[Intel-gfx] [PATCH 4/6] drm/i915: Record the default hw state after reset upon load

Chris Wilson chris at chris-wilson.co.uk
Thu Nov 2 12:42:24 UTC 2017


Take a copy of the HW state after a reset upon module loading by
executing a context switch from a blank context to the kernel context,
thus saving the default hw state over the blank context image.
We can then use the default hw state to initialise any future context,
ensuring that each starts with the default view of hw state.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gvt/scheduler.c    |  2 -
 drivers/gpu/drm/i915/i915_debugfs.c     |  1 -
 drivers/gpu/drm/i915/i915_gem.c         | 69 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_gem_context.c | 50 +++---------------------
 drivers/gpu/drm/i915/i915_gem_context.h |  4 +-
 drivers/gpu/drm/i915/intel_engine_cs.c  |  3 ++
 drivers/gpu/drm/i915/intel_lrc.c        | 35 ++++++++++-------
 drivers/gpu/drm/i915/intel_ringbuffer.c | 47 +++++++++++++++-------
 drivers/gpu/drm/i915/intel_ringbuffer.h |  1 +
 9 files changed, 137 insertions(+), 75 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index f6ded475bb2c..42cc61230ca7 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -723,8 +723,6 @@ int intel_vgpu_init_gvt_context(struct intel_vgpu *vgpu)
 	if (IS_ERR(vgpu->shadow_ctx))
 		return PTR_ERR(vgpu->shadow_ctx);
 
-	vgpu->shadow_ctx->engine[RCS].initialised = true;
-
 	bitmap_zero(vgpu->shadow_ctx_desc_updated, I915_NUM_ENGINES);
 
 	return 0;
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 39883cd915db..cfcef1899da8 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1974,7 +1974,6 @@ static int i915_context_status(struct seq_file *m, void *unused)
 			struct intel_context *ce = &ctx->engine[engine->id];
 
 			seq_printf(m, "%s: ", engine->name);
-			seq_putc(m, ce->initialised ? 'I' : 'i');
 			if (ce->state)
 				describe_obj(m, ce->state->obj);
 			if (ce->ring)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e36a3a840552..ed4b1708fec5 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4967,6 +4967,71 @@ bool intel_sanitize_semaphores(struct drm_i915_private *dev_priv, int value)
 	return true;
 }
 
+static int __intel_engines_record_defaults(struct drm_i915_private *i915)
+{
+	struct i915_gem_context *ctx;
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	int err;
+
+	/*
+	 * As we reset the gpu during very early sanitisation, the current
+	 * register state on the GPU should reflect its defaults values.
+	 * We load a context onto the hw (with restore-inhibit), then switch
+	 * over to a second context to save that default register state. We
+	 * can then prime every new context with that state so they all start
+	 * from defaults.
+	 */
+
+	ctx = i915_gem_context_create_kernel(i915, 0);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	for_each_engine(engine, i915, id) {
+		struct drm_i915_gem_request *rq;
+
+		rq = i915_gem_request_alloc(engine, ctx);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			goto out_ctx;
+		}
+
+		err = i915_switch_context(rq);
+		if (engine->init_context)
+			err = engine->init_context(rq);
+
+		__i915_add_request(rq, true);
+		if (err)
+			goto out_ctx;
+	}
+
+	err = i915_gem_switch_to_kernel_context(i915);
+	if (err)
+		goto out_ctx;
+
+	err = i915_gem_wait_for_idle(i915, I915_WAIT_LOCKED);
+	if (err)
+		goto out_ctx;
+
+	for_each_engine(engine, i915, id) {
+		if (!ctx->engine[id].state)
+			continue;
+
+		engine->default_state =
+			i915_gem_object_get(ctx->engine[id].state->obj);
+
+		err = i915_gem_object_set_to_cpu_domain(engine->default_state,
+							false);
+		if (err)
+			goto out_ctx;
+	}
+
+out_ctx:
+	i915_gem_context_set_closed(ctx);
+	i915_gem_context_put(ctx);
+	return err;
+}
+
 int i915_gem_init(struct drm_i915_private *dev_priv)
 {
 	int ret;
@@ -5022,6 +5087,10 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 
 	intel_init_gt_powersave(dev_priv);
 
