[PATCH 01/17] drm/i915: Hold a ref to the ring while retiring

[PATCH 01/17] drm/i915: Hold a ref to the ring while retiring

[Chris Wilson]

As the final request on a ring may hold the reference to this ring (via
retiring the last pinned context), we may find ourselves chasing a
dangling pointer on completion of the list.

A quick solution is to hold a reference to the ring itself as we retire
along it so that we only free it after we stop dereferencing it.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_request.c          |  6 +++++-
 drivers/gpu/drm/i915/intel_engine_types.h    |  2 ++
 drivers/gpu/drm/i915/intel_lrc.c             |  4 ++--
 drivers/gpu/drm/i915/intel_ringbuffer.c      |  9 +++++----
 drivers/gpu/drm/i915/intel_ringbuffer.h      | 13 ++++++++++++-
 drivers/gpu/drm/i915/selftests/mock_engine.c |  1 +
 6 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 9533a85cb0b3..0a3d94517d0a 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1332,8 +1332,12 @@ void i915_retire_requests(struct drm_i915_private *i915)
 	if (!i915->gt.active_requests)
 		return;
 
-	list_for_each_entry_safe(ring, tmp, &i915->gt.active_rings, active_link)
+	list_for_each_entry_safe(ring, tmp,
+				 &i915->gt.active_rings, active_link) {
+		intel_ring_get(ring); /* last rq holds reference! */
 		ring_retire_requests(ring);
+		intel_ring_put(ring);
+	}
 }
 
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
diff --git a/drivers/gpu/drm/i915/intel_engine_types.h b/drivers/gpu/drm/i915/intel_engine_types.h
index b0aa1f0d4e47..88ed7ba8886f 100644
--- a/drivers/gpu/drm/i915/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/intel_engine_types.h
@@ -9,6 +9,7 @@
 
 #include <linux/hashtable.h>
 #include <linux/irq_work.h>
+#include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/types.h>
 
@@ -51,6 +52,7 @@ struct intel_engine_hangcheck {
 };
 
 struct intel_ring {
+	struct kref ref;
 	struct i915_vma *vma;
 	void *vaddr;
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index dc3de09c7586..00fa4a3bc9a3 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1236,7 +1236,7 @@ static void execlists_submit_request(struct i915_request *request)
 
 static void __execlists_context_fini(struct intel_context *ce)
 {
-	intel_ring_free(ce->ring);
+	intel_ring_put(ce->ring);
 
 	GEM_BUG_ON(i915_gem_object_is_active(ce->state->obj));
 	i915_gem_object_put(ce->state->obj);
@@ -2869,7 +2869,7 @@ static int execlists_context_deferred_alloc(struct intel_context *ce,
 	return 0;
 
 error_ring_free:
-	intel_ring_free(ring);
+	intel_ring_put(ring);
 error_deref_obj:
 	i915_gem_object_put(ctx_obj);
 	return ret;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index f26f5cc1584c..ebac752e092d 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1311,6 +1311,7 @@ intel_engine_create_ring(struct intel_engine_cs *engine,
 	if (!ring)
 		return ERR_PTR(-ENOMEM);
 
+	kref_init(&ring->ref);
 	INIT_LIST_HEAD(&ring->request_list);
 	ring->timeline = i915_timeline_get(timeline);
 
@@ -1335,9 +1336,9 @@ intel_engine_create_ring(struct intel_engine_cs *engine,
 	return ring;
 }
 
-void
-intel_ring_free(struct intel_ring *ring)
+void intel_ring_free(struct kref *ref)
 {
+	struct intel_ring *ring = container_of(ref, typeof(*ring), ref);
 	struct drm_i915_gem_object *obj = ring->vma->obj;
 
 	i915_vma_close(ring->vma);
@@ -1591,7 +1592,7 @@ static int intel_init_ring_buffer(struct intel_engine_cs *engine)
 err_unpin:
 	intel_ring_unpin(ring);
 err_ring:
-	intel_ring_free(ring);
+	intel_ring_put(ring);
 err:
 	intel_engine_cleanup_common(engine);
 	return err;
@@ -1605,7 +1606,7 @@ void intel_engine_cleanup(struct intel_engine_cs *engine)
 		(I915_READ_MODE(engine) & MODE_IDLE) == 0);
 
 	intel_ring_unpin(engine->buffer);
-	intel_ring_free(engine->buffer);
+	intel_ring_put(engine->buffer);
 
 	if (engine->cleanup)
 		engine->cleanup(engine);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index e612bdca9fd9..a57489fcb302 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -231,7 +231,18 @@ int intel_ring_pin(struct intel_ring *ring);
 void intel_ring_reset(struct intel_ring *ring, u32 tail);
 unsigned int intel_ring_update_space(struct intel_ring *ring);
 void intel_ring_unpin(struct intel_ring *ring);
-void intel_ring_free(struct intel_ring *ring);
+void intel_ring_free(struct kref *ref);
+
+static inline struct intel_ring *intel_ring_get(struct intel_ring *ring)
+{
+	kref_get(&ring->ref);
+	return ring;
+}
+
+static inline void intel_ring_put(struct intel_ring *ring)
+{
+	kref_put(&ring->ref, intel_ring_free);
+}
 
 void intel_engine_stop(struct intel_engine_cs *engine);
 void intel_engine_cleanup(struct intel_engine_cs *engine);
diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index f6d120e05ee4..881450c694e9 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -57,6 +57,7 @@ static struct intel_ring *mock_ring(struct intel_engine_cs *engine)
 		return NULL;
 	}
 
+	kref_init(&ring->base.ref);
 	ring->base.size = sz;
 	ring->base.effective_size = sz;
 	ring->base.vaddr = (void *)(ring + 1);
-- 
2.20.1

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[PATCH 02/17] drm/i915: Lock the gem_context->active_list while dropping the link

[Chris Wilson]

On unpinning the intel_context, we remove it from the active list
inside the GEM context. This list is supposed to be guarded by the GEM
context mutex, so remember to take it!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_context.c         | 15 +++++++++++----
 drivers/gpu/drm/i915/intel_lrc.c             |  3 ---
 drivers/gpu/drm/i915/intel_ringbuffer.c      |  3 ---
 drivers/gpu/drm/i915/selftests/mock_engine.c |  2 --
 4 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_context.c b/drivers/gpu/drm/i915/intel_context.c
index 5a16c9bb2778..0ab894a058f6 100644
--- a/drivers/gpu/drm/i915/intel_context.c
+++ b/drivers/gpu/drm/i915/intel_context.c
@@ -165,13 +165,13 @@ intel_context_pin(struct i915_gem_context *ctx,
 		if (err)
 			goto err;
 
+		i915_gem_context_get(ctx);
+		GEM_BUG_ON(ce->gem_context != ctx);
+
 		mutex_lock(&ctx->mutex);
 		list_add(&ce->active_link, &ctx->active_engines);
 		mutex_unlock(&ctx->mutex);
 
-		i915_gem_context_get(ctx);
-		GEM_BUG_ON(ce->gem_context != ctx);
-
 		smp_mb__before_atomic(); /* flush pin before it is visible */
 	}
 
@@ -194,9 +194,16 @@ void intel_context_unpin(struct intel_context *ce)
 	/* We may be called from inside intel_context_pin() to evict another */
 	mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING);
 
-	if (likely(atomic_dec_and_test(&ce->pin_count)))
+	if (likely(atomic_dec_and_test(&ce->pin_count))) {
 		ce->ops->unpin(ce);
 
+		mutex_lock(&ce->gem_context->mutex);
+		list_del(&ce->active_link);
+		mutex_unlock(&ce->gem_context->mutex);
+
+		i915_gem_context_put(ce->gem_context);
+	}
+
 	mutex_unlock(&ce->pin_mutex);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 00fa4a3bc9a3..e0fb8853477c 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1283,9 +1283,6 @@ static void execlists_context_unpin(struct intel_context *ce)
 	ce->state->obj->pin_global--;
 	i915_gem_object_unpin_map(ce->state->obj);
 	i915_vma_unpin(ce->state);
-
-	list_del(&ce->active_link);
-	i915_gem_context_put(ce->gem_context);
 }
 
 static int __context_pin(struct i915_vma *vma)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index ebac752e092d..175070ea0f50 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1434,9 +1434,6 @@ static void ring_context_unpin(struct intel_context *ce)
 {
 	__context_unpin_ppgtt(ce->gem_context);
 	__context_unpin(ce);
-
-	list_del(&ce->active_link);
-	i915_gem_context_put(ce->gem_context);
 }
 
 static struct i915_vma *
diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index 881450c694e9..7641b74ada98 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -126,8 +126,6 @@ static void hw_delay_complete(struct timer_list *t)
 static void mock_context_unpin(struct intel_context *ce)
 {
 	mock_timeline_unpin(ce->ring->timeline);
-	list_del(&ce->active_link);
-	i915_gem_context_put(ce->gem_context);
 }
 
 static void mock_context_destroy(struct intel_context *ce)
-- 
2.20.1

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[PATCH 03/17] drm/i915: Hold a reference to the active HW context

[Chris Wilson]

For virtual engines, we need to keep the HW context alive while it
remains in use. For regular HW contexts, they are created and kept alive
until the end of the GEM context. For simplicity, generalise the
requirements and keep an active reference to each HW context.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_context.c      |  2 +-
 drivers/gpu/drm/i915/intel_context.c         |  6 ++++++
 drivers/gpu/drm/i915/intel_context.h         | 11 +++++++++++
 drivers/gpu/drm/i915/intel_context_types.h   |  6 +++++-
 drivers/gpu/drm/i915/intel_lrc.c             |  4 +++-
 drivers/gpu/drm/i915/intel_ringbuffer.c      |  4 +++-
 drivers/gpu/drm/i915/selftests/mock_engine.c |  7 ++++++-
 7 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index b6370225dcb5..4af51b689cbd 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -232,7 +232,7 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 	i915_ppgtt_put(ctx->ppgtt);
 
 	rbtree_postorder_for_each_entry_safe(it, n, &ctx->hw_contexts, node)
-		it->ops->destroy(it);
+		intel_context_put(it);
 
 	kfree(ctx->name);
 	put_pid(ctx->pid);
diff --git a/drivers/gpu/drm/i915/intel_context.c b/drivers/gpu/drm/i915/intel_context.c
index 0ab894a058f6..8931e0fee873 100644
--- a/drivers/gpu/drm/i915/intel_context.c
+++ b/drivers/gpu/drm/i915/intel_context.c
@@ -172,6 +172,7 @@ intel_context_pin(struct i915_gem_context *ctx,
 		list_add(&ce->active_link, &ctx->active_engines);
 		mutex_unlock(&ctx->mutex);
 
+		intel_context_get(ce);
 		smp_mb__before_atomic(); /* flush pin before it is visible */
 	}
 
@@ -192,6 +193,7 @@ void intel_context_unpin(struct intel_context *ce)
 		return;
 
 	/* We may be called from inside intel_context_pin() to evict another */
+	intel_context_get(ce);
 	mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING);
 
 	if (likely(atomic_dec_and_test(&ce->pin_count))) {
@@ -202,9 +204,11 @@ void intel_context_unpin(struct intel_context *ce)
 		mutex_unlock(&ce->gem_context->mutex);
 
 		i915_gem_context_put(ce->gem_context);
+		intel_context_put(ce);
 	}
 
 	mutex_unlock(&ce->pin_mutex);
+	intel_context_put(ce);
 }
 
 static void intel_context_retire(struct i915_active_request *active,
@@ -221,6 +225,8 @@ intel_context_init(struct intel_context *ce,
 		   struct i915_gem_context *ctx,
 		   struct intel_engine_cs *engine)
 {
+	kref_init(&ce->ref);
+
 	ce->gem_context = ctx;
 	ce->engine = engine;
 	ce->ops = engine->cops;
diff --git a/drivers/gpu/drm/i915/intel_context.h b/drivers/gpu/drm/i915/intel_context.h
index 9546d932406a..ebc861b1a49e 100644
--- a/drivers/gpu/drm/i915/intel_context.h
+++ b/drivers/gpu/drm/i915/intel_context.h
@@ -73,4 +73,15 @@ static inline void __intel_context_pin(struct intel_context *ce)
 
 void intel_context_unpin(struct intel_context *ce);
 
+static inline struct intel_context *intel_context_get(struct intel_context *ce)
+{
+	kref_get(&ce->ref);
+	return ce;
+}
+
+static inline void intel_context_put(struct intel_context *ce)
+{
+	kref_put(&ce->ref, ce->ops->destroy);
+}
+
 #endif /* __INTEL_CONTEXT_H__ */
diff --git a/drivers/gpu/drm/i915/intel_context_types.h b/drivers/gpu/drm/i915/intel_context_types.h
index 6dc9b4b9067b..624729a35875 100644
--- a/drivers/gpu/drm/i915/intel_context_types.h
+++ b/drivers/gpu/drm/i915/intel_context_types.h
@@ -7,6 +7,7 @@
 #ifndef __INTEL_CONTEXT_TYPES__
 #define __INTEL_CONTEXT_TYPES__
 
+#include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/rbtree.h>
@@ -22,7 +23,8 @@ struct intel_ring;
 struct intel_context_ops {
 	int (*pin)(struct intel_context *ce);
 	void (*unpin)(struct intel_context *ce);
-	void (*destroy)(struct intel_context *ce);
+
+	void (*destroy)(struct kref *kref);
 };
 
 /*
@@ -36,6 +38,8 @@ struct intel_sseu {
 };
 
 struct intel_context {
+	struct kref ref;
+
 	struct i915_gem_context *gem_context;
 	struct intel_engine_cs *engine;
 	struct intel_engine_cs *active;
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index e0fb8853477c..44e75bc520c1 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1242,8 +1242,10 @@ static void __execlists_context_fini(struct intel_context *ce)
 	i915_gem_object_put(ce->state->obj);
 }
 
-static void execlists_context_destroy(struct intel_context *ce)
+static void execlists_context_destroy(struct kref *kref)
 {
+	struct intel_context *ce = container_of(kref, typeof(*ce), ref);
+
 	GEM_BUG_ON(intel_context_is_pinned(ce));
 
 	if (ce->state)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 175070ea0f50..a021c9545649 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1354,8 +1354,10 @@ static void __ring_context_fini(struct intel_context *ce)
 	i915_gem_object_put(ce->state->obj);
 }
 
-static void ring_context_destroy(struct intel_context *ce)
+static void ring_context_destroy(struct kref *ref)
 {
+	struct intel_context *ce = container_of(ref, typeof(*ce), ref);
+
 	GEM_BUG_ON(intel_context_is_pinned(ce));
 
 	if (ce->state)
diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index 7641b74ada98..639d36eb904a 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -128,12 +128,16 @@ static void mock_context_unpin(struct intel_context *ce)
 	mock_timeline_unpin(ce->ring->timeline);
 }
 
-static void mock_context_destroy(struct intel_context *ce)
+static void mock_context_destroy(struct kref *ref)
 {
+	struct intel_context *ce = container_of(ref, typeof(*ce), ref);
+
 	GEM_BUG_ON(intel_context_is_pinned(ce));
 
 	if (ce->ring)
 		mock_ring_free(ce->ring);
+
+	intel_context_free(ce);
 }
 
 static int mock_context_pin(struct intel_context *ce)
@@ -151,6 +155,7 @@ static int mock_context_pin(struct intel_context *ce)
 static const struct intel_context_ops mock_context_ops = {
 	.pin = mock_context_pin,
 	.unpin = mock_context_unpin,
+
 	.destroy = mock_context_destroy,
 };
 
-- 
2.20.1

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[PATCH 04/17] drm/i915: Stop needlessly acquiring wakeref for debugfs/drop_caches_set

[Chris Wilson]

We only need to acquire a wakeref for ourselves for a few operations, as
most either already acquire their own wakeref or imply a wakeref. In
particular, it is i915_gem_set_wedged() that needed us to present it
with a wakeref, which is incongruous with its "use anywhere" ability.

Suggested-by: Yokoyama, Caz <caz.yokoyama@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Yokoyama, Caz <caz.yokoyama@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 12 ++++--------
 drivers/gpu/drm/i915/i915_reset.c   |  4 +++-
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 6a90558de213..08683dca7775 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3888,12 +3888,9 @@ static int
 i915_drop_caches_set(void *data, u64 val)
 {
 	struct drm_i915_private *i915 = data;
-	intel_wakeref_t wakeref;
-	int ret = 0;
 
 	DRM_DEBUG("Dropping caches: 0x%08llx [0x%08llx]\n",
 		  val, val & DROP_ALL);
-	wakeref = intel_runtime_pm_get(i915);
 
 	if (val & DROP_RESET_ACTIVE &&
 	    wait_for(intel_engines_are_idle(i915), I915_IDLE_ENGINES_TIMEOUT))
@@ -3902,9 +3899,11 @@ i915_drop_caches_set(void *data, u64 val)
 	/* No need to check and wait for gpu resets, only libdrm auto-restarts
 	 * on ioctls on -EAGAIN. */
 	if (val & (DROP_ACTIVE | DROP_RETIRE | DROP_RESET_SEQNO)) {
+		int ret;
+
 		ret = mutex_lock_interruptible(&i915->drm.struct_mutex);
 		if (ret)
-			goto out;
+			return ret;
 
 		if (val & DROP_ACTIVE)
 			ret = i915_gem_wait_for_idle(i915,
@@ -3943,10 +3942,7 @@ i915_drop_caches_set(void *data, u64 val)
 	if (val & DROP_FREED)
 		i915_gem_drain_freed_objects(i915);
 
-out:
-	intel_runtime_pm_put(i915, wakeref);
-
-	return ret;
+	return 0;
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(i915_drop_caches_fops,
diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c
index 3c08e08837d0..955c22b8dfc7 100644
--- a/drivers/gpu/drm/i915/i915_reset.c
+++ b/drivers/gpu/drm/i915/i915_reset.c
@@ -861,9 +861,11 @@ static void __i915_gem_set_wedged(struct drm_i915_private *i915)
 void i915_gem_set_wedged(struct drm_i915_private *i915)
 {
 	struct i915_gpu_error *error = &i915->gpu_error;
+	intel_wakeref_t wakeref;
 
 	mutex_lock(&error->wedge_mutex);
-	__i915_gem_set_wedged(i915);
+	with_intel_runtime_pm(i915, wakeref)
+		__i915_gem_set_wedged(i915);
 	mutex_unlock(&error->wedge_mutex);
 }
 
-- 
2.20.1

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[PATCH 05/17] drm/i915/selftests: Provide stub reset functions

[Chris Wilson]

If a test fails, we quite often mark the device as wedged. Provide the
stub functions so that we can wedge the mock device, and avoid exploding
on test failures.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109981
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/selftests/mock_engine.c | 36 ++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index 639d36eb904a..61744819172b 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -198,6 +198,37 @@ static void mock_submit_request(struct i915_request *request)
 	spin_unlock_irqrestore(&engine->hw_lock, flags);
 }
 
+static void mock_reset_prepare(struct intel_engine_cs *engine)
+{
+}
+
+static void mock_reset(struct intel_engine_cs *engine, bool stalled)
+{
+	GEM_BUG_ON(stalled);
+}
+
+static void mock_reset_finish(struct intel_engine_cs *engine)
+{
+}
+
+static void mock_cancel_requests(struct intel_engine_cs *engine)
+{
+	struct i915_request *request;
+	unsigned long flags;
+
+	spin_lock_irqsave(&engine->timeline.lock, flags);
+
+	/* Mark all submitted requests as skipped. */
+	list_for_each_entry(request, &engine->timeline.requests, sched.link) {
+		if (!i915_request_signaled(request))
+			dma_fence_set_error(&request->fence, -EIO);
+
+		i915_request_mark_complete(request);
+	}
+
+	spin_unlock_irqrestore(&engine->timeline.lock, flags);
+}
+
 struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
 				    const char *name,
 				    int id)
@@ -223,6 +254,11 @@ struct intel_engine_cs *mock_engine(struct drm_i915_private *i915,
 	engine->base.emit_fini_breadcrumb = mock_emit_breadcrumb;
 	engine->base.submit_request = mock_submit_request;
 
+	engine->base.reset.prepare = mock_reset_prepare;
+	engine->base.reset.reset = mock_reset;
+	engine->base.reset.finish = mock_reset_finish;
+	engine->base.cancel_requests = mock_cancel_requests;
+
 	if (i915_timeline_init(i915,
 			       &engine->base.timeline,
 			       engine->base.name,
-- 
2.20.1

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[PATCH 06/17] drm/i915: Switch to use HWS indices rather than addresses

[Chris Wilson]

If we use the STORE_DATA_INDEX function we can use a fixed offset and
avoid having to lookup up the engine HWS address. A step closer to being
able to emit the final breadcrumb during request_add rather than later
in the submission interrupt handler.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_guc_submission.c |  3 ++-
 drivers/gpu/drm/i915/intel_lrc.c            | 17 +++++++----------
 drivers/gpu/drm/i915/intel_ringbuffer.c     | 16 ++++++----------
 drivers/gpu/drm/i915/intel_ringbuffer.h     |  4 ++--
 4 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c
index 4a5727233419..c4ad73980988 100644
--- a/drivers/gpu/drm/i915/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/intel_guc_submission.c
@@ -583,7 +583,8 @@ static void inject_preempt_context(struct work_struct *work)
 		} else {
 			cs = gen8_emit_ggtt_write(cs,
 						  GUC_PREEMPT_FINISHED,
-						  addr);
+						  addr,
+						  0);
 			*cs++ = MI_NOOP;
 			*cs++ = MI_NOOP;
 		}
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 44e75bc520c1..5669823f6901 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -173,12 +173,6 @@ static void execlists_init_reg_state(u32 *reg_state,
 				     struct intel_engine_cs *engine,
 				     struct intel_ring *ring);
 
-static inline u32 intel_hws_hangcheck_address(struct intel_engine_cs *engine)
-{
-	return (i915_ggtt_offset(engine->status_page.vma) +
-		I915_GEM_HWS_HANGCHECK_ADDR);
-}
-
 static inline struct i915_priolist *to_priolist(struct rb_node *rb)
 {
 	return rb_entry(rb, struct i915_priolist, node);
@@ -2212,11 +2206,14 @@ static u32 *gen8_emit_fini_breadcrumb(struct i915_request *request, u32 *cs)
 {
 	cs = gen8_emit_ggtt_write(cs,
 				  request->fence.seqno,
-				  request->timeline->hwsp_offset);
+				  request->timeline->hwsp_offset,
+				  0);
 
 	cs = gen8_emit_ggtt_write(cs,
 				  intel_engine_next_hangcheck_seqno(request->engine),
-				  intel_hws_hangcheck_address(request->engine));
+				  I915_GEM_HWS_HANGCHECK_ADDR,
+				  MI_FLUSH_DW_STORE_INDEX);
+
 
 	*cs++ = MI_USER_INTERRUPT;
 	*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
@@ -2240,8 +2237,8 @@ static u32 *gen8_emit_fini_breadcrumb_rcs(struct i915_request *request, u32 *cs)
 
 	cs = gen8_emit_ggtt_write_rcs(cs,
 				      intel_engine_next_hangcheck_seqno(request->engine),
-				      intel_hws_hangcheck_address(request->engine),
-				      0);
+				      I915_GEM_HWS_HANGCHECK_ADDR,
+				      PIPE_CONTROL_STORE_DATA_INDEX);
 
 	*cs++ = MI_USER_INTERRUPT;
 	*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index a021c9545649..9e7ad17b5250 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -43,12 +43,6 @@
  */
 #define LEGACY_REQUEST_SIZE 200
 
-static inline u32 hws_hangcheck_address(struct intel_engine_cs *engine)
-{
-	return (i915_ggtt_offset(engine->status_page.vma) +
-		I915_GEM_HWS_HANGCHECK_ADDR);
-}
-
 unsigned int intel_ring_update_space(struct intel_ring *ring)
 {
 	unsigned int space;
@@ -317,8 +311,8 @@ static u32 *gen6_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
 	*cs++ = rq->fence.seqno;
 
 	*cs++ = GFX_OP_PIPE_CONTROL(4);
-	*cs++ = PIPE_CONTROL_QW_WRITE;
-	*cs++ = hws_hangcheck_address(rq->engine) | PIPE_CONTROL_GLOBAL_GTT;
+	*cs++ = PIPE_CONTROL_QW_WRITE | PIPE_CONTROL_STORE_DATA_INDEX;
+	*cs++ = I915_GEM_HWS_HANGCHECK_ADDR | PIPE_CONTROL_GLOBAL_GTT;
 	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
 
 	*cs++ = MI_USER_INTERRUPT;
@@ -423,8 +417,10 @@ static u32 *gen7_rcs_emit_breadcrumb(struct i915_request *rq, u32 *cs)
 	*cs++ = rq->fence.seqno;
 
 	*cs++ = GFX_OP_PIPE_CONTROL(4);
-	*cs++ = PIPE_CONTROL_QW_WRITE | PIPE_CONTROL_GLOBAL_GTT_IVB;
-	*cs++ = hws_hangcheck_address(rq->engine);
+	*cs++ = (PIPE_CONTROL_QW_WRITE |
+		 PIPE_CONTROL_STORE_DATA_INDEX |
+		 PIPE_CONTROL_GLOBAL_GTT_IVB);
+	*cs++ = I915_GEM_HWS_HANGCHECK_ADDR;
 	*cs++ = intel_engine_next_hangcheck_seqno(rq->engine);
 
 	*cs++ = MI_USER_INTERRUPT;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index a57489fcb302..a02c92dac5da 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -419,14 +419,14 @@ gen8_emit_ggtt_write_rcs(u32 *cs, u32 value, u32 gtt_offset, u32 flags)
 }
 
 static inline u32 *
-gen8_emit_ggtt_write(u32 *cs, u32 value, u32 gtt_offset)
+gen8_emit_ggtt_write(u32 *cs, u32 value, u32 gtt_offset, u32 flags)
 {
 	/* w/a: bit 5 needs to be zero for MI_FLUSH_DW address. */
 	GEM_BUG_ON(gtt_offset & (1 << 5));
 	/* Offset should be aligned to 8 bytes for both (QW/DW) write types */
 	GEM_BUG_ON(!IS_ALIGNED(gtt_offset, 8));
 
-	*cs++ = (MI_FLUSH_DW + 1) | MI_FLUSH_DW_OP_STOREDW;
+	*cs++ = (MI_FLUSH_DW + 1) | MI_FLUSH_DW_OP_STOREDW | flags;
 	*cs++ = gtt_offset | MI_FLUSH_DW_USE_GTT;
 	*cs++ = 0;
 	*cs++ = value;
-- 
2.20.1

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[PATCH 07/17] drm/i915: Introduce the i915_user_extension_method

[Chris Wilson]

An idea for extending uABI inspired by Vulkan's extension chains.
Instead of expanding the data struct for each ioctl every time we need
to add a new feature, define an extension chain instead. As we add
optional interfaces to control the ioctl, we define a new extension
struct that can be linked into the ioctl data only when required by the
user. The key advantage being able to ignore large control structs for
optional interfaces/extensions, while being able to process them in a
consistent manner.

In comparison to other extensible ioctls, the key difference is the
use of a linked chain of extension structs vs an array of tagged
pointers. For example,

struct drm_amdgpu_cs_chunk {
        __u32           chunk_id;
        __u32           length_dw;
        __u64           chunk_data;
};

struct drm_amdgpu_cs_in {
        __u32           ctx_id;
        __u32           bo_list_handle;
        __u32           num_chunks;
        __u32           _pad;
        __u64           chunks;
};

allows userspace to pass in array of pointers to extension structs, but
must therefore keep constructing that array along side the command stream.
In dynamic situations like that, a linked list is preferred and does not
similar from extra cache line misses as the extension structs themselves
must still be loaded separate to the chunks array.

v2: Apply the tail call optimisation directly to nip the worry of stack
overflow in the bud.
v3: Defend against recursion.

Opens:
- do we include the result as an out-field in each chain?
struct i915_user_extension {
	__u64 next_extension;
	__u64 name;
	__s32 result;
	__u32 mbz; /* reserved for future use */
};
* Undecided, so provision some room for future expansion.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/Makefile               |  1 +
 drivers/gpu/drm/i915/i915_user_extensions.c | 59 +++++++++++++++++++++
 drivers/gpu/drm/i915/i915_user_extensions.h | 20 +++++++
 drivers/gpu/drm/i915/i915_utils.h           | 12 +++++
 include/uapi/drm/i915_drm.h                 | 22 ++++++++
 5 files changed, 114 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/i915_user_extensions.c
 create mode 100644 drivers/gpu/drm/i915/i915_user_extensions.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 68fecf355471..60de05f3fa60 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -46,6 +46,7 @@ i915-y := i915_drv.o \
 	  i915_sw_fence.o \
 	  i915_syncmap.o \
 	  i915_sysfs.o \
+	  i915_user_extensions.o \
 	  intel_csr.o \
 	  intel_device_info.o \
 	  intel_pm.o \
diff --git a/drivers/gpu/drm/i915/i915_user_extensions.c b/drivers/gpu/drm/i915/i915_user_extensions.c
new file mode 100644
index 000000000000..d28c95221db4
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_user_extensions.c
@@ -0,0 +1,59 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2018 Intel Corporation
+ */
+
+#include <linux/nospec.h>
+#include <linux/sched/signal.h>
+#include <linux/uaccess.h>
+
+#include <uapi/drm/i915_drm.h>
+
+#include "i915_user_extensions.h"
+#include "i915_utils.h"
+
+int i915_user_extensions(struct i915_user_extension __user *ext,
+			 const i915_user_extension_fn *tbl,
+			 unsigned long count,
+			 void *data)
+{
+	unsigned int stackdepth = 512;
+
+	while (ext) {
+		int i, err;
+		u64 x;
+
+		if (!stackdepth--) /* recursion vs useful flexibility */
+			return -E2BIG;
+
+		err = check_user_mbz(&ext->flags);
+		if (err)
+			return err;
+
+		for (i = 0; i < ARRAY_SIZE(ext->rsvd); i++) {
+			err = check_user_mbz(&ext->rsvd[i]);
+			if (err)
+				return err;
+		}
+
+		if (get_user(x, &ext->name))
+			return -EFAULT;
+
+		err = -EINVAL;
+		if (x < count) {
+			x = array_index_nospec(x, count);
+			if (tbl[x])
+				err = tbl[x](ext, data);
+		}
+		if (err)
+			return err;
+
+		if (get_user(x, &ext->next_extension))
+			return -EFAULT;
+
+		ext = u64_to_user_ptr(x);
+	}
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/i915/i915_user_extensions.h b/drivers/gpu/drm/i915/i915_user_extensions.h
new file mode 100644
index 000000000000..313a510b068a
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_user_extensions.h
@@ -0,0 +1,20 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright © 2018 Intel Corporation
+ */
+
+#ifndef I915_USER_EXTENSIONS_H
+#define I915_USER_EXTENSIONS_H
+
+struct i915_user_extension;
+
+typedef int (*i915_user_extension_fn)(struct i915_user_extension __user *ext,
+				      void *data);
+
+int i915_user_extensions(struct i915_user_extension __user *ext,
+			 const i915_user_extension_fn *tbl,
+			 unsigned long count,
+			 void *data);
+
+#endif /* I915_USER_EXTENSIONS_H */
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 9726df37c4c4..51b658fa966d 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -105,6 +105,18 @@
 	__T;								\
 })
 
+#define container_of_user(ptr, type, member) ({				\
+	void __user *__mptr = (void __user *)(ptr);			\
+	BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&	\
+			 !__same_type(*(ptr), void),			\
+			 "pointer type mismatch in container_of()");	\
+	((type __user *)(__mptr - offsetof(type, member))); })
+
+#define check_user_mbz(U) ({						\
+	typeof(*(U)) mbz__;						\
+	get_user(mbz__, (U)) ? -EFAULT : mbz__ ? -EINVAL : 0;		\
+})
+
 static inline u64 ptr_to_u64(const void *ptr)
 {
 	return (uintptr_t)ptr;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index aa2d4c73a97d..1c69ed16a923 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -62,6 +62,28 @@ extern "C" {
 #define I915_ERROR_UEVENT		"ERROR"
 #define I915_RESET_UEVENT		"RESET"
 
+/*
+ * i915_user_extension: Base class for defining a chain of extensions
+ *
+ * Many interfaces need to grow over time. In most cases we can simply
+ * extend the struct and have userspace pass in more data. Another option,
+ * as demonstrated by Vulkan's approach to providing extensions for forward
+ * and backward compatibility, is to use a list of optional structs to
+ * provide those extra details.
+ *
+ * The key advantage to using an extension chain is that it allows us to
+ * redefine the interface more easily than an ever growing struct of
+ * increasing complexity, and for large parts of that interface to be
+ * entirely optional. The downside is more pointer chasing; chasing across
+ * the __user boundary with pointers encapsulated inside u64.
+ */
+struct i915_user_extension {
+	__u64 next_extension;
+	__u32 name;
+	__u32 flags; /* All undefined bits must be zero. */
+	__u32 rsvd[4]; /* Reserved for future use; must be zero. */
+};
+
 /*
  * MOCS indexes used for GPU surfaces, defining the cacheability of the
  * surface data and the coherency for this data wrt. CPU vs. GPU accesses.
-- 
2.20.1

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[PATCH 08/17] drm/i915: Create/destroy VM (ppGTT) for use with contexts

[Chris Wilson]

In preparation to making the ppGTT binding for a context explicit (to
facilitate reusing the same ppGTT between different contexts), allow the
user to create and destroy named ppGTT.

v2: Replace global barrier for swapping over the ppgtt and tlbs with a
local context barrier (Tvrtko)
v3: serialise with struct_mutex; it's lazy but required dammit
v4: Rewrite igt_ctx_shared_exec to be more different (aimed to be more
similarly, turned out different!)

v2: Fix up test unwind for aliasing-ppgtt (snb)
v3: Tighten language for uapi struct drm_i915_gem_vm_control.
v4: Patch the context image for runtime ppgtt switching!

