO(0x25380), 0x00000010 },
> +	{ _MMIO(0x2538c), 0x00300000 },
> +	{ _MMIO(0x25384), 0xaa8aaaaa },
> +	{ _MMIO(0x25404), 0xffffffff },
> +	{ _MMIO(0x26800), 0x00004202 },
> +	{ _MMIO(0x26808), 0x00605817 },
> +	{ _MMIO(0x2680c), 0x10001005 },
> +	{ _MMIO(0x26804), 0x00000000 },
> +	{ _MMIO(0x27800), 0x00000102 },
> +	{ _MMIO(0x27808), 0x0c0701e0 },
> +	{ _MMIO(0x2780c), 0x000200a0 },
> +	{ _MMIO(0x27804), 0x00000000 },
> +	{ _MMIO(0x26484), 0x44000000 },
> +	{ _MMIO(0x26704), 0x44000000 },
> +	{ _MMIO(0x26500), 0x00000006 },
> +	{ _MMIO(0x26510), 0x00000001 },
> +	{ _MMIO(0x26504), 0x88000000 },
> +	{ _MMIO(0x26580), 0x00000006 },
> +	{ _MMIO(0x26590), 0x00000020 },
> +	{ _MMIO(0x26584), 0x00000000 },
> +	{ _MMIO(0x26104), 0x55822222 },
> +	{ _MMIO(0x26184), 0xaa866666 },
> +	{ _MMIO(0x25420), 0x08320c83 },
> +	{ _MMIO(0x25424), 0x06820c83 },
> +	{ _MMIO(0x2541c), 0x00000000 },
> +	{ _MMIO(0x25428), 0x00000c03 },
> +};
> +
> +static const struct i915_oa_reg *
> +get_compute_basic_mux_config(struct drm_i915_private *dev_priv,
> +			     int *len)
> +{
> +	*len = ARRAY_SIZE(mux_config_compute_basic);
> +	return mux_config_compute_basic;
> +}

> @@ -140,6 +437,106 @@ int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv)
>  			ARRAY_SIZE(b_counter_config_render_basic);
>  
>  		return 0;
> +	case METRIC_SET_ID_COMPUTE_BASIC:
> +		dev_priv->perf.oa.mux_regs =
> +			get_compute_basic_mux_config(dev_priv,
> +						     &dev_priv->perf.oa.mux_regs_len);
> +		if (!dev_priv->perf.oa.mux_regs) {
> +			DRM_DEBUG_DRIVER("No suitable MUX config for \"COMPUTE_BASIC\" metric set");
> +
> +			/* EINVAL because *_register_sysfs already checked this
> +			 * and so it wouldn't have been advertised so userspace and
> +			 * so shouldn't have been requested
> +			 */
> +			return -EINVAL;
> +		}
> +
> +		dev_priv->perf.oa.b_counter_regs =
> +			b_counter_config_compute_basic;
> +		dev_priv->perf.oa.b_counter_regs_len =
> +			ARRAY_SIZE(b_counter_config_compute_basic);
> +
> +		return 0;

>  int
>  i915_perf_register_sysfs_hsw(struct drm_i915_private *dev_priv)
>  {
> @@ -178,9 +685,49 @@ i915_perf_register_sysfs_hsw(struct drm_i915_private *dev_priv)
>  		if (ret)
>  			goto error_render_basic;
>  	}
> +	if (get_compute_basic_mux_config(dev_priv, &mux_len)) {

Why not use the derived state in dev_priv->perf.oa.mux_regs? Then we
only expose what is initialised.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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Re: [PATCH v8 11/12] drm/i915: Add more Haswell OA metric sets

[Robert Bragg]

[-- Attachment #1.1: Type: text/plain, Size: 7343 bytes --]

On Tue, Nov 1, 2016 at 2:57 PM, Chris Wilson <chris@chris-wilson.co.uk>
wrote:

> On Fri, Oct 28, 2016 at 03:14:29AM +0100, Robert Bragg wrote:
> > This adds 'compute', 'compute extended', 'memory reads', 'memory writes'
> > and 'sampler balance' metric sets for Haswell.
> >
> > The code is auto generated from an XML description of metric sets,
> > currently maintained in gputop, ref:
> >
> >  https://github.com/rib/gputop
> >  > gputop-data/oa-*.xml
> >  > scripts/i915-perf-kernelgen.py
> >
> >  $ make -C gputop-data -f Makefile.xml
> >
> > Signed-off-by: Robert Bragg <robert@sixbynine.org>
> > Reviewed-by: Matthew Auld <matthew.auld@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_oa_hsw.c | 559 ++++++++++++++++++++++++++++++
> ++++++-
> >  1 file changed, 558 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.c
> b/drivers/gpu/drm/i915/i915_oa_hsw.c
> > index 6af25cf..4ddf756 100644
> > --- a/drivers/gpu/drm/i915/i915_oa_hsw.c
> > +++ b/drivers/gpu/drm/i915/i915_oa_hsw.c
> > @@ -31,9 +31,14 @@
> >
> >  enum metric_set_id {
> >       METRIC_SET_ID_RENDER_BASIC = 1,
> > +     METRIC_SET_ID_COMPUTE_BASIC,
> > +     METRIC_SET_ID_COMPUTE_EXTENDED,
> > +     METRIC_SET_ID_MEMORY_READS,
> > +     METRIC_SET_ID_MEMORY_WRITES,
> > +     METRIC_SET_ID_SAMPLER_BALANCE,
> >  };
> >
> > -int i915_oa_n_builtin_metric_sets_hsw = 1;
> > +int i915_oa_n_builtin_metric_sets_hsw = 6;
> >
> >  static const struct i915_oa_reg b_counter_config_render_basic[] = {
> >       { _MMIO(0x2724), 0x00800000 },
> > @@ -112,6 +117,298 @@ get_render_basic_mux_config(struct
> drm_i915_private *dev_priv,
> >       return mux_config_render_basic;
> >  }
> >
> > +static const struct i915_oa_reg b_counter_config_compute_basic[] = {
> > +     { _MMIO(0x2710), 0x00000000 },
> > +     { _MMIO(0x2714), 0x00800000 },
> > +     { _MMIO(0x2718), 0xaaaaaaaa },
> > +     { _MMIO(0x271c), 0xaaaaaaaa },
> > +     { _MMIO(0x2720), 0x00000000 },
> > +     { _MMIO(0x2724), 0x00800000 },
> > +     { _MMIO(0x2728), 0xaaaaaaaa },
> > +     { _MMIO(0x272c), 0xaaaaaaaa },
> > +     { _MMIO(0x2740), 0x00000000 },
> > +     { _MMIO(0x2744), 0x00000000 },
> > +     { _MMIO(0x2748), 0x00000000 },
> > +     { _MMIO(0x274c), 0x00000000 },
> > +     { _MMIO(0x2750), 0x00000000 },
> > +     { _MMIO(0x2754), 0x00000000 },
> > +     { _MMIO(0x2758), 0x00000000 },
> > +     { _MMIO(0x275c), 0x00000000 },
> > +     { _MMIO(0x236c), 0x00000000 },
> > +};
> > +
> > +static const struct i915_oa_reg mux_config_compute_basic[] = {
> > +     { _MMIO(0x253a4), 0x00000000 },
> > +     { _MMIO(0x2681c), 0x01f00800 },
> > +     { _MMIO(0x26820), 0x00001000 },
> > +     { _MMIO(0x2781c), 0x01f00800 },
> > +     { _MMIO(0x26520), 0x00000007 },
> > +     { _MMIO(0x265a0), 0x00000007 },
> > +     { _MMIO(0x25380), 0x00000010 },
> > +     { _MMIO(0x2538c), 0x00300000 },
> > +     { _MMIO(0x25384), 0xaa8aaaaa },
> > +     { _MMIO(0x25404), 0xffffffff },
> > +     { _MMIO(0x26800), 0x00004202 },
> > +     { _MMIO(0x26808), 0x00605817 },
> > +     { _MMIO(0x2680c), 0x10001005 },
> > +     { _MMIO(0x26804), 0x00000000 },
> > +     { _MMIO(0x27800), 0x00000102 },
> > +     { _MMIO(0x27808), 0x0c0701e0 },
> > +     { _MMIO(0x2780c), 0x000200a0 },
> > +     { _MMIO(0x27804), 0x00000000 },
> > +     { _MMIO(0x26484), 0x44000000 },
> > +     { _MMIO(0x26704), 0x44000000 },
> > +     { _MMIO(0x26500), 0x00000006 },
> > +     { _MMIO(0x26510), 0x00000001 },
> > +     { _MMIO(0x26504), 0x88000000 },
> > +     { _MMIO(0x26580), 0x00000006 },
> > +     { _MMIO(0x26590), 0x00000020 },
> > +     { _MMIO(0x26584), 0x00000000 },
> > +     { _MMIO(0x26104), 0x55822222 },
> > +     { _MMIO(0x26184), 0xaa866666 },
> > +     { _MMIO(0x25420), 0x08320c83 },
> > +     { _MMIO(0x25424), 0x06820c83 },
> > +     { _MMIO(0x2541c), 0x00000000 },
> > +     { _MMIO(0x25428), 0x00000c03 },
> > +};
> > +
> > +static const struct i915_oa_reg *
> > +get_compute_basic_mux_config(struct drm_i915_private *dev_priv,
> > +                          int *len)
> > +{
> > +     *len = ARRAY_SIZE(mux_config_compute_basic);
> > +     return mux_config_compute_basic;
> > +}
>
> > @@ -140,6 +437,106 @@ int i915_oa_select_metric_set_hsw(struct
> drm_i915_private *dev_priv)
> >                       ARRAY_SIZE(b_counter_config_render_basic);
> >
> >               return 0;
> > +     case METRIC_SET_ID_COMPUTE_BASIC:
> > +             dev_priv->perf.oa.mux_regs =
> > +                     get_compute_basic_mux_config(dev_priv,
> > +
> &dev_priv->perf.oa.mux_regs_len);
> > +             if (!dev_priv->perf.oa.mux_regs) {
> > +                     DRM_DEBUG_DRIVER("No suitable MUX config for
> \"COMPUTE_BASIC\" metric set");
> > +
> > +                     /* EINVAL because *_register_sysfs already checked
> this
> > +                      * and so it wouldn't have been advertised so
> userspace and
> > +                      * so shouldn't have been requested
> > +                      */
> > +                     return -EINVAL;
> > +             }
> > +
> > +             dev_priv->perf.oa.b_counter_regs =
> > +                     b_counter_config_compute_basic;
> > +             dev_priv->perf.oa.b_counter_regs_len =
> > +                     ARRAY_SIZE(b_counter_config_compute_basic);
> > +
> > +             return 0;
>
> >  int
> >  i915_perf_register_sysfs_hsw(struct drm_i915_private *dev_priv)
> >  {
> > @@ -178,9 +685,49 @@ i915_perf_register_sysfs_hsw(struct
> drm_i915_private *dev_priv)
> >               if (ret)
> >                       goto error_render_basic;
> >       }
> > +     if (get_compute_basic_mux_config(dev_priv, &mux_len)) {
>
> Why not use the derived state in dev_priv->perf.oa.mux_regs? Then we
> only expose what is initialised.
>