+	ret = __intel_engines_record_defaults(dev_priv);
+	if (ret)
+		goto out_unlock;
+
 out_unlock:
 	if (ret == -EIO) {
 		/* Allow engine initialisation to fail by marking the GPU as
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 10affb35ac56..499cc0f25653 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -343,7 +343,7 @@ static void __destroy_hw_context(struct i915_gem_context *ctx,
  * context state of the GPU for applications that don't utilize HW contexts, as
  * well as an idle case.
  */
-static struct i915_gem_context *
+struct i915_gem_context *
 i915_gem_create_context(struct drm_i915_private *dev_priv,
 			struct drm_i915_file_private *file_priv)
 {
@@ -418,8 +418,8 @@ i915_gem_context_create_gvt(struct drm_device *dev)
 	return ctx;
 }
 
-static struct i915_gem_context *
-create_kernel_context(struct drm_i915_private *i915, int prio)
+struct i915_gem_context *
+i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio)
 {
 	struct i915_gem_context *ctx;
 
@@ -473,7 +473,7 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv)
 	ida_init(&dev_priv->contexts.hw_ida);
 
 	/* lowest priority; idle task */
-	ctx = create_kernel_context(dev_priv, I915_PRIORITY_MIN);
+	ctx = i915_gem_context_create_kernel(dev_priv, I915_PRIORITY_MIN);
 	if (IS_ERR(ctx)) {
 		DRM_ERROR("Failed to create default global context\n");
 		err = PTR_ERR(ctx);
@@ -487,7 +487,7 @@ int i915_gem_contexts_init(struct drm_i915_private *dev_priv)
 	dev_priv->kernel_context = ctx;
 
 	/* highest priority; preempting task */
-	ctx = create_kernel_context(dev_priv, INT_MAX);
+	ctx = i915_gem_context_create_kernel(dev_priv, INT_MAX);
 	if (IS_ERR(ctx)) {
 		DRM_ERROR("Failed to create default preempt context\n");
 		err = PTR_ERR(ctx);
@@ -522,28 +522,6 @@ void i915_gem_contexts_lost(struct drm_i915_private *dev_priv)
 		engine->context_unpin(engine, engine->last_retired_context);
 		engine->last_retired_context = NULL;
 	}
-
-	/* Force the GPU state to be restored on enabling */
-	if (!i915_modparams.enable_execlists) {
-		struct i915_gem_context *ctx;
-
-		list_for_each_entry(ctx, &dev_priv->contexts.list, link) {
-			if (!i915_gem_context_is_default(ctx))
-				continue;
-
-			for_each_engine(engine, dev_priv, id)
-				ctx->engine[engine->id].initialised = false;
-
-			ctx->remap_slice = ALL_L3_SLICES(dev_priv);
-		}
-
-		for_each_engine(engine, dev_priv, id) {
-			struct intel_context *kce =
-				&dev_priv->kernel_context->engine[engine->id];
-
-			kce->initialised = true;
-		}
-	}
 }
 
 void i915_gem_contexts_fini(struct drm_i915_private *i915)
@@ -718,9 +696,6 @@ static inline bool skip_rcs_switch(struct i915_hw_ppgtt *ppgtt,
 	if (to->remap_slice)
 		return false;
 
-	if (!to->engine[RCS].initialised)
-		return false;
-
 	if (ppgtt && (intel_engine_flag(engine) & ppgtt->pd_dirty_rings))
 		return false;
 
@@ -795,11 +770,7 @@ static int do_rcs_switch(struct drm_i915_gem_request *req)
 			return ret;
 	}
 
-	if (!to->engine[RCS].initialised || i915_gem_context_is_default(to))
-		/* NB: If we inhibit the restore, the context is not allowed to
-		 * die because future work may end up depending on valid address
-		 * space. This means we must enforce that a page table load
-		 * occur when this occurs. */
+	if (i915_gem_context_is_kernel(to))
 		hw_flags = MI_RESTORE_INHIBIT;
 	else if (ppgtt && intel_engine_flag(engine) & ppgtt->pd_dirty_rings)
 		hw_flags = MI_FORCE_RESTORE;
@@ -843,15 +814,6 @@ static int do_rcs_switch(struct drm_i915_gem_request *req)
 		to->remap_slice &= ~(1<<i);
 	}
 