Testcase: igt/gem_ctx_param/vm
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c               |   2 +
 drivers/gpu/drm/i915/i915_drv.h               |   3 +
 drivers/gpu/drm/i915/i915_gem_context.c       | 322 +++++++++++++++++-
 drivers/gpu/drm/i915/i915_gem_context.h       |   5 +
 drivers/gpu/drm/i915/i915_gem_gtt.c           |  30 +-
 drivers/gpu/drm/i915/i915_gem_gtt.h           |  17 +-
 drivers/gpu/drm/i915/selftests/huge_pages.c   |   1 -
 .../gpu/drm/i915/selftests/i915_gem_context.c | 237 ++++++++++---
 drivers/gpu/drm/i915/selftests/i915_gem_gtt.c |   1 -
 drivers/gpu/drm/i915/selftests/mock_context.c |   8 +-
 include/uapi/drm/i915_drm.h                   |  43 +++
 11 files changed, 594 insertions(+), 75 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 0d743907e7bc..5d53efc4c5d9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -3121,6 +3121,8 @@ static const struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I915_PERF_ADD_CONFIG, i915_perf_add_config_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_PERF_REMOVE_CONFIG, i915_perf_remove_config_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_QUERY, i915_query_ioctl, DRM_UNLOCKED|DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_GEM_VM_CREATE, i915_gem_vm_create_ioctl, DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_GEM_VM_DESTROY, i915_gem_vm_destroy_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 dc63303225fc..4675355916ff 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -218,6 +218,9 @@ struct drm_i915_file_private {
 	} mm;
 	struct idr context_idr;
 
+	struct mutex vm_lock;
+	struct idr vm_idr;
+
 	unsigned int bsd_engine;
 
 /*
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 4af51b689cbd..71464ae91d61 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -120,12 +120,15 @@ static void lut_close(struct i915_gem_context *ctx)
 		list_del(&lut->obj_link);
 		i915_lut_handle_free(lut);
 	}
+	INIT_LIST_HEAD(&ctx->handles_list);
 
 	rcu_read_lock();
 	radix_tree_for_each_slot(slot, &ctx->handles_vma, &iter, 0) {
 		struct i915_vma *vma = rcu_dereference_raw(*slot);
 
 		radix_tree_iter_delete(&ctx->handles_vma, &iter, slot);
+
+		vma->open_count--;
 		__i915_gem_object_release_unless_active(vma->obj);
 	}
 	rcu_read_unlock();
@@ -306,7 +309,7 @@ static void context_close(struct i915_gem_context *ctx)
 	 */
 	lut_close(ctx);
 	if (ctx->ppgtt)
-		i915_ppgtt_close(&ctx->ppgtt->vm);
+		i915_ppgtt_close(ctx->ppgtt);
 
 	ctx->file_priv = ERR_PTR(-EBADF);
 	i915_gem_context_put(ctx);
@@ -417,6 +420,32 @@ static void __destroy_hw_context(struct i915_gem_context *ctx,
 	context_close(ctx);
 }
 
+static struct i915_hw_ppgtt *
+__set_ppgtt(struct i915_gem_context *ctx, struct i915_hw_ppgtt *ppgtt)
+{
+	struct i915_hw_ppgtt *old = ctx->ppgtt;
+
+	i915_ppgtt_open(ppgtt);
+	ctx->ppgtt = i915_ppgtt_get(ppgtt);
+
+	ctx->desc_template = default_desc_template(ctx->i915, ppgtt);
+
+	return old;
+}
+
+static void __assign_ppgtt(struct i915_gem_context *ctx,
+			   struct i915_hw_ppgtt *ppgtt)
+{
+	if (ppgtt == ctx->ppgtt)
+		return;
+
+	ppgtt = __set_ppgtt(ctx, ppgtt);
+	if (ppgtt) {
+		i915_ppgtt_close(ppgtt);
+		i915_ppgtt_put(ppgtt);
+	}
+}
+
 static struct i915_gem_context *
 i915_gem_create_context(struct drm_i915_private *dev_priv,
 			struct drm_i915_file_private *file_priv)
@@ -443,8 +472,8 @@ i915_gem_create_context(struct drm_i915_private *dev_priv,
 			return ERR_CAST(ppgtt);
 		}
 
-		ctx->ppgtt = ppgtt;
-		ctx->desc_template = default_desc_template(dev_priv, ppgtt);
+		__assign_ppgtt(ctx, ppgtt);
+		i915_ppgtt_put(ppgtt);
 	}
 
 	trace_i915_context_create(ctx);
@@ -625,19 +654,29 @@ static int context_idr_cleanup(int id, void *p, void *data)
 	return 0;
 }
 
+static int vm_idr_cleanup(int id, void *p, void *data)
+{
+	i915_ppgtt_put(p);
+	return 0;
+}
+
 int i915_gem_context_open(struct drm_i915_private *i915,
 			  struct drm_file *file)
 {
 	struct drm_i915_file_private *file_priv = file->driver_priv;
 	struct i915_gem_context *ctx;
 
+	mutex_init(&file_priv->vm_lock);
+
 	idr_init(&file_priv->context_idr);
+	idr_init_base(&file_priv->vm_idr, 1);
 
 	mutex_lock(&i915->drm.struct_mutex);
 	ctx = i915_gem_create_context(i915, file_priv);
 	mutex_unlock(&i915->drm.struct_mutex);
 	if (IS_ERR(ctx)) {
 		idr_destroy(&file_priv->context_idr);
+		idr_destroy(&file_priv->vm_idr);
 		return PTR_ERR(ctx);
 	}
 
@@ -654,6 +693,89 @@ void i915_gem_context_close(struct drm_file *file)
 
 	idr_for_each(&file_priv->context_idr, context_idr_cleanup, NULL);
 	idr_destroy(&file_priv->context_idr);
+
+	idr_for_each(&file_priv->vm_idr, vm_idr_cleanup, NULL);
+	idr_destroy(&file_priv->vm_idr);
+
+	mutex_destroy(&file_priv->vm_lock);
+}
+
+int i915_gem_vm_create_ioctl(struct drm_device *dev, void *data,
+			     struct drm_file *file)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	struct drm_i915_gem_vm_control *args = data;
+	struct drm_i915_file_private *file_priv = file->driver_priv;
+	struct i915_hw_ppgtt *ppgtt;
+	int err;
+
+	if (!HAS_FULL_PPGTT(i915))
+		return -ENODEV;
+
+	if (args->flags)
+		return -EINVAL;
+
+	if (args->extensions)
+		return -EINVAL;
+
+	ppgtt = i915_ppgtt_create(i915, file_priv);
+	if (IS_ERR(ppgtt))
+		return PTR_ERR(ppgtt);
+
+	err = mutex_lock_interruptible(&file_priv->vm_lock);
+	if (err)
+		goto err_put;
+
+	err = idr_alloc(&file_priv->vm_idr, ppgtt, 0, 0, GFP_KERNEL);
+	mutex_unlock(&file_priv->vm_lock);
+	if (err < 0)
+		goto err_put;
+
+	GEM_BUG_ON(err == 0); /* reserved for default/unassigned ppgtt */
+	ppgtt->user_handle = err;
+	args->id = err;
+	return 0;
+
+err_put:
+	i915_ppgtt_put(ppgtt);
+	return err;
+}
+
+int i915_gem_vm_destroy_ioctl(struct drm_device *dev, void *data,
+			      struct drm_file *file)
+{
+	struct drm_i915_file_private *file_priv = file->driver_priv;
+	struct drm_i915_gem_vm_control *args = data;
+	struct i915_hw_ppgtt *ppgtt;
+	int err;
+	u32 id;
+
+	if (args->flags)
+		return -EINVAL;
+
+	if (args->extensions)
+		return -EINVAL;
+
+	id = args->id;
+	if (!id)
+		return -ENOENT;
+
+	err = mutex_lock_interruptible(&file_priv->vm_lock);
+	if (err)
+		return err;
+
+	ppgtt = idr_remove(&file_priv->vm_idr, id);
+	if (ppgtt) {
+		GEM_BUG_ON(!ppgtt->user_handle);
+		ppgtt->user_handle = 0;
+	}
+
+	mutex_unlock(&file_priv->vm_lock);
+	if (!ppgtt)
+		return -ENOENT;
+
+	i915_ppgtt_put(ppgtt);
+	return 0;
 }
 
 static struct i915_request *
@@ -697,12 +819,13 @@ static void cb_retire(struct i915_active *base)
 I915_SELFTEST_DECLARE(static unsigned long context_barrier_inject_fault);
 static int context_barrier_task(struct i915_gem_context *ctx,
 				unsigned long engines,
+				int (*emit)(struct i915_request *rq, void *data),
 				void (*task)(void *data),
 				void *data)
 {
 	struct drm_i915_private *i915 = ctx->i915;
 	struct context_barrier_task *cb;
-	struct intel_context *ce;
+	struct intel_context *ce, *next;
 	intel_wakeref_t wakeref;
 	int err = 0;
 
@@ -717,11 +840,11 @@ static int context_barrier_task(struct i915_gem_context *ctx,
 	i915_active_acquire(&cb->base);
 
 	wakeref = intel_runtime_pm_get(i915);
-	list_for_each_entry(ce, &ctx->active_engines, active_link) {
+	rbtree_postorder_for_each_entry_safe(ce, next, &ctx->hw_contexts, node) {
 		struct intel_engine_cs *engine = ce->engine;
 		struct i915_request *rq;
 
-		if (!(ce->engine->mask & engines))
+		if (!(engine->mask & engines))
 			continue;
 
 		if (I915_SELFTEST_ONLY(context_barrier_inject_fault &
@@ -736,7 +859,12 @@ static int context_barrier_task(struct i915_gem_context *ctx,
 			break;
 		}
 
-		err = i915_active_ref(&cb->base, rq->fence.context, rq);
+		err = 0;
+		if (emit)
+			err = emit(rq, data);
+		if (err == 0)
+			err = i915_active_ref(&cb->base, rq->fence.context, rq);
+
 		i915_request_add(rq);
 		if (err)
 			break;
@@ -799,6 +927,173 @@ int i915_gem_switch_to_kernel_context(struct drm_i915_private *i915,
 	return 0;
 }
 
+static int get_ppgtt(struct i915_gem_context *ctx,
+		     struct drm_i915_gem_context_param *args)
+{
+	struct drm_i915_file_private *file_priv = ctx->file_priv;
+	struct i915_hw_ppgtt *ppgtt;
+	int ret;
+
+	if (!ctx->ppgtt)
+		return -ENODEV;
+
+	/* XXX rcu acquire? */
+	ret = mutex_lock_interruptible(&ctx->i915->drm.struct_mutex);
+	if (ret)
+		return ret;
+
+	ppgtt = i915_ppgtt_get(ctx->ppgtt);
+	mutex_unlock(&ctx->i915->drm.struct_mutex);
+
+	ret = mutex_lock_interruptible(&file_priv->vm_lock);
+	if (ret)
+		goto err_put;
+
+	if (!ppgtt->user_handle) {
+		ret = idr_alloc(&file_priv->vm_idr, ppgtt, 0, 0, GFP_KERNEL);
+		GEM_BUG_ON(!ret);
+		if (ret < 0)
+			goto err_unlock;
+
+		ppgtt->user_handle = ret;
+		i915_ppgtt_get(ppgtt);
+	}
+
+	args->size = 0;
+	args->value = ppgtt->user_handle;
+
+	ret = 0;
+err_unlock:
+	mutex_unlock(&file_priv->vm_lock);
+err_put:
+	i915_ppgtt_put(ppgtt);
+	return ret;
+}
+
+static void set_ppgtt_barrier(void *data)
+{
+	struct i915_hw_ppgtt *old = data;
+
+	if (INTEL_GEN(old->vm.i915) < 8)
+		gen6_ppgtt_unpin_all(old);
+
+	i915_ppgtt_close(old);
+	i915_ppgtt_put(old);
+}
+
+static int emit_ppgtt_update(struct i915_request *rq, void *data)
+{
+	struct i915_hw_ppgtt *ppgtt = rq->gem_context->ppgtt;
+	struct intel_engine_cs *engine = rq->engine;
+	u32 *cs;
+	int i;
+
+	if (i915_vm_is_48bit(&ppgtt->vm)) {
+		const dma_addr_t pd_daddr = px_dma(&ppgtt->pml4);
+
+		cs = intel_ring_begin(rq, 6);
+		if (IS_ERR(cs))
+			return PTR_ERR(cs);
+
+		*cs++ = MI_LOAD_REGISTER_IMM(2);
+
+		*cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(engine, 0));
+		*cs++ = upper_32_bits(pd_daddr);
+		*cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(engine, 0));
+		*cs++ = lower_32_bits(pd_daddr);
+
+		*cs++ = MI_NOOP;
+		intel_ring_advance(rq, cs);
+	} else if (HAS_LOGICAL_RING_CONTEXTS(engine->i915)) {
+		cs = intel_ring_begin(rq, 4 * GEN8_3LVL_PDPES + 2);
+		if (IS_ERR(cs))
+			return PTR_ERR(cs);
+
+		*cs++ = MI_LOAD_REGISTER_IMM(2 * GEN8_3LVL_PDPES);
+		for (i = GEN8_3LVL_PDPES; i--; ) {
+			const dma_addr_t pd_daddr = i915_page_dir_dma_addr(ppgtt, i);
+
+			*cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(engine, i));
+			*cs++ = upper_32_bits(pd_daddr);
+			*cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(engine, i));
+			*cs++ = lower_32_bits(pd_daddr);
+		}
+		*cs++ = MI_NOOP;
+		intel_ring_advance(rq, cs);
+	} else {
+		/* ppGTT is not part of the legacy context image */
+		gen6_ppgtt_pin(ppgtt);
+	}
+
+	return 0;
+}
+
+static int set_ppgtt(struct i915_gem_context *ctx,
+		     struct drm_i915_gem_context_param *args)
+{
+	struct drm_i915_file_private *file_priv = ctx->file_priv;
+	struct i915_hw_ppgtt *ppgtt, *old;
+	int err;
+
+	if (args->size)
+		return -EINVAL;
+
+	if (!ctx->ppgtt)
+		return -ENODEV;
+
+	if (upper_32_bits(args->value))
+		return -ENOENT;
+
+	err = mutex_lock_interruptible(&file_priv->vm_lock);
+	if (err)
+		return err;
+
+	ppgtt = idr_find(&file_priv->vm_idr, args->value);
+	if (ppgtt) {
+		GEM_BUG_ON(ppgtt->user_handle != args->value);
+		i915_ppgtt_get(ppgtt);
+	}
+	mutex_unlock(&file_priv->vm_lock);
+	if (!ppgtt)
+		return -ENOENT;
+
+	err = mutex_lock_interruptible(&ctx->i915->drm.struct_mutex);
+	if (err)
+		goto out;
+
+	if (ppgtt == ctx->ppgtt)
+		goto unlock;
+
+	/* Teardown the existing obj:vma cache, it will have to be rebuilt. */
+	lut_close(ctx);
+
+	old = __set_ppgtt(ctx, ppgtt);
+
+	/*
+	 * We need to flush any requests using the current ppgtt before
+	 * we release it as the requests do not hold a reference themselves,
+	 * only indirectly through the context.
+	 */
+	err = context_barrier_task(ctx, ALL_ENGINES,
+				   emit_ppgtt_update,
+				   set_ppgtt_barrier,
+				   old);
+	if (err) {
+		ctx->ppgtt = old;
+		ctx->desc_template = default_desc_template(ctx->i915, old);
+
+		i915_ppgtt_close(ppgtt);
+		i915_ppgtt_put(ppgtt);
+	}
+
+unlock:
+	mutex_unlock(&ctx->i915->drm.struct_mutex);
+
+out:
+	i915_ppgtt_put(ppgtt);
+	return err;
+}
+
 static bool client_is_banned(struct drm_i915_file_private *file_priv)
 {
 	return atomic_read(&file_priv->ban_score) >= I915_CLIENT_SCORE_BANNED;
@@ -973,6 +1268,9 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
 	case I915_CONTEXT_PARAM_SSEU:
 		ret = get_sseu(ctx, args);
 		break;
+	case I915_CONTEXT_PARAM_VM:
+		ret = get_ppgtt(ctx, args);
+		break;
 	default:
 		ret = -EINVAL;
 		break;
@@ -1274,9 +1572,6 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 		return -ENOENT;
 
 	switch (args->param) {
-	case I915_CONTEXT_PARAM_BAN_PERIOD:
-		ret = -EINVAL;
-		break;
 	case I915_CONTEXT_PARAM_NO_ZEROMAP:
 		if (args->size)
 			ret = -EINVAL;
@@ -1332,9 +1627,16 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 					I915_USER_PRIORITY(priority);
 		}
 		break;
+
 	case I915_CONTEXT_PARAM_SSEU:
 		ret = set_sseu(ctx, args);
 		break;
+
+	case I915_CONTEXT_PARAM_VM:
+		ret = set_ppgtt(ctx, args);
+		break;
+
+	case I915_CONTEXT_PARAM_BAN_PERIOD:
 	default:
 		ret = -EINVAL;
 		break;
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index 5a32c4b4816f..1e670372892c 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -153,6 +153,11 @@ void i915_gem_context_release(struct kref *ctx_ref);
 struct i915_gem_context *
 i915_gem_context_create_gvt(struct drm_device *dev);
 
+int i915_gem_vm_create_ioctl(struct drm_device *dev, void *data,
+			     struct drm_file *file);
+int i915_gem_vm_destroy_ioctl(struct drm_device *dev, void *data,
+			      struct drm_file *file);
+
 int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
 				  struct drm_file *file);
 int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index dac08d9c3fab..c0972cd95283 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1939,6 +1939,8 @@ int gen6_ppgtt_pin(struct i915_hw_ppgtt *base)
 	struct gen6_hw_ppgtt *ppgtt = to_gen6_ppgtt(base);
 	int err;
 
+	GEM_BUG_ON(ppgtt->base.vm.closed);
+
 	/*
 	 * Workaround the limited maximum vma->pin_count and the aliasing_ppgtt
 	 * which will be pinned into every active context.
@@ -1977,6 +1979,17 @@ void gen6_ppgtt_unpin(struct i915_hw_ppgtt *base)
 	i915_vma_unpin(ppgtt->vma);
 }
 
+void gen6_ppgtt_unpin_all(struct i915_hw_ppgtt *base)
+{
+	struct gen6_hw_ppgtt *ppgtt = to_gen6_ppgtt(base);
+
+	if (!ppgtt->pin_count)
+		return;
+
+	ppgtt->pin_count = 0;
+	i915_vma_unpin(ppgtt->vma);
+}
+
 static struct i915_hw_ppgtt *gen6_ppgtt_create(struct drm_i915_private *i915)
 {
 	struct i915_ggtt * const ggtt = &i915->ggtt;
@@ -2099,10 +2112,21 @@ i915_ppgtt_create(struct drm_i915_private *i915,
 	return ppgtt;
 }
 
-void i915_ppgtt_close(struct i915_address_space *vm)
+void i915_ppgtt_open(struct i915_hw_ppgtt *ppgtt)
 {
-	GEM_BUG_ON(vm->closed);
-	vm->closed = true;
+	GEM_BUG_ON(ppgtt->vm.closed);
+
+	ppgtt->open_count++;
+}
+
+void i915_ppgtt_close(struct i915_hw_ppgtt *ppgtt)
+{
+	GEM_BUG_ON(!ppgtt->open_count);
+	if (--ppgtt->open_count)
+		return;
+
+	GEM_BUG_ON(ppgtt->vm.closed);
+	ppgtt->vm.closed = true;
 }
 
 static void ppgtt_destroy_vma(struct i915_address_space *vm)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index a47e11e6fc1b..5973d92e45fc 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -391,11 +391,15 @@ struct i915_hw_ppgtt {
 	struct kref ref;
 
 	unsigned long pd_dirty_engines;
+	unsigned int open_count;
+
 	union {
 		struct i915_pml4 pml4;		/* GEN8+ & 48b PPGTT */
 		struct i915_page_directory_pointer pdp;	/* GEN8+ */
 		struct i915_page_directory pd;		/* GEN6-7 */
 	};
+
+	u32 user_handle;
 };
 
 struct gen6_hw_ppgtt {
@@ -606,12 +610,16 @@ int i915_ppgtt_init_hw(struct drm_i915_private *dev_priv);
 void i915_ppgtt_release(struct kref *kref);
 struct i915_hw_ppgtt *i915_ppgtt_create(struct drm_i915_private *dev_priv,
 					struct drm_i915_file_private *fpriv);
-void i915_ppgtt_close(struct i915_address_space *vm);
-static inline void i915_ppgtt_get(struct i915_hw_ppgtt *ppgtt)
+
+void i915_ppgtt_open(struct i915_hw_ppgtt *ppgtt);
+void i915_ppgtt_close(struct i915_hw_ppgtt *ppgtt);
+
+static inline struct i915_hw_ppgtt *i915_ppgtt_get(struct i915_hw_ppgtt *ppgtt)
 {
-	if (ppgtt)
-		kref_get(&ppgtt->ref);
+	kref_get(&ppgtt->ref);
+	return ppgtt;
 }
+
 static inline void i915_ppgtt_put(struct i915_hw_ppgtt *ppgtt)
 {
 	if (ppgtt)
@@ -620,6 +628,7 @@ static inline void i915_ppgtt_put(struct i915_hw_ppgtt *ppgtt)
 
 int gen6_ppgtt_pin(struct i915_hw_ppgtt *base);
 void gen6_ppgtt_unpin(struct i915_hw_ppgtt *base);
+void gen6_ppgtt_unpin_all(struct i915_hw_ppgtt *base);
 
 void i915_check_and_clear_faults(struct drm_i915_private *dev_priv);
 void i915_gem_suspend_gtt_mappings(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/selftests/huge_pages.c b/drivers/gpu/drm/i915/selftests/huge_pages.c
index 1e66cff985f8..0b7740dc18cb 100644
--- a/drivers/gpu/drm/i915/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/selftests/huge_pages.c
@@ -1734,7 +1734,6 @@ int i915_gem_huge_page_mock_selftests(void)
 	err = i915_subtests(tests, ppgtt);
 
 out_close:
-	i915_ppgtt_close(&ppgtt->vm);
 	i915_ppgtt_put(ppgtt);
 
 out_unlock:
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index 4399ef9ebf15..1ba354a916c0 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -372,7 +372,8 @@ static int cpu_fill(struct drm_i915_gem_object *obj, u32 value)
 	return 0;
 }
 
-static int cpu_check(struct drm_i915_gem_object *obj, unsigned int max)
+static noinline int cpu_check(struct drm_i915_gem_object *obj,
+			      unsigned int idx, unsigned int max)
 {
 	unsigned int n, m, needs_flush;
 	int err;
@@ -390,8 +391,10 @@ static int cpu_check(struct drm_i915_gem_object *obj, unsigned int max)
 
 		for (m = 0; m < max; m++) {
 			if (map[m] != m) {
-				pr_err("Invalid value at page %d, offset %d: found %x expected %x\n",
-				       n, m, map[m], m);
+				pr_err("%pS: Invalid value at object %d page %d/%ld, offset %d/%d: found %x expected %x\n",
+				       __builtin_return_address(0), idx,
+				       n, real_page_count(obj), m, max,
+				       map[m], m);
 				err = -EINVAL;
 				goto out_unmap;
 			}
@@ -399,8 +402,9 @@ static int cpu_check(struct drm_i915_gem_object *obj, unsigned int max)
 
 		for (; m < DW_PER_PAGE; m++) {
 			if (map[m] != STACK_MAGIC) {
-				pr_err("Invalid value at page %d, offset %d: found %x expected %x\n",
-				       n, m, map[m], STACK_MAGIC);
+				pr_err("%pS: Invalid value at object %d page %d, offset %d: found %x expected %x (uninitialised)\n",
+				       __builtin_return_address(0), idx, n, m,
+				       map[m], STACK_MAGIC);
 				err = -EINVAL;
 				goto out_unmap;
 			}
@@ -478,12 +482,8 @@ static unsigned long max_dwords(struct drm_i915_gem_object *obj)
 static int igt_ctx_exec(void *arg)
 {
 	struct drm_i915_private *i915 = arg;
-	struct drm_i915_gem_object *obj = NULL;
-	unsigned long ncontexts, ndwords, dw;
-	struct igt_live_test t;
-	struct drm_file *file;
-	IGT_TIMEOUT(end_time);
-	LIST_HEAD(objects);
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
 	int err = -ENODEV;
 
 	/*
@@ -495,44 +495,169 @@ static int igt_ctx_exec(void *arg)
 	if (!DRIVER_CAPS(i915)->has_logical_contexts)
 		return 0;
 
+	for_each_engine(engine, i915, id) {
+		struct drm_i915_gem_object *obj = NULL;
+		unsigned long ncontexts, ndwords, dw;
+		struct igt_live_test t;
+		struct drm_file *file;
+		IGT_TIMEOUT(end_time);
+		LIST_HEAD(objects);
+
+		if (!intel_engine_can_store_dword(engine))
+			continue;
+
+		if (!engine->context_size)
+			continue; /* No logical context support in HW */
+
+		file = mock_file(i915);
+		if (IS_ERR(file))
+			return PTR_ERR(file);
+
+		mutex_lock(&i915->drm.struct_mutex);
+
+		err = igt_live_test_begin(&t, i915, __func__, engine->name);
+		if (err)
+			goto out_unlock;
+
+		ncontexts = 0;
+		ndwords = 0;
+		dw = 0;
+		while (!time_after(jiffies, end_time)) {
+			struct i915_gem_context *ctx;
+			intel_wakeref_t wakeref;
+
+			ctx = i915_gem_create_context(i915, file->driver_priv);
+			if (IS_ERR(ctx)) {
+				err = PTR_ERR(ctx);
+				goto out_unlock;
+			}
+
+			if (!obj) {
+				obj = create_test_object(ctx, file, &objects);
+				if (IS_ERR(obj)) {
+					err = PTR_ERR(obj);
+					goto out_unlock;
+				}
+			}
+
+			with_intel_runtime_pm(i915, wakeref)
+				err = gpu_fill(obj, ctx, engine, dw);
+			if (err) {
+				pr_err("Failed to fill dword %lu [%lu/%lu] with gpu (%s) in ctx %u [full-ppgtt? %s], err=%d\n",
+				       ndwords, dw, max_dwords(obj),
+				       engine->name, ctx->hw_id,
+				       yesno(!!ctx->ppgtt), err);
+				goto out_unlock;
+			}
+
+			if (++dw == max_dwords(obj)) {
+				obj = NULL;
+				dw = 0;
+			}
+
+			ndwords++;
+			ncontexts++;
+		}
+
+		pr_info("Submitted %lu contexts to %s, filling %lu dwords\n",
+			ncontexts, engine->name, ndwords);
+
+		ncontexts = dw = 0;
+		list_for_each_entry(obj, &objects, st_link) {
+			unsigned int rem =
+				min_t(unsigned int, ndwords - dw, max_dwords(obj));
+
+			err = cpu_check(obj, ncontexts++, rem);
+			if (err)
+				break;
+
+			dw += rem;
+		}
+
+out_unlock:
+		if (igt_live_test_end(&t))
+			err = -EIO;
+		mutex_unlock(&i915->drm.struct_mutex);
+
+		mock_file_free(i915, file);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int igt_shared_ctx_exec(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct i915_gem_context *parent;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	struct igt_live_test t;
+	struct drm_file *file;
+	int err = 0;
+
+	/*
+	 * Create a few different contexts with the same mm and write
+	 * through each ctx using the GPU making sure those writes end
+	 * up in the expected pages of our obj.
+	 */
+	if (!DRIVER_CAPS(i915)->has_logical_contexts)
+		return 0;
+
 	file = mock_file(i915);
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
 	mutex_lock(&i915->drm.struct_mutex);
 
+	parent = i915_gem_create_context(i915, file->driver_priv);
+	if (IS_ERR(parent)) {
+		err = PTR_ERR(parent);
+		goto out_unlock;
+	}
+
+	if (!parent->ppgtt) { /* not full-ppgtt; nothing to share */
+		err = -ENODEV;
+		goto out_unlock;
+	}
+
 	err = igt_live_test_begin(&t, i915, __func__, "");
 	if (err)
 		goto out_unlock;
 
-	ncontexts = 0;
-	ndwords = 0;
-	dw = 0;
-	while (!time_after(jiffies, end_time)) {
-		struct intel_engine_cs *engine;
-		struct i915_gem_context *ctx;
-		unsigned int id;
+	for_each_engine(engine, i915, id) {
+		unsigned long ncontexts, ndwords, dw;
+		struct drm_i915_gem_object *obj = NULL;
+		struct i915_gem_context *ctx = NULL;
+		IGT_TIMEOUT(end_time);
+		LIST_HEAD(objects);
 
-		ctx = i915_gem_create_context(i915, file->driver_priv);
-		if (IS_ERR(ctx)) {
-			err = PTR_ERR(ctx);
-			goto out_unlock;
-		}
+		if (!intel_engine_can_store_dword(engine))
+			continue;
 
-		for_each_engine(engine, i915, id) {
+		dw = 0;
+		ndwords = 0;
+		ncontexts = 0;
+		while (!time_after(jiffies, end_time)) {
 			intel_wakeref_t wakeref;
 
-			if (!engine->context_size)
-				continue; /* No logical context support in HW */
+			if (ctx)
+				__destroy_hw_context(ctx, file->driver_priv);
 
-			if (!intel_engine_can_store_dword(engine))
-				continue;
+			ctx = i915_gem_create_context(i915, file->driver_priv);
+			if (IS_ERR(ctx)) {
+				err = PTR_ERR(ctx);
+				goto out_test;
+			}
+
+			__assign_ppgtt(ctx, parent->ppgtt);
 
 			if (!obj) {
-				obj = create_test_object(ctx, file, &objects);
+				obj = create_test_object(parent, file, &objects);
 				if (IS_ERR(obj)) {
 					err = PTR_ERR(obj);
-					goto out_unlock;
+					goto out_test;
 				}
 			}
 
@@ -544,35 +669,36 @@ static int igt_ctx_exec(void *arg)
 				       ndwords, dw, max_dwords(obj),
 				       engine->name, ctx->hw_id,
 				       yesno(!!ctx->ppgtt), err);
-				goto out_unlock;
+				goto out_test;
 			}
 
 			if (++dw == max_dwords(obj)) {
 				obj = NULL;
 				dw = 0;
 			}
+
 			ndwords++;
+			ncontexts++;
 		}
-		ncontexts++;
-	}
-	pr_info("Submitted %lu contexts (across %u engines), filling %lu dwords\n",
-		ncontexts, RUNTIME_INFO(i915)->num_engines, ndwords);
+		pr_info("Submitted %lu contexts to %s, filling %lu dwords\n",
+			ncontexts, engine->name, ndwords);
 
-	dw = 0;
-	list_for_each_entry(obj, &objects, st_link) {
-		unsigned int rem =
-			min_t(unsigned int, ndwords - dw, max_dwords(obj));
+		ncontexts = dw = 0;
+		list_for_each_entry(obj, &objects, st_link) {
+			unsigned int rem =
+				min_t(unsigned int, ndwords - dw, max_dwords(obj));
 
-		err = cpu_check(obj, rem);
-		if (err)
-			break;
+			err = cpu_check(obj, ncontexts++, rem);
+			if (err)
+				goto out_test;
 
-		dw += rem;
+			dw += rem;
+		}
 	}
-
-out_unlock:
+out_test:
 	if (igt_live_test_end(&t))
 		err = -EIO;
+out_unlock:
 	mutex_unlock(&i915->drm.struct_mutex);
 
 	mock_file_free(i915, file);
@@ -1048,7 +1174,7 @@ static int igt_ctx_readonly(void *arg)
 	struct drm_i915_gem_object *obj = NULL;
 	struct i915_gem_context *ctx;
 	struct i915_hw_ppgtt *ppgtt;
-	unsigned long ndwords, dw;
+	unsigned long idx, ndwords, dw;
 	struct igt_live_test t;
 	struct drm_file *file;
 	I915_RND_STATE(prng);
@@ -1129,6 +1255,7 @@ static int igt_ctx_readonly(void *arg)
 		ndwords, RUNTIME_INFO(i915)->num_engines);
 
 	dw = 0;
+	idx = 0;
 	list_for_each_entry(obj, &objects, st_link) {
 		unsigned int rem =
 			min_t(unsigned int, ndwords - dw, max_dwords(obj));
@@ -1138,7 +1265,7 @@ static int igt_ctx_readonly(void *arg)
 		if (i915_gem_object_is_readonly(obj))
 			num_writes = 0;
 
-		err = cpu_check(obj, num_writes);
+		err = cpu_check(obj, idx++, num_writes);
 		if (err)
 			break;
 