Although for Haswell none of our metric sets have conditional MUX
configurations, the generated code should already be in shape to only
advertising metric sets applicable to the system (which becomes an issue
for gen8+). This was changed relatively recently in the gen8+ series after
Mark Janes was hitting issues on Skylake in some of his tooling due to Mesa
advertising one of the compute metric sets that wasn't really available on
the system he had, which was only discoverable as a GL error when
attempting to use it.

The perf.oa.mux_regs state only pertains to one current metric set that the
OA unit has been configured with, after calling the generated
i915_oa_select_metric_set_hsw() function in hsw_enable_metric_set(). Until
an OA stream is opened and enabled perf.oa.mux_regs won't be initialised.

Notably the recent change for gen8+ mentioned above was to have the
_select_metric_set_<gen>() code and the _register_sysfs_<gen>() code both
work in terms of the get_<metric_set>_mux_config() functions since it's
these functions that will check the fiddly sku specfic details on gen8+ to
select the right MUX config or potentially fail if the metric set isn't
available on the current system. So for gen8+ we can expect
get_compute_basic_mux_config() will fail if the config isn't available and
then won't be advertised via sysfs. On Haswell it looks a little redundant
having these get_ functions unconditionally return a pointer to a
corresponding array.

Hope that clarifies,
- Robert



> -Chris
>
> --
> Chris Wilson, Intel Open Source Technology Centre
>

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Re: [PATCH v8 10/12] drm/i915: add oa_event_min_timer_exponent sysctl

[sourab gupta]

On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> The minimal sampling period is now configurable via a
> dev.i915.oa_min_timer_exponent sysctl parameter.
> 
> Following the precedent set by perf, the default is the minimum that
> won't (on its own) exceed the default kernel.perf_event_max_sample_rate
> default of 100000 samples/s.
> 
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_perf.c | 42 ++++++++++++++++++++++++++++------------
>  1 file changed, 30 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 4e42073..e3c6f51 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -82,6 +82,22 @@ static u32 i915_perf_stream_paranoid = true;
>  #define INVALID_CTX_ID 0xffffffff
>  
> 
> +/* for sysctl proc_dointvec_minmax of i915_oa_min_timer_exponent */
> +static int oa_exponent_max = OA_EXPONENT_MAX;
> +
> +/* Theoretically we can program the OA unit to sample every 160ns but don't
> + * allow that by default unless root...
> + *
> + * The period is derived from the exponent as:
> + *
> + *   period = 80ns * 2^(exponent + 1)
> + *
> + * Referring to perf's kernel.perf_event_max_sample_rate for a precedent
> + * (100000 by default); with an OA exponent of 6 we get a period of 10.240
> + * microseconds - just under 100000Hz
> + */
> +static u32 i915_oa_min_timer_exponent = 6;

