From: Sourab Gupta <sourab.gupta@xxxxxxxxx>
Considering how we don't currently give userspace control over the
OA buffer size and always configure a large 16MB buffer,
then a buffer overflow does anyway likely indicate that something
has gone quite badly wrong.
Here we set a status flag to detect overflow and inform userspace
of the report_lost condition accordingly. This is in line with the
behavior of the periodic OA buffer.
Signed-off-by: Sourab Gupta <sourab.gupta@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 2 ++
drivers/gpu/drm/i915/i915_perf.c | 15 +++++++++++++++
2 files changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d0f43e9..0f2a552 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2609,6 +2609,8 @@ struct drm_i915_private {
struct {
struct i915_vma *vma;
u8 *vaddr;
+#define I915_PERF_CMD_STREAM_BUF_STATUS_OVERFLOW (1<<0)
+ u32 status;
} command_stream_buf;
struct list_head cs_samples;
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index d1d9853..2841d0a 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -478,6 +478,8 @@ static void insert_perf_sample(struct drm_i915_private *dev_priv,
else {
u32 target_size = sample_size - first->offset;
+ dev_priv->perf.command_stream_buf.status |=
+ I915_PERF_CMD_STREAM_BUF_STATUS_OVERFLOW;
release_perf_samples(dev_priv, target_size);
sample->offset = 0;
}
@@ -491,6 +493,8 @@ static void insert_perf_sample(struct drm_i915_private *dev_priv,
(first->offset - last->offset -
sample_size);
+ dev_priv->perf.command_stream_buf.status |=
+ I915_PERF_CMD_STREAM_BUF_STATUS_OVERFLOW;
release_perf_samples(dev_priv, target_size);
sample->offset = last->offset + sample_size;
}
@@ -1577,6 +1581,17 @@ static int oa_rcs_append_reports(struct i915_perf_stream *stream,
struct i915_perf_cs_sample *entry, *next;
LIST_HEAD(free_list);
int ret = 0;
+ u32 status = dev_priv->perf.command_stream_buf.status;
+
+ if (unlikely(status & I915_PERF_CMD_STREAM_BUF_STATUS_OVERFLOW)) {
+ ret = append_oa_status(stream, buf, count, offset,
+ DRM_I915_PERF_RECORD_OA_BUFFER_LOST);
+ if (ret)
+ return ret;
+
+ dev_priv->perf.command_stream_buf.status &=
+ ~I915_PERF_CMD_STREAM_BUF_STATUS_OVERFLOW;
+ }
spin_lock(&dev_priv->perf.sample_lock);
if (list_empty(&dev_priv->perf.cs_samples)) {
--
1.9.1
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