@@ -1626,7 +1753,8 @@ static int mock_context_barrier(void *arg)
 	}
 
 	counter = 0;
-	err = context_barrier_task(ctx, 0, mock_barrier_task, &counter);
+	err = context_barrier_task(ctx, 0,
+				   NULL, mock_barrier_task, &counter);
 	if (err) {
 		pr_err("Failed at line %d, err=%d\n", __LINE__, err);
 		goto out;
@@ -1638,8 +1766,8 @@ static int mock_context_barrier(void *arg)
 	}
 
 	counter = 0;
-	err = context_barrier_task(ctx,
-				   ALL_ENGINES, mock_barrier_task, &counter);
+	err = context_barrier_task(ctx, ALL_ENGINES,
+				   NULL, mock_barrier_task, &counter);
 	if (err) {
 		pr_err("Failed at line %d, err=%d\n", __LINE__, err);
 		goto out;
@@ -1662,8 +1790,8 @@ static int mock_context_barrier(void *arg)
 
 	counter = 0;
 	context_barrier_inject_fault = BIT(RCS0);
-	err = context_barrier_task(ctx,
-				   ALL_ENGINES, mock_barrier_task, &counter);
+	err = context_barrier_task(ctx, ALL_ENGINES,
+				   NULL, mock_barrier_task, &counter);
 	context_barrier_inject_fault = 0;
 	if (err == -ENXIO)
 		err = 0;
@@ -1677,8 +1805,8 @@ static int mock_context_barrier(void *arg)
 		goto out;
 
 	counter = 0;
-	err = context_barrier_task(ctx,
-				   ALL_ENGINES, mock_barrier_task, &counter);
+	err = context_barrier_task(ctx, ALL_ENGINES,
+				   NULL, mock_barrier_task, &counter);
 	if (err) {
 		pr_err("Failed at line %d, err=%d\n", __LINE__, err);
 		goto out;
@@ -1726,6 +1854,7 @@ int i915_gem_context_live_selftests(struct drm_i915_private *dev_priv)
 		SUBTEST(igt_ctx_exec),
 		SUBTEST(igt_ctx_readonly),
 		SUBTEST(igt_ctx_sseu),
+		SUBTEST(igt_shared_ctx_exec),
 		SUBTEST(igt_vm_isolation),
 	};
 
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index 826fd51c331e..57b3d9867070 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -1020,7 +1020,6 @@ static int exercise_ppgtt(struct drm_i915_private *dev_priv,
 
 	err = func(dev_priv, &ppgtt->vm, 0, ppgtt->vm.total, end_time);
 
-	i915_ppgtt_close(&ppgtt->vm);
 	i915_ppgtt_put(ppgtt);
 out_unlock:
 	mutex_unlock(&dev_priv->drm.struct_mutex);
diff --git a/drivers/gpu/drm/i915/selftests/mock_context.c b/drivers/gpu/drm/i915/selftests/mock_context.c
index 8efa6892c6cd..f90328b21763 100644
--- a/drivers/gpu/drm/i915/selftests/mock_context.c
+++ b/drivers/gpu/drm/i915/selftests/mock_context.c
@@ -54,13 +54,17 @@ mock_context(struct drm_i915_private *i915,
 		goto err_handles;
 
 	if (name) {
+		struct i915_hw_ppgtt *ppgtt;
+
 		ctx->name = kstrdup(name, GFP_KERNEL);
 		if (!ctx->name)
 			goto err_put;
 
-		ctx->ppgtt = mock_ppgtt(i915, name);
-		if (!ctx->ppgtt)
+		ppgtt = mock_ppgtt(i915, name);
+		if (!ppgtt)
 			goto err_put;
+
+		__set_ppgtt(ctx, ppgtt);
 	}
 
 	return ctx;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 1c69ed16a923..5079e25909ef 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -343,6 +343,8 @@ typedef struct _drm_i915_sarea {
 #define DRM_I915_PERF_ADD_CONFIG	0x37
 #define DRM_I915_PERF_REMOVE_CONFIG	0x38
 #define DRM_I915_QUERY			0x39
+#define DRM_I915_GEM_VM_CREATE		0x3a
+#define DRM_I915_GEM_VM_DESTROY		0x3b
 /* Must be kept compact -- no holes */
 
 #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
@@ -402,6 +404,8 @@ typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_PERF_ADD_CONFIG	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_PERF_ADD_CONFIG, struct drm_i915_perf_oa_config)
 #define DRM_IOCTL_I915_PERF_REMOVE_CONFIG	DRM_IOW(DRM_COMMAND_BASE + DRM_I915_PERF_REMOVE_CONFIG, __u64)
 #define DRM_IOCTL_I915_QUERY			DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_QUERY, struct drm_i915_query)
+#define DRM_IOCTL_I915_GEM_VM_CREATE	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_CREATE, struct drm_i915_gem_vm_control)
+#define DRM_IOCTL_I915_GEM_VM_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_VM_DESTROY, struct drm_i915_gem_vm_control)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -1453,6 +1457,33 @@ struct drm_i915_gem_context_destroy {
 	__u32 pad;
 };
 
+/*
+ * DRM_I915_GEM_VM_CREATE -
+ *
+ * Create a new virtual memory address space (ppGTT) for use within a context
+ * on the same file. Extensions can be provided to configure exactly how the
+ * address space is setup upon creation.
+ *
+ * The id of new VM (bound to the fd) for use with I915_CONTEXT_PARAM_VM is
+ * returned in the outparam @id.
+ *
+ * No flags are defined, with all bits reserved and must be zero.
+ *
+ * An extension chain maybe provided, starting with @extensions, and terminated
+ * by the @next_extension being 0. Currently, no extensions are defined.
+ *
+ * DRM_I915_GEM_VM_DESTROY -
+ *
+ * Destroys a previously created VM id, specified in @id.
+ *
+ * No extensions or flags are allowed currently, and so must be zero.
+ */
+struct drm_i915_gem_vm_control {
+	__u64 extensions;
+	__u32 flags;
+	__u32 id;
+};
+
 struct drm_i915_reg_read {
 	/*
 	 * Register offset.
@@ -1542,7 +1573,19 @@ struct drm_i915_gem_context_param {
  * On creation, all new contexts are marked as recoverable.
  */
 #define I915_CONTEXT_PARAM_RECOVERABLE	0x8
+
+	/*
+	 * The id of the associated virtual memory address space (ppGTT) of
+	 * this context. Can be retrieved and passed to another context
+	 * (on the same fd) for both to use the same ppGTT and so share
+	 * address layouts, and avoid reloading the page tables on context
+	 * switches between themselves.
+	 *
+	 * See DRM_I915_GEM_VM_CREATE and DRM_I915_GEM_VM_DESTROY.
+	 */
+#define I915_CONTEXT_PARAM_VM		0x9
 /* Must be kept compact -- no holes and well documented */
+
 	__u64 value;
 };
 
-- 
2.20.1

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

[PATCH 09/17] drm/i915: Extend CONTEXT_CREATE to set parameters upon construction

[Chris Wilson]

It can be useful to have a single ioctl to create a context with all
the initial parameters instead of a series of create + setparam + setparam
ioctls. This extension to create context allows any of the parameters
to be passed in as a linked list to be applied to the newly constructed
context.

v2: Make a local copy of user setparam (Tvrtko)
v3: Use flags to detect availability of extension interface

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c         |   2 +-
 drivers/gpu/drm/i915/i915_gem_context.c | 439 +++++++++++++-----------
 include/uapi/drm/i915_drm.h             | 180 +++++-----
 3 files changed, 342 insertions(+), 279 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 5d53efc4c5d9..93e41c937d96 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -3110,7 +3110,7 @@ static const struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I915_SET_SPRITE_COLORKEY, intel_sprite_set_colorkey_ioctl, DRM_MASTER),
 	DRM_IOCTL_DEF_DRV(I915_GET_SPRITE_COLORKEY, drm_noop, DRM_MASTER),
 	DRM_IOCTL_DEF_DRV(I915_GEM_WAIT, i915_gem_wait_ioctl, DRM_AUTH|DRM_RENDER_ALLOW),
-	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_CREATE, i915_gem_context_create_ioctl, DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_CREATE_EXT, i915_gem_context_create_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_DESTROY, i915_gem_context_destroy_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_REG_READ, i915_reg_read_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GET_RESET_STATS, i915_gem_context_reset_stats_ioctl, DRM_RENDER_ALLOW),
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 71464ae91d61..07c097ad83ee 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -90,6 +90,7 @@
 #include "i915_drv.h"
 #include "i915_globals.h"
 #include "i915_trace.h"
+#include "i915_user_extensions.h"
 #include "intel_lrc_reg.h"
 #include "intel_workarounds.h"
 
@@ -1094,192 +1095,6 @@ static int set_ppgtt(struct i915_gem_context *ctx,
 	return err;
 }
 
-static bool client_is_banned(struct drm_i915_file_private *file_priv)
-{
-	return atomic_read(&file_priv->ban_score) >= I915_CLIENT_SCORE_BANNED;
-}
-
-int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
-				  struct drm_file *file)
-{
-	struct drm_i915_private *i915 = to_i915(dev);
-	struct drm_i915_gem_context_create *args = data;
-	struct drm_i915_file_private *file_priv = file->driver_priv;
-	struct i915_gem_context *ctx;
-	int ret;
-
-	if (!DRIVER_CAPS(i915)->has_logical_contexts)
-		return -ENODEV;
-
-	if (args->pad != 0)
-		return -EINVAL;
-
-	ret = i915_terminally_wedged(i915);
-	if (ret)
-		return ret;
-
-	if (client_is_banned(file_priv)) {
-		DRM_DEBUG("client %s[%d] banned from creating ctx\n",
-			  current->comm,
-			  pid_nr(get_task_pid(current, PIDTYPE_PID)));
-
-		return -EIO;
-	}
-
-	ret = i915_mutex_lock_interruptible(dev);
-	if (ret)
-		return ret;
-
-	ctx = i915_gem_create_context(i915, file_priv);
-	mutex_unlock(&dev->struct_mutex);
-	if (IS_ERR(ctx))
-		return PTR_ERR(ctx);
-
-	GEM_BUG_ON(i915_gem_context_is_kernel(ctx));
-
-	args->ctx_id = ctx->user_handle;
-	DRM_DEBUG("HW context %d created\n", args->ctx_id);
-
-	return 0;
-}
-
-int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
-				   struct drm_file *file)
-{
-	struct drm_i915_gem_context_destroy *args = data;
-	struct drm_i915_file_private *file_priv = file->driver_priv;
-	struct i915_gem_context *ctx;
-	int ret;
-
-	if (args->pad != 0)
-		return -EINVAL;
-
-	if (args->ctx_id == DEFAULT_CONTEXT_HANDLE)
-		return -ENOENT;
-
-	ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
-	if (!ctx)
-		return -ENOENT;
-
-	ret = mutex_lock_interruptible(&dev->struct_mutex);
-	if (ret)
-		goto out;
-
-	__destroy_hw_context(ctx, file_priv);
-	mutex_unlock(&dev->struct_mutex);
-
-out:
-	i915_gem_context_put(ctx);
-	return 0;
-}
-
-static int get_sseu(struct i915_gem_context *ctx,
-		    struct drm_i915_gem_context_param *args)
-{
-	struct drm_i915_gem_context_param_sseu user_sseu;
-	struct intel_engine_cs *engine;
-	struct intel_context *ce;
-
-	if (args->size == 0)
-		goto out;
-	else if (args->size < sizeof(user_sseu))
-		return -EINVAL;
-
-	if (copy_from_user(&user_sseu, u64_to_user_ptr(args->value),
-			   sizeof(user_sseu)))
-		return -EFAULT;
-
-	if (user_sseu.flags || user_sseu.rsvd)
-		return -EINVAL;
-
-	engine = intel_engine_lookup_user(ctx->i915,
-					  user_sseu.engine_class,
-					  user_sseu.engine_instance);
-	if (!engine)
-		return -EINVAL;
-
-	ce = intel_context_pin_lock(ctx, engine); /* serialises with set_sseu */
-	if (IS_ERR(ce))
-		return PTR_ERR(ce);
-
-	user_sseu.slice_mask = ce->sseu.slice_mask;
-	user_sseu.subslice_mask = ce->sseu.subslice_mask;
-	user_sseu.min_eus_per_subslice = ce->sseu.min_eus_per_subslice;
-	user_sseu.max_eus_per_subslice = ce->sseu.max_eus_per_subslice;
-
-	intel_context_pin_unlock(ce);
-
-	if (copy_to_user(u64_to_user_ptr(args->value), &user_sseu,
-			 sizeof(user_sseu)))
-		return -EFAULT;
-
-out:
-	args->size = sizeof(user_sseu);
-
-	return 0;
-}
-
-int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
-				    struct drm_file *file)
-{
-	struct drm_i915_file_private *file_priv = file->driver_priv;
-	struct drm_i915_gem_context_param *args = data;
-	struct i915_gem_context *ctx;
-	int ret = 0;
-
-	ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
-	if (!ctx)
-		return -ENOENT;
-
-	switch (args->param) {
-	case I915_CONTEXT_PARAM_BAN_PERIOD:
-		ret = -EINVAL;
-		break;
-	case I915_CONTEXT_PARAM_NO_ZEROMAP:
-		args->size = 0;
-		args->value = test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
-		break;
-	case I915_CONTEXT_PARAM_GTT_SIZE:
-		args->size = 0;
-
-		if (ctx->ppgtt)
-			args->value = ctx->ppgtt->vm.total;
-		else if (to_i915(dev)->mm.aliasing_ppgtt)
-			args->value = to_i915(dev)->mm.aliasing_ppgtt->vm.total;
-		else
-			args->value = to_i915(dev)->ggtt.vm.total;
-		break;
-	case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
-		args->size = 0;
-		args->value = i915_gem_context_no_error_capture(ctx);
-		break;
-	case I915_CONTEXT_PARAM_BANNABLE:
-		args->size = 0;
-		args->value = i915_gem_context_is_bannable(ctx);
-		break;
-	case I915_CONTEXT_PARAM_RECOVERABLE:
-		args->size = 0;
-		args->value = i915_gem_context_is_recoverable(ctx);
-		break;
-	case I915_CONTEXT_PARAM_PRIORITY:
-		args->size = 0;
-		args->value = ctx->sched.priority >> I915_USER_PRIORITY_SHIFT;
-		break;
-	case I915_CONTEXT_PARAM_SSEU:
-		ret = get_sseu(ctx, args);
-		break;
-	case I915_CONTEXT_PARAM_VM:
-		ret = get_ppgtt(ctx, args);
-		break;
-	default:
-		ret = -EINVAL;
-		break;
-	}
-
-	i915_gem_context_put(ctx);
-	return ret;
-}
-
 static int gen8_emit_rpcs_config(struct i915_request *rq,
 				 struct intel_context *ce,
 				 struct intel_sseu sseu)
@@ -1559,18 +1374,11 @@ static int set_sseu(struct i915_gem_context *ctx,
 	return 0;
 }
 
-int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
-				    struct drm_file *file)
+static int ctx_setparam(struct i915_gem_context *ctx,
+			struct drm_i915_gem_context_param *args)
 {
-	struct drm_i915_file_private *file_priv = file->driver_priv;
-	struct drm_i915_gem_context_param *args = data;
-	struct i915_gem_context *ctx;
 	int ret = 0;
 
-	ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
-	if (!ctx)
-		return -ENOENT;
-
 	switch (args->param) {
 	case I915_CONTEXT_PARAM_NO_ZEROMAP:
 		if (args->size)
@@ -1580,6 +1388,7 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 		else
 			clear_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
 		break;
+
 	case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
 		if (args->size)
 			ret = -EINVAL;
@@ -1588,6 +1397,7 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 		else
 			i915_gem_context_clear_no_error_capture(ctx);
 		break;
+
 	case I915_CONTEXT_PARAM_BANNABLE:
 		if (args->size)
 			ret = -EINVAL;
@@ -1614,7 +1424,7 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 
 			if (args->size)
 				ret = -EINVAL;
-			else if (!(to_i915(dev)->caps.scheduler & I915_SCHEDULER_CAP_PRIORITY))
+			else if (!(ctx->i915->caps.scheduler & I915_SCHEDULER_CAP_PRIORITY))
 				ret = -ENODEV;
 			else if (priority > I915_CONTEXT_MAX_USER_PRIORITY ||
 				 priority < I915_CONTEXT_MIN_USER_PRIORITY)
@@ -1642,6 +1452,243 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 		break;
 	}
 
+	return ret;
+}
+
+static int create_setparam(struct i915_user_extension __user *ext, void *data)
+{
+	struct drm_i915_gem_context_create_ext_setparam local;
+
+	if (copy_from_user(&local, ext, sizeof(local)))
+		return -EFAULT;
+
+	if (local.setparam.ctx_id)
+		return -EINVAL;
+
+	return ctx_setparam(data, &local.setparam);
+}
+
+static const i915_user_extension_fn create_extensions[] = {
+	[I915_CONTEXT_CREATE_EXT_SETPARAM] = create_setparam,
+};
+
+static bool client_is_banned(struct drm_i915_file_private *file_priv)
+{
+	return atomic_read(&file_priv->ban_score) >= I915_CLIENT_SCORE_BANNED;
+}
+
+int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
+				  struct drm_file *file)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	struct drm_i915_gem_context_create_ext *args = data;
+	struct drm_i915_file_private *file_priv = file->driver_priv;
+	struct i915_gem_context *ctx;
+	int ret;
+
+	if (!DRIVER_CAPS(i915)->has_logical_contexts)
+		return -ENODEV;
+
+	if (args->flags & I915_CONTEXT_CREATE_FLAGS_UNKNOWN)
+		return -EINVAL;
+
+	ret = i915_terminally_wedged(i915);
+	if (ret)
+		return ret;
+
+	if (client_is_banned(file_priv)) {
+		DRM_DEBUG("client %s[%d] banned from creating ctx\n",
+			  current->comm,
+			  pid_nr(get_task_pid(current, PIDTYPE_PID)));
+
+		return -EIO;
+	}
+
+	ret = i915_mutex_lock_interruptible(dev);
+	if (ret)
+		return ret;
+
+	ctx = i915_gem_create_context(i915, file_priv);
+	mutex_unlock(&dev->struct_mutex);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	GEM_BUG_ON(i915_gem_context_is_kernel(ctx));
+
+	if (args->flags & I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS) {
+		ret = i915_user_extensions(u64_to_user_ptr(args->extensions),
+					   create_extensions,
+					   ARRAY_SIZE(create_extensions),
+					   ctx);
+		if (ret) {
+			idr_remove(&file_priv->context_idr, ctx->user_handle);
+			context_close(ctx);
+			return ret;
+		}
+	}
+
+	args->ctx_id = ctx->user_handle;
+	DRM_DEBUG("HW context %d created\n", args->ctx_id);
+
+	return 0;
+}
+
+int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
+				   struct drm_file *file)
+{
+	struct drm_i915_gem_context_destroy *args = data;
+	struct drm_i915_file_private *file_priv = file->driver_priv;
+	struct i915_gem_context *ctx;
+	int ret;
+
+	if (args->pad != 0)
+		return -EINVAL;
+
+	if (args->ctx_id == DEFAULT_CONTEXT_HANDLE)
+		return -ENOENT;
+
+	ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
+	if (!ctx)
+		return -ENOENT;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		goto out;
+
+	__destroy_hw_context(ctx, file_priv);
+	mutex_unlock(&dev->struct_mutex);
+
+out:
+	i915_gem_context_put(ctx);
+	return 0;
+}
+
+static int get_sseu(struct i915_gem_context *ctx,
+		    struct drm_i915_gem_context_param *args)
+{
+	struct drm_i915_gem_context_param_sseu user_sseu;
+	struct intel_engine_cs *engine;
+	struct intel_context *ce;
+
+	if (args->size == 0)
+		goto out;
+	else if (args->size < sizeof(user_sseu))
+		return -EINVAL;
+
+	if (copy_from_user(&user_sseu, u64_to_user_ptr(args->value),
+			   sizeof(user_sseu)))
+		return -EFAULT;
+
+	if (user_sseu.flags || user_sseu.rsvd)
+		return -EINVAL;
+
+	engine = intel_engine_lookup_user(ctx->i915,
+					  user_sseu.engine_class,
+					  user_sseu.engine_instance);
+	if (!engine)
+		return -EINVAL;
+
+	ce = intel_context_pin_lock(ctx, engine); /* serialises with set_sseu */
+	if (IS_ERR(ce))
+		return PTR_ERR(ce);
+
+	user_sseu.slice_mask = ce->sseu.slice_mask;
+	user_sseu.subslice_mask = ce->sseu.subslice_mask;
+	user_sseu.min_eus_per_subslice = ce->sseu.min_eus_per_subslice;
+	user_sseu.max_eus_per_subslice = ce->sseu.max_eus_per_subslice;
+
+	intel_context_pin_unlock(ce);
+
+	if (copy_to_user(u64_to_user_ptr(args->value), &user_sseu,
+			 sizeof(user_sseu)))
+		return -EFAULT;
+
+out:
+	args->size = sizeof(user_sseu);
+
+	return 0;
+}
+
+int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
+				    struct drm_file *file)
+{
+	struct drm_i915_file_private *file_priv = file->driver_priv;
+	struct drm_i915_gem_context_param *args = data;
+	struct i915_gem_context *ctx;
+	int ret = 0;
+
+	ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
+	if (!ctx)
+		return -ENOENT;
+
+	switch (args->param) {
+	case I915_CONTEXT_PARAM_NO_ZEROMAP:
+		args->size = 0;
+		args->value = test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
+		break;
+
+	case I915_CONTEXT_PARAM_GTT_SIZE:
+		args->size = 0;
+		if (ctx->ppgtt)
+			args->value = ctx->ppgtt->vm.total;
+		else if (to_i915(dev)->mm.aliasing_ppgtt)
+			args->value = to_i915(dev)->mm.aliasing_ppgtt->vm.total;
+		else
+			args->value = to_i915(dev)->ggtt.vm.total;
+		break;
+
+	case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
+		args->size = 0;
+		args->value = i915_gem_context_no_error_capture(ctx);
+		break;
+
+	case I915_CONTEXT_PARAM_BANNABLE:
+		args->size = 0;
+		args->value = i915_gem_context_is_bannable(ctx);
+		break;
+
+	case I915_CONTEXT_PARAM_RECOVERABLE:
+		args->size = 0;
+		args->value = i915_gem_context_is_recoverable(ctx);
+		break;
+
+	case I915_CONTEXT_PARAM_PRIORITY:
+		args->size = 0;
+		args->value = ctx->sched.priority >> I915_USER_PRIORITY_SHIFT;
+		break;
+
+	case I915_CONTEXT_PARAM_SSEU:
+		ret = get_sseu(ctx, args);
+		break;
+
+	case I915_CONTEXT_PARAM_VM:
+		ret = get_ppgtt(ctx, args);
+		break;
+
+	case I915_CONTEXT_PARAM_BAN_PERIOD:
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	i915_gem_context_put(ctx);
+	return ret;
+}
+
+int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
+				    struct drm_file *file)
+{
+	struct drm_i915_file_private *file_priv = file->driver_priv;
+	struct drm_i915_gem_context_param *args = data;
+	struct i915_gem_context *ctx;
+	int ret;
+
+	ctx = i915_gem_context_lookup(file_priv, args->ctx_id);
+	if (!ctx)
+		return -ENOENT;
+
+	ret = ctx_setparam(ctx, args);
+
 	i915_gem_context_put(ctx);
 	return ret;
 }
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 5079e25909ef..46189a8eaecb 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -394,6 +394,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_GET_SPRITE_COLORKEY DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GET_SPRITE_COLORKEY, struct drm_intel_sprite_colorkey)
 #define DRM_IOCTL_I915_GEM_WAIT		DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_WAIT, struct drm_i915_gem_wait)
 #define DRM_IOCTL_I915_GEM_CONTEXT_CREATE	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_CREATE, struct drm_i915_gem_context_create)
+#define DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_CREATE, struct drm_i915_gem_context_create_ext)
 #define DRM_IOCTL_I915_GEM_CONTEXT_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_DESTROY, struct drm_i915_gem_context_destroy)
 #define DRM_IOCTL_I915_REG_READ			DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_REG_READ, struct drm_i915_reg_read)
 #define DRM_IOCTL_I915_GET_RESET_STATS		DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GET_RESET_STATS, struct drm_i915_reset_stats)
@@ -1447,92 +1448,17 @@ struct drm_i915_gem_wait {
 };
 
 struct drm_i915_gem_context_create {
-	/*  output: id of new context*/
-	__u32 ctx_id;
-	__u32 pad;
-};
-
-struct drm_i915_gem_context_destroy {
-	__u32 ctx_id;
-	__u32 pad;
-};
-
-/*
- * DRM_I915_GEM_VM_CREATE -
- *
- * Create a new virtual memory address space (ppGTT) for use within a context
- * on the same file. Extensions can be provided to configure exactly how the
- * address space is setup upon creation.
- *
- * The id of new VM (bound to the fd) for use with I915_CONTEXT_PARAM_VM is
- * returned in the outparam @id.
- *
- * No flags are defined, with all bits reserved and must be zero.
- *
- * An extension chain maybe provided, starting with @extensions, and terminated
- * by the @next_extension being 0. Currently, no extensions are defined.
- *
- * DRM_I915_GEM_VM_DESTROY -
- *
- * Destroys a previously created VM id, specified in @id.
- *
- * No extensions or flags are allowed currently, and so must be zero.
- */
-struct drm_i915_gem_vm_control {
-	__u64 extensions;
-	__u32 flags;
-	__u32 id;
-};
-
-struct drm_i915_reg_read {
-	/*
-	 * Register offset.
-	 * For 64bit wide registers where the upper 32bits don't immediately
-	 * follow the lower 32bits, the offset of the lower 32bits must
-	 * be specified
-	 */
-	__u64 offset;
-#define I915_REG_READ_8B_WA (1ul << 0)
-
-	__u64 val; /* Return value */
-};
-/* Known registers:
- *
- * Render engine timestamp - 0x2358 + 64bit - gen7+
- * - Note this register returns an invalid value if using the default
- *   single instruction 8byte read, in order to workaround that pass
- *   flag I915_REG_READ_8B_WA in offset field.
- *
- */
-
-struct drm_i915_reset_stats {
-	__u32 ctx_id;
-	__u32 flags;
-
-	/* All resets since boot/module reload, for all contexts */
-	__u32 reset_count;
-
-	/* Number of batches lost when active in GPU, for this context */
-	__u32 batch_active;
-
-	/* Number of batches lost pending for execution, for this context */
-	__u32 batch_pending;
-
+	__u32 ctx_id; /* output: id of new context*/
 	__u32 pad;
 };
 
-struct drm_i915_gem_userptr {
-	__u64 user_ptr;
-	__u64 user_size;
+struct drm_i915_gem_context_create_ext {
+	__u32 ctx_id; /* output: id of new context*/
 	__u32 flags;
-#define I915_USERPTR_READ_ONLY 0x1
-#define I915_USERPTR_UNSYNCHRONIZED 0x80000000
-	/**
-	 * Returned handle for the object.
-	 *
-	 * Object handles are nonzero.
-	 */
-	__u32 handle;
+#define I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS	(1u << 0)
+#define I915_CONTEXT_CREATE_FLAGS_UNKNOWN \
+	(-(I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS << 1))
+	__u64 extensions;
 };
 
 struct drm_i915_gem_context_param {
@@ -1648,6 +1574,96 @@ struct drm_i915_gem_context_param_sseu {
 	__u32 rsvd;
 };
 
+struct drm_i915_gem_context_create_ext_setparam {
+#define I915_CONTEXT_CREATE_EXT_SETPARAM 0
+	struct i915_user_extension base;
+	struct drm_i915_gem_context_param setparam;
+};
+
+struct drm_i915_gem_context_destroy {
+	__u32 ctx_id;
+	__u32 pad;
+};
+
+/*
+ * DRM_I915_GEM_VM_CREATE -
+ *
+ * Create a new virtual memory address space (ppGTT) for use within a context
+ * on the same file. Extensions can be provided to configure exactly how the
+ * address space is setup upon creation.
+ *
+ * The id of new VM (bound to the fd) for use with I915_CONTEXT_PARAM_VM is
+ * returned in the outparam @id.
+ *
+ * No flags are defined, with all bits reserved and must be zero.
+ *
+ * An extension chain maybe provided, starting with @extensions, and terminated
+ * by the @next_extension being 0. Currently, no extensions are defined.
+ *
+ * DRM_I915_GEM_VM_DESTROY -
+ *
+ * Destroys a previously created VM id, specified in @id.
+ *
+ * No extensions or flags are allowed currently, and so must be zero.
+ */
+struct drm_i915_gem_vm_control {
+	__u64 extensions;
+	__u32 flags;
+	__u32 id;
+};
+
+struct drm_i915_reg_read {
+	/*
+	 * Register offset.
+	 * For 64bit wide registers where the upper 32bits don't immediately
+	 * follow the lower 32bits, the offset of the lower 32bits must
+	 * be specified
+	 */
+	__u64 offset;
+#define I915_REG_READ_8B_WA (1ul << 0)
+
+	__u64 val; /* Return value */
+};
+
+/* Known registers:
+ *
+ * Render engine timestamp - 0x2358 + 64bit - gen7+
+ * - Note this register returns an invalid value if using the default
+ *   single instruction 8byte read, in order to workaround that pass
+ *   flag I915_REG_READ_8B_WA in offset field.
+ *
+ */
+
+struct drm_i915_reset_stats {
+	__u32 ctx_id;
+	__u32 flags;
+
+	/* All resets since boot/module reload, for all contexts */
+	__u32 reset_count;
+
+	/* Number of batches lost when active in GPU, for this context */
+	__u32 batch_active;
+
+	/* Number of batches lost pending for execution, for this context */
+	__u32 batch_pending;
+
+	__u32 pad;
+};
+
+struct drm_i915_gem_userptr {
+	__u64 user_ptr;
+	__u64 user_size;
+	__u32 flags;
+#define I915_USERPTR_READ_ONLY 0x1
+#define I915_USERPTR_UNSYNCHRONIZED 0x80000000
+	/**
+	 * Returned handle for the object.
+	 *
+	 * Object handles are nonzero.
+	 */
+	__u32 handle;
+};
+
 enum drm_i915_oa_format {
 	I915_OA_FORMAT_A13 = 1,	    /* HSW only */
 	I915_OA_FORMAT_A29,	    /* HSW only */
-- 
2.20.1

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

[PATCH 10/17] drm/i915: Allow contexts to share a single timeline across all engines

[Chris Wilson]

Previously, our view has been always to run the engines independently
within a context. (Multiple engines happened before we had contexts and
timelines, so they always operated independently and that behaviour
persisted into contexts.) However, at the user level the context often
represents a single timeline (e.g. GL contexts) and userspace must
ensure that the individual engines are serialised to present that
ordering to the client (or forgot about this detail entirely and hope no
one notices - a fair ploy if the client can only directly control one
engine themselves ;)

In the next patch, we will want to construct a set of engines that
operate as one, that have a single timeline interwoven between them, to
present a single virtual engine to the user. (They submit to the virtual
engine, then we decide which engine to execute on based.)