For HSW, the timestamp period is 80ns, so the exponent of 6 translates
to sampling rate of ~100000Hz. But the timestamp period may change for
other platforms, leading to different values of oa_min_timer_exponent
corresponding to sampling rate of ~100000Hz. Do we plan to have this
value platform specific subsequently, or the guidance value of ~100000Hz
min sampling rate needn't be strictly followed?

> +
>  /* XXX: beware if future OA HW adds new report formats that the current
>   * code assumes all reports have a power-of-two size and ~(size - 1) can
>   * be used as a mask to align the OA tail pointer.
> @@ -1353,21 +1369,14 @@ static int read_properties_unlocked(struct drm_i915_private *dev_priv,
>  				return -EINVAL;
>  			}
>  
> -			/* NB: The exponent represents a period as follows:
> -			 *
> -			 *   80ns * 2^(period_exponent + 1)
> -			 *
> -			 * Theoretically we can program the OA unit to sample
> +			/* Theoretically we can program the OA unit to sample
>  			 * every 160ns but don't allow that by default unless
>  			 * root.
> -			 *
> -			 * Referring to perf's
> -			 * kernel.perf_event_max_sample_rate for a precedent
> -			 * (100000 by default); with an OA exponent of 6 we get
> -			 * a period of 10.240 microseconds -just under 100000Hz
>  			 */
> -			if (value < 6 && !capable(CAP_SYS_ADMIN)) {
> -				DRM_ERROR("Minimum OA sampling exponent is 6 without root privileges\n");
> +			if (value < i915_oa_min_timer_exponent &&
> +			    !capable(CAP_SYS_ADMIN)) {
> +				DRM_ERROR("Minimum OA sampling exponent (sysctl dev.i915.oa_min_timer_exponent) is %u without root privileges\n",
> +					  i915_oa_min_timer_exponent);
>  				return -EACCES;
>  			}
>  
> @@ -1475,6 +1484,15 @@ static struct ctl_table oa_table[] = {
>  	 .extra1 = &zero,
>  	 .extra2 = &one,
>  	 },
> +	{
> +	 .procname = "oa_min_timer_exponent",
> +	 .data = &i915_oa_min_timer_exponent,
> +	 .maxlen = sizeof(i915_oa_min_timer_exponent),
> +	 .mode = 0644,
> +	 .proc_handler = proc_dointvec_minmax,
> +	 .extra1 = &zero,
> +	 .extra2 = &oa_exponent_max,
> +	 },
>  	{}
>  };
>  


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Re: [PATCH v8 03/12] drm/i915: rename OACONTROL GEN7_OACONTROL

[sourab gupta]

On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> OACONTROL changes quite a bit for gen8, with some bits split out into a
> per-context OACTXCONTROL register. Rename now before adding more gen7 OA
> registers
> 
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Sourab Gupta <sourab.gupta@intel.com>

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Re: [PATCH v8 10/12] drm/i915: add oa_event_min_timer_exponent sysctl

[Robert Bragg]

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On Wed, Nov 2, 2016 at 6:29 AM, sourab gupta <sourab.gupta@intel.com> wrote:

> On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> > The minimal sampling period is now configurable via a
> > dev.i915.oa_min_timer_exponent sysctl parameter.
> >
> > Following the precedent set by perf, the default is the minimum that
> > won't (on its own) exceed the default kernel.perf_event_max_sample_rate
> > default of 100000 samples/s.
> >
> > Signed-off-by: Robert Bragg <robert@sixbynine.org>
> > Reviewed-by: Matthew Auld <matthew.auld@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_perf.c | 42 ++++++++++++++++++++++++++++--
> ----------
> >  1 file changed, 30 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_perf.c
> b/drivers/gpu/drm/i915/i915_perf.c
> > index 4e42073..e3c6f51 100644
> > --- a/drivers/gpu/drm/i915/i915_perf.c
> > +++ b/drivers/gpu/drm/i915/i915_perf.c
> > @@ -82,6 +82,22 @@ static u32 i915_perf_stream_paranoid = true;
> >  #define INVALID_CTX_ID 0xffffffff
> >
> >
> > +/* for sysctl proc_dointvec_minmax of i915_oa_min_timer_exponent */
> > +static int oa_exponent_max = OA_EXPONENT_MAX;
> > +
> > +/* Theoretically we can program the OA unit to sample every 160ns but
> don't
> > + * allow that by default unless root...
> > + *
> > + * The period is derived from the exponent as:
> > + *
> > + *   period = 80ns * 2^(exponent + 1)
> > + *
> > + * Referring to perf's kernel.perf_event_max_sample_rate for a
> precedent
> > + * (100000 by default); with an OA exponent of 6 we get a period of
> 10.240
> > + * microseconds - just under 100000Hz
> > + */
> > +static u32 i915_oa_min_timer_exponent = 6;
>
> For HSW, the timestamp period is 80ns, so the exponent of 6 translates
> to sampling rate of ~100000Hz. But the timestamp period may change for
> other platforms, leading to different values of oa_min_timer_exponent
> corresponding to sampling rate of ~100000Hz. Do we plan to have this
> value platform specific subsequently, or the guidance value of ~100000Hz
> min sampling rate needn't be strictly followed?
>