To that end, we want to be able to create contexts which have a single
timeline (fence context) shared between all engines, rather than multiple
timelines.

v2: Move the specialised timeline ordering to its own function.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_context.c       | 32 ++++++--
 drivers/gpu/drm/i915/i915_gem_context_types.h |  2 +
 drivers/gpu/drm/i915/i915_request.c           | 80 +++++++++++++------
 drivers/gpu/drm/i915/i915_request.h           |  5 +-
 drivers/gpu/drm/i915/i915_sw_fence.c          | 39 +++++++--
 drivers/gpu/drm/i915/i915_sw_fence.h          | 13 ++-
 drivers/gpu/drm/i915/intel_lrc.c              |  5 +-
 .../gpu/drm/i915/selftests/i915_gem_context.c | 18 +++--
 drivers/gpu/drm/i915/selftests/mock_context.c |  2 +-
 include/uapi/drm/i915_drm.h                   |  3 +-
 10 files changed, 149 insertions(+), 50 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 07c097ad83ee..4e4b0b5c4be0 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -238,6 +238,9 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 	rbtree_postorder_for_each_entry_safe(it, n, &ctx->hw_contexts, node)
 		intel_context_put(it);
 
+	if (ctx->timeline)
+		i915_timeline_put(ctx->timeline);
+
 	kfree(ctx->name);
 	put_pid(ctx->pid);
 
@@ -449,12 +452,17 @@ static void __assign_ppgtt(struct i915_gem_context *ctx,
 
 static struct i915_gem_context *
 i915_gem_create_context(struct drm_i915_private *dev_priv,
-			struct drm_i915_file_private *file_priv)
+			struct drm_i915_file_private *file_priv,
+			unsigned int flags)
 {
 	struct i915_gem_context *ctx;
 
 	lockdep_assert_held(&dev_priv->drm.struct_mutex);
 
+	if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE &&
+	    !HAS_EXECLISTS(dev_priv))
+		return ERR_PTR(-EINVAL);
+
 	/* Reap the most stale context */
 	contexts_free_first(dev_priv);
 
@@ -477,6 +485,18 @@ i915_gem_create_context(struct drm_i915_private *dev_priv,
 		i915_ppgtt_put(ppgtt);
 	}
 
+	if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE) {
+		struct i915_timeline *timeline;
+
+		timeline = i915_timeline_create(dev_priv, ctx->name, NULL);
+		if (IS_ERR(timeline)) {
+			__destroy_hw_context(ctx, file_priv);
+			return ERR_CAST(timeline);
+		}
+
+		ctx->timeline = timeline;
+	}
+
 	trace_i915_context_create(ctx);
 
 	return ctx;
@@ -505,7 +525,7 @@ i915_gem_context_create_gvt(struct drm_device *dev)
 	if (ret)
 		return ERR_PTR(ret);
 
-	ctx = i915_gem_create_context(to_i915(dev), NULL);
+	ctx = i915_gem_create_context(to_i915(dev), NULL, 0);
 	if (IS_ERR(ctx))
 		goto out;
 
@@ -541,7 +561,7 @@ i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio)
 	struct i915_gem_context *ctx;
 	int err;
 
-	ctx = i915_gem_create_context(i915, NULL);
+	ctx = i915_gem_create_context(i915, NULL, 0);
 	if (IS_ERR(ctx))
 		return ctx;
 
@@ -673,7 +693,7 @@ int i915_gem_context_open(struct drm_i915_private *i915,
 	idr_init_base(&file_priv->vm_idr, 1);
 
 	mutex_lock(&i915->drm.struct_mutex);
-	ctx = i915_gem_create_context(i915, file_priv);
+	ctx = i915_gem_create_context(i915, file_priv, 0);
 	mutex_unlock(&i915->drm.struct_mutex);
 	if (IS_ERR(ctx)) {
 		idr_destroy(&file_priv->context_idr);
@@ -789,7 +809,7 @@ last_request_on_engine(struct i915_timeline *timeline,
 
 	rq = i915_active_request_raw(&timeline->last_request,
 				     &engine->i915->drm.struct_mutex);
-	if (rq && rq->engine == engine) {
+	if (rq && rq->engine->mask & engine->mask) {
 		GEM_TRACE("last request for %s on engine %s: %llx:%llu\n",
 			  timeline->name, engine->name,
 			  rq->fence.context, rq->fence.seqno);
@@ -1508,7 +1528,7 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
 	if (ret)
 		return ret;
 
-	ctx = i915_gem_create_context(i915, file_priv);
+	ctx = i915_gem_create_context(i915, file_priv, args->flags);
 	mutex_unlock(&dev->struct_mutex);
 	if (IS_ERR(ctx))
 		return PTR_ERR(ctx);
diff --git a/drivers/gpu/drm/i915/i915_gem_context_types.h b/drivers/gpu/drm/i915/i915_gem_context_types.h
index 2bf19730eaa9..f8f6e6c960a7 100644
--- a/drivers/gpu/drm/i915/i915_gem_context_types.h
+++ b/drivers/gpu/drm/i915/i915_gem_context_types.h
@@ -41,6 +41,8 @@ struct i915_gem_context {
 	/** file_priv: owning file descriptor */
 	struct drm_i915_file_private *file_priv;
 
+	struct i915_timeline *timeline;
+
 	/**
 	 * @ppgtt: unique address space (GTT)
 	 *
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 0a3d94517d0a..2382339172b4 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -993,6 +993,60 @@ void i915_request_skip(struct i915_request *rq, int error)
 	memset(vaddr + head, 0, rq->postfix - head);
 }
 
+static struct i915_request *
+__i915_request_add_to_timeline(struct i915_request *rq)
+{
+	struct i915_timeline *timeline = rq->timeline;
+	struct i915_request *prev;
+
+	/*
+	 * Dependency tracking and request ordering along the timeline
+	 * is special cased so that we can eliminate redundant ordering
+	 * operations while building the request (we know that the timeline
+	 * itself is ordered, and here we guarantee it).
+	 *
+	 * As we know we will need to emit tracking along the timeline,
+	 * we embed the hooks into our request struct -- at the cost of
+	 * having to have specialised no-allocation interfaces (which will
+	 * be beneficial elsewhere).
+	 *
+	 * A second benefit to open-coding i915_request_await_request is
+	 * that we can apply a slight variant of the rules specialised
+	 * for timelines that jump between engines (such as virtual engines).
+	 * If we consider the case of virtual engine, we must emit a dma-fence
+	 * to prevent scheduling of the second request until the first is
+	 * complete (to maximise our greedy late load balancing) and this
+	 * precludes optimising to use semaphores serialisation of a single
+	 * timeline across engines.
+	 */
+	prev = i915_active_request_raw(&timeline->last_request,
+				       &rq->i915->drm.struct_mutex);
+	if (prev && !i915_request_completed(prev)) {
+		if (is_power_of_2(prev->engine->mask | rq->engine->mask))
+			i915_sw_fence_await_sw_fence(&rq->submit,
+						     &prev->submit,
+						     &rq->submitq);
+		else
+			__i915_sw_fence_await_dma_fence(&rq->submit,
+							&prev->fence,
+							&rq->dmaq);
+		if (rq->engine->schedule)
+			__i915_sched_node_add_dependency(&rq->sched,
+							 &prev->sched,
+							 &rq->dep,
+							 0);
+	}
+
+	spin_lock_irq(&timeline->lock);
+	list_add_tail(&rq->link, &timeline->requests);
+	spin_unlock_irq(&timeline->lock);
+
+	GEM_BUG_ON(timeline->seqno != rq->fence.seqno);
+	__i915_active_request_set(&timeline->last_request, rq);
+
+	return prev;
+}
+
 /*
  * NB: This function is not allowed to fail. Doing so would mean the the
  * request is not being tracked for completion but the work itself is
@@ -1037,31 +1091,7 @@ void i915_request_add(struct i915_request *request)
 	GEM_BUG_ON(IS_ERR(cs));
 	request->postfix = intel_ring_offset(request, cs);
 
-	/*
-	 * Seal the request and mark it as pending execution. Note that
-	 * we may inspect this state, without holding any locks, during
-	 * hangcheck. Hence we apply the barrier to ensure that we do not
-	 * see a more recent value in the hws than we are tracking.
-	 */
-
-	prev = i915_active_request_raw(&timeline->last_request,
-				       &request->i915->drm.struct_mutex);
-	if (prev && !i915_request_completed(prev)) {
-		i915_sw_fence_await_sw_fence(&request->submit, &prev->submit,
-					     &request->submitq);
-		if (engine->schedule)
-			__i915_sched_node_add_dependency(&request->sched,
-							 &prev->sched,
-							 &request->dep,
-							 0);
-	}
-
-	spin_lock_irq(&timeline->lock);
-	list_add_tail(&request->link, &timeline->requests);
-	spin_unlock_irq(&timeline->lock);
-
-	GEM_BUG_ON(timeline->seqno != request->fence.seqno);
-	__i915_active_request_set(&timeline->last_request, request);
+	prev = __i915_request_add_to_timeline(request);
 
 	list_add_tail(&request->ring_link, &ring->request_list);
 	if (list_is_first(&request->ring_link, &ring->request_list)) {
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 8c8fa5010644..cd6c130964cd 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -128,7 +128,10 @@ struct i915_request {
 	 * It is used by the driver to then queue the request for execution.
 	 */
 	struct i915_sw_fence submit;
-	wait_queue_entry_t submitq;
+	union {
+		wait_queue_entry_t submitq;
+		struct i915_sw_dma_fence_cb dmaq;
+	};
 	struct list_head execute_cb;
 
 	/*
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
index 8d1400d378d7..5387aafd3424 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/i915_sw_fence.c
@@ -359,11 +359,6 @@ int i915_sw_fence_await_sw_fence_gfp(struct i915_sw_fence *fence,
 	return __i915_sw_fence_await_sw_fence(fence, signaler, NULL, gfp);
 }
 
-struct i915_sw_dma_fence_cb {
-	struct dma_fence_cb base;
-	struct i915_sw_fence *fence;
-};
-
 struct i915_sw_dma_fence_cb_timer {
 	struct i915_sw_dma_fence_cb base;
 	struct dma_fence *dma;
@@ -480,6 +475,40 @@ int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
 	return ret;
 }
 
+static void __dma_i915_sw_fence_wake(struct dma_fence *dma,
+				     struct dma_fence_cb *data)
+{
+	struct i915_sw_dma_fence_cb *cb = container_of(data, typeof(*cb), base);
+
+	i915_sw_fence_complete(cb->fence);
+}
+
+int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
+				    struct dma_fence *dma,
+				    struct i915_sw_dma_fence_cb *cb)
+{
+	int ret;
+
+	debug_fence_assert(fence);
+
+	if (dma_fence_is_signaled(dma))
+		return 0;
+
+	cb->fence = fence;
+	i915_sw_fence_await(fence);
+
+	ret = dma_fence_add_callback(dma, &cb->base, __dma_i915_sw_fence_wake);
+	if (ret == 0) {
+		ret = 1;
+	} else {
+		i915_sw_fence_complete(fence);
+		if (ret == -ENOENT) /* fence already signaled */
+			ret = 0;
+	}
+
+	return ret;
+}
+
 int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
 				    struct reservation_object *resv,
 				    const struct dma_fence_ops *exclude,
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.h b/drivers/gpu/drm/i915/i915_sw_fence.h
index 6dec9e1d1102..9cb5c3b307a6 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.h
+++ b/drivers/gpu/drm/i915/i915_sw_fence.h
@@ -9,14 +9,13 @@
 #ifndef _I915_SW_FENCE_H_
 #define _I915_SW_FENCE_H_
 
+#include <linux/dma-fence.h>
 #include <linux/gfp.h>
 #include <linux/kref.h>
 #include <linux/notifier.h> /* for NOTIFY_DONE */
 #include <linux/wait.h>
 
 struct completion;
-struct dma_fence;
-struct dma_fence_ops;
 struct reservation_object;
 
 struct i915_sw_fence {
@@ -68,10 +67,20 @@ int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
 int i915_sw_fence_await_sw_fence_gfp(struct i915_sw_fence *fence,
 				     struct i915_sw_fence *after,
 				     gfp_t gfp);
+
+struct i915_sw_dma_fence_cb {
+	struct dma_fence_cb base;
+	struct i915_sw_fence *fence;
+};
+
+int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
+				    struct dma_fence *dma,
+				    struct i915_sw_dma_fence_cb *cb);
 int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
 				  struct dma_fence *dma,
 				  unsigned long timeout,
 				  gfp_t gfp);
+
 int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
 				    struct reservation_object *resv,
 				    const struct dma_fence_ops *exclude,
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 5669823f6901..6e9bd70f5e92 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2804,7 +2804,10 @@ populate_lr_context(struct intel_context *ce,
 
 static struct i915_timeline *get_timeline(struct i915_gem_context *ctx)
 {
-	return i915_timeline_create(ctx->i915, ctx->name, NULL);
+	if (ctx->timeline)
+		return i915_timeline_get(ctx->timeline);
+	else
+		return i915_timeline_create(ctx->i915, ctx->name, NULL);
 }
 
 static int execlists_context_deferred_alloc(struct intel_context *ce,
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index 1ba354a916c0..86b86569ee21 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -76,7 +76,7 @@ static int live_nop_switch(void *arg)
 	}
 
 	for (n = 0; n < nctx; n++) {
-		ctx[n] = i915_gem_create_context(i915, file->driver_priv);
+		ctx[n] = i915_gem_create_context(i915, file->driver_priv, 0);
 		if (IS_ERR(ctx[n])) {
 			err = PTR_ERR(ctx[n]);
 			goto out_unlock;
@@ -526,7 +526,8 @@ static int igt_ctx_exec(void *arg)
 			struct i915_gem_context *ctx;
 			intel_wakeref_t wakeref;
 
-			ctx = i915_gem_create_context(i915, file->driver_priv);
+			ctx = i915_gem_create_context(i915,
+						      file->driver_priv, 0);
 			if (IS_ERR(ctx)) {
 				err = PTR_ERR(ctx);
 				goto out_unlock;
@@ -611,7 +612,7 @@ static int igt_shared_ctx_exec(void *arg)
 
 	mutex_lock(&i915->drm.struct_mutex);
 
-	parent = i915_gem_create_context(i915, file->driver_priv);
+	parent = i915_gem_create_context(i915, file->driver_priv, 0);
 	if (IS_ERR(parent)) {
 		err = PTR_ERR(parent);
 		goto out_unlock;
@@ -645,7 +646,8 @@ static int igt_shared_ctx_exec(void *arg)
 			if (ctx)
 				__destroy_hw_context(ctx, file->driver_priv);
 
-			ctx = i915_gem_create_context(i915, file->driver_priv);
+			ctx = i915_gem_create_context(i915,
+						      file->driver_priv, 0);
 			if (IS_ERR(ctx)) {
 				err = PTR_ERR(ctx);
 				goto out_test;
@@ -1088,7 +1090,7 @@ __igt_ctx_sseu(struct drm_i915_private *i915,
 
 	mutex_lock(&i915->drm.struct_mutex);
 
-	ctx = i915_gem_create_context(i915, file->driver_priv);
+	ctx = i915_gem_create_context(i915, file->driver_priv, 0);
 	if (IS_ERR(ctx)) {
 		ret = PTR_ERR(ctx);
 		goto out_unlock;
@@ -1198,7 +1200,7 @@ static int igt_ctx_readonly(void *arg)
 	if (err)
 		goto out_unlock;
 
-	ctx = i915_gem_create_context(i915, file->driver_priv);
+	ctx = i915_gem_create_context(i915, file->driver_priv, 0);
 	if (IS_ERR(ctx)) {
 		err = PTR_ERR(ctx);
 		goto out_unlock;
@@ -1524,13 +1526,13 @@ static int igt_vm_isolation(void *arg)
 	if (err)
 		goto out_unlock;
 
-	ctx_a = i915_gem_create_context(i915, file->driver_priv);
+	ctx_a = i915_gem_create_context(i915, file->driver_priv, 0);
 	if (IS_ERR(ctx_a)) {
 		err = PTR_ERR(ctx_a);
 		goto out_unlock;
 	}
 
-	ctx_b = i915_gem_create_context(i915, file->driver_priv);
+	ctx_b = i915_gem_create_context(i915, file->driver_priv, 0);
 	if (IS_ERR(ctx_b)) {
 		err = PTR_ERR(ctx_b);
 		goto out_unlock;
diff --git a/drivers/gpu/drm/i915/selftests/mock_context.c b/drivers/gpu/drm/i915/selftests/mock_context.c
index f90328b21763..1d6dc2fe36ab 100644
--- a/drivers/gpu/drm/i915/selftests/mock_context.c
+++ b/drivers/gpu/drm/i915/selftests/mock_context.c
@@ -94,7 +94,7 @@ live_context(struct drm_i915_private *i915, struct drm_file *file)
 {
 	lockdep_assert_held(&i915->drm.struct_mutex);
 
-	return i915_gem_create_context(i915, file->driver_priv);
+	return i915_gem_create_context(i915, file->driver_priv, 0);
 }
 
 struct i915_gem_context *
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 46189a8eaecb..5206d0006043 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1456,8 +1456,9 @@ struct drm_i915_gem_context_create_ext {
 	__u32 ctx_id; /* output: id of new context*/
 	__u32 flags;
 #define I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS	(1u << 0)
+#define I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE	(1u << 1)
 #define I915_CONTEXT_CREATE_FLAGS_UNKNOWN \
-	(-(I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS << 1))
+	(-(I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE << 1))
 	__u64 extensions;
 };
 
-- 
2.20.1

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[PATCH 11/17] drm/i915: Allow userspace to clone contexts on creation

[Chris Wilson]

A usecase arose out of handling context recovery in mesa, whereby they
wish to recreate a context with fresh logical state but preserving all
other details of the original. Currently, they create a new context and
iterate over which bits they want to copy across, but it would much more
convenient if they were able to just pass in a target context to clone
during creation. This essentially extends the setparam during creation
to pull the details from a target context instead of the user supplied
parameters.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 103 ++++++++++++++++++++++++
 include/uapi/drm/i915_drm.h             |  14 ++++
 2 files changed, 117 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 4e4b0b5c4be0..bac548584091 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -1488,8 +1488,111 @@ static int create_setparam(struct i915_user_extension __user *ext, void *data)
 	return ctx_setparam(data, &local.setparam);
 }
 
+static int clone_sseu(struct i915_gem_context *dst,
+		      struct i915_gem_context *src)
+{
+	const struct intel_sseu default_sseu =
+		intel_device_default_sseu(dst->i915);
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+
+	for_each_engine(engine, dst->i915, id) {
+		struct intel_context *ce;
+		struct intel_sseu sseu;
+
+		ce = intel_context_lookup(src, engine);
+		if (!ce)
+			continue;
+
+		sseu = ce->sseu;
+		if (!memcmp(&sseu, &default_sseu, sizeof(sseu)))
+			continue;
+
+		ce = intel_context_pin_lock(dst, engine);
+		if (IS_ERR(ce))
+			return PTR_ERR(ce);
+
+		ce->sseu = sseu;
+		intel_context_pin_unlock(ce);
+	}
+
+	return 0;
+}
+
+static int create_clone(struct i915_user_extension __user *ext, void *data)
+{
+	struct drm_i915_gem_context_create_ext_clone local;
+	struct i915_gem_context *dst = data;
+	struct i915_gem_context *src;
+	int err;
+
+	if (copy_from_user(&local, ext, sizeof(local)))
+		return -EFAULT;
+
+	if (local.flags & I915_CONTEXT_CLONE_UNKNOWN)
+		return -EINVAL;
+
+	if (local.rsvd)
+		return -EINVAL;
+
+	if (local.clone_id == dst->user_handle) /* good guess! denied. */
+		return -ENOENT;
+
+	rcu_read_lock();
+	src = __i915_gem_context_lookup_rcu(dst->file_priv, local.clone_id);
+	rcu_read_unlock();
+	if (!src)
+		return -ENOENT;
+
+	GEM_BUG_ON(src == dst);
+
+	if (local.flags & I915_CONTEXT_CLONE_FLAGS)
+		dst->user_flags = src->user_flags;
+
+	if (local.flags & I915_CONTEXT_CLONE_SCHED)
+		dst->sched = src->sched;
+
+	if (local.flags & I915_CONTEXT_CLONE_SSEU) {
+		err = clone_sseu(dst, src);
+		if (err)
+			return err;
+	}
+
+	if (local.flags & I915_CONTEXT_CLONE_TIMELINE && src->timeline) {
+		if (dst->timeline)
+			i915_timeline_put(dst->timeline);
+		dst->timeline = i915_timeline_get(src->timeline);
+	}
+
+	if (local.flags & I915_CONTEXT_CLONE_VM) {
+		struct i915_hw_ppgtt *ppgtt;
+
+		do {
+			ppgtt = READ_ONCE(src->ppgtt);
+			if (!ppgtt)
+				break;
+
+			if (!kref_get_unless_zero(&ppgtt->ref))
+				continue;
+
+			if (ppgtt == READ_ONCE(src->ppgtt))
+				break;
+
+			i915_ppgtt_put(ppgtt);
+		} while (1);
+
+		if (ppgtt) {
+			__assign_ppgtt(dst, ppgtt);
+			i915_ppgtt_put(ppgtt);
+		}
+	}
+
+	return 0;
+}
+
 static const i915_user_extension_fn create_extensions[] = {
 	[I915_CONTEXT_CREATE_EXT_SETPARAM] = create_setparam,
+	[I915_CONTEXT_CREATE_EXT_CLONE] = create_clone,
 };
 
 static bool client_is_banned(struct drm_i915_file_private *file_priv)
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 5206d0006043..9714520f43da 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1581,6 +1581,20 @@ struct drm_i915_gem_context_create_ext_setparam {
 	struct drm_i915_gem_context_param setparam;
 };
 
+struct drm_i915_gem_context_create_ext_clone {
+#define I915_CONTEXT_CREATE_EXT_CLONE 1
+	struct i915_user_extension base;
+	__u32 clone_id;
+	__u32 flags;
+#define I915_CONTEXT_CLONE_FLAGS	(1u << 0)
+#define I915_CONTEXT_CLONE_SCHED	(1u << 1)
+#define I915_CONTEXT_CLONE_SSEU		(1u << 2)
+#define I915_CONTEXT_CLONE_TIMELINE	(1u << 3)
+#define I915_CONTEXT_CLONE_VM		(1u << 4)
+#define I915_CONTEXT_CLONE_UNKNOWN -(I915_CONTEXT_CLONE_VM << 1)
+	__u64 rsvd;
+};
+
 struct drm_i915_gem_context_destroy {
 	__u32 ctx_id;
 	__u32 pad;
-- 
2.20.1

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[PATCH 12/17] drm/i915: Allow a context to define its set of engines

[Chris Wilson]

Over the last few years, we have debated how to extend the user API to
support an increase in the number of engines, that may be sparse and
even be heterogeneous within a class (not all video decoders created
equal). We settled on using (class, instance) tuples to identify a
specific engine, with an API for the user to construct a map of engines
to capabilities. Into this picture, we then add a challenge of virtual
engines; one user engine that maps behind the scenes to any number of
physical engines. To keep it general, we want the user to have full
control over that mapping. To that end, we allow the user to constrain a
context to define the set of engines that it can access, order fully
controlled by the user via (class, instance). With such precise control
in context setup, we can continue to use the existing execbuf uABI of
specifying a single index; only now it doesn't automagically map onto
the engines, it uses the user defined engine map from the context.

The I915_EXEC_DEFAULT slot is left empty, and invalid for use by
execbuf. It's use will be revealed in the next patch.

v2: Fixup freeing of local on success of get_engines()
v3: Allow empty engines[]

Testcase: igt/gem_ctx_engines
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.c       | 223 +++++++++++++++++-
 drivers/gpu/drm/i915/i915_gem_context_types.h |   4 +
 drivers/gpu/drm/i915/i915_gem_execbuffer.c    |  19 +-
 drivers/gpu/drm/i915/i915_utils.h             |  23 ++
 include/uapi/drm/i915_drm.h                   |  42 +++-
 5 files changed, 298 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index bac548584091..07377b75b563 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -86,7 +86,9 @@
  */
 
 #include <linux/log2.h>
+
 #include <drm/i915_drm.h>
+
 #include "i915_drv.h"
 #include "i915_globals.h"
 #include "i915_trace.h"
@@ -101,6 +103,21 @@ static struct i915_global_gem_context {
 	struct kmem_cache *slab_luts;
 } global;
 
+static struct intel_engine_cs *
+lookup_user_engine(struct i915_gem_context *ctx,
+		   unsigned long flags, u16 class, u16 instance)
+#define LOOKUP_USER_INDEX BIT(0)
+{
+	if (flags & LOOKUP_USER_INDEX) {
+		if (instance >= ctx->nengine)
+			return NULL;
+
+		return ctx->engines[instance];
+	}
+
+	return intel_engine_lookup_user(ctx->i915, class, instance);
+}
+
 struct i915_lut_handle *i915_lut_handle_alloc(void)
 {
 	return kmem_cache_alloc(global.slab_luts, GFP_KERNEL);
@@ -235,6 +252,8 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 	release_hw_id(ctx);
 	i915_ppgtt_put(ctx->ppgtt);
 
+	kfree(ctx->engines);
+
 	rbtree_postorder_for_each_entry_safe(it, n, &ctx->hw_contexts, node)
 		intel_context_put(it);
 
@@ -1371,9 +1390,9 @@ static int set_sseu(struct i915_gem_context *ctx,
 	if (user_sseu.flags || user_sseu.rsvd)
 		return -EINVAL;
 
-	engine = intel_engine_lookup_user(i915,
-					  user_sseu.engine_class,
-					  user_sseu.engine_instance);
+	engine = lookup_user_engine(ctx, 0,
+				    user_sseu.engine_class,
+				    user_sseu.engine_instance);
 	if (!engine)
 		return -EINVAL;
 
@@ -1391,9 +1410,163 @@ static int set_sseu(struct i915_gem_context *ctx,
 
 	args->size = sizeof(user_sseu);
 
+	return 0;
+};
+
+struct set_engines {
+	struct i915_gem_context *ctx;
+	struct intel_engine_cs **engines;
+	unsigned int nengine;
+};
+
+static const i915_user_extension_fn set_engines__extensions[] = {
+};
+
+static int
+set_engines(struct i915_gem_context *ctx,
+	    const struct drm_i915_gem_context_param *args)
+{
+	struct i915_context_param_engines __user *user;
+	struct set_engines set = { .ctx = ctx };
+	u64 size, extensions;
+	unsigned int n;
+	int err;
+
+	user = u64_to_user_ptr(args->value);
+	size = args->size;
+	if (!size)
+		goto out;
+
+	BUILD_BUG_ON(!IS_ALIGNED(sizeof(*user), sizeof(*user->class_instance)));
+	if (size < sizeof(*user) ||
+	    !IS_ALIGNED(size, sizeof(*user->class_instance)))
+		return -EINVAL;
+
+	set.nengine = (size - sizeof(*user)) / sizeof(*user->class_instance);
+	if (set.nengine > I915_EXEC_RING_MASK + 1)
+		return -EINVAL;
+
+	set.engines = kmalloc_array(set.nengine,
+				    sizeof(*set.engines),
+				    GFP_KERNEL);
+	if (!set.engines)
+		return -ENOMEM;
+
+	for (n = 0; n < set.nengine; n++) {
+		u16 class, inst;
+
+		if (get_user(class, &user->class_instance[n].engine_class) ||
+		    get_user(inst, &user->class_instance[n].engine_instance)) {
+			kfree(set.engines);
+			return -EFAULT;
+		}
+
+		if (class == (u16)I915_ENGINE_CLASS_INVALID &&
+		    inst == (u16)I915_ENGINE_CLASS_INVALID_NONE) {
+			set.engines[n] = NULL;
+			continue;
+		}
+
+		set.engines[n] = lookup_user_engine(ctx, 0, class, inst);
+		if (!set.engines[n]) {
+			kfree(set.engines);
+			return -ENOENT;
+		}
+	}
+
+	err = -EFAULT;
+	if (!get_user(extensions, &user->extensions))
+		err = i915_user_extensions(u64_to_user_ptr(extensions),
+					   set_engines__extensions,
+					   ARRAY_SIZE(set_engines__extensions),
+					   &set);
+	if (err) {
+		kfree(set.engines);
+		return err;
+	}
+
+out:
+	mutex_lock(&ctx->i915->drm.struct_mutex);
+	kfree(ctx->engines);
+	ctx->engines = set.engines;
+	ctx->nengine = set.nengine;
+	mutex_unlock(&ctx->i915->drm.struct_mutex);
+
 	return 0;
 }
 
+static int
+get_engines(struct i915_gem_context *ctx,
+	    struct drm_i915_gem_context_param *args)
+{
+	struct i915_context_param_engines *local;
+	size_t n, count, size;
+	int err = 0;
+
+restart:
+	if (!READ_ONCE(ctx->engines)) {
+		args->size = 0;
+		return 0;
+	}
+
+	count = READ_ONCE(ctx->nengine);
+
+	/* Be paranoid in case we have an impedance mismatch */
+	if (!check_struct_size(local, class_instance, count, &size))
+		return -ENOMEM;
+	if (unlikely(overflows_type(size, args->size)))
+		return -ENOMEM;
+
+	if (!args->size) {
+		args->size = size;
+		return 0;
+	}
+	if (args->size < size)
+		return -EINVAL;
+
+	local = kmalloc(size, GFP_KERNEL);
+	if (!local)
+		return -ENOMEM;
+
+	if (mutex_lock_interruptible(&ctx->i915->drm.struct_mutex)) {
+		err = -EINTR;
+		goto out;
+	}
+
+	if (!ctx->engines || ctx->nengine != count) {
+		mutex_unlock(&ctx->i915->drm.struct_mutex);
+		kfree(local);
+		goto restart;
+	}
+
+	local->extensions = 0;
+	for (n = 0; n < count; n++) {
+		if (ctx->engines[n]) {
+			local->class_instance[n].engine_class =
+				ctx->engines[n]->uabi_class;
+			local->class_instance[n].engine_instance =
+				ctx->engines[n]->instance;
+		} else {
+			local->class_instance[n].engine_class =
+				I915_ENGINE_CLASS_INVALID;
+			local->class_instance[n].engine_instance =
+				I915_ENGINE_CLASS_INVALID_NONE;
+		}
+	}
+
+	mutex_unlock(&ctx->i915->drm.struct_mutex);
+
+	if (copy_to_user(u64_to_user_ptr(args->value), local, size)) {
+		err = -EFAULT;
+		goto out;
+	}
+	args->size = size;
+
+out:
+	kfree(local);
+	return err;
+}
+
 static int ctx_setparam(struct i915_gem_context *ctx,
 			struct drm_i915_gem_context_param *args)
 {
@@ -1466,6 +1639,10 @@ static int ctx_setparam(struct i915_gem_context *ctx,
 		ret = set_ppgtt(ctx, args);
 		break;
 
+	case I915_CONTEXT_PARAM_ENGINES:
+		ret = set_engines(ctx, args);
+		break;
+
 	case I915_CONTEXT_PARAM_BAN_PERIOD:
 	default:
 		ret = -EINVAL;
@@ -1519,6 +1696,30 @@ static int clone_sseu(struct i915_gem_context *dst,
 	return 0;
 }
 
+static int clone_engines(struct i915_gem_context *dst,
+			 struct i915_gem_context *src)
+{
+	struct intel_engine_cs **engines;
+	unsigned int nengine;
+
+	mutex_lock(&src->i915->drm.struct_mutex); /* serialise src->engine[] */
+	nengine = src->nengine;
+	if (!ZERO_OR_NULL_PTR(src->engines))
+		engines = kmemdup(src->engines,
+				  sizeof(*src->engines) * nengine,
+				  GFP_KERNEL);
+	else
+		engines = src->engines;
+	mutex_unlock(&src->i915->drm.struct_mutex);
+	if (!engines && nengine)
+		return -ENOMEM;
+
+	kfree(dst->engines);
+	dst->engines = engines;
+	dst->nengine = nengine;
+	return 0;
+}
+
 static int create_clone(struct i915_user_extension __user *ext, void *data)
 {
 	struct drm_i915_gem_context_create_ext_clone local;
@@ -1587,6 +1788,12 @@ static int create_clone(struct i915_user_extension __user *ext, void *data)
 		}
 	}
 
+	if (local.flags & I915_CONTEXT_CLONE_ENGINES) {
+		err = clone_engines(dst, src);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
@@ -1705,9 +1912,9 @@ static int get_sseu(struct i915_gem_context *ctx,
 	if (user_sseu.flags || user_sseu.rsvd)
 		return -EINVAL;
 
-	engine = intel_engine_lookup_user(ctx->i915,
-					  user_sseu.engine_class,
-					  user_sseu.engine_instance);
+	engine = lookup_user_engine(ctx, 0,
+				    user_sseu.engine_class,
+				    user_sseu.engine_instance);
 	if (!engine)
 		return -EINVAL;
 
@@ -1788,6 +1995,10 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
 		ret = get_ppgtt(ctx, args);
 		break;
 
+	case I915_CONTEXT_PARAM_ENGINES:
+		ret = get_engines(ctx, args);
+		break;
+
 	case I915_CONTEXT_PARAM_BAN_PERIOD:
 	default:
 		ret = -EINVAL;
diff --git a/drivers/gpu/drm/i915/i915_gem_context_types.h b/drivers/gpu/drm/i915/i915_gem_context_types.h
index f8f6e6c960a7..8a89f3053f73 100644
--- a/drivers/gpu/drm/i915/i915_gem_context_types.h
+++ b/drivers/gpu/drm/i915/i915_gem_context_types.h
@@ -41,6 +41,8 @@ struct i915_gem_context {
 	/** file_priv: owning file descriptor */
 	struct drm_i915_file_private *file_priv;
 
+	struct intel_engine_cs **engines;
+
 	struct i915_timeline *timeline;
 
 	/**
@@ -110,6 +112,8 @@ struct i915_gem_context {
 #define CONTEXT_CLOSED			1
 #define CONTEXT_FORCE_SINGLE_SUBMISSION	2
 
+	unsigned int nengine;
+
 	/**
 	 * @hw_id: - unique identifier for the context
 	 *
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index ee6d301a9627..70a26f0a9f1e 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -2090,13 +2090,20 @@ static const enum intel_engine_id user_ring_map[I915_USER_RINGS + 1] = {
 };
 
 static struct intel_engine_cs *
-eb_select_engine(struct drm_i915_private *dev_priv,
+eb_select_engine(struct i915_execbuffer *eb,
 		 struct drm_file *file,
 		 struct drm_i915_gem_execbuffer2 *args)
 {
 	unsigned int user_ring_id = args->flags & I915_EXEC_RING_MASK;
 	struct intel_engine_cs *engine;
 
+	if (eb->ctx->engines) {
+		if (user_ring_id >= eb->ctx->nengine)
+			return NULL;
+
+		return eb->ctx->engines[user_ring_id];
+	}
+
 	if (user_ring_id > I915_USER_RINGS) {
 		DRM_DEBUG("execbuf with unknown ring: %u\n", user_ring_id);
 		return NULL;
@@ -2109,11 +2116,11 @@ eb_select_engine(struct drm_i915_private *dev_priv,
 		return NULL;
 	}
 
-	if (user_ring_id == I915_EXEC_BSD && HAS_ENGINE(dev_priv, VCS1)) {
+	if (user_ring_id == I915_EXEC_BSD && HAS_ENGINE(eb->i915, VCS1)) {
 		unsigned int bsd_idx = args->flags & I915_EXEC_BSD_MASK;
 
 		if (bsd_idx == I915_EXEC_BSD_DEFAULT) {
-			bsd_idx = gen8_dispatch_bsd_engine(dev_priv, file);
+			bsd_idx = gen8_dispatch_bsd_engine(eb->i915, file);
 		} else if (bsd_idx >= I915_EXEC_BSD_RING1 &&
 			   bsd_idx <= I915_EXEC_BSD_RING2) {
 			bsd_idx >>= I915_EXEC_BSD_SHIFT;
@@ -2124,9 +2131,9 @@ eb_select_engine(struct drm_i915_private *dev_priv,
 			return NULL;
 		}
 