actually it's bothered me a bit that I've been lazy with not having this
adapt for gen9+ in later patches

I think it would probably be better to make this a Hz based threshold for
userspace, otherwise any userspace policy here needs to be adapted for each
system with a different timestamp frequency which isn't great.

I've updated the patch locally to make this an oa_max_sample_rate parameter
in Hz, which I'll aim to test on haswell tomorrow and send out.

Thanks,
- Robert

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Re: [PATCH v8 04/12] drm/i915: return EACCES for check_cmd() failures

[sourab gupta]

On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> check_cmd() is checking whether a command adheres to certain
> restrictions that ensure it's safe to execute within a privileged batch
> buffer. Returning false implies a privilege problem, not that the
> command is invalid.
> 
> The distinction makes the difference between allowing the buffer to be
> executed as an unprivileged batch buffer or returning an EINVAL error to
> userspace without executing anything.
> 
> In a case where userspace may want to test whether it can successfully
> write to a register that needs privileges the distinction may be
> important and an EINVAL error may be considered fatal.
> 
> In particular this is currently true for Mesa, which includes a test for
> whether OACONTROL can be written too, but Mesa treats any error when
> flushing a batch buffer as fatal, calling exit(1).
> 
> As it is currently Mesa can gracefully handle a failure to write to
> OACONTROL if the command parser is disabled, but if we were to remove
> OACONTROL from the parser's whitelist then the returned EINVAL would
> break Mesa applications as they attempt an OACONTROL write.
> 
> This bumps the command parser version from 7 to 8, as the change is
> visible to userspace.
> 
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Well, looks reasonable to me.

Reviewed-by: Sourab Gupta <sourab.gupta@intel.com>

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Re: [PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[sourab gupta]

On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> 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: Robert Bragg <robert@sixbynine.org>
> ---
>  drivers/gpu/drm/i915/Makefile    |   3 +
>  drivers/gpu/drm/i915/i915_drv.c  |   4 +
>  drivers/gpu/drm/i915/i915_drv.h  |  91 ++++++++
>  drivers/gpu/drm/i915/i915_perf.c | 443 +++++++++++++++++++++++++++++++++++++++
>  include/uapi/drm/i915_drm.h      |  67 ++++++
>  5 files changed, 608 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/i915_perf.c
> 
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 6123400..8d4e25f 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -113,6 +113,9 @@ 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
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index af3559d..685c96e 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -836,6 +836,8 @@ 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_workqueues:
> @@ -849,6 +851,7 @@ 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);
>  }
> @@ -2556,6 +2559,7 @@ 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 = {
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 5a260db..7a65c0b 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1767,6 +1767,84 @@ 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;
>  
> @@ -2069,6 +2147,12 @@ 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 *);
> @@ -3482,6 +3566,9 @@ 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,
> @@ -3607,6 +3694,10 @@ 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);
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> new file mode 100644
> index 0000000..c45cf92
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -0,0 +1,443 @@
> +/*
> + * 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);

Should interruptible version be used here, to allow for reads to be
interrupted?
> +			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);
Likewise.

> +		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);
Same question. Can interruptible versions be used here, and likewise
other instances in the patch?