-		engine = dev_priv->engine[_VCS(bsd_idx)];
+		engine = eb->i915->engine[_VCS(bsd_idx)];
 	} else {
-		engine = dev_priv->engine[user_ring_map[user_ring_id]];
+		engine = eb->i915->engine[user_ring_map[user_ring_id]];
 	}
 
 	if (!engine) {
@@ -2336,7 +2343,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 	if (unlikely(err))
 		goto err_destroy;
 
-	eb.engine = eb_select_engine(eb.i915, file, args);
+	eb.engine = eb_select_engine(&eb, file, args);
 	if (!eb.engine) {
 		err = -EINVAL;
 		goto err_engine;
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 51b658fa966d..b96d110c1c2b 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -25,6 +25,9 @@
 #ifndef __I915_UTILS_H
 #define __I915_UTILS_H
 
+#include <linux/kernel.h>
+#include <linux/overflow.h>
+
 #undef WARN_ON
 /* Many gcc seem to no see through this and fall over :( */
 #if 0
@@ -73,6 +76,26 @@
 #define overflows_type(x, T) \
 	(sizeof(x) > sizeof(T) && (x) >> BITS_PER_TYPE(T))
 
+static inline bool
+__check_struct_size(size_t base, size_t arr, size_t count, size_t *size)
+{
+	size_t sz;
+
+	if (check_mul_overflow(count, arr, &sz))
+		return false;
+
+	if (check_add_overflow(sz, base, &sz))
+		return false;
+
+	*size = sz;
+	return true;
+}
+
+#define check_struct_size(T, A, C, SZ) \
+	likely(__check_struct_size(sizeof(*(T)), \
+				   sizeof(*(T)->A) + __must_be_array((T)->A), \
+				   C, SZ))
+
 #define ptr_mask_bits(ptr, n) ({					\
 	unsigned long __v = (unsigned long)(ptr);			\
 	(typeof(ptr))(__v & -BIT(n));					\
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 9714520f43da..6dde864e14e7 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -126,6 +126,8 @@ enum drm_i915_gem_engine_class {
 	I915_ENGINE_CLASS_INVALID	= -1
 };
 
+#define I915_ENGINE_CLASS_INVALID_NONE -1
+
 /**
  * DOC: perf_events exposed by i915 through /sys/bus/event_sources/drivers/i915
  *
@@ -1511,6 +1513,26 @@ struct drm_i915_gem_context_param {
 	 * See DRM_I915_GEM_VM_CREATE and DRM_I915_GEM_VM_DESTROY.
 	 */
 #define I915_CONTEXT_PARAM_VM		0x9
+
+/*
+ * I915_CONTEXT_PARAM_ENGINES:
+ *
+ * Bind this context to operate on this subset of available engines. Henceforth,
+ * the I915_EXEC_RING selector for DRM_IOCTL_I915_GEM_EXECBUFFER2 operates as
+ * an index into this array of engines; I915_EXEC_DEFAULT selecting engine[0]
+ * and upwards. Slots 0...N are filled in using the specified (class, instance).
+ * Use
+ *	engine_class: I915_ENGINE_CLASS_INVALID,
+ *	engine_instance: I915_ENGINE_CLASS_INVALID_NONE
+ * to specify a gap in the array that can be filled in later, e.g. by a
+ * virtual engine used for load balancing.
+ *
+ * Setting the number of engines bound to the context to 0, by passing a zero
+ * sized argument, will revert back to default settings.
+ *
+ * See struct i915_context_param_engines.
+ */
+#define I915_CONTEXT_PARAM_ENGINES	0xa
 /* Must be kept compact -- no holes and well documented */
 
 	__u64 value;
@@ -1575,6 +1597,23 @@ struct drm_i915_gem_context_param_sseu {
 	__u32 rsvd;
 };
 
+struct i915_context_param_engines {
+	__u64 extensions; /* linked chain of extension blocks, 0 terminates */
+
+	struct {
+		__u16 engine_class; /* see enum drm_i915_gem_engine_class */
+		__u16 engine_instance;
+	} class_instance[0];
+} __attribute__((packed));
+
+#define I915_DEFINE_CONTEXT_PARAM_ENGINES(name__, N__) struct { \
+	__u64 extensions; \
+	struct { \
+		__u16 engine_class; \
+		__u16 engine_instance; \
+	} class_instance[N__]; \
+} __attribute__((packed)) name__
+
 struct drm_i915_gem_context_create_ext_setparam {
 #define I915_CONTEXT_CREATE_EXT_SETPARAM 0
 	struct i915_user_extension base;
@@ -1591,7 +1630,8 @@ struct drm_i915_gem_context_create_ext_clone {
 #define I915_CONTEXT_CLONE_SSEU		(1u << 2)
 #define I915_CONTEXT_CLONE_TIMELINE	(1u << 3)
 #define I915_CONTEXT_CLONE_VM		(1u << 4)
-#define I915_CONTEXT_CLONE_UNKNOWN -(I915_CONTEXT_CLONE_VM << 1)
+#define I915_CONTEXT_CLONE_ENGINES	(1u << 5)
+#define I915_CONTEXT_CLONE_UNKNOWN -(I915_CONTEXT_CLONE_ENGINES << 1)
 	__u64 rsvd;
 };
 
-- 
2.20.1

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[PATCH 13/17] drm/i915: Extend I915_CONTEXT_PARAM_SSEU to support local ctx->engine[]

[Chris Wilson]

Allow the user to specify a local engine index (as opposed to
class:index) that they can use to refer to a preset engine inside the
ctx->engine[] array defined by an earlier I915_CONTEXT_PARAM_ENGINES.
This will be useful for setting SSEU parameters on virtual engines that
are local to the context and do not have a valid global class:instance
lookup.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 24 ++++++++++++++++++++----
 include/uapi/drm/i915_drm.h             |  3 ++-
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 07377b75b563..7ae28622b709 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -1375,6 +1375,7 @@ static int set_sseu(struct i915_gem_context *ctx,
 	struct drm_i915_gem_context_param_sseu user_sseu;
 	struct intel_engine_cs *engine;
 	struct intel_sseu sseu;
+	unsigned long lookup;
 	int ret;
 
 	if (args->size < sizeof(user_sseu))
@@ -1387,10 +1388,17 @@ static int set_sseu(struct i915_gem_context *ctx,
 			   sizeof(user_sseu)))
 		return -EFAULT;
 
-	if (user_sseu.flags || user_sseu.rsvd)
+	if (user_sseu.rsvd)
 		return -EINVAL;
 
-	engine = lookup_user_engine(ctx, 0,
+	if (user_sseu.flags & ~(I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX))
+		return -EINVAL;
+
+	lookup = 0;
+	if (user_sseu.flags & I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX)
+		lookup |= LOOKUP_USER_INDEX;
+
+	engine = lookup_user_engine(ctx, lookup,
 				    user_sseu.engine_class,
 				    user_sseu.engine_instance);
 	if (!engine)
@@ -1899,6 +1907,7 @@ static int get_sseu(struct i915_gem_context *ctx,
 	struct drm_i915_gem_context_param_sseu user_sseu;
 	struct intel_engine_cs *engine;
 	struct intel_context *ce;
+	unsigned long lookup;
 
 	if (args->size == 0)
 		goto out;
@@ -1909,10 +1918,17 @@ static int get_sseu(struct i915_gem_context *ctx,
 			   sizeof(user_sseu)))
 		return -EFAULT;
 
-	if (user_sseu.flags || user_sseu.rsvd)
+	if (user_sseu.rsvd)
 		return -EINVAL;
 
-	engine = lookup_user_engine(ctx, 0,
+	if (user_sseu.flags & ~(I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX))
+		return -EINVAL;
+
+	lookup = 0;
+	if (user_sseu.flags & I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX)
+		lookup |= LOOKUP_USER_INDEX;
+
+	engine = lookup_user_engine(ctx, lookup,
 				    user_sseu.engine_class,
 				    user_sseu.engine_instance);
 	if (!engine)
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 6dde864e14e7..e17c7375248c 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1567,9 +1567,10 @@ struct drm_i915_gem_context_param_sseu {
 	__u16 engine_instance;
 
 	/*
-	 * Unused for now. Must be cleared to zero.
+	 * Unknown flags must be cleared to zero.
 	 */
 	__u32 flags;
+#define I915_CONTEXT_SSEU_FLAG_ENGINE_INDEX (1u << 0)
 
 	/*
 	 * Mask of slices to enable for the context. Valid values are a subset
-- 
2.20.1

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[PATCH 14/17] drm/i915: Load balancing across a virtual engine

[Chris Wilson]

Having allowed the user to define a set of engines that they will want
to only use, we go one step further and allow them to bind those engines
into a single virtual instance. Submitting a batch to the virtual engine
will then forward it to any one of the set in a manner as best to
distribute load.  The virtual engine has a single timeline across all
engines (it operates as a single queue), so it is not able to concurrently
run batches across multiple engines by itself; that is left up to the user
to submit multiple concurrent batches to multiple queues. Multiple users
will be load balanced across the system.

The mechanism used for load balancing in this patch is a late greedy
balancer. When a request is ready for execution, it is added to each
engine's queue, and when an engine is ready for its next request it
claims it from the virtual engine. The first engine to do so, wins, i.e.
the request is executed at the earliest opportunity (idle moment) in the
system.

As not all HW is created equal, the user is still able to skip the
virtual engine and execute the batch on a specific engine, all within the
same queue. It will then be executed in order on the correct engine,
with execution on other virtual engines being moved away due to the load
detection.

A couple of areas for potential improvement left!

- The virtual engine always take priority over equal-priority tasks.
Mostly broken up by applying FQ_CODEL rules for prioritising new clients,
and hopefully the virtual and real engines are not then congested (i.e.
all work is via virtual engines, or all work is to the real engine).

- We require the breadcrumb irq around every virtual engine request. For
normal engines, we eliminate the need for the slow round trip via
interrupt by using the submit fence and queueing in order. For virtual
engines, we have to allow any job to transfer to a new ring, and cannot
coalesce the submissions, so require the completion fence instead,
forcing the persistent use of interrupts.

- We only drip feed single requests through each virtual engine and onto
the physical engines, even if there was enough work to fill all ELSP,
leaving small stalls with an idle CS event at the end of every request.
Could we be greedy and fill both slots? Being lazy is virtuous for load
distribution on less-than-full workloads though.

Other areas of improvement are more general, such as reducing lock
contention, reducing dispatch overhead, looking at direct submission
rather than bouncing around tasklets etc.

sseu: Lift the restriction to allow sseu to be reconfigured on virtual
engines composed of RENDER_CLASS (rcs).

v2: macroize check_user_mbz()
v3: Cancel virtual engines on wedging
v4: Commence commenting

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_gem.h            |   5 +
 drivers/gpu/drm/i915/i915_gem_context.c    | 128 ++++-
 drivers/gpu/drm/i915/i915_scheduler.c      |  18 +-
 drivers/gpu/drm/i915/i915_timeline_types.h |   1 +
 drivers/gpu/drm/i915/intel_engine_types.h  |   8 +
 drivers/gpu/drm/i915/intel_lrc.c           | 570 ++++++++++++++++++++-
 drivers/gpu/drm/i915/intel_lrc.h           |  11 +
 drivers/gpu/drm/i915/selftests/intel_lrc.c | 165 ++++++
 include/uapi/drm/i915_drm.h                |  30 ++
 9 files changed, 917 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 74a2ddc1b52f..dbcea6e29d48 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -91,4 +91,9 @@ static inline bool __tasklet_is_enabled(const struct tasklet_struct *t)
 	return !atomic_read(&t->count);
 }
 
+static inline bool __tasklet_is_scheduled(struct tasklet_struct *t)
+{
+	return test_bit(TASKLET_STATE_SCHED, &t->state);
+}
+
 #endif /* __I915_GEM_H__ */
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 7ae28622b709..98763d3f1b12 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -86,6 +86,7 @@
  */
 
 #include <linux/log2.h>
+#include <linux/nospec.h>
 
 #include <drm/i915_drm.h>
 
@@ -94,6 +95,7 @@
 #include "i915_trace.h"
 #include "i915_user_extensions.h"
 #include "intel_lrc_reg.h"
+#include "intel_lrc.h"
 #include "intel_workarounds.h"
 
 #define ALL_L3_SLICES(dev) (1 << NUM_L3_SLICES(dev)) - 1
@@ -241,6 +243,20 @@ static void release_hw_id(struct i915_gem_context *ctx)
 	mutex_unlock(&i915->contexts.mutex);
 }
 
+static void free_engines(struct intel_engine_cs **engines, int count)
+{
+	int i;
+
+	if (ZERO_OR_NULL_PTR(engines))
+		return;
+
+	/* We own the veng we created; regular engines are ignored */
+	for (i = 0; i < count; i++)
+		intel_virtual_engine_destroy(engines[i]);
+
+	kfree(engines);
+}
+
 static void i915_gem_context_free(struct i915_gem_context *ctx)
 {
 	struct intel_context *it, *n;
@@ -251,8 +267,7 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
 
 	release_hw_id(ctx);
 	i915_ppgtt_put(ctx->ppgtt);
-
-	kfree(ctx->engines);
+	free_engines(ctx->engines, ctx->nengine);
 
 	rbtree_postorder_for_each_entry_safe(it, n, &ctx->hw_contexts, node)
 		intel_context_put(it);
@@ -1233,7 +1248,6 @@ __i915_gem_context_reconfigure_sseu(struct i915_gem_context *ctx,
 	int ret = 0;
 
 	GEM_BUG_ON(INTEL_GEN(ctx->i915) < 8);
-	GEM_BUG_ON(engine->id != RCS0);
 
 	ce = intel_context_pin_lock(ctx, engine);
 	if (IS_ERR(ce))
@@ -1427,7 +1441,80 @@ struct set_engines {
 	unsigned int nengine;
 };
 
+static int
+set_engines__load_balance(struct i915_user_extension __user *base, void *data)
+{
+	struct i915_context_engines_load_balance __user *ext =
+		container_of_user(base, typeof(*ext), base);
+	const struct set_engines *set = data;
+	struct intel_engine_cs *ve;
+	unsigned int n;
+	u64 mask;
+	u16 idx;
+	int err;
+
+	if (!HAS_EXECLISTS(set->ctx->i915))
+		return -ENODEV;
+
+	if (USES_GUC_SUBMISSION(set->ctx->i915))
+		return -ENODEV; /* not implement yet */
+
+	if (get_user(idx, &ext->engine_index))
+		return -EFAULT;
+
+	if (idx >= set->nengine)
+		return -EINVAL;
+
+	idx = array_index_nospec(idx, set->nengine);
+	if (set->engines[idx])
+		return -EEXIST;
+
+	err = check_user_mbz(&ext->mbz16);
+	if (err)
+		return err;
+
+	err = check_user_mbz(&ext->flags);
+	if (err)
+		return err;
+
+	for (n = 0; n < ARRAY_SIZE(ext->mbz64); n++) {
+		err = check_user_mbz(&ext->mbz64[n]);
+		if (err)
+			return err;
+	}
+
+	if (get_user(mask, &ext->engines_mask))
+		return -EFAULT;
+
+	mask &= GENMASK_ULL(set->nengine - 1, 0) & ~BIT_ULL(idx);
+	if (!mask)
+		return -EINVAL;
+
+	if (is_power_of_2(mask)) {
+		ve = set->engines[__ffs64(mask)];
+	} else {
+		struct intel_engine_cs *stack[64];
+		int bit;
+
+		n = 0;
+		for_each_set_bit(bit, (unsigned long *)&mask, set->nengine)
+			stack[n++] = set->engines[bit];
+
+		ve = intel_execlists_create_virtual(set->ctx, stack, n);
+	}
+	if (IS_ERR(ve))
+		return PTR_ERR(ve);
+
+	if (cmpxchg(&set->engines[idx], NULL, ve)) {
+		intel_virtual_engine_destroy(ve);
+		return -EEXIST;
+	}
+
+	return 0;
+}
+
 static const i915_user_extension_fn set_engines__extensions[] = {
+	[I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE] = set_engines__load_balance,
 };
 
 static int
@@ -1489,13 +1576,13 @@ set_engines(struct i915_gem_context *ctx,
 					   ARRAY_SIZE(set_engines__extensions),
 					   &set);
 	if (err) {
-		kfree(set.engines);
+		free_engines(set.engines, set.nengine);
 		return err;
 	}
 
 out:
 	mutex_lock(&ctx->i915->drm.struct_mutex);
-	kfree(ctx->engines);
+	free_engines(ctx->engines, ctx->nengine);
 	ctx->engines = set.engines;
 	ctx->nengine = set.nengine;
 	mutex_unlock(&ctx->i915->drm.struct_mutex);
@@ -1708,9 +1795,10 @@ static int clone_engines(struct i915_gem_context *dst,
 			 struct i915_gem_context *src)
 {
 	struct intel_engine_cs **engines;
-	unsigned int nengine;
+	unsigned int nengine, i;
 
 	mutex_lock(&src->i915->drm.struct_mutex); /* serialise src->engine[] */
+
 	nengine = src->nengine;
 	if (!ZERO_OR_NULL_PTR(src->engines))
 		engines = kmemdup(src->engines,
@@ -1718,11 +1806,37 @@ static int clone_engines(struct i915_gem_context *dst,
 				  GFP_KERNEL);
 	else
 		engines = src->engines;
+
+	/*
+	 * Virtual engines are singletons; they can only exist
+	 * inside a single context, because they embed their
+	 * HW context... As each virtual context implies a single
+	 * timeline (each engine can only dequeue a single request
+	 * at any time), it would be surprising for two contexts
+	 * to use the same engine. So let's create a copy of
+	 * the virtual engine instead.
+	 */
+	for (i = 0; i < nengine; i++) {
+		struct intel_engine_cs *engine = engines[i];
+
+		if (!intel_engine_is_virtual(engine))
+			continue;
+
+		engine = intel_execlists_clone_virtual(dst, engine);
+		if (IS_ERR(engine)) {
+			free_engines(engines, i);
+			mutex_unlock(&src->i915->drm.struct_mutex);
+			return PTR_ERR(engine);
+		}
+
+		engines[i] = engine;
+	}
+
 	mutex_unlock(&src->i915->drm.struct_mutex);
 	if (!engines && nengine)
 		return -ENOMEM;
 
-	kfree(dst->engines);
+	free_engines(dst->engines, dst->nengine);
 	dst->engines = engines;
 	dst->nengine = nengine;
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index e0f609d01564..8cff4f6d6158 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -247,17 +247,26 @@ sched_lock_engine(const struct i915_sched_node *node,
 		  struct intel_engine_cs *locked,
 		  struct sched_cache *cache)
 {
-	struct intel_engine_cs *engine = node_to_request(node)->engine;
+	const struct i915_request *rq = node_to_request(node);
+	struct intel_engine_cs *engine;
 
 	GEM_BUG_ON(!locked);
 
-	if (engine != locked) {
+	/*
+	 * Virtual engines complicate acquiring the engine timeline lock,
+	 * as their rq->engine pointer is not stable until under that
+	 * engine lock. The simple ploy we use is to take the lock then
+	 * check that the rq still belongs to the newly locked engine.
+	 */
+	while (locked != (engine = READ_ONCE(rq->engine))) {
 		spin_unlock(&locked->timeline.lock);
 		memset(cache, 0, sizeof(*cache));
 		spin_lock(&engine->timeline.lock);
+		locked = engine;
 	}
 
-	return engine;
+	GEM_BUG_ON(locked != engine);
+	return locked;
 }
 
 static bool inflight(const struct i915_request *rq,
@@ -370,8 +379,11 @@ static void __i915_schedule(struct i915_request *rq,
 		if (prio <= node->attr.priority || node_signaled(node))
 			continue;
 
+		GEM_BUG_ON(node_to_request(node)->engine != engine);
+
 		node->attr.priority = prio;
 		if (!list_empty(&node->link)) {
+			GEM_BUG_ON(intel_engine_is_virtual(engine));
 			if (!cache.priolist)
 				cache.priolist =
 					i915_sched_lookup_priolist(engine,
diff --git a/drivers/gpu/drm/i915/i915_timeline_types.h b/drivers/gpu/drm/i915/i915_timeline_types.h
index 8ff146dc05ba..5e445f145eb1 100644
--- a/drivers/gpu/drm/i915/i915_timeline_types.h
+++ b/drivers/gpu/drm/i915/i915_timeline_types.h
@@ -25,6 +25,7 @@ struct i915_timeline {
 	spinlock_t lock;
 #define TIMELINE_CLIENT 0 /* default subclass */
 #define TIMELINE_ENGINE 1
+#define TIMELINE_VIRTUAL 2
 	struct mutex mutex; /* protects the flow of requests */
 
 	unsigned int pin_count;
diff --git a/drivers/gpu/drm/i915/intel_engine_types.h b/drivers/gpu/drm/i915/intel_engine_types.h
index 88ed7ba8886f..322fbda65190 100644
--- a/drivers/gpu/drm/i915/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/intel_engine_types.h
@@ -218,6 +218,7 @@ struct intel_engine_execlists {
 	 * @queue: queue of requests, in priority lists
 	 */
 	struct rb_root_cached queue;
+	struct rb_root_cached virtual;
 
 	/**
 	 * @csb_write: control register for Context Switch buffer
@@ -423,6 +424,7 @@ struct intel_engine_cs {
 #define I915_ENGINE_SUPPORTS_STATS   BIT(1)
 #define I915_ENGINE_HAS_PREEMPTION   BIT(2)
 #define I915_ENGINE_HAS_SEMAPHORES   BIT(3)
+#define I915_ENGINE_IS_VIRTUAL       BIT(4)
 	unsigned int flags;
 
 	/*
@@ -506,6 +508,12 @@ intel_engine_has_semaphores(const struct intel_engine_cs *engine)
 	return engine->flags & I915_ENGINE_HAS_SEMAPHORES;
 }
 
+static inline bool
+intel_engine_is_virtual(const struct intel_engine_cs *engine)
+{
+	return engine->flags & I915_ENGINE_IS_VIRTUAL;
+}
+
 #define instdone_slice_mask(dev_priv__) \
 	(IS_GEN(dev_priv__, 7) ? \
 	 1 : RUNTIME_INFO(dev_priv__)->sseu.slice_mask)
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 6e9bd70f5e92..d54b7cc43633 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -166,6 +166,41 @@
 
 #define ACTIVE_PRIORITY (I915_PRIORITY_NEWCLIENT | I915_PRIORITY_NOSEMAPHORE)
 
+struct virtual_engine {
+	struct intel_engine_cs base;
+	struct intel_context context;
+
+	/*
+	 * We allow only a single request through the virtual engine at a time
+	 * (each request in the timeline waits for the completion fence of
+	 * the previous before being submitted). By restricting ourselves to
+	 * only submitting a single request, each request is placed on to a
+	 * physical to maximise load spreading (by virtue of the late greedy
+	 * scheduling -- each real engine takes the next available request
+	 * upon idling).
+	 */
+	struct i915_request *request;
+
+	/*
+	 * We keep a rbtree of available virtual engines inside each physical
+	 * engine, sorted by priority. Here we preallocate the nodes we need
+	 * for the virtual engine, indexed by physical_engine->id.
+	 */
+	struct ve_node {
+		struct rb_node rb;
+		int prio;
+	} nodes[I915_NUM_ENGINES];
+
+	/* And finally, which physical engines this virtual engine maps onto. */
+	unsigned int count;
+	struct intel_engine_cs *siblings[0];
+};
+
+static struct virtual_engine *to_virtual_engine(struct intel_engine_cs *engine)
+{
+	return container_of(engine, struct virtual_engine, base);
+}
+
 static int execlists_context_deferred_alloc(struct intel_context *ce,
 					    struct intel_engine_cs *engine);
 static void execlists_init_reg_state(u32 *reg_state,
@@ -229,7 +264,8 @@ static int queue_prio(const struct intel_engine_execlists *execlists)
 }
 
 static inline bool need_preempt(const struct intel_engine_cs *engine,
-				const struct i915_request *rq)
+				const struct i915_request *rq,
+				struct rb_node *rb)
 {
 	int last_prio;
 
@@ -264,6 +300,22 @@ static inline bool need_preempt(const struct intel_engine_cs *engine,
 	    rq_prio(list_next_entry(rq, link)) > last_prio)
 		return true;
 
+	if (rb) { /* XXX virtual precedence */
+		struct virtual_engine *ve =
+			rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+		bool preempt = false;
+
+		if (engine == ve->siblings[0]) { /* only preempt one sibling */
+			spin_lock(&ve->base.timeline.lock);
+			if (ve->request)
+				preempt = rq_prio(ve->request) > last_prio;
+			spin_unlock(&ve->base.timeline.lock);
+		}
+
+		if (preempt)
+			return preempt;
+	}
+
 	/*
 	 * If the inflight context did not trigger the preemption, then maybe
 	 * it was the set of queued requests? Pick the highest priority in
@@ -382,6 +434,8 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine)
 	list_for_each_entry_safe_reverse(rq, rn,
 					 &engine->timeline.requests,
 					 link) {
+		struct intel_engine_cs *owner;
+
 		if (i915_request_completed(rq))
 			break;
 
@@ -390,14 +444,30 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine)
 
 		GEM_BUG_ON(rq->hw_context->active);
 
-		GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID);
-		if (rq_prio(rq) != prio) {
-			prio = rq_prio(rq);
-			pl = i915_sched_lookup_priolist(engine, prio);
-		}
-		GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
+		/*
+		 * Push the request back into the queue for later resubmission.
+		 * If this request is not native to this physical engine (i.e.
+		 * it came from a virtual source), push it back onto the virtual
+		 * engine so that it can be moved across onto another physical
+		 * engine as load dictates.
+		 */
+		owner = rq->hw_context->engine;
+		if (likely(owner == engine)) {
+			GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID);
+			if (rq_prio(rq) != prio) {
+				prio = rq_prio(rq);
+				pl = i915_sched_lookup_priolist(engine, prio);
+			}
+			GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
 
-		list_add(&rq->sched.link, pl);
+			list_add(&rq->sched.link, pl);
+		} else {
+			if (__i915_request_has_started(rq))
+				rq->sched.attr.priority |= ACTIVE_PRIORITY;
+
+			rq->engine = owner;
+			owner->submit_request(rq);
+		}
 
 		active = rq;
 	}
@@ -659,6 +729,50 @@ static void complete_preempt_context(struct intel_engine_execlists *execlists)
 						  execlists));
 }
 
+static void virtual_update_register_offsets(u32 *regs,
+					    struct intel_engine_cs *engine)
+{
+	u32 base = engine->mmio_base;
+
+	regs[CTX_CONTEXT_CONTROL] =
+		i915_mmio_reg_offset(RING_CONTEXT_CONTROL(engine));
+	regs[CTX_RING_HEAD] = i915_mmio_reg_offset(RING_HEAD(base));
+	regs[CTX_RING_TAIL] = i915_mmio_reg_offset(RING_TAIL(base));
+	regs[CTX_RING_BUFFER_START] = i915_mmio_reg_offset(RING_START(base));
+	regs[CTX_RING_BUFFER_CONTROL] = i915_mmio_reg_offset(RING_CTL(base));
+
+	regs[CTX_BB_HEAD_U] = i915_mmio_reg_offset(RING_BBADDR_UDW(base));
+	regs[CTX_BB_HEAD_L] = i915_mmio_reg_offset(RING_BBADDR(base));
+	regs[CTX_BB_STATE] = i915_mmio_reg_offset(RING_BBSTATE(base));
+	regs[CTX_SECOND_BB_HEAD_U] =
+		i915_mmio_reg_offset(RING_SBBADDR_UDW(base));
+	regs[CTX_SECOND_BB_HEAD_L] = i915_mmio_reg_offset(RING_SBBADDR(base));
+	regs[CTX_SECOND_BB_STATE] = i915_mmio_reg_offset(RING_SBBSTATE(base));
+
+	regs[CTX_CTX_TIMESTAMP] =
+		i915_mmio_reg_offset(RING_CTX_TIMESTAMP(base));
+	regs[CTX_PDP3_UDW] = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(engine, 3));
+	regs[CTX_PDP3_LDW] = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(engine, 3));
+	regs[CTX_PDP2_UDW] = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(engine, 2));
+	regs[CTX_PDP2_LDW] = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(engine, 2));
+	regs[CTX_PDP1_UDW] = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(engine, 1));
+	regs[CTX_PDP1_LDW] = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(engine, 1));
+	regs[CTX_PDP0_UDW] = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(engine, 0));
+	regs[CTX_PDP0_LDW] = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(engine, 0));
+
+	if (engine->class == RENDER_CLASS) {
+		regs[CTX_RCS_INDIRECT_CTX] =
+			i915_mmio_reg_offset(RING_INDIRECT_CTX(base));
+		regs[CTX_RCS_INDIRECT_CTX_OFFSET] =
+			i915_mmio_reg_offset(RING_INDIRECT_CTX_OFFSET(base));
+		regs[CTX_BB_PER_CTX_PTR] =
+			i915_mmio_reg_offset(RING_BB_PER_CTX_PTR(base));
+
+		regs[CTX_R_PWR_CLK_STATE] =
+			i915_mmio_reg_offset(GEN8_R_PWR_CLK_STATE);
+	}
+}
+
 static void execlists_dequeue(struct intel_engine_cs *engine)
 {
 	struct intel_engine_execlists * const execlists = &engine->execlists;
@@ -691,6 +805,37 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 	 * and context switches) submission.
 	 */
 
+	for (rb = rb_first_cached(&execlists->virtual); rb; ) {
+		struct virtual_engine *ve =
+			rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+		struct i915_request *rq = READ_ONCE(ve->request);
+		struct intel_engine_cs *active;
+
+		if (!rq) { /* lazily cleanup after another engine handled rq */
+			rb_erase_cached(rb, &execlists->virtual);
+			RB_CLEAR_NODE(rb);
+			rb = rb_first_cached(&execlists->virtual);
+			continue;
+		}
+
+		/*
+		 * We track when the HW has completed saving the context image
+		 * (i.e. when we have seen the final CS event switching out of
+		 * the context) and must not overwrite the context image before
+		 * then. This restricts us to only using the active engine
+		 * while the previous virtualized request is inflight (so
+		 * we reuse the register offsets). This is a very small
+		 * hystersis on the greedy seelction algorithm.
+		 */
+		active = READ_ONCE(ve->context.active);
+		if (active && active != engine) {
+			rb = rb_next(rb);
+			continue;
+		}
+
+		break;
+	}
+
 	if (last) {
 		/*
 		 * Don't resubmit or switch until all outstanding
@@ -712,7 +857,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 		if (!execlists_is_active(execlists, EXECLISTS_ACTIVE_HWACK))
 			return;
 
-		if (need_preempt(engine, last)) {
+		if (need_preempt(engine, last, rb)) {
 			inject_preempt_context(engine);
 			return;
 		}
@@ -752,6 +897,72 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 		last->tail = last->wa_tail;
 	}
 
+	while (rb) { /* XXX virtual is always taking precedence */
+		struct virtual_engine *ve =
+			rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+		struct i915_request *rq;
+
+		spin_lock(&ve->base.timeline.lock);
+
+		rq = ve->request;
+		if (unlikely(!rq)) { /* lost the race to a sibling */
+			spin_unlock(&ve->base.timeline.lock);
+			rb_erase_cached(rb, &execlists->virtual);
+			RB_CLEAR_NODE(rb);
+			rb = rb_first_cached(&execlists->virtual);
+			continue;
+		}
+
+		if (rq_prio(rq) >= queue_prio(execlists)) {
+			if (last && !can_merge_rq(last, rq)) {
+				spin_unlock(&ve->base.timeline.lock);
+				return; /* leave this rq for another engine */
+			}
+
+			GEM_BUG_ON(rq->engine != &ve->base);
+			ve->request = NULL;
+			ve->base.execlists.queue_priority_hint = INT_MIN;
+			rb_erase_cached(rb, &execlists->virtual);
+			RB_CLEAR_NODE(rb);
+
+			GEM_BUG_ON(rq->hw_context != &ve->context);
+			rq->engine = engine;
+
+			if (engine != ve->siblings[0]) {
+				u32 *regs = ve->context.lrc_reg_state;
+				unsigned int n;
+
+				GEM_BUG_ON(READ_ONCE(ve->context.active));
+				virtual_update_register_offsets(regs, engine);
+
+				/*
+				 * Move the bound engine to the top of the list
+				 * for future execution. We then kick this
+				 * tasklet first before checking others, so that
+				 * we preferentially reuse this set of bound
+				 * registers.
+				 */
+				for (n = 1; n < ve->count; n++) {
+					if (ve->siblings[n] == engine) {
+						swap(ve->siblings[n],
+						     ve->siblings[0]);
+						break;
+					}
+				}
+
+				GEM_BUG_ON(ve->siblings[0] != engine);
+			}
+
+			__i915_request_submit(rq);
+			trace_i915_request_in(rq, port_index(port, execlists));
+			submit = true;
+			last = rq;
+		}
+
+		spin_unlock(&ve->base.timeline.lock);
+		break;
+	}
+
 	while ((rb = rb_first_cached(&execlists->queue))) {
 		struct i915_priolist *p = to_priolist(rb);
 		struct i915_request *rq, *rn;
@@ -971,6 +1182,24 @@ static void execlists_cancel_requests(struct intel_engine_cs *engine)
 		i915_priolist_free(p);
 	}
 