> +	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;
> +	}
> +
> +	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;
> +}
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 03725fe..98cd493 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/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.
> @@ -1222,6 +1224,71 @@ 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


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Re: [PATCH v8 08/12] drm/i915: advertise available metrics via sysfs

[sourab gupta]

On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> Each metric set is given a sysfs entry like:
> 
> /sys/class/drm/card0/metrics/<guid>/id
> 
> This allows userspace to enumerate the specific sets that are available
> for the current system. The 'id' file contains an unsigned integer that
> can be used to open the associated metric set via
> DRM_IOCTL_I915_PERF_OPEN. The <guid> is a globally unique ID for a
> specific OA unit register configuration that can be reliably used by
> userspace as a key to lookup corresponding counter meta data and
> normalization equations.
> 
> The guid registry is currently maintained as part of gputop along with
> the XML metric set descriptions and code generation scripts, ref:
> 
>  https://github.com/rib/gputop
>  > gputop-data/guids.xml
>  > scripts/update-guids.py
>  > gputop-data/oa-*.xml
>  > scripts/i915-perf-kernelgen.py
> 
>  $ make -C gputop-data -f Makefile.xml SYSFS=1 WHITELIST=RenderBasic
> 
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Looks good to me.
Reviewed-by: Sourab Gupta <sourab.gupta@intel.com>

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Re: [PATCH v8 09/12] drm/i915: Add dev.i915.perf_stream_paranoid sysctl option

[sourab gupta]

On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> Consistent with the kernel.perf_event_paranoid sysctl option that can
> allow non-root users to access system wide cpu metrics, this can
> optionally allow non-root users to access system wide OA counter metrics
> from Gen graphics hardware.
> 
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  |  1 +
>  drivers/gpu/drm/i915/i915_perf.c | 50 +++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 50 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 01438fb..a138f86 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2171,6 +2171,7 @@ struct drm_i915_private {
>  		bool initialized;
>  
>  		struct kobject *metrics_kobj;
> +		struct ctl_table_header *sysctl_header;
>  
>  		struct mutex lock;
>  		struct list_head streams;
> diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
> index 8d07c41..4e42073 100644
> --- a/drivers/gpu/drm/i915/i915_perf.c
> +++ b/drivers/gpu/drm/i915/i915_perf.c
> @@ -64,6 +64,11 @@
>  #define POLL_FREQUENCY 200
>  #define POLL_PERIOD (NSEC_PER_SEC / POLL_FREQUENCY)
>  
> +/* for sysctl proc_dointvec_minmax of dev.i915.perf_stream_paranoid */
> +static int zero;
> +static int one = 1;
> +static u32 i915_perf_stream_paranoid = true;
> +
>  /* The maximum exponent the hardware accepts is 63 (essentially it selects one
>   * of the 64bit timestamp bits to trigger reports from) but there's currently
>   * no known use case for sampling as infrequently as once per 47 thousand years.
> @@ -1207,7 +1212,13 @@ i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
>  		}
>  	}
>  
> -	if (!specific_ctx && !capable(CAP_SYS_ADMIN)) {
> +	/* Similar to perf's kernel.perf_paranoid_cpu sysctl option
> +	 * we check a dev.i915.perf_stream_paranoid sysctl option
> +	 * to determine if it's ok to access system wide OA counters
> +	 * without CAP_SYS_ADMIN privileges.
> +	 */
> +	if (!specific_ctx &&
> +	    i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
>  		DRM_ERROR("Insufficient privileges to open system-wide i915 perf stream\n");
>  		ret = -EACCES;
>  		goto err_ctx;
> @@ -1454,6 +1465,39 @@ void i915_perf_unregister(struct drm_i915_private *dev_priv)
>  	dev_priv->perf.metrics_kobj = NULL;
>  }
>  
> +static struct ctl_table oa_table[] = {
> +	{
> +	 .procname = "perf_stream_paranoid",
> +	 .data = &i915_perf_stream_paranoid,
> +	 .maxlen = sizeof(i915_perf_stream_paranoid),
> +	 .mode = 0644,
> +	 .proc_handler = proc_dointvec_minmax,
> +	 .extra1 = &zero,
> +	 .extra2 = &one,
> +	 },
> +	{}
> +};
> +
> +static struct ctl_table i915_root[] = {
> +	{
> +	 .procname = "i915",
> +	 .maxlen = 0,
> +	 .mode = 0555,
> +	 .child = oa_table,
> +	 },
> +	{}
> +};
> +
> +static struct ctl_table dev_root[] = {
> +	{
> +	 .procname = "dev",
> +	 .maxlen = 0,
> +	 .mode = 0555,
> +	 .child = i915_root,
> +	 },
> +	{}
> +};
> +
>  void i915_perf_init(struct drm_i915_private *dev_priv)
>  {
>  	if (!IS_HASWELL(dev_priv))
> @@ -1484,6 +1528,8 @@ void i915_perf_init(struct drm_i915_private *dev_priv)
>  	dev_priv->perf.oa.n_builtin_sets =
>  		i915_oa_n_builtin_metric_sets_hsw;
>  
> +	dev_priv->perf.sysctl_header = register_sysctl_table(dev_root);
> +
>  	dev_priv->perf.initialized = true;
>  }
>  
> @@ -1492,6 +1538,8 @@ void i915_perf_fini(struct drm_i915_private *dev_priv)
>  	if (!dev_priv->perf.initialized)
>  		return;
>  
> +	unregister_sysctl_table(dev_priv->perf.sysctl_header);
> +
>  	memset(&dev_priv->perf.oa.ops, 0, sizeof(dev_priv->perf.oa.ops));
>  	dev_priv->perf.initialized = false;
>  }