+	/* Cancel all attached virtual engines */
+	while ((rb = rb_first_cached(&execlists->virtual))) {
+		struct virtual_engine *ve =
+			rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+
+		rb_erase_cached(rb, &execlists->virtual);
+		RB_CLEAR_NODE(rb);
+
+		spin_lock(&ve->base.timeline.lock);
+		if (ve->request) {
+			__i915_request_submit(ve->request);
+			dma_fence_set_error(&ve->request->fence, -EIO);
+			i915_request_mark_complete(ve->request);
+			ve->request = NULL;
+		}
+		spin_unlock(&ve->base.timeline.lock);
+	}
+
 	/* Remaining _unready_ requests will be nop'ed when submitted */
 
 	execlists->queue_priority_hint = INT_MIN;
@@ -2899,6 +3128,306 @@ void intel_lr_context_resume(struct drm_i915_private *i915)
 	}
 }
 
+static void virtual_context_destroy(struct kref *kref)
+{
+	struct virtual_engine *ve =
+		container_of(kref, typeof(*ve), context.ref);
+	unsigned int n;
+
+	GEM_BUG_ON(ve->request);
+	GEM_BUG_ON(ve->context.active);
+
+	for (n = 0; n < ve->count; n++) {
+		struct intel_engine_cs *sibling = ve->siblings[n];
+		struct rb_node *node = &ve->nodes[sibling->id].rb;
+
+		if (RB_EMPTY_NODE(node))
+			continue;
+
+		spin_lock_irq(&sibling->timeline.lock);
+
+		if (!RB_EMPTY_NODE(node))
+			rb_erase_cached(node, &sibling->execlists.virtual);
+
+		spin_unlock_irq(&sibling->timeline.lock);
+	}
+	GEM_BUG_ON(__tasklet_is_scheduled(&ve->base.execlists.tasklet));
+
+	if (ve->context.state)
+		__execlists_context_fini(&ve->context);
+
+	i915_timeline_fini(&ve->base.timeline);
+	kfree(ve);
+}
+
+static void virtual_engine_initial_hint(struct virtual_engine *ve)
+{
+	int swp;
+
+	/*
+	 * Pick a random sibling on starting to help spread the load around.
+	 *
+	 * New contexts are typically created with exactly the same order
+	 * of siblings, and often started in batches. Due to the way we iterate
+	 * the array of sibling when submitting requests, sibling[0] is
+	 * prioritised for dequeuing. If we make sure that sibling[0] is fairly
+	 * randomised across the system, we also help spread the load by the
+	 * first engine we inspect being different each time.
+	 *
+	 * NB This does not force us to execute on this engine, it will just
+	 * typically be the first we inspect for submission.
+	 */
+	swp = prandom_u32_max(ve->count);
+	if (!swp)
+		return;
+
+	swap(ve->siblings[swp], ve->siblings[0]);
+	virtual_update_register_offsets(ve->context.lrc_reg_state,
+					ve->siblings[0]);
+}
+
+static int virtual_context_pin(struct intel_context *ce)
+{
+	struct virtual_engine *ve = container_of(ce, typeof(*ve), context);
+	int err;
+
+	/* Note: we must use a real engine class for setting up reg state */
+	err = __execlists_context_pin(ce, ve->siblings[0]);
+	if (err)
+		return err;
+
+	virtual_engine_initial_hint(ve);
+	return 0;
+}
+
+static const struct intel_context_ops virtual_context_ops = {
+	.pin = virtual_context_pin,
+	.unpin = execlists_context_unpin,
+
+	.destroy = virtual_context_destroy,
+};
+
+static void virtual_submission_tasklet(unsigned long data)
+{
+	struct virtual_engine * const ve = (struct virtual_engine *)data;
+	unsigned int n;
+	int prio;
+
+	prio = READ_ONCE(ve->base.execlists.queue_priority_hint);
+	if (prio == INT_MIN)
+		return;
+
+	local_irq_disable();
+	for (n = 0; READ_ONCE(ve->request) && n < ve->count; n++) {
+		struct intel_engine_cs *sibling = ve->siblings[n];
+		struct ve_node * const node = &ve->nodes[sibling->id];
+		struct rb_node **parent, *rb;
+		bool first;
+
+		spin_lock(&sibling->timeline.lock);
+
+		if (!RB_EMPTY_NODE(&node->rb)) {
+			/*
+			 * Cheat and avoid rebalancing the tree if we can
+			 * reuse this node in situ.
+			 */
+			first = rb_first_cached(&sibling->execlists.virtual) ==
+				&node->rb;
+			if (prio == node->prio || (prio > node->prio && first))
+				goto submit_engine;
+
+			rb_erase_cached(&node->rb, &sibling->execlists.virtual);
+		}
+
+		rb = NULL;
+		first = true;
+		parent = &sibling->execlists.virtual.rb_root.rb_node;
+		while (*parent) {
+			struct ve_node *other;
+
+			rb = *parent;
+			other = rb_entry(rb, typeof(*other), rb);
+			if (prio > other->prio) {
+				parent = &rb->rb_left;
+			} else {
+				parent = &rb->rb_right;
+				first = false;
+			}
+		}
+
+		rb_link_node(&node->rb, rb, parent);
+		rb_insert_color_cached(&node->rb,
+				       &sibling->execlists.virtual,
+				       first);
+
+submit_engine:
+		GEM_BUG_ON(RB_EMPTY_NODE(&node->rb));
+		node->prio = prio;
+		if (first && prio > sibling->execlists.queue_priority_hint) {
+			sibling->execlists.queue_priority_hint = prio;
+			tasklet_hi_schedule(&sibling->execlists.tasklet);
+		}
+
+		spin_unlock(&sibling->timeline.lock);
+	}
+	local_irq_enable();
+}
+
+static void virtual_submit_request(struct i915_request *request)
+{
+	struct virtual_engine *ve = to_virtual_engine(request->engine);
+
+	GEM_BUG_ON(ve->base.submit_request != virtual_submit_request);
+
+	GEM_BUG_ON(ve->request);
+	ve->base.execlists.queue_priority_hint = rq_prio(request);
+	WRITE_ONCE(ve->request, request);
+
+	tasklet_schedule(&ve->base.execlists.tasklet);
+}
+
+struct intel_engine_cs *
+intel_execlists_create_virtual(struct i915_gem_context *ctx,
+			       struct intel_engine_cs **siblings,
+			       unsigned int count)
+{
+	struct virtual_engine *ve;
+	unsigned int n;
+	int err;
+
+	if (!count)
+		return ERR_PTR(-EINVAL);
+
+	ve = kzalloc(struct_size(ve, siblings, count), GFP_KERNEL);
+	if (!ve)
+		return ERR_PTR(-ENOMEM);
+
+	ve->base.i915 = ctx->i915;
+	ve->base.id = -1;
+	ve->base.class = OTHER_CLASS;
+	ve->base.uabi_class = I915_ENGINE_CLASS_INVALID;
+	ve->base.instance = I915_ENGINE_CLASS_INVALID_VIRTUAL;
+	ve->base.flags = I915_ENGINE_IS_VIRTUAL;
+
+	snprintf(ve->base.name, sizeof(ve->base.name), "virtual");
+
+	err = i915_timeline_init(ctx->i915,
+				 &ve->base.timeline,
+				 ve->base.name,
+				 NULL);
+	if (err)
+		goto err_put;
+	i915_timeline_set_subclass(&ve->base.timeline, TIMELINE_VIRTUAL);
+
+	ve->base.cops = &virtual_context_ops;
+	ve->base.request_alloc = execlists_request_alloc;
+
+	ve->base.schedule = i915_schedule;
+	ve->base.submit_request = virtual_submit_request;
+
+	ve->base.execlists.queue_priority_hint = INT_MIN;
+	tasklet_init(&ve->base.execlists.tasklet,
+		     virtual_submission_tasklet,
+		     (unsigned long)ve);
+
+	intel_context_init(&ve->context, ctx, &ve->base);
+
+	for (n = 0; n < count; n++) {
+		struct intel_engine_cs *sibling = siblings[n];
+
+		GEM_BUG_ON(!is_power_of_2(sibling->mask));
+		if (sibling->mask & ve->base.mask)
+			continue;
+
+		/*
+		 * The virtual engine implementation is tightly coupled to
+		 * the execlists backend -- we push out request directly
+		 * into a tree inside each physical engine. We could support
+		 * layering if we handling cloning of the requests and
+		 * submitting a copy into each backend.
+		 */
+		if (sibling->execlists.tasklet.func !=
+		    execlists_submission_tasklet) {
+			err = -ENODEV;
+			goto err_put;
+		}
+
+		GEM_BUG_ON(RB_EMPTY_NODE(&ve->nodes[sibling->id].rb));
+		RB_CLEAR_NODE(&ve->nodes[sibling->id].rb);
+
+		ve->siblings[ve->count++] = sibling;
+		ve->base.mask |= sibling->mask;
+
+		/*
+		 * All physical engines must be compatible for their emission
+		 * functions (as we build the instructions during request
+		 * construction and do not alter them before submission
+		 * on the physical engine). We use the engine class as a guide
+		 * here, although that could be refined.
+		 */
+		if (ve->base.class != OTHER_CLASS) {
+			if (ve->base.class != sibling->class) {
+				err = -EINVAL;
+				goto err_put;
+			}
+			continue;
+		}
+
+		ve->base.class = sibling->class;
+		snprintf(ve->base.name, sizeof(ve->base.name),
+			 "v%dx%d", ve->base.class, count);
+		ve->base.context_size = sibling->context_size;
+
+		ve->base.emit_bb_start = sibling->emit_bb_start;
+		ve->base.emit_flush = sibling->emit_flush;
+		ve->base.emit_init_breadcrumb = sibling->emit_init_breadcrumb;
+		ve->base.emit_fini_breadcrumb = sibling->emit_fini_breadcrumb;
+		ve->base.emit_fini_breadcrumb_dw =
+			sibling->emit_fini_breadcrumb_dw;
+	}
+
+	/* gracefully replace a degenerate virtual engine */
+	if (ve->count == 1) {
+		struct intel_engine_cs *actual = ve->siblings[0];
+		intel_context_put(&ve->context);
+		return actual;
+	}
+
+	__intel_context_insert(ctx, &ve->base, &ve->context);
+	return &ve->base;
+
+err_put:
+	intel_context_put(&ve->context);
+	return ERR_PTR(err);
+}
+
+struct intel_engine_cs *
+intel_execlists_clone_virtual(struct i915_gem_context *ctx,
+			      struct intel_engine_cs *src)
+{
+	struct virtual_engine *se = to_virtual_engine(src);
+	struct intel_engine_cs *dst;
+
+	dst = intel_execlists_create_virtual(ctx,
+					     se->siblings,
+					     se->count);
+	if (IS_ERR(dst))
+		return dst;
+
+	return dst;
+}
+
+void intel_virtual_engine_destroy(struct intel_engine_cs *engine)
+{
+	struct virtual_engine *ve = to_virtual_engine(engine);
+
+	if (!engine || !intel_engine_is_virtual(engine))
+		return;
+
+	__intel_context_remove(&ve->context);
+	intel_context_put(&ve->context);
+}
+
 void intel_execlists_show_requests(struct intel_engine_cs *engine,
 				   struct drm_printer *m,
 				   void (*show_request)(struct drm_printer *m,
@@ -2956,6 +3485,29 @@ void intel_execlists_show_requests(struct intel_engine_cs *engine,
 		show_request(m, last, "\t\tQ ");
 	}
 
+	last = NULL;
+	count = 0;
+	for (rb = rb_first_cached(&execlists->virtual); rb; rb = rb_next(rb)) {
+		struct virtual_engine *ve =
+			rb_entry(rb, typeof(*ve), nodes[engine->id].rb);
+		struct i915_request *rq = READ_ONCE(ve->request);
+
+		if (rq) {
+			if (count++ < max - 1)
+				show_request(m, rq, "\t\tV ");
+			else
+				last = rq;
+		}
+	}
+	if (last) {
+		if (count > max) {
+			drm_printf(m,
+				   "\t\t...skipping %d virtual requests...\n",
+				   count - max);
+		}
+		show_request(m, last, "\t\tV ");
+	}
+
 	spin_unlock_irqrestore(&engine->timeline.lock, flags);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index f1aec8a6986f..9d90dc68e02b 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -112,6 +112,17 @@ void intel_execlists_show_requests(struct intel_engine_cs *engine,
 							const char *prefix),
 				   unsigned int max);
 
+struct intel_engine_cs *
+intel_execlists_create_virtual(struct i915_gem_context *ctx,
+			       struct intel_engine_cs **siblings,
+			       unsigned int count);
+
+struct intel_engine_cs *
+intel_execlists_clone_virtual(struct i915_gem_context *ctx,
+			      struct intel_engine_cs *src);
+
+void intel_virtual_engine_destroy(struct intel_engine_cs *engine);
+
 u32 gen8_make_rpcs(struct drm_i915_private *i915, struct intel_sseu *ctx_sseu);
 
 #endif /* _INTEL_LRC_H_ */
diff --git a/drivers/gpu/drm/i915/selftests/intel_lrc.c b/drivers/gpu/drm/i915/selftests/intel_lrc.c
index d61520ea03c1..4b8a339529d1 100644
--- a/drivers/gpu/drm/i915/selftests/intel_lrc.c
+++ b/drivers/gpu/drm/i915/selftests/intel_lrc.c
@@ -10,6 +10,7 @@
 
 #include "../i915_selftest.h"
 #include "igt_flush_test.h"
+#include "igt_live_test.h"
 #include "igt_spinner.h"
 #include "i915_random.h"
 
@@ -1060,6 +1061,169 @@ static int live_preempt_smoke(void *arg)
 	return err;
 }
 
+static int nop_virtual_engine(struct drm_i915_private *i915,
+			      struct intel_engine_cs **siblings,
+			      unsigned int nsibling,
+			      unsigned int nctx,
+			      unsigned int flags)
+#define CHAIN BIT(0)
+{
+	IGT_TIMEOUT(end_time);
+	struct i915_request *request[16];
+	struct i915_gem_context *ctx[16];
+	struct intel_engine_cs *ve[16];
+	unsigned long n, prime, nc;
+	struct igt_live_test t;
+	ktime_t times[2] = {};
+	int err;
+
+	GEM_BUG_ON(!nctx || nctx > ARRAY_SIZE(ctx));
+
+	for (n = 0; n < nctx; n++) {
+		ctx[n] = kernel_context(i915);
+		if (!ctx[n])
+			return -ENOMEM;
+
+		ve[n] = intel_execlists_create_virtual(ctx[n],
+						       siblings, nsibling);
+		if (IS_ERR(ve[n]))
+			return PTR_ERR(ve[n]);
+	}
+
+	err = igt_live_test_begin(&t, i915, __func__, ve[0]->name);
+	if (err)
+		goto out;
+
+	for_each_prime_number_from(prime, 1, 8192) {
+		times[1] = ktime_get_raw();
+
+		if (flags & CHAIN) {
+			for (nc = 0; nc < nctx; nc++) {
+				for (n = 0; n < prime; n++) {
+					request[nc] =
+						i915_request_alloc(ve[nc], ctx[nc]);
+					if (IS_ERR(request[nc])) {
+						err = PTR_ERR(request[nc]);
+						goto out;
+					}
+
+					i915_request_add(request[nc]);
+				}
+			}
+		} else {
+			for (n = 0; n < prime; n++) {
+				for (nc = 0; nc < nctx; nc++) {
+					request[nc] =
+						i915_request_alloc(ve[nc], ctx[nc]);
+					if (IS_ERR(request[nc])) {
+						err = PTR_ERR(request[nc]);
+						goto out;
+					}
+
+					i915_request_add(request[nc]);
+				}
+			}
+		}
+
+		for (nc = 0; nc < nctx; nc++) {
+			if (i915_request_wait(request[nc],
+					      I915_WAIT_LOCKED,
+					      HZ / 10) < 0) {
+				pr_err("%s(%s): wait for %llx:%lld timed out\n",
+				       __func__, ve[0]->name,
+				       request[nc]->fence.context,
+				       request[nc]->fence.seqno);
+
+				GEM_TRACE("%s(%s) failed at request %llx:%lld\n",
+					  __func__, ve[0]->name,
+					  request[nc]->fence.context,
+					  request[nc]->fence.seqno);
+				GEM_TRACE_DUMP();
+				i915_gem_set_wedged(i915);
+				break;
+			}
+		}
+
+		times[1] = ktime_sub(ktime_get_raw(), times[1]);
+		if (prime == 1)
+			times[0] = times[1];
+
+		if (__igt_timeout(end_time, NULL))
+			break;
+	}
+
+	err = igt_live_test_end(&t);
+	if (err)
+		goto out;
+
+	pr_info("Requestx%d latencies on %s: 1 = %lluns, %lu = %lluns\n",
+		nctx, ve[0]->name, ktime_to_ns(times[0]),
+		prime, div64_u64(ktime_to_ns(times[1]), prime));
+
+out:
+	if (igt_flush_test(i915, I915_WAIT_LOCKED))
+		err = -EIO;
+
+	for (nc = 0; nc < nctx; nc++) {
+		intel_virtual_engine_destroy(ve[nc]);
+		kernel_context_close(ctx[nc]);
+	}
+	return err;
+}
+
+static int live_virtual_engine(void *arg)
+{
+	struct drm_i915_private *i915 = arg;
+	struct intel_engine_cs *siblings[MAX_ENGINE_INSTANCE + 1];
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	unsigned int class, inst;
+	int err = -ENODEV;
+
+	if (USES_GUC_SUBMISSION(i915))
+		return 0;
+
+	mutex_lock(&i915->drm.struct_mutex);
+
+	for_each_engine(engine, i915, id) {
+		err = nop_virtual_engine(i915, &engine, 1, 1, 0);
+		if (err) {
+			pr_err("Failed to wrap engine %s: err=%d\n",
+			       engine->name, err);
+			goto out_unlock;
+		}
+	}
+
+	for (class = 0; class <= MAX_ENGINE_CLASS; class++) {
+		int nsibling, n;
+
+		nsibling = 0;
+		for (inst = 0; inst <= MAX_ENGINE_INSTANCE; inst++) {
+			if (!i915->engine_class[class][inst])
+				break;
+
+			siblings[nsibling++] = i915->engine_class[class][inst];
+		}
+		if (nsibling < 2)
+			continue;
+
+		for (n = 1; n <= nsibling + 1; n++) {
+			err = nop_virtual_engine(i915, siblings, nsibling,
+						 n, 0);
+			if (err)
+				goto out_unlock;
+		}
+
+		err = nop_virtual_engine(i915, siblings, nsibling, n, CHAIN);
+		if (err)
+			goto out_unlock;
+	}
+
+out_unlock:
+	mutex_unlock(&i915->drm.struct_mutex);
+	return err;
+}
+
 int intel_execlists_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
@@ -1071,6 +1235,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(live_chain_preempt),
 		SUBTEST(live_preempt_hang),
 		SUBTEST(live_preempt_smoke),
+		SUBTEST(live_virtual_engine),
 	};
 
 	if (!HAS_EXECLISTS(i915))
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index e17c7375248c..c057536df5cd 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -127,6 +127,7 @@ enum drm_i915_gem_engine_class {
 };
 
 #define I915_ENGINE_CLASS_INVALID_NONE -1
+#define I915_ENGINE_CLASS_INVALID_VIRTUAL 0
 
 /**
  * DOC: perf_events exposed by i915 through /sys/bus/event_sources/drivers/i915
@@ -1598,8 +1599,37 @@ struct drm_i915_gem_context_param_sseu {
 	__u32 rsvd;
 };
 
+/*
+ * i915_context_engines_load_balance:
+ *
+ * Enable load balancing across this set of engines.
+ *
+ * Into the I915_EXEC_DEFAULT slot [0], a virtual engine is created that when
+ * used will proxy the execbuffer request onto one of the set of engines
+ * in such a way as to distribute the load evenly across the set.
+ *
+ * The set of engines must be compatible (e.g. the same HW class) as they
+ * will share the same logical GPU context and ring.
+ *
+ * To intermix rendering with the virtual engine and direct rendering onto
+ * the backing engines (bypassing the load balancing proxy), the context must
+ * be defined to use a single timeline for all engines.
+ */
+struct i915_context_engines_load_balance {
+	struct i915_user_extension base;
+
+	__u16 engine_index;
+	__u16 mbz16; /* reserved for future use; must be zero */
+	__u32 flags; /* all undefined flags must be zero */
+
+	__u64 engines_mask; /* selection mask of engines[] */
+
+	__u64 mbz64[4]; /* reserved for future use; must be zero */
+};
+
 struct i915_context_param_engines {
 	__u64 extensions; /* linked chain of extension blocks, 0 terminates */
+#define I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE 0
 
 	struct {
 		__u16 engine_class; /* see enum drm_i915_gem_engine_class */
-- 
2.20.1

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[PATCH 15/17] drm/i915: Extend execution fence to support a callback

[Chris Wilson]

In the next patch, we will want to configure the slave request
depending on which physical engine the master request is executed on.
For this, we introduce a callback from the execute fence to convey this
information.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_request.c | 84 +++++++++++++++++++++++++++--
 drivers/gpu/drm/i915/i915_request.h |  4 ++
 2 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 2382339172b4..0a46f8113f5c 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -38,6 +38,8 @@ struct execute_cb {
 	struct list_head link;
 	struct irq_work work;
 	struct i915_sw_fence *fence;
+	void (*hook)(struct i915_request *rq, struct dma_fence *signal);
+	struct i915_request *signal;
 };
 
 static struct i915_global_request {
@@ -343,6 +345,17 @@ static void irq_execute_cb(struct irq_work *wrk)
 	kmem_cache_free(global.slab_execute_cbs, cb);
 }
 
+static void irq_execute_cb_hook(struct irq_work *wrk)
+{
+	struct execute_cb *cb = container_of(wrk, typeof(*cb), work);
+
+	cb->hook(container_of(cb->fence, struct i915_request, submit),
+		 &cb->signal->fence);
+	i915_request_put(cb->signal);
+
+	irq_execute_cb(wrk);
+}
+
 static void __notify_execute_cb(struct i915_request *rq)
 {
 	struct execute_cb *cb;
@@ -369,14 +382,19 @@ static void __notify_execute_cb(struct i915_request *rq)
 }
 
 static int
-i915_request_await_execution(struct i915_request *rq,
-			     struct i915_request *signal,
-			     gfp_t gfp)
+__i915_request_await_execution(struct i915_request *rq,
+			       struct i915_request *signal,
+			       void (*hook)(struct i915_request *rq,
+					    struct dma_fence *signal),
+			       gfp_t gfp)
 {
 	struct execute_cb *cb;
 
-	if (i915_request_is_active(signal))
+	if (i915_request_is_active(signal)) {
+		if (hook)
+			hook(rq, &signal->fence);
 		return 0;
+	}
 
 	cb = kmem_cache_alloc(global.slab_execute_cbs, gfp);
 	if (!cb)
@@ -386,8 +404,18 @@ i915_request_await_execution(struct i915_request *rq,
 	i915_sw_fence_await(cb->fence);
 	init_irq_work(&cb->work, irq_execute_cb);
 
+	if (hook) {
+		cb->hook = hook;
+		cb->signal = i915_request_get(signal);
+		cb->work.func = irq_execute_cb_hook;
+	}
+
 	spin_lock_irq(&signal->lock);
 	if (i915_request_is_active(signal)) {
+		if (hook) {
+			hook(rq, &signal->fence);
+			i915_request_put(signal);
+		}
 		i915_sw_fence_complete(cb->fence);
 		kmem_cache_free(global.slab_execute_cbs, cb);
 	} else {
@@ -790,7 +818,7 @@ emit_semaphore_wait(struct i915_request *to,
 		return err;
 
 	/* Only submit our spinner after the signaler is running! */
-	err = i915_request_await_execution(to, from, gfp);
+	err = __i915_request_await_execution(to, from, NULL, gfp);
 	if (err)
 		return err;
 
@@ -910,6 +938,52 @@ i915_request_await_dma_fence(struct i915_request *rq, struct dma_fence *fence)
 	return 0;
 }
 
+int
+i915_request_await_execution(struct i915_request *rq,
+			     struct dma_fence *fence,
+			     void (*hook)(struct i915_request *rq,
+					  struct dma_fence *signal))
+{
+	struct dma_fence **child = &fence;
+	unsigned int nchild = 1;
+	int ret;
+
+	if (dma_fence_is_array(fence)) {
+		struct dma_fence_array *array = to_dma_fence_array(fence);
+
+		/* XXX Error for signal-on-any fence arrays */
+
+		child = array->fences;
+		nchild = array->num_fences;
+		GEM_BUG_ON(!nchild);
+	}
+
+	do {
+		fence = *child++;
+		if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+			continue;
+
+		/*
+		 * We don't squash repeated fence dependencies here as we
+		 * want to run our callback in all cases.
+		 */
+
+		if (dma_fence_is_i915(fence))
+			ret = __i915_request_await_execution(rq,
+							     to_request(fence),
+							     hook,
+							     I915_FENCE_GFP);
+		else
+			ret = i915_sw_fence_await_dma_fence(&rq->submit, fence,
+							    I915_FENCE_TIMEOUT,
+							    GFP_KERNEL);
+		if (ret < 0)
+			return ret;
+	} while (--nchild);
+
+	return 0;
+}
+
 /**
  * i915_request_await_object - set this request to (async) wait upon a bo
  * @to: request we are wishing to use
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index cd6c130964cd..d4f6b2940130 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -265,6 +265,10 @@ int i915_request_await_object(struct i915_request *to,
 			      bool write);
 int i915_request_await_dma_fence(struct i915_request *rq,
 				 struct dma_fence *fence);
+int i915_request_await_execution(struct i915_request *rq,
+				 struct dma_fence *fence,
+				 void (*hook)(struct i915_request *rq,
+					      struct dma_fence *signal));
 
 void i915_request_add(struct i915_request *rq);
 
-- 
2.20.1

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[PATCH 16/17] drm/i915/execlists: Virtual engine bonding

[Chris Wilson]

Some users require that when a master batch is executed on one particular
engine, a companion batch is run simultaneously on a specific slave
engine. For this purpose, we introduce virtual engine bonding, allowing
maps of master:slaves to be constructed to constrain which physical
engines a virtual engine may select given a fence on a master engine.

For the moment, we continue to ignore the issue of preemption deferring
the master request for later. Ideally, we would like to then also remove
the slave and run something else rather than have it stall the pipeline.
With load balancing, we should be able to move workload around it, but
there is a similar stall on the master pipeline while it may wait for
the slave to be executed. At the cost of more latency for the bonded
request, it may be interesting to launch both on their engines in
lockstep. (Bubbles abound.)

Opens: Also what about bonding an engine as its own master? It doesn't
break anything internally, so allow the silliness.

v2: Emancipate the bonds
v3: Couple in delayed scheduling for the selftests
v4: Handle invalid mutually exclusive bonding
v5: Mention what the uapi does

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_context.c       |  50 +++++
 drivers/gpu/drm/i915/i915_request.c           |   1 +
 drivers/gpu/drm/i915/i915_request.h           |   1 +
 drivers/gpu/drm/i915/intel_engine_types.h     |   7 +
 drivers/gpu/drm/i915/intel_lrc.c              | 143 ++++++++++++++
 drivers/gpu/drm/i915/intel_lrc.h              |   4 +
 drivers/gpu/drm/i915/selftests/intel_lrc.c    | 185 ++++++++++++++++++
 drivers/gpu/drm/i915/selftests/lib_sw_fence.c |   3 +
 include/uapi/drm/i915_drm.h                   |  33 ++++
 9 files changed, 427 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 98763d3f1b12..0ec78c386473 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -1513,8 +1513,58 @@ set_engines__load_balance(struct i915_user_extension __user *base, void *data)
 	return 0;
 }
 
+static int
+set_engines__bond(struct i915_user_extension __user *base, void *data)
+{
+	struct i915_context_engines_bond __user *ext =
+		container_of_user(base, typeof(*ext), base);
+	const struct set_engines *set = data;
+	struct intel_engine_cs *master;
+	u32 class, instance, siblings;
+	u16 idx;
+	int err;
+
+	if (get_user(idx, &ext->virtual_index))
+		return -EFAULT;
+
+	if (idx >= set->nengine)
+		return -EINVAL;
+
+	idx = array_index_nospec(idx, set->nengine);
+	if (!set->engines[idx])
+		return -EINVAL;
+
+	/*
+	 * A non-virtual engine has 0 siblings to choose between; and submit
+	 * fence will always be directed to the one engine.
+	 */
+	if (!intel_engine_is_virtual(set->engines[idx]))
+		return 0;
+
+	err = check_user_mbz(&ext->mbz);
+	if (err)
+		return err;
+
+	if (get_user(class, &ext->master_class))
+		return -EFAULT;
+
+	if (get_user(instance, &ext->master_instance))
+		return -EFAULT;
+
+	master = intel_engine_lookup_user(set->ctx->i915, class, instance);
+	if (!master)
+		return -EINVAL;
+
+	if (get_user(siblings, &ext->sibling_mask))
+		return -EFAULT;
+
+	return intel_virtual_engine_attach_bond(set->engines[idx],
+						master, siblings);
+}
+
 static const i915_user_extension_fn set_engines__extensions[] = {
 	[I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE] = set_engines__load_balance,
+	[I915_CONTEXT_ENGINES_EXT_BOND] = set_engines__bond,
 };
 
 static int
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 0a46f8113f5c..9ce710baa452 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -743,6 +743,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
 	rq->batch = NULL;
 	rq->capture_list = NULL;
 	rq->waitboost = false;
+	rq->execution_mask = ~0u;
 
 	/*
 	 * Reserve space in the ring buffer for all the commands required to
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index d4f6b2940130..862b25930de0 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -145,6 +145,7 @@ struct i915_request {
 	 */
 	struct i915_sched_node sched;
 	struct i915_dependency dep;
+	unsigned int execution_mask;
 
 	/*
 	 * A convenience pointer to the current breadcrumb value stored in
diff --git a/drivers/gpu/drm/i915/intel_engine_types.h b/drivers/gpu/drm/i915/intel_engine_types.h
index 322fbda65190..1da35509d811 100644
--- a/drivers/gpu/drm/i915/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/intel_engine_types.h
@@ -384,6 +384,13 @@ struct intel_engine_cs {
 	 */
 	void		(*submit_request)(struct i915_request *rq);
 
+	/*
+	 * Called on signaling of a SUBMIT_FENCE, passing along the signaling
+	 * request down to the bonded pairs.
+	 */
+	void            (*bond_execute)(struct i915_request *rq,
+					struct dma_fence *signal);
+
 	/*
 	 * Call when the priority on a request has changed and it and its
 	 * dependencies may need rescheduling. Note the request itself may
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index d54b7cc43633..79ab4bc543fd 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -191,6 +191,18 @@ struct virtual_engine {
 		int prio;
 	} nodes[I915_NUM_ENGINES];
 
+	/*
+	 * Keep track of bonded pairs -- restrictions upon on our selection
+	 * of physical engines any particular request may be submitted to.
+	 * If we receive a submit-fence from a master engine, we will only
+	 * use one of sibling_mask physical engines.
+	 */
+	struct ve_bond {
+		struct intel_engine_cs *master;
+		unsigned int sibling_mask;
+	} *bonds;
+	unsigned int nbond;
+
 	/* And finally, which physical engines this virtual engine maps onto. */
 	unsigned int count;
 	struct intel_engine_cs *siblings[0];
@@ -3156,6 +3168,8 @@ static void virtual_context_destroy(struct kref *kref)
 	if (ve->context.state)
 		__execlists_context_fini(&ve->context);
 
+	kfree(ve->bonds);
+
 	i915_timeline_fini(&ve->base.timeline);
 	kfree(ve);
 }
@@ -3207,9 +3221,28 @@ static const struct intel_context_ops virtual_context_ops = {
 	.destroy = virtual_context_destroy,
 };
 
+static void virtual_submit_error(struct virtual_engine *ve)
+{
+	struct i915_request *rq = fetch_and_zero(&ve->request);
+	struct intel_engine_cs *engine = ve->siblings[0]; /* any victim */
+
+	dma_fence_set_error(&rq->fence, -ENODEV);
+	i915_request_mark_complete(rq);
+
+	spin_lock(&engine->timeline.lock);
+	rq->engine = engine;
+
+	__i915_request_submit(rq);
+	/* move to start of list to avoid unwind complications */
+	list_move(&rq->link, &engine->timeline.requests);
+
+	spin_unlock(&engine->timeline.lock);
+}
+
 static void virtual_submission_tasklet(unsigned long data)
 {
 	struct virtual_engine * const ve = (struct virtual_engine *)data;
+	unsigned int mask;
 	unsigned int n;
 	int prio;
 
@@ -3218,12 +3251,35 @@ static void virtual_submission_tasklet(unsigned long data)
 		return;
 
 	local_irq_disable();
+
+	mask = 0;
+	spin_lock(&ve->base.timeline.lock);
+	if (ve->request) {
+		mask = ve->request->execution_mask;
+		if (unlikely(!mask))
+			virtual_submit_error(ve);
+	}
+	spin_unlock(&ve->base.timeline.lock);
+	if (!mask)
+		goto out_irq;
+
 	for (n = 0; READ_ONCE(ve->request) && n < ve->count; n++) {
 		struct intel_engine_cs *sibling = ve->siblings[n];
 		struct ve_node * const node = &ve->nodes[sibling->id];
 		struct rb_node **parent, *rb;
 		bool first;
 
+		if (unlikely(!(mask & sibling->mask))) {
+			if (!RB_EMPTY_NODE(&node->rb)) {
+				spin_lock(&sibling->timeline.lock);
+				rb_erase_cached(&node->rb,
+						&sibling->execlists.virtual);
+				RB_CLEAR_NODE(&node->rb);
+				spin_unlock(&sibling->timeline.lock);
+			}
+			continue;
+		}
+
 		spin_lock(&sibling->timeline.lock);
 
 		if (!RB_EMPTY_NODE(&node->rb)) {
@@ -3270,6 +3326,7 @@ static void virtual_submission_tasklet(unsigned long data)
 
 		spin_unlock(&sibling->timeline.lock);
 	}
+out_irq:
 	local_irq_enable();
 }
 
@@ -3286,6 +3343,30 @@ static void virtual_submit_request(struct i915_request *request)
 	tasklet_schedule(&ve->base.execlists.tasklet);
 }
 
+static struct ve_bond *
+virtual_find_bond(struct virtual_engine *ve, struct intel_engine_cs *master)
+{
+	int i;
+
+	for (i = 0; i < ve->nbond; i++) {
+		if (ve->bonds[i].master == master)
+			return &ve->bonds[i];
+	}
+
+	return NULL;
+}
+
+static void
+virtual_bond_execute(struct i915_request *rq, struct dma_fence *signal)
+{
+	struct virtual_engine *ve = to_virtual_engine(rq->engine);
+	struct ve_bond *bond;
+
+	bond = virtual_find_bond(ve, to_request(signal)->engine);
+	if (bond) /* XXX serialise with rq->lock? */
+		rq->execution_mask &= bond->sibling_mask;
+}
+
 struct intel_engine_cs *
 intel_execlists_create_virtual(struct i915_gem_context *ctx,
 			       struct intel_engine_cs **siblings,
@@ -3324,6 +3405,7 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx,
 
 	ve->base.schedule = i915_schedule;
 	ve->base.submit_request = virtual_submit_request;
+	ve->base.bond_execute = virtual_bond_execute;
 
 	ve->base.execlists.queue_priority_hint = INT_MIN;
 	tasklet_init(&ve->base.execlists.tasklet,
@@ -3414,9 +3496,70 @@ intel_execlists_clone_virtual(struct i915_gem_context *ctx,
 	if (IS_ERR(dst))
 		return dst;
 
+	if (se->nbond) {
+		struct virtual_engine *de = to_virtual_engine(dst);
+
+		de->bonds = kmemdup(se->bonds,
+				    sizeof(*se->bonds) * se->nbond,
+				    GFP_KERNEL);
+		if (!de->bonds) {
+			intel_virtual_engine_destroy(dst);
+			return ERR_PTR(-ENOMEM);
+		}
+
+		de->nbond = se->nbond;
+	}
+
 	return dst;
 }
 
+static unsigned long
+virtual_execution_mask(struct virtual_engine *ve, unsigned long mask)
+{
+	unsigned long emask = 0;
+	int bit;
+
+	for_each_set_bit(bit, &mask, ve->count)
+		emask |= ve->siblings[bit]->mask;
+
+	return emask;
+}
+
+int intel_virtual_engine_attach_bond(struct intel_engine_cs *engine,
+				     struct intel_engine_cs *master,
+				     unsigned long mask)
+{
+	struct virtual_engine *ve = to_virtual_engine(engine);
+	struct ve_bond *bond;
+
+	if (mask >> ve->count)
+		return -EINVAL;
+
+	mask = virtual_execution_mask(ve, mask);
+	if (!mask)
+		return -EINVAL;
+
+	bond = virtual_find_bond(ve, master);
+	if (bond) {
+		bond->sibling_mask |= mask;
+		return 0;
+	}
+
+	bond = krealloc(ve->bonds,
+			sizeof(*bond) * (ve->nbond + 1),
+			GFP_KERNEL);
+	if (!bond)
+		return -ENOMEM;
+
+	bond[ve->nbond].master = master;
+	bond[ve->nbond].sibling_mask = mask;
+
+	ve->bonds = bond;
+	ve->nbond++;
+
+	return 0;
+}
+
 void intel_virtual_engine_destroy(struct intel_engine_cs *engine)
 {
 	struct virtual_engine *ve = to_virtual_engine(engine);
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 9d90dc68e02b..77b85648045a 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -121,6 +121,10 @@ struct intel_engine_cs *
 intel_execlists_clone_virtual(struct i915_gem_context *ctx,
 			      struct intel_engine_cs *src);
 
+int intel_virtual_engine_attach_bond(struct intel_engine_cs *engine,
+				     struct intel_engine_cs *master,
+				     unsigned long mask);
+
 void intel_virtual_engine_destroy(struct intel_engine_cs *engine);
 
 u32 gen8_make_rpcs(struct drm_i915_private *i915, struct intel_sseu *ctx_sseu);
diff --git a/drivers/gpu/drm/i915/selftests/intel_lrc.c b/drivers/gpu/drm/i915/selftests/intel_lrc.c
index 4b8a339529d1..22a0f5a11922 100644
--- a/drivers/gpu/drm/i915/selftests/intel_lrc.c
+++ b/drivers/gpu/drm/i915/selftests/intel_lrc.c
@@ -13,6 +13,7 @@
 #include "igt_live_test.h"
 #include "igt_spinner.h"
 #include "i915_random.h"
+#include "lib_sw_fence.h"
 
 #include "mock_context.h"
 
@@ -1224,6 +1225,189 @@ static int live_virtual_engine(void *arg)
 	return err;
 }
 
+static int bond_virtual_engine(struct drm_i915_private *i915,
+			       unsigned int class,
+			       struct intel_engine_cs **siblings,
+			       unsigned int nsibling,
+			       unsigned int flags)
+#define BOND_SCHEDULE BIT(0)
+{
+	struct intel_engine_cs *master;
+	struct i915_gem_context *ctx;
+	struct i915_request *rq[16];
+	enum intel_engine_id id;
+	unsigned long n;
+	int err;
+
+	GEM_BUG_ON(nsibling >= ARRAY_SIZE(rq) - 1);
+
+	ctx = kernel_context(i915);
+	if (!ctx)
+		return -ENOMEM;
+
+	err = 0;
+	rq[0] = ERR_PTR(-ENOMEM);
+	for_each_engine(master, i915, id) {
+		struct i915_sw_fence fence = {};
+
+		if (master->class == class)
+			continue;
+
+		memset_p((void *)rq, ERR_PTR(-EINVAL), ARRAY_SIZE(rq));
+
+		rq[0] = i915_request_alloc(master, ctx);
+		if (IS_ERR(rq[0])) {
+			err = PTR_ERR(rq[0]);
+			goto out;
+		}
+		i915_request_get(rq[0]);
+
+		if (flags & BOND_SCHEDULE) {
+			onstack_fence_init(&fence);
+			err = i915_sw_fence_await_sw_fence_gfp(&rq[0]->submit,
+							       &fence,
+							       GFP_KERNEL);
+		}
+		i915_request_add(rq[0]);
+		if (err)
+			goto out;
+
+		for (n = 0; n < nsibling; n++) {
+			struct intel_engine_cs *engine;
+
+			engine = intel_execlists_create_virtual(ctx,
+								siblings,
+								nsibling);
+			if (IS_ERR(engine)) {
+				err = PTR_ERR(engine);
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+
+			err = intel_virtual_engine_attach_bond(engine,
+							       master,
+							       BIT(n));
+			if (err) {
+				intel_virtual_engine_destroy(engine);
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+
+			rq[n + 1] = i915_request_alloc(engine, ctx);
+			if (IS_ERR(rq[n + 1])) {
+				err = PTR_ERR(rq[n + 1]);
+				intel_virtual_engine_destroy(engine);
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+			i915_request_get(rq[n + 1]);
+
+			err = i915_request_await_execution(rq[n + 1],
+							   &rq[0]->fence,
+							   engine->bond_execute);
+			i915_request_add(rq[n + 1]);
+			intel_virtual_engine_destroy(engine);
+			if (err < 0) {
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+		}
+		onstack_fence_fini(&fence);
+
+		if (i915_request_wait(rq[0],
+					I915_WAIT_LOCKED,
+					HZ / 10) < 0) {
+			pr_err("Master request did not execute (on %s)!\n",
+			       rq[0]->engine->name);
+			err = -EIO;
+			goto out;
+		}
+
+		for (n = 0; n < nsibling; n++) {
+			if (i915_request_wait(rq[n + 1],
+					      I915_WAIT_LOCKED,
+					      MAX_SCHEDULE_TIMEOUT) < 0) {
+				err = -EIO;
+				goto out;
+			}
+
+			if (rq[n + 1]->engine != siblings[n]) {
+				pr_err("Bonded request did not execute on target engine: expected %s, used %s; master was %s\n",
+				       siblings[n]->name,
+				       rq[n + 1]->engine->name,
+				       rq[0]->engine->name);
+				err = -EINVAL;
+				goto out;
+			}
+		}
+
+		for (n = 0; !IS_ERR(rq[n]); n++)
+			i915_request_put(rq[n]);
+		rq[0] = ERR_PTR(-ENOMEM);
+	}
+
+out:
+	for (n = 0; !IS_ERR(rq[n]); n++)
+		i915_request_put(rq[n]);
+	if (igt_flush_test(i915, I915_WAIT_LOCKED))
+		err = -EIO;
+
+	kernel_context_close(ctx);
+	return err;
+}
+
+static int live_virtual_bond(void *arg)
+{
+	static const struct phase {
+		const char *name;
+		unsigned int flags;
+	} phases[] = {
+		{ "", 0 },
+		{ "schedule", BOND_SCHEDULE },
+		{ },
+	};
+	struct drm_i915_private *i915 = arg;
+	struct intel_engine_cs *siblings[MAX_ENGINE_INSTANCE + 1];
+	unsigned int class, inst;
+	int err = 0;
+
+	if (USES_GUC_SUBMISSION(i915))
+		return 0;
+
+	mutex_lock(&i915->drm.struct_mutex);
+
+	for (class = 0; class <= MAX_ENGINE_CLASS; class++) {
+		const struct phase *p;
+		int nsibling;
+
+		nsibling = 0;
+		for (inst = 0; inst <= MAX_ENGINE_INSTANCE; inst++) {
+			if (!i915->engine_class[class][inst])
+				break;
+
+			GEM_BUG_ON(nsibling == ARRAY_SIZE(siblings));
+			siblings[nsibling++] = i915->engine_class[class][inst];
+		}
+		if (nsibling < 2)
+			continue;
+
+		for (p = phases; p->name; p++) {
+			err = bond_virtual_engine(i915,
+						  class, siblings, nsibling,
+						  p->flags);
+			if (err) {
+				pr_err("%s(%s): failed class=%d, nsibling=%d, err=%d\n",
+				       __func__, p->name, class, nsibling, err);
+				goto out_unlock;
+			}
+		}
+	}
+
+out_unlock:
+	mutex_unlock(&i915->drm.struct_mutex);
+	return err;
+}
+
 int intel_execlists_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
@@ -1236,6 +1420,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(live_preempt_hang),
 		SUBTEST(live_preempt_smoke),
 		SUBTEST(live_virtual_engine),
+		SUBTEST(live_virtual_bond),
 	};
 
 	if (!HAS_EXECLISTS(i915))
diff --git a/drivers/gpu/drm/i915/selftests/lib_sw_fence.c b/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
index 2bfa72c1654b..b976c12817c5 100644
--- a/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
+++ b/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
@@ -45,6 +45,9 @@ void __onstack_fence_init(struct i915_sw_fence *fence,
 
 void onstack_fence_fini(struct i915_sw_fence *fence)
 {
+	if (!fence->flags)
+		return;
+
 	i915_sw_fence_commit(fence);
 	i915_sw_fence_fini(fence);
 }
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index c057536df5cd..ed33b8af8692 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1532,6 +1532,10 @@ struct drm_i915_gem_context_param {
  * sized argument, will revert back to default settings.
  *
  * See struct i915_context_param_engines.
+ *
+ * Extensions:
+ *   i915_context_engines_load_balance (I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE)
+ *   i915_context_engines_bond (I915_CONTEXT_ENGINES_EXT_BOND)
  */
 #define I915_CONTEXT_PARAM_ENGINES	0xa
 /* Must be kept compact -- no holes and well documented */
@@ -1627,9 +1631,38 @@ struct i915_context_engines_load_balance {
 	__u64 mbz64[4]; /* reserved for future use; must be zero */
 };
 
+/*
+ * i915_context_engines_bond:
+ *
+ * Constructed bonded pairs for execution within a virtual engine.
+ *
+ * All engines are equal, but some are more equal than others. Given
+ * the distribution of resources in the HW, it may be preferable to run
+ * a request on a given subset of engines in parallel to a request on a
+ * specific engine. We enable this selection of engines within a virtual
+ * engine by specifying bonding pairs, for any given master engine we will
+ * only execute on one of the corresponding siblings within the virtual engine.
+ *
+ * To execute a request in parallel on the master engine and a sibling requires
+ * coordination with a I915_EXEC_FENCE_SUBMIT.
+ */
+struct i915_context_engines_bond {
+	struct i915_user_extension base;
+
+	__u16 virtual_index; /* index of virtual engine in ctx->engines[] */
+	__u16 mbz;
+
+	__u16 master_class;
+	__u16 master_instance;
+
+	__u64 sibling_mask; /* bitmask of BIT(sibling_index) wrt the v.engine */
+	__u64 flags; /* all undefined flags must be zero */
+};
+
 struct i915_context_param_engines {
 	__u64 extensions; /* linked chain of extension blocks, 0 terminates */
 #define I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE 0
+#define I915_CONTEXT_ENGINES_EXT_BOND 1
 
 	struct {
 		__u16 engine_class; /* see enum drm_i915_gem_engine_class */
-- 
2.20.1

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Re: [PATCH 16/17] drm/i915/execlists: Virtual engine bonding

[Chris Wilson]

Quoting Chris Wilson (2019-03-13 13:39:33)
> +               if (flags & BOND_SCHEDULE) {
> +                       onstack_fence_init(&fence);
> +                       err = i915_sw_fence_await_sw_fence_gfp(&rq[0]->submit,
> +                                                              &fence,
> +                                                              GFP_KERNEL);
> +               }
> +               i915_request_add(rq[0]);
> +               if (err)

Missed the git add: if (err < 0) !!!
-Chris
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[PATCH] drm/i915/execlists: Virtual engine bonding

[Chris Wilson]

Some users require that when a master batch is executed on one particular
engine, a companion batch is run simultaneously on a specific slave
engine. For this purpose, we introduce virtual engine bonding, allowing
maps of master:slaves to be constructed to constrain which physical
engines a virtual engine may select given a fence on a master engine.

For the moment, we continue to ignore the issue of preemption deferring
the master request for later. Ideally, we would like to then also remove
the slave and run something else rather than have it stall the pipeline.
With load balancing, we should be able to move workload around it, but
there is a similar stall on the master pipeline while it may wait for
the slave to be executed. At the cost of more latency for the bonded
request, it may be interesting to launch both on their engines in
lockstep. (Bubbles abound.)

Opens: Also what about bonding an engine as its own master? It doesn't
break anything internally, so allow the silliness.

v2: Emancipate the bonds
v3: Couple in delayed scheduling for the selftests
v4: Handle invalid mutually exclusive bonding
v5: Mention what the uapi does

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_context.c       |  50 +++++
 drivers/gpu/drm/i915/i915_request.c           |   1 +
 drivers/gpu/drm/i915/i915_request.h           |   1 +
 drivers/gpu/drm/i915/intel_engine_types.h     |   7 +
 drivers/gpu/drm/i915/intel_lrc.c              | 143 ++++++++++++++
 drivers/gpu/drm/i915/intel_lrc.h              |   4 +
 drivers/gpu/drm/i915/selftests/intel_lrc.c    | 185 ++++++++++++++++++
 drivers/gpu/drm/i915/selftests/lib_sw_fence.c |   3 +
 include/uapi/drm/i915_drm.h                   |  33 ++++
 9 files changed, 427 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 98763d3f1b12..0ec78c386473 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -1513,8 +1513,58 @@ set_engines__load_balance(struct i915_user_extension __user *base, void *data)
 	return 0;
 }
 
+static int
+set_engines__bond(struct i915_user_extension __user *base, void *data)
+{
+	struct i915_context_engines_bond __user *ext =
+		container_of_user(base, typeof(*ext), base);
+	const struct set_engines *set = data;
+	struct intel_engine_cs *master;
+	u32 class, instance, siblings;
+	u16 idx;
+	int err;
+
+	if (get_user(idx, &ext->virtual_index))
+		return -EFAULT;
+
+	if (idx >= set->nengine)
+		return -EINVAL;
+
+	idx = array_index_nospec(idx, set->nengine);
+	if (!set->engines[idx])
+		return -EINVAL;
+
+	/*
+	 * A non-virtual engine has 0 siblings to choose between; and submit
+	 * fence will always be directed to the one engine.
+	 */
+	if (!intel_engine_is_virtual(set->engines[idx]))
+		return 0;
+
+	err = check_user_mbz(&ext->mbz);
+	if (err)
+		return err;
+
+	if (get_user(class, &ext->master_class))
+		return -EFAULT;
+
+	if (get_user(instance, &ext->master_instance))
+		return -EFAULT;
+
+	master = intel_engine_lookup_user(set->ctx->i915, class, instance);
+	if (!master)
+		return -EINVAL;
+
+	if (get_user(siblings, &ext->sibling_mask))
+		return -EFAULT;
+
+	return intel_virtual_engine_attach_bond(set->engines[idx],
+						master, siblings);
+}
+
 static const i915_user_extension_fn set_engines__extensions[] = {
 	[I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE] = set_engines__load_balance,
+	[I915_CONTEXT_ENGINES_EXT_BOND] = set_engines__bond,
 };
 
 static int
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 0a46f8113f5c..9ce710baa452 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -743,6 +743,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
 	rq->batch = NULL;
 	rq->capture_list = NULL;
 	rq->waitboost = false;
+	rq->execution_mask = ~0u;
 
 	/*
 	 * Reserve space in the ring buffer for all the commands required to
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index d4f6b2940130..862b25930de0 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -145,6 +145,7 @@ struct i915_request {
 	 */
 	struct i915_sched_node sched;
 	struct i915_dependency dep;
+	unsigned int execution_mask;
 
 	/*
 	 * A convenience pointer to the current breadcrumb value stored in
diff --git a/drivers/gpu/drm/i915/intel_engine_types.h b/drivers/gpu/drm/i915/intel_engine_types.h
index 322fbda65190..1da35509d811 100644
--- a/drivers/gpu/drm/i915/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/intel_engine_types.h
@@ -384,6 +384,13 @@ struct intel_engine_cs {
 	 */
 	void		(*submit_request)(struct i915_request *rq);
 
+	/*
+	 * Called on signaling of a SUBMIT_FENCE, passing along the signaling
+	 * request down to the bonded pairs.
+	 */
+	void            (*bond_execute)(struct i915_request *rq,
+					struct dma_fence *signal);
+
 	/*
 	 * Call when the priority on a request has changed and it and its
 	 * dependencies may need rescheduling. Note the request itself may
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index d54b7cc43633..79ab4bc543fd 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -191,6 +191,18 @@ struct virtual_engine {
 		int prio;
 	} nodes[I915_NUM_ENGINES];
 
+	/*
+	 * Keep track of bonded pairs -- restrictions upon on our selection
+	 * of physical engines any particular request may be submitted to.
+	 * If we receive a submit-fence from a master engine, we will only
+	 * use one of sibling_mask physical engines.
+	 */
+	struct ve_bond {
+		struct intel_engine_cs *master;
+		unsigned int sibling_mask;
+	} *bonds;
+	unsigned int nbond;
+
 	/* And finally, which physical engines this virtual engine maps onto. */
 	unsigned int count;
 	struct intel_engine_cs *siblings[0];
@@ -3156,6 +3168,8 @@ static void virtual_context_destroy(struct kref *kref)
 	if (ve->context.state)
 		__execlists_context_fini(&ve->context);
 
+	kfree(ve->bonds);
+
 	i915_timeline_fini(&ve->base.timeline);
 	kfree(ve);
 }
@@ -3207,9 +3221,28 @@ static const struct intel_context_ops virtual_context_ops = {
 	.destroy = virtual_context_destroy,
 };
 
+static void virtual_submit_error(struct virtual_engine *ve)
+{
+	struct i915_request *rq = fetch_and_zero(&ve->request);
+	struct intel_engine_cs *engine = ve->siblings[0]; /* any victim */
+
+	dma_fence_set_error(&rq->fence, -ENODEV);
+	i915_request_mark_complete(rq);
+
+	spin_lock(&engine->timeline.lock);
+	rq->engine = engine;
+
+	__i915_request_submit(rq);
+	/* move to start of list to avoid unwind complications */
+	list_move(&rq->link, &engine->timeline.requests);
+
+	spin_unlock(&engine->timeline.lock);
+}
+
 static void virtual_submission_tasklet(unsigned long data)
 {
 	struct virtual_engine * const ve = (struct virtual_engine *)data;
+	unsigned int mask;
 	unsigned int n;
 	int prio;
 
@@ -3218,12 +3251,35 @@ static void virtual_submission_tasklet(unsigned long data)
 		return;
 
 	local_irq_disable();
+
+	mask = 0;
+	spin_lock(&ve->base.timeline.lock);
+	if (ve->request) {
+		mask = ve->request->execution_mask;
+		if (unlikely(!mask))
+			virtual_submit_error(ve);
+	}
+	spin_unlock(&ve->base.timeline.lock);
+	if (!mask)
+		goto out_irq;
+
 	for (n = 0; READ_ONCE(ve->request) && n < ve->count; n++) {
 		struct intel_engine_cs *sibling = ve->siblings[n];
 		struct ve_node * const node = &ve->nodes[sibling->id];
 		struct rb_node **parent, *rb;
 		bool first;
 
+		if (unlikely(!(mask & sibling->mask))) {
+			if (!RB_EMPTY_NODE(&node->rb)) {
+				spin_lock(&sibling->timeline.lock);
+				rb_erase_cached(&node->rb,
+						&sibling->execlists.virtual);
+				RB_CLEAR_NODE(&node->rb);
+				spin_unlock(&sibling->timeline.lock);
+			}
+			continue;
+		}
+
 		spin_lock(&sibling->timeline.lock);
 
 		if (!RB_EMPTY_NODE(&node->rb)) {
@@ -3270,6 +3326,7 @@ static void virtual_submission_tasklet(unsigned long data)
 
 		spin_unlock(&sibling->timeline.lock);
 	}
+out_irq:
 	local_irq_enable();
 }
 
@@ -3286,6 +3343,30 @@ static void virtual_submit_request(struct i915_request *request)
 	tasklet_schedule(&ve->base.execlists.tasklet);
 }
 
+static struct ve_bond *
+virtual_find_bond(struct virtual_engine *ve, struct intel_engine_cs *master)
+{
+	int i;
+
+	for (i = 0; i < ve->nbond; i++) {
+		if (ve->bonds[i].master == master)
+			return &ve->bonds[i];
+	}
+
+	return NULL;
+}
+
+static void
+virtual_bond_execute(struct i915_request *rq, struct dma_fence *signal)
+{
+	struct virtual_engine *ve = to_virtual_engine(rq->engine);
+	struct ve_bond *bond;
+
+	bond = virtual_find_bond(ve, to_request(signal)->engine);
+	if (bond) /* XXX serialise with rq->lock? */
+		rq->execution_mask &= bond->sibling_mask;
+}
+
 struct intel_engine_cs *
 intel_execlists_create_virtual(struct i915_gem_context *ctx,
 			       struct intel_engine_cs **siblings,
@@ -3324,6 +3405,7 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx,
 
 	ve->base.schedule = i915_schedule;
 	ve->base.submit_request = virtual_submit_request;
+	ve->base.bond_execute = virtual_bond_execute;
 
 	ve->base.execlists.queue_priority_hint = INT_MIN;
 	tasklet_init(&ve->base.execlists.tasklet,
@@ -3414,9 +3496,70 @@ intel_execlists_clone_virtual(struct i915_gem_context *ctx,
 	if (IS_ERR(dst))
 		return dst;
 
+	if (se->nbond) {
+		struct virtual_engine *de = to_virtual_engine(dst);
+
+		de->bonds = kmemdup(se->bonds,
+				    sizeof(*se->bonds) * se->nbond,
+				    GFP_KERNEL);
+		if (!de->bonds) {
+			intel_virtual_engine_destroy(dst);
+			return ERR_PTR(-ENOMEM);
+		}
+
+		de->nbond = se->nbond;
+	}
+
 	return dst;
 }
 
+static unsigned long
+virtual_execution_mask(struct virtual_engine *ve, unsigned long mask)
+{
+	unsigned long emask = 0;
+	int bit;
+
+	for_each_set_bit(bit, &mask, ve->count)
+		emask |= ve->siblings[bit]->mask;
+
+	return emask;
+}
+
+int intel_virtual_engine_attach_bond(struct intel_engine_cs *engine,
+				     struct intel_engine_cs *master,
+				     unsigned long mask)
+{
+	struct virtual_engine *ve = to_virtual_engine(engine);
+	struct ve_bond *bond;
+
+	if (mask >> ve->count)
+		return -EINVAL;
+
+	mask = virtual_execution_mask(ve, mask);
+	if (!mask)
+		return -EINVAL;
+
+	bond = virtual_find_bond(ve, master);
+	if (bond) {
+		bond->sibling_mask |= mask;
+		return 0;
+	}
+
+	bond = krealloc(ve->bonds,
+			sizeof(*bond) * (ve->nbond + 1),
+			GFP_KERNEL);
+	if (!bond)
+		return -ENOMEM;
+
+	bond[ve->nbond].master = master;
+	bond[ve->nbond].sibling_mask = mask;
+
+	ve->bonds = bond;
+	ve->nbond++;
+
+	return 0;
+}
+
 void intel_virtual_engine_destroy(struct intel_engine_cs *engine)
 {
 	struct virtual_engine *ve = to_virtual_engine(engine);
diff --git a/drivers/gpu/drm/i915/intel_lrc.h b/drivers/gpu/drm/i915/intel_lrc.h
index 9d90dc68e02b..77b85648045a 100644
--- a/drivers/gpu/drm/i915/intel_lrc.h
+++ b/drivers/gpu/drm/i915/intel_lrc.h
@@ -121,6 +121,10 @@ struct intel_engine_cs *
 intel_execlists_clone_virtual(struct i915_gem_context *ctx,
 			      struct intel_engine_cs *src);
 
+int intel_virtual_engine_attach_bond(struct intel_engine_cs *engine,
+				     struct intel_engine_cs *master,
+				     unsigned long mask);
+
 void intel_virtual_engine_destroy(struct intel_engine_cs *engine);
 
 u32 gen8_make_rpcs(struct drm_i915_private *i915, struct intel_sseu *ctx_sseu);
diff --git a/drivers/gpu/drm/i915/selftests/intel_lrc.c b/drivers/gpu/drm/i915/selftests/intel_lrc.c
index 4b8a339529d1..d2e00175c417 100644
--- a/drivers/gpu/drm/i915/selftests/intel_lrc.c
+++ b/drivers/gpu/drm/i915/selftests/intel_lrc.c
@@ -13,6 +13,7 @@
 #include "igt_live_test.h"
 #include "igt_spinner.h"
 #include "i915_random.h"
+#include "lib_sw_fence.h"
 
 #include "mock_context.h"
 
@@ -1224,6 +1225,189 @@ static int live_virtual_engine(void *arg)
 	return err;
 }
 
+static int bond_virtual_engine(struct drm_i915_private *i915,
+			       unsigned int class,
+			       struct intel_engine_cs **siblings,
+			       unsigned int nsibling,
+			       unsigned int flags)
+#define BOND_SCHEDULE BIT(0)
+{
+	struct intel_engine_cs *master;
+	struct i915_gem_context *ctx;
+	struct i915_request *rq[16];
+	enum intel_engine_id id;
+	unsigned long n;
+	int err;
+
+	GEM_BUG_ON(nsibling >= ARRAY_SIZE(rq) - 1);
+
+	ctx = kernel_context(i915);
+	if (!ctx)
+		return -ENOMEM;
+
+	err = 0;
+	rq[0] = ERR_PTR(-ENOMEM);
+	for_each_engine(master, i915, id) {
+		struct i915_sw_fence fence = {};
+
+		if (master->class == class)
+			continue;
+
+		memset_p((void *)rq, ERR_PTR(-EINVAL), ARRAY_SIZE(rq));
+
+		rq[0] = i915_request_alloc(master, ctx);
+		if (IS_ERR(rq[0])) {
+			err = PTR_ERR(rq[0]);
+			goto out;
+		}
+		i915_request_get(rq[0]);
+
+		if (flags & BOND_SCHEDULE) {
+			onstack_fence_init(&fence);
+			err = i915_sw_fence_await_sw_fence_gfp(&rq[0]->submit,
+							       &fence,
+							       GFP_KERNEL);
+		}
+		i915_request_add(rq[0]);
+		if (err < 0)
+			goto out;
+
+		for (n = 0; n < nsibling; n++) {
+			struct intel_engine_cs *engine;
+
+			engine = intel_execlists_create_virtual(ctx,
+								siblings,
+								nsibling);
+			if (IS_ERR(engine)) {
+				err = PTR_ERR(engine);
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+
+			err = intel_virtual_engine_attach_bond(engine,
+							       master,
+							       BIT(n));
+			if (err) {
+				intel_virtual_engine_destroy(engine);
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+
+			rq[n + 1] = i915_request_alloc(engine, ctx);
+			if (IS_ERR(rq[n + 1])) {
+				err = PTR_ERR(rq[n + 1]);
+				intel_virtual_engine_destroy(engine);
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+			i915_request_get(rq[n + 1]);
+
+			err = i915_request_await_execution(rq[n + 1],
+							   &rq[0]->fence,
+							   engine->bond_execute);
+			i915_request_add(rq[n + 1]);
+			intel_virtual_engine_destroy(engine);
+			if (err < 0) {
+				onstack_fence_fini(&fence);
+				goto out;
+			}
+		}
+		onstack_fence_fini(&fence);
+
+		if (i915_request_wait(rq[0],
+					I915_WAIT_LOCKED,
+					HZ / 10) < 0) {
+			pr_err("Master request did not execute (on %s)!\n",
+			       rq[0]->engine->name);
+			err = -EIO;
+			goto out;
+		}
+
+		for (n = 0; n < nsibling; n++) {
+			if (i915_request_wait(rq[n + 1],
+					      I915_WAIT_LOCKED,
+					      MAX_SCHEDULE_TIMEOUT) < 0) {
+				err = -EIO;
+				goto out;
+			}
+
+			if (rq[n + 1]->engine != siblings[n]) {
+				pr_err("Bonded request did not execute on target engine: expected %s, used %s; master was %s\n",
+				       siblings[n]->name,
+				       rq[n + 1]->engine->name,
+				       rq[0]->engine->name);
+				err = -EINVAL;
+				goto out;
+			}
+		}
+
+		for (n = 0; !IS_ERR(rq[n]); n++)
+			i915_request_put(rq[n]);
+		rq[0] = ERR_PTR(-ENOMEM);
+	}
+
+out:
+	for (n = 0; !IS_ERR(rq[n]); n++)
+		i915_request_put(rq[n]);
+	if (igt_flush_test(i915, I915_WAIT_LOCKED))
+		err = -EIO;
+
+	kernel_context_close(ctx);
+	return err;
+}
+
+static int live_virtual_bond(void *arg)
+{
+	static const struct phase {
+		const char *name;
+		unsigned int flags;
+	} phases[] = {
+		{ "", 0 },
+		{ "schedule", BOND_SCHEDULE },
+		{ },
+	};
+	struct drm_i915_private *i915 = arg;
+	struct intel_engine_cs *siblings[MAX_ENGINE_INSTANCE + 1];
+	unsigned int class, inst;
+	int err = 0;
+
+	if (USES_GUC_SUBMISSION(i915))
+		return 0;
+
+	mutex_lock(&i915->drm.struct_mutex);
+
+	for (class = 0; class <= MAX_ENGINE_CLASS; class++) {
+		const struct phase *p;
+		int nsibling;
+
+		nsibling = 0;
+		for (inst = 0; inst <= MAX_ENGINE_INSTANCE; inst++) {
+			if (!i915->engine_class[class][inst])
+				break;
+
+			GEM_BUG_ON(nsibling == ARRAY_SIZE(siblings));
+			siblings[nsibling++] = i915->engine_class[class][inst];
+		}
+		if (nsibling < 2)
+			continue;
+
+		for (p = phases; p->name; p++) {
+			err = bond_virtual_engine(i915,
+						  class, siblings, nsibling,
+						  p->flags);
+			if (err) {
+				pr_err("%s(%s): failed class=%d, nsibling=%d, err=%d\n",
+				       __func__, p->name, class, nsibling, err);
+				goto out_unlock;
+			}
+		}
+	}
+
+out_unlock:
+	mutex_unlock(&i915->drm.struct_mutex);
+	return err;
+}
+
 int intel_execlists_live_selftests(struct drm_i915_private *i915)
 {
 	static const struct i915_subtest tests[] = {
@@ -1236,6 +1420,7 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(live_preempt_hang),
 		SUBTEST(live_preempt_smoke),
 		SUBTEST(live_virtual_engine),
+		SUBTEST(live_virtual_bond),
 	};
 
 	if (!HAS_EXECLISTS(i915))
diff --git a/drivers/gpu/drm/i915/selftests/lib_sw_fence.c b/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
index 2bfa72c1654b..b976c12817c5 100644
--- a/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
+++ b/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
@@ -45,6 +45,9 @@ void __onstack_fence_init(struct i915_sw_fence *fence,
 
 void onstack_fence_fini(struct i915_sw_fence *fence)
 {
+	if (!fence->flags)
+		return;
+
 	i915_sw_fence_commit(fence);
 	i915_sw_fence_fini(fence);
 }
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index c057536df5cd..ed33b8af8692 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1532,6 +1532,10 @@ struct drm_i915_gem_context_param {
  * sized argument, will revert back to default settings.
  *
  * See struct i915_context_param_engines.
+ *
+ * Extensions:
+ *   i915_context_engines_load_balance (I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE)
+ *   i915_context_engines_bond (I915_CONTEXT_ENGINES_EXT_BOND)
  */
 #define I915_CONTEXT_PARAM_ENGINES	0xa
 /* Must be kept compact -- no holes and well documented */
@@ -1627,9 +1631,38 @@ struct i915_context_engines_load_balance {
 	__u64 mbz64[4]; /* reserved for future use; must be zero */
 };
 
+/*
+ * i915_context_engines_bond:
+ *
+ * Constructed bonded pairs for execution within a virtual engine.
+ *
+ * All engines are equal, but some are more equal than others. Given
+ * the distribution of resources in the HW, it may be preferable to run
+ * a request on a given subset of engines in parallel to a request on a
+ * specific engine. We enable this selection of engines within a virtual
+ * engine by specifying bonding pairs, for any given master engine we will
+ * only execute on one of the corresponding siblings within the virtual engine.
+ *
+ * To execute a request in parallel on the master engine and a sibling requires
+ * coordination with a I915_EXEC_FENCE_SUBMIT.
+ */
+struct i915_context_engines_bond {
+	struct i915_user_extension base;
+
+	__u16 virtual_index; /* index of virtual engine in ctx->engines[] */
+	__u16 mbz;
+
+	__u16 master_class;
+	__u16 master_instance;
+
+	__u64 sibling_mask; /* bitmask of BIT(sibling_index) wrt the v.engine */
+	__u64 flags; /* all undefined flags must be zero */
+};
+
 struct i915_context_param_engines {
 	__u64 extensions; /* linked chain of extension blocks, 0 terminates */
 #define I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE 0
+#define I915_CONTEXT_ENGINES_EXT_BOND 1
 
 	struct {
 		__u16 engine_class; /* see enum drm_i915_gem_engine_class */
-- 
2.20.1

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[PATCH 17/17] drm/i915: Allow specification of parallel execbuf

[Chris Wilson]

There is a desire to split a task onto two engines and have them run at
the same time, e.g. scanline interleaving to spread the workload evenly.
Through the use of the out-fence from the first execbuf, we can
coordinate secondary execbuf to only become ready simultaneously with
the first, so that with all things idle the second execbufs are executed
in parallel with the first. The key difference here between the new
EXEC_FENCE_SUBMIT and the existing EXEC_FENCE_IN is that the in-fence
waits for the completion of the first request (so that all of its
rendering results are visible to the second execbuf, the more common
userspace fence requirement).