Looks fine.
Reviewed-by: Sourab Gupta <sourab.gupta@intel.com> 


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Re: [PATCH v8 05/12] drm/i915: don't whitelist oacontrol in cmd parser

[sourab gupta]

On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> Being able to program OACONTROL from a non-privileged batch buffer is
> not sufficient to be able to configure the OA unit. This was originally
> allowed to help enable Mesa to expose OA counters via the
> INTEL_performance_query extension, but the current implementation based
> on programming OACONTROL via a batch buffer isn't able to report useable
> data without a more complete OA unit configuration. Mesa handles the
> possibility that writes to OACONTROL may not be allowed and so only
> advertises the extension after explicitly testing that a write to
> OACONTROL succeeds. Based on this; removing OACONTROL from the whitelist
> should be ok for userspace.
> 
> Removing this simplifies adding a new kernel api for configuring the OA
> unit without needing to consider the possibility that userspace might
> trample on OACONTROL state which we'd like to start managing within
> the kernel instead. In particular running any Mesa based GL application
> currently results in clearing OACONTROL when initializing which would
> disable the capturing of metrics.
> 
> Signed-off-by: Robert Bragg <robert@sixbynine.org>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Seems reasonable.
Reviewed-by: Sourab Gupta <sourab.gupta@intel.com>

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Re: [PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[Robert Bragg]

[-- Attachment #1.1: Type: text/plain, Size: 15107 bytes --]

On Fri, Nov 4, 2016 at 8:59 AM, sourab gupta <sourab.gupta@intel.com> wrote:

> On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
> > 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: Robert Bragg <robert@sixbynine.org>
> > ---
> >  drivers/gpu/drm/i915/Makefile    |   3 +
> >  drivers/gpu/drm/i915/i915_drv.c  |   4 +
> >  drivers/gpu/drm/i915/i915_drv.h  |  91 ++++++++
> >  drivers/gpu/drm/i915/i915_perf.c | 443 ++++++++++++++++++++++++++++++
> +++++++++
> >  include/uapi/drm/i915_drm.h      |  67 ++++++
> >  5 files changed, 608 insertions(+)
> >  create mode 100644 drivers/gpu/drm/i915/i915_perf.c
> >
> > diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/
> Makefile
> > index 6123400..8d4e25f 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -113,6 +113,9 @@ 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
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c
> b/drivers/gpu/drm/i915/i915_drv.c
> > index af3559d..685c96e 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -836,6 +836,8 @@ 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_workqueues:
> > @@ -849,6 +851,7 @@ 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);
> >  }
> > @@ -2556,6 +2559,7 @@ 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 = {
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> b/drivers/gpu/drm/i915/i915_drv.h
> > index 5a260db..7a65c0b 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1767,6 +1767,84 @@ 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;
> >
> > @@ -2069,6 +2147,12 @@ 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 *);
> > @@ -3482,6 +3566,9 @@ 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,
> > @@ -3607,6 +3694,10 @@ 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);
> > diff --git a/drivers/gpu/drm/i915/i915_perf.c
> b/drivers/gpu/drm/i915/i915_perf.c
> > new file mode 100644
> > index 0000000..c45cf92
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/i915_perf.c
> > @@ -0,0 +1,443 @@
> > +/*
> > + * 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);
>
> Should interruptible version be used here, to allow for reads to be
> interrupted?
>

Now that we don't have the context pin hook on haswell we could /almost/
get away without this lock except for its use to synchronize
i915_perf_register with i915_perf_open_ioctl.

Most of the i915-perf state access is synchronized as a result of being
fops driven, so this perf.lock was added to deal with a few entrypoints
outside of fops such as the contect pinning hook we used to have (though we
avoid it in the hrtimer callback).

Although the recent change to remove the pin hook has made the lock look a
bit redundant for now, I think I'd prefer to leave the locks as they are to
avoid the churn with the gen8+ patches where we do have some other
entrypoints into i915-perf outside of the fops.

Given that though, there's currently not really much argument either way
for them being interruptible. The expectation I have atm is that there
shouldn't be anything running async within i915-perf outside of fops that's
expected to be long running. We will probably also want to consider the
risk of bouncing lots of reads, starving userspace and increasing the risk
of a buffer overflow if this is interruptible.

- Robert

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Re: [PATCH v8 02/12] drm/i915: Add i915 perf infrastructure

[sourab gupta]

On Fri, 2016-11-04 at 06:19 -0700, Robert Bragg wrote:
> 
> 
> On Fri, Nov 4, 2016 at 8:59 AM, sourab gupta <sourab.gupta@intel.com>
> wrote:
>         On Thu, 2016-10-27 at 19:14 -0700, Robert Bragg wrote:
>         > 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: Robert Bragg <robert@sixbynine.org>
>         > ---
>         >  drivers/gpu/drm/i915/Makefile    |   3 +
>         >  drivers/gpu/drm/i915/i915_drv.c  |   4 +
>         >  drivers/gpu/drm/i915/i915_drv.h  |  91 ++++++++
>         >  drivers/gpu/drm/i915/i915_perf.c | 443
>         +++++++++++++++++++++++++++++++++++++++
>         >  include/uapi/drm/i915_drm.h      |  67 ++++++
>         >  5 files changed, 608 insertions(+)
>         >  create mode 100644 drivers/gpu/drm/i915/i915_perf.c
>         >
>         > diff --git a/drivers/gpu/drm/i915/Makefile
>         b/drivers/gpu/drm/i915/Makefile
>         > index 6123400..8d4e25f 100644
>         > --- a/drivers/gpu/drm/i915/Makefile
>         > +++ b/drivers/gpu/drm/i915/Makefile
>         > @@ -113,6 +113,9 @@ 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
>         > diff --git a/drivers/gpu/drm/i915/i915_drv.c
>         b/drivers/gpu/drm/i915/i915_drv.c
>         > index af3559d..685c96e 100644
>         > --- a/drivers/gpu/drm/i915/i915_drv.c
>         > +++ b/drivers/gpu/drm/i915/i915_drv.c
>         > @@ -836,6 +836,8 @@ 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_workqueues:
>         > @@ -849,6 +851,7 @@ 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);
>         >  }
>         > @@ -2556,6 +2559,7 @@ 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 = {
>         > diff --git a/drivers/gpu/drm/i915/i915_drv.h
>         b/drivers/gpu/drm/i915/i915_drv.h
>         > index 5a260db..7a65c0b 100644
>         > --- a/drivers/gpu/drm/i915/i915_drv.h
>         > +++ b/drivers/gpu/drm/i915/i915_drv.h
>         > @@ -1767,6 +1767,84 @@ 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;
>         >
>         > @@ -2069,6 +2147,12 @@ 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 *);
>         > @@ -3482,6 +3566,9 @@ 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,
>         > @@ -3607,6 +3694,10 @@ 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);
>         > diff --git a/drivers/gpu/drm/i915/i915_perf.c
>         b/drivers/gpu/drm/i915/i915_perf.c
>         > new file mode 100644
>         > index 0000000..c45cf92
>         > --- /dev/null
>         > +++ b/drivers/gpu/drm/i915/i915_perf.c
>         > @@ -0,0 +1,443 @@
>         > +/*
>         > + * 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);
>         
>         
>         Should interruptible version be used here, to allow for reads
>         to be
>         interrupted?
> 
> 
> Now that we don't have the context pin hook on haswell we
> could /almost/ get away without this lock except for its use to
> synchronize i915_perf_register with i915_perf_open_ioctl.
> 
> 
> Most of the i915-perf state access is synchronized as a result of
> being fops driven, so this perf.lock was added to deal with a few
> entrypoints outside of fops such as the contect pinning hook we used
> to have (though we avoid it in the hrtimer callback).
> 
> 
> 
> Although the recent change to remove the pin hook has made the lock
> look a bit redundant for now, I think I'd prefer to leave the locks as
> they are to avoid the churn with the gen8+ patches where we do have
> some other entrypoints into i915-perf outside of the fops.
> 
> 
> Given that though, there's currently not really much argument either
> way for them being interruptible. The expectation I have atm is that
> there shouldn't be anything running async within i915-perf outside of
> fops that's expected to be long running. We will probably also want to
> consider the risk of bouncing lots of reads, starving userspace and
> increasing the risk of a buffer overflow if this is interruptible.
> 
Well, that makes sense. I'm okay with rest of the interfaces exposed
here (Have been using them for my work too). So,
Reviewed-by: Sourab Gupta <sourab.gupta@intel.com>
> 
> - Robert
> 


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