Since we only have a single input fence slot, userspace cannot mix an
in-fence and a submit-fence. It has to use one or the other! This is not
such a harsh requirement, since by virtue of the submit-fence, the
secondary execbuf inherit all of the dependencies from the first
request, and for the application the dependencies should be common
between the primary and secondary execbuf.

Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Testcase: igt/gem_exec_fence/parallel
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c            |  1 +
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 25 +++++++++++++++++++++-
 include/uapi/drm/i915_drm.h                | 17 ++++++++++++++-
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 93e41c937d96..afdfced262e6 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -421,6 +421,7 @@ static int i915_getparam_ioctl(struct drm_device *dev, void *data,
 	case I915_PARAM_HAS_EXEC_CAPTURE:
 	case I915_PARAM_HAS_EXEC_BATCH_FIRST:
 	case I915_PARAM_HAS_EXEC_FENCE_ARRAY:
+	case I915_PARAM_HAS_EXEC_SUBMIT_FENCE:
 		/* For the time being all of these are always true;
 		 * if some supported hardware does not have one of these
 		 * features this value needs to be provided from
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 70a26f0a9f1e..064c649f3f46 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -2282,6 +2282,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 {
 	struct i915_execbuffer eb;
 	struct dma_fence *in_fence = NULL;
+	struct dma_fence *exec_fence = NULL;
 	struct sync_file *out_fence = NULL;
 	intel_wakeref_t wakeref;
 	int out_fence_fd = -1;
@@ -2325,11 +2326,24 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 			return -EINVAL;
 	}
 
+	if (args->flags & I915_EXEC_FENCE_SUBMIT) {
+		if (in_fence) {
+			err = -EINVAL;
+			goto err_in_fence;
+		}
+
+		exec_fence = sync_file_get_fence(lower_32_bits(args->rsvd2));
+		if (!exec_fence) {
+			err = -EINVAL;
+			goto err_in_fence;
+		}
+	}
+
 	if (args->flags & I915_EXEC_FENCE_OUT) {
 		out_fence_fd = get_unused_fd_flags(O_CLOEXEC);
 		if (out_fence_fd < 0) {
 			err = out_fence_fd;
-			goto err_in_fence;
+			goto err_exec_fence;
 		}
 	}
 
@@ -2461,6 +2475,13 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 			goto err_request;
 	}
 
+	if (exec_fence) {
+		err = i915_request_await_execution(eb.request, exec_fence,
+						   eb.engine->bond_execute);
+		if (err < 0)
+			goto err_request;
+	}
+
 	if (fences) {
 		err = await_fence_array(&eb, fences);
 		if (err)
@@ -2521,6 +2542,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
 err_out_fence:
 	if (out_fence_fd != -1)
 		put_unused_fd(out_fence_fd);
+err_exec_fence:
+	dma_fence_put(exec_fence);
 err_in_fence:
 	dma_fence_put(in_fence);
 	return err;
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index ed33b8af8692..dbab4d365a6d 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -593,6 +593,12 @@ typedef struct drm_i915_irq_wait {
  */
 #define I915_PARAM_MMAP_GTT_COHERENT	52
 
+/*
+ * Query whether DRM_I915_GEM_EXECBUFFER2 supports coordination of parallel
+ * execution through use of explicit fence support.
+ * See I915_EXEC_FENCE_OUT and I915_EXEC_FENCE_SUBMIT.
+ */
+#define I915_PARAM_HAS_EXEC_SUBMIT_FENCE 53
 /* Must be kept compact -- no holes and well documented */
 
 typedef struct drm_i915_getparam {
@@ -1115,7 +1121,16 @@ struct drm_i915_gem_execbuffer2 {
  */
 #define I915_EXEC_FENCE_ARRAY   (1<<19)
 
-#define __I915_EXEC_UNKNOWN_FLAGS (-(I915_EXEC_FENCE_ARRAY<<1))
+/*
+ * Setting I915_EXEC_FENCE_SUBMIT implies that lower_32_bits(rsvd2) represent
+ * a sync_file fd to wait upon (in a nonblocking manner) prior to executing
+ * the batch.
+ *
+ * Returns -EINVAL if the sync_file fd cannot be found.
+ */
+#define I915_EXEC_FENCE_SUBMIT		(1 << 20)
+
+#define __I915_EXEC_UNKNOWN_FLAGS (-(I915_EXEC_FENCE_SUBMIT << 1))
 
 #define I915_EXEC_CONTEXT_ID_MASK	(0xffffffff)
 #define i915_execbuffer2_set_context_id(eb2, context) \
-- 
2.20.1

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✗ Fi.CI.CHECKPATCH: warning for series starting with [01/17] drm/i915: Hold a ref to the ring while retiring (rev2)

[Patchwork]

== Series Details ==

Series: series starting with [01/17] drm/i915: Hold a ref to the ring while retiring (rev2)
URL   : https://patchwork.freedesktop.org/series/57937/
State : warning

== Summary ==

$ dim checkpatch origin/drm-tip
d62cd9df9172 drm/i915: Hold a ref to the ring while retiring
4a377a0ed26c drm/i915: Lock the gem_context->active_list while dropping the link
425baf413268 drm/i915: Hold a reference to the active HW context
064792100ce5 drm/i915: Stop needlessly acquiring wakeref for debugfs/drop_caches_set
f1d375f07c30 drm/i915/selftests: Provide stub reset functions
9537812e0fbb drm/i915: Switch to use HWS indices rather than addresses
467096587006 drm/i915: Introduce the i915_user_extension_method
-:70: WARNING:FILE_PATH_CHANGES: added, moved or deleted file(s), does MAINTAINERS need updating?
#70: 
new file mode 100644

-:75: WARNING:SPDX_LICENSE_TAG: Missing or malformed SPDX-License-Identifier tag in line 1
#75: FILE: drivers/gpu/drm/i915/i915_user_extensions.c:1:
+/*

-:140: WARNING:SPDX_LICENSE_TAG: Missing or malformed SPDX-License-Identifier tag in line 1
#140: FILE: drivers/gpu/drm/i915/i915_user_extensions.h:1:
+/*

-:168: CHECK:MACRO_ARG_REUSE: Macro argument reuse 'ptr' - possible side-effects?
#168: FILE: drivers/gpu/drm/i915/i915_utils.h:108:
+#define container_of_user(ptr, type, member) ({				\
+	void __user *__mptr = (void __user *)(ptr);			\
+	BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&	\
+			 !__same_type(*(ptr), void),			\
+			 "pointer type mismatch in container_of()");	\
+	((type __user *)(__mptr - offsetof(type, member))); })

-:168: CHECK:MACRO_ARG_REUSE: Macro argument reuse 'member' - possible side-effects?
#168: FILE: drivers/gpu/drm/i915/i915_utils.h:108:
+#define container_of_user(ptr, type, member) ({				\
+	void __user *__mptr = (void __user *)(ptr);			\
+	BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&	\
+			 !__same_type(*(ptr), void),			\
+			 "pointer type mismatch in container_of()");	\
+	((type __user *)(__mptr - offsetof(type, member))); })

-:168: CHECK:MACRO_ARG_PRECEDENCE: Macro argument 'member' may be better as '(member)' to avoid precedence issues
#168: FILE: drivers/gpu/drm/i915/i915_utils.h:108:
+#define container_of_user(ptr, type, member) ({				\
+	void __user *__mptr = (void __user *)(ptr);			\
+	BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) &&	\
+			 !__same_type(*(ptr), void),			\
+			 "pointer type mismatch in container_of()");	\
+	((type __user *)(__mptr - offsetof(type, member))); })

-:175: CHECK:MACRO_ARG_REUSE: Macro argument reuse 'U' - possible side-effects?
#175: FILE: drivers/gpu/drm/i915/i915_utils.h:115:
+#define check_user_mbz(U) ({						\
+	typeof(*(U)) mbz__;						\
+	get_user(mbz__, (U)) ? -EFAULT : mbz__ ? -EINVAL : 0;		\
+})

total: 0 errors, 3 warnings, 4 checks, 132 lines checked
f1b31528e84d drm/i915: Create/destroy VM (ppGTT) for use with contexts
-:45: CHECK:UNCOMMENTED_DEFINITION: struct mutex definition without comment
#45: FILE: drivers/gpu/drm/i915/i915_drv.h:221:
+	struct mutex vm_lock;

-:694: WARNING:LINE_SPACING: Missing a blank line after declarations
#694: FILE: drivers/gpu/drm/i915/selftests/i915_gem_context.c:503:
+		struct drm_file *file;
+		IGT_TIMEOUT(end_time);

-:756: CHECK:MULTIPLE_ASSIGNMENTS: multiple assignments should be avoided
#756: FILE: drivers/gpu/drm/i915/selftests/i915_gem_context.c:565:
+		ncontexts = dw = 0;

-:831: WARNING:LINE_SPACING: Missing a blank line after declarations
#831: FILE: drivers/gpu/drm/i915/selftests/i915_gem_context.c:633:
+		struct i915_gem_context *ctx = NULL;
+		IGT_TIMEOUT(end_time);

-:901: CHECK:MULTIPLE_ASSIGNMENTS: multiple assignments should be avoided
#901: FILE: drivers/gpu/drm/i915/selftests/i915_gem_context.c:686:
+		ncontexts = dw = 0;

-:1056: WARNING:LONG_LINE: line over 100 characters
#1056: FILE: include/uapi/drm/i915_drm.h:407:
+#define DRM_IOCTL_I915_GEM_VM_CREATE	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_CREATE, struct drm_i915_gem_vm_control)

-:1057: WARNING:LONG_LINE: line over 100 characters
#1057: FILE: include/uapi/drm/i915_drm.h:408:
+#define DRM_IOCTL_I915_GEM_VM_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_VM_DESTROY, struct drm_i915_gem_vm_control)

-:1057: WARNING:SPACING: space prohibited between function name and open parenthesis '('
#1057: FILE: include/uapi/drm/i915_drm.h:408:
+#define DRM_IOCTL_I915_GEM_VM_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_VM_DESTROY, struct drm_i915_gem_vm_control)

-:1057: ERROR:COMPLEX_MACRO: Macros with complex values should be enclosed in parentheses
#1057: FILE: include/uapi/drm/i915_drm.h:408:
+#define DRM_IOCTL_I915_GEM_VM_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_VM_DESTROY, struct drm_i915_gem_vm_control)

total: 1 errors, 5 warnings, 3 checks, 1004 lines checked
03995ebe1cda drm/i915: Extend CONTEXT_CREATE to set parameters upon construction
-:28: WARNING:LONG_LINE: line over 100 characters
#28: FILE: drivers/gpu/drm/i915/i915_drv.c:3113:
+	DRM_IOCTL_DEF_DRV(I915_GEM_CONTEXT_CREATE_EXT, i915_gem_context_create_ioctl, DRM_RENDER_ALLOW),

-:535: WARNING:LONG_LINE: line over 100 characters
#535: FILE: include/uapi/drm/i915_drm.h:397:
+#define DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_CREATE, struct drm_i915_gem_context_create_ext)

-:535: WARNING:SPACING: space prohibited between function name and open parenthesis '('
#535: FILE: include/uapi/drm/i915_drm.h:397:
+#define DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_CREATE, struct drm_i915_gem_context_create_ext)

-:535: ERROR:COMPLEX_MACRO: Macros with complex values should be enclosed in parentheses
#535: FILE: include/uapi/drm/i915_drm.h:397:
+#define DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT	DRM_IOWR (DRM_COMMAND_BASE + DRM_I915_GEM_CONTEXT_CREATE, struct drm_i915_gem_context_create_ext)

total: 1 errors, 3 warnings, 0 checks, 694 lines checked
a60ae2cf83e0 drm/i915: Allow contexts to share a single timeline across all engines
bf975e154c20 drm/i915: Allow userspace to clone contexts on creation
8ff51d7f4412 drm/i915: Allow a context to define its set of engines
-:448: CHECK:MACRO_ARG_REUSE: Macro argument reuse 'T' - possible side-effects?
#448: FILE: drivers/gpu/drm/i915/i915_utils.h:94:
+#define check_struct_size(T, A, C, SZ) \
+	likely(__check_struct_size(sizeof(*(T)), \
+				   sizeof(*(T)->A) + __must_be_array((T)->A), \
+				   C, SZ))

-:448: CHECK:MACRO_ARG_REUSE: Macro argument reuse 'A' - possible side-effects?
#448: FILE: drivers/gpu/drm/i915/i915_utils.h:94:
+#define check_struct_size(T, A, C, SZ) \
+	likely(__check_struct_size(sizeof(*(T)), \
+				   sizeof(*(T)->A) + __must_be_array((T)->A), \
+				   C, SZ))

-:448: CHECK:MACRO_ARG_PRECEDENCE: Macro argument 'A' may be better as '(A)' to avoid precedence issues
#448: FILE: drivers/gpu/drm/i915/i915_utils.h:94:
+#define check_struct_size(T, A, C, SZ) \
+	likely(__check_struct_size(sizeof(*(T)), \
+				   sizeof(*(T)->A) + __must_be_array((T)->A), \
+				   C, SZ))

total: 0 errors, 0 warnings, 3 checks, 457 lines checked
bbe22f0d1657 drm/i915: Extend I915_CONTEXT_PARAM_SSEU to support local ctx->engine[]
ac7a61238e94 drm/i915: Load balancing across a virtual engine
-:962: WARNING:LINE_SPACING: Missing a blank line after declarations
#962: FILE: drivers/gpu/drm/i915/intel_lrc.c:3392:
+		struct intel_engine_cs *actual = ve->siblings[0];
+		intel_context_put(&ve->context);

total: 0 errors, 1 warnings, 0 checks, 1163 lines checked
232df8a89674 drm/i915: Extend execution fence to support a callback
12cee20f7d30 drm/i915/execlists: Virtual engine bonding
-:472: CHECK:PARENTHESIS_ALIGNMENT: Alignment should match open parenthesis
#472: FILE: drivers/gpu/drm/i915/selftests/intel_lrc.c:1318:
+		if (i915_request_wait(rq[0],
+					I915_WAIT_LOCKED,

total: 0 errors, 0 warnings, 1 checks, 558 lines checked
c68377160c45 drm/i915: Allow specification of parallel execbuf

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✗ Fi.CI.SPARSE: warning for series starting with [01/17] drm/i915: Hold a ref to the ring while retiring (rev2)

[Patchwork]

== Series Details ==

Series: series starting with [01/17] drm/i915: Hold a ref to the ring while retiring (rev2)
URL   : https://patchwork.freedesktop.org/series/57937/
State : warning

== Summary ==

$ dim sparse origin/drm-tip
Sparse version: v0.5.2
Commit: drm/i915: Hold a ref to the ring while retiring
Okay!

Commit: drm/i915: Lock the gem_context->active_list while dropping the link
Okay!

Commit: drm/i915: Hold a reference to the active HW context
Okay!

Commit: drm/i915: Stop needlessly acquiring wakeref for debugfs/drop_caches_set
Okay!

Commit: drm/i915/selftests: Provide stub reset functions
Okay!

Commit: drm/i915: Switch to use HWS indices rather than addresses
Okay!

Commit: drm/i915: Introduce the i915_user_extension_method
Okay!

Commit: drm/i915: Create/destroy VM (ppGTT) for use with contexts
-drivers/gpu/drm/i915/selftests/../i915_drv.h:3560:16: warning: expression using sizeof(void)
-O:drivers/gpu/drm/i915/selftests/i915_gem_context.c:1134:25: warning: expression using sizeof(void)
-O:drivers/gpu/drm/i915/selftests/i915_gem_context.c:1134:25: warning: expression using sizeof(void)
+drivers/gpu/drm/i915/selftests/../i915_drv.h:3563:16: warning: expression using sizeof(void)
+drivers/gpu/drm/i915/selftests/i915_gem_context.c:1261:25: warning: expression using sizeof(void)
+drivers/gpu/drm/i915/selftests/i915_gem_context.c:1261:25: warning: expression using sizeof(void)
-O:drivers/gpu/drm/i915/selftests/i915_gem_context.c:564:25: warning: expression using sizeof(void)
-O:drivers/gpu/drm/i915/selftests/i915_gem_context.c:564:25: warning: expression using sizeof(void)
+drivers/gpu/drm/i915/selftests/i915_gem_context.c:568:33: warning: expression using sizeof(void)
+drivers/gpu/drm/i915/selftests/i915_gem_context.c:568:33: warning: expression using sizeof(void)
+drivers/gpu/drm/i915/selftests/i915_gem_context.c:689:33: warning: expression using sizeof(void)
+drivers/gpu/drm/i915/selftests/i915_gem_context.c:689:33: warning: expression using sizeof(void)

Commit: drm/i915: Extend CONTEXT_CREATE to set parameters upon construction
Okay!

Commit: drm/i915: Allow contexts to share a single timeline across all engines
Okay!

Commit: drm/i915: Allow userspace to clone contexts on creation
Okay!

Commit: drm/i915: Allow a context to define its set of engines
+drivers/gpu/drm/i915/i915_utils.h:84:13: error: incorrect type in conditional
+drivers/gpu/drm/i915/i915_utils.h:84:13: error: undefined identifier '__builtin_mul_overflow'
+drivers/gpu/drm/i915/i915_utils.h:84:13:    got void
+drivers/gpu/drm/i915/i915_utils.h:84:13: warning: call with no type!
+drivers/gpu/drm/i915/i915_utils.h:87:13: error: incorrect type in conditional
+drivers/gpu/drm/i915/i915_utils.h:87:13: error: undefined identifier '__builtin_add_overflow'
+drivers/gpu/drm/i915/i915_utils.h:87:13:    got void
+drivers/gpu/drm/i915/i915_utils.h:87:13: warning: call with no type!
+./include/linux/slab.h:664:13: error: not a function <noident>

Commit: drm/i915: Extend I915_CONTEXT_PARAM_SSEU to support local ctx->engine[]
Okay!

Commit: drm/i915: Load balancing across a virtual engine
+./include/linux/overflow.h:285:13: error: incorrect type in conditional
+./include/linux/overflow.h:285:13: error: undefined identifier '__builtin_mul_overflow'
+./include/linux/overflow.h:285:13:    got void
+./include/linux/overflow.h:285:13: warning: call with no type!
+./include/linux/overflow.h:287:13: error: incorrect type in conditional
+./include/linux/overflow.h:287:13: error: undefined identifier '__builtin_add_overflow'
+./include/linux/overflow.h:287:13:    got void
+./include/linux/overflow.h:287:13: warning: call with no type!

Commit: drm/i915: Extend execution fence to support a callback
Okay!

Commit: drm/i915/execlists: Virtual engine bonding
Okay!

Commit: drm/i915: Allow specification of parallel execbuf
Okay!

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✗ Fi.CI.BAT: failure for series starting with [01/17] drm/i915: Hold a ref to the ring while retiring (rev2)

[Patchwork]

== Series Details ==

Series: series starting with [01/17] drm/i915: Hold a ref to the ring while retiring (rev2)
URL   : https://patchwork.freedesktop.org/series/57937/
State : failure

== Summary ==

CI Bug Log - changes from CI_DRM_5742 -> Patchwork_12450
====================================================

Summary
-------

  **FAILURE**

  Serious unknown changes coming with Patchwork_12450 absolutely need to be
  verified manually.
  
  If you think the reported changes have nothing to do with the changes
  introduced in Patchwork_12450, please notify your bug team to allow them
  to document this new failure mode, which will reduce false positives in CI.

  External URL: https://patchwork.freedesktop.org/api/1.0/series/57937/revisions/2/mbox/

Possible new issues
-------------------

  Here are the unknown changes that may have been introduced in Patchwork_12450:

### IGT changes ###

#### Possible regressions ####

  * igt@i915_selftest@live_contexts:
    - fi-snb-2520m:       NOTRUN -> DMESG-FAIL
    - fi-bdw-gvtdvm:      PASS -> DMESG-FAIL
    - fi-snb-2600:        PASS -> DMESG-FAIL

  
Known issues
------------

  Here are the changes found in Patchwork_12450 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@amdgpu/amd_basic@userptr:
    - fi-whl-u:           NOTRUN -> SKIP [fdo#109271] +41

  * igt@amdgpu/amd_cs_nop@fork-gfx0:
    - fi-icl-u2:          NOTRUN -> SKIP [fdo#109315] +17

  * igt@debugfs_test@read_all_entries:
    - fi-kbl-7567u:       PASS -> DMESG-WARN [fdo#103558] / [fdo#105602]

  * igt@gem_ctx_create@basic-files:
    - fi-gdg-551:         NOTRUN -> SKIP [fdo#109271] +106

  * igt@gem_exec_basic@readonly-bsd1:
    - fi-snb-2520m:       NOTRUN -> SKIP [fdo#109271] +57
    - fi-icl-u2:          NOTRUN -> SKIP [fdo#109276] +7

  * igt@gem_exec_parse@basic-allowed:
    - fi-icl-u2:          NOTRUN -> SKIP [fdo#109289] +1

  * igt@i915_pm_rpm@basic-pci-d3-state:
    - fi-bsw-kefka:       PASS -> SKIP [fdo#109271]

  * igt@i915_pm_rpm@basic-rte:
    - fi-bsw-kefka:       PASS -> FAIL [fdo#108800]

  * igt@i915_selftest@live_contexts:
    - fi-icl-u2:          NOTRUN -> DMESG-FAIL [fdo#108569]

  * igt@kms_busy@basic-flip-a:
    - fi-gdg-551:         NOTRUN -> FAIL [fdo#103182] +1

  * igt@kms_busy@basic-flip-c:
    - fi-blb-e6850:       NOTRUN -> SKIP [fdo#109271] / [fdo#109278]
    - fi-gdg-551:         NOTRUN -> SKIP [fdo#109271] / [fdo#109278]
    - fi-snb-2520m:       NOTRUN -> SKIP [fdo#109271] / [fdo#109278]

  * igt@kms_chamelium@common-hpd-after-suspend:
    - fi-kbl-7567u:       PASS -> WARN [fdo#109380]

  * igt@kms_chamelium@dp-edid-read:
    - fi-icl-u2:          NOTRUN -> SKIP [fdo#109316] +2

  * igt@kms_chamelium@hdmi-edid-read:
    - fi-hsw-peppy:       NOTRUN -> SKIP [fdo#109271] +46

  * igt@kms_chamelium@vga-hpd-fast:
    - fi-icl-u2:          NOTRUN -> SKIP [fdo#109309] +1

  * igt@kms_force_connector_basic@prune-stale-modes:
    - fi-icl-u2:          NOTRUN -> SKIP [fdo#109285] +3

  * igt@kms_frontbuffer_tracking@basic:
    - fi-hsw-peppy:       NOTRUN -> DMESG-FAIL [fdo#102614] / [fdo#107814]
    - fi-icl-u2:          NOTRUN -> FAIL [fdo#103167]

  * igt@kms_pipe_crc_basic@hang-read-crc-pipe-c:
    - fi-blb-e6850:       NOTRUN -> SKIP [fdo#109271] +48

  * igt@kms_pipe_crc_basic@nonblocking-crc-pipe-c:
    - fi-kbl-7567u:       PASS -> SKIP [fdo#109271] +33

  * igt@kms_psr@cursor_plane_move:
    - fi-whl-u:           NOTRUN -> FAIL [fdo#107383] +3

  * igt@prime_vgem@basic-fence-flip:
    - fi-cfl-guc:         PASS -> FAIL [fdo#104008]

  * igt@runner@aborted:
    - fi-bxt-dsi:         NOTRUN -> FAIL [fdo#109516]

  
#### Possible fixes ####

  * igt@gem_exec_suspend@basic-s3:
    - fi-blb-e6850:       INCOMPLETE [fdo#107718] -> PASS

  * igt@i915_selftest@live_evict:
    - fi-bsw-kefka:       DMESG-WARN [fdo#107709] -> PASS

  
  [fdo#102614]: https://bugs.freedesktop.org/show_bug.cgi?id=102614
  [fdo#103167]: https://bugs.freedesktop.org/show_bug.cgi?id=103167
  [fdo#103182]: https://bugs.freedesktop.org/show_bug.cgi?id=103182
  [fdo#103558]: https://bugs.freedesktop.org/show_bug.cgi?id=103558
  [fdo#104008]: https://bugs.freedesktop.org/show_bug.cgi?id=104008
  [fdo#105602]: https://bugs.freedesktop.org/show_bug.cgi?id=105602
  [fdo#107383]: https://bugs.freedesktop.org/show_bug.cgi?id=107383
  [fdo#107709]: https://bugs.freedesktop.org/show_bug.cgi?id=107709
  [fdo#107718]: https://bugs.freedesktop.org/show_bug.cgi?id=107718
  [fdo#107814]: https://bugs.freedesktop.org/show_bug.cgi?id=107814
  [fdo#108569]: https://bugs.freedesktop.org/show_bug.cgi?id=108569
  [fdo#108800]: https://bugs.freedesktop.org/show_bug.cgi?id=108800
  [fdo#109271]: https://bugs.freedesktop.org/show_bug.cgi?id=109271
  [fdo#109276]: https://bugs.freedesktop.org/show_bug.cgi?id=109276
  [fdo#109278]: https://bugs.freedesktop.org/show_bug.cgi?id=109278
  [fdo#109285]: https://bugs.freedesktop.org/show_bug.cgi?id=109285
  [fdo#109289]: https://bugs.freedesktop.org/show_bug.cgi?id=109289
  [fdo#109309]: https://bugs.freedesktop.org/show_bug.cgi?id=109309
  [fdo#109315]: https://bugs.freedesktop.org/show_bug.cgi?id=109315
  [fdo#109316]: https://bugs.freedesktop.org/show_bug.cgi?id=109316
  [fdo#109380]: https://bugs.freedesktop.org/show_bug.cgi?id=109380
  [fdo#109516]: https://bugs.freedesktop.org/show_bug.cgi?id=109516


Participating hosts (42 -> 41)
------------------------------

  Additional (6): fi-bxt-dsi fi-hsw-peppy fi-icl-u2 fi-snb-2520m fi-whl-u fi-gdg-551 
  Missing    (7): fi-ilk-m540 fi-hsw-4200u fi-byt-squawks fi-bsw-cyan fi-kbl-7500u fi-ivb-3770 fi-bdw-samus 


Build changes
-------------

    * Linux: CI_DRM_5742 -> Patchwork_12450

  CI_DRM_5742: 519a3f67aadea184cb97720c838946c1ba81c875 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_4884: c46051337b972f8b5a302afb6f603df06fea527d @ git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
  Patchwork_12450: c68377160c45b1e28d4513858774cf2f8de41b37 @ git://anongit.freedesktop.org/gfx-ci/linux


== Kernel 32bit build ==

Warning: Kernel 32bit buildtest failed:
https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_12450/build_32bit.log

  CALL    scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  CC [M]  drivers/gpu/drm/i915/i915_user_extensions.o
In file included from ./include/asm-generic/barrier.h:20:0,
                 from ./arch/x86/include/asm/barrier.h:86,
                 from ./include/linux/nospec.h:8,
                 from drivers/gpu/drm/i915/i915_user_extensions.c:7:
drivers/gpu/drm/i915/i915_user_extensions.c: In function ‘i915_user_extensions’:
./include/linux/compiler.h:344:38: error: call to ‘__compiletime_assert_45’ declared with attribute error: BUILD_BUG_ON failed: sizeof(_s) > sizeof(long)
  _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
                                      ^
./include/linux/compiler.h:325:4: note: in definition of macro ‘__compiletime_assert’
    prefix ## suffix();    \
    ^~~~~~
./include/linux/compiler.h:344:2: note: in expansion of macro ‘_compiletime_assert’
  _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
  ^~~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                     ^~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
  BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
  ^~~~~~~~~~~~~~~~
./include/linux/nospec.h:55:2: note: in expansion of macro ‘BUILD_BUG_ON’
  BUILD_BUG_ON(sizeof(_i) > sizeof(long));   \
  ^~~~~~~~~~~~
drivers/gpu/drm/i915/i915_user_extensions.c:45:8: note: in expansion of macro ‘array_index_nospec’
    x = array_index_nospec(x, count);
        ^~~~~~~~~~~~~~~~~~
scripts/Makefile.build:276: recipe for target 'drivers/gpu/drm/i915/i915_user_extensions.o' failed
make[4]: *** [drivers/gpu/drm/i915/i915_user_extensions.o] Error 1
scripts/Makefile.build:492: recipe for target 'drivers/gpu/drm/i915' failed
make[3]: *** [drivers/gpu/drm/i915] Error 2
scripts/Makefile.build:492: recipe for target 'drivers/gpu/drm' failed
make[2]: *** [drivers/gpu/drm] Error 2
scripts/Makefile.build:492: recipe for target 'drivers/gpu' failed
make[1]: *** [drivers/gpu] Error 2
Makefile:1043: recipe for target 'drivers' failed
make: *** [drivers] Error 2


== Linux commits ==

c68377160c45 drm/i915: Allow specification of parallel execbuf
12cee20f7d30 drm/i915/execlists: Virtual engine bonding
232df8a89674 drm/i915: Extend execution fence to support a callback
ac7a61238e94 drm/i915: Load balancing across a virtual engine
bbe22f0d1657 drm/i915: Extend I915_CONTEXT_PARAM_SSEU to support local ctx->engine[]
8ff51d7f4412 drm/i915: Allow a context to define its set of engines
bf975e154c20 drm/i915: Allow userspace to clone contexts on creation
a60ae2cf83e0 drm/i915: Allow contexts to share a single timeline across all engines
03995ebe1cda drm/i915: Extend CONTEXT_CREATE to set parameters upon construction
f1b31528e84d drm/i915: Create/destroy VM (ppGTT) for use with contexts
467096587006 drm/i915: Introduce the i915_user_extension_method
9537812e0fbb drm/i915: Switch to use HWS indices rather than addresses
f1d375f07c30 drm/i915/selftests: Provide stub reset functions
064792100ce5 drm/i915: Stop needlessly acquiring wakeref for debugfs/drop_caches_set
425baf413268 drm/i915: Hold a reference to the active HW context
4a377a0ed26c drm/i915: Lock the gem_context->active_list while dropping the link
d62cd9df9172 drm/i915: Hold a ref to the ring while retiring

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_12450/
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