-	if (!to->engine[RCS].initialised) {
-		if (engine->init_context) {
-			ret = engine->init_context(req);
-			if (ret)
-				return ret;
-		}
-		to->engine[RCS].initialised = true;
-	}
-
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index 44688e22a5c2..4bfb72f8e1cb 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -157,7 +157,6 @@ struct i915_gem_context {
 		u32 *lrc_reg_state;
 		u64 lrc_desc;
 		int pin_count;
-		bool initialised;
 	} engine[I915_NUM_ENGINES];
 
 	/** ring_size: size for allocating the per-engine ring buffer */
@@ -292,6 +291,9 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, void *data,
 				       struct drm_file *file);
 
+struct i915_gem_context *
+i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio);
+
 static inline struct i915_gem_context *
 i915_gem_context_get(struct i915_gem_context *ctx)
 {
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index c15e288bed02..6b8519401d4d 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -679,6 +679,9 @@ void intel_engine_cleanup_common(struct intel_engine_cs *engine)
 	intel_engine_cleanup_cmd_parser(engine);
 	i915_gem_batch_pool_fini(&engine->batch_pool);
 
+	if (engine->default_state)
+		i915_gem_object_put(engine->default_state);
+
 	if (HAS_LOGICAL_RING_PREEMPTION(engine->i915))
 		engine->context_unpin(engine, engine->i915->preempt_context);
 	engine->context_unpin(engine, engine->i915->kernel_context);
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 6840ec8db037..297ce0327273 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1147,7 +1147,6 @@ static int execlists_request_alloc(struct drm_i915_gem_request *request)
 	struct intel_engine_cs *engine = request->engine;
 	struct intel_context *ce = &request->ctx->engine[engine->id];
 	u32 *cs;
-	int ret;
 
 	GEM_BUG_ON(!ce->pin_count);
 
@@ -1161,14 +1160,6 @@ static int execlists_request_alloc(struct drm_i915_gem_request *request)
 	if (IS_ERR(cs))
 		return PTR_ERR(cs);
 
-	if (!ce->initialised) {
-		ret = engine->init_context(request);
-		if (ret)
-			return ret;
-
-		ce->initialised = true;
-	}
-
 	/* Note that after this point, we have committed to using
 	 * this request as it is being used to both track the
 	 * state of engine initialisation and liveness of the
@@ -2100,7 +2091,6 @@ static void execlists_init_reg_state(u32 *regs,
 
 	CTX_REG(regs, CTX_CONTEXT_CONTROL, RING_CONTEXT_CONTROL(engine),
 		_MASKED_BIT_ENABLE(CTX_CTRL_INHIBIT_SYN_CTX_SWITCH |
-				   CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
 				   (HAS_RESOURCE_STREAMER(dev_priv) ?
 				   CTX_CTRL_RS_CTX_ENABLE : 0)));
 	CTX_REG(regs, CTX_RING_HEAD, RING_HEAD(base), 0);
@@ -2177,6 +2167,7 @@ populate_lr_context(struct i915_gem_context *ctx,
 		    struct intel_ring *ring)
 {
 	void *vaddr;
+	u32 *regs;
 	int ret;
 
 	ret = i915_gem_object_set_to_cpu_domain(ctx_obj, true);
@@ -2193,11 +2184,28 @@ populate_lr_context(struct i915_gem_context *ctx,
 	}
 	ctx_obj->mm.dirty = true;
 
+	if (engine->default_state) {
+		void *defaults;
+
+		defaults = i915_gem_object_pin_map(engine->default_state,
+						   I915_MAP_WB);
+		if (IS_ERR(defaults))
+			return PTR_ERR(defaults);
+
+		memcpy(vaddr + LRC_HEADER_PAGES * PAGE_SIZE,
+		       defaults + LRC_HEADER_PAGES * PAGE_SIZE,
+		       engine->context_size);
+		i915_gem_object_unpin_map(engine->default_state);
+	}
+
 	/* The second page of the context object contains some fields which must
 	 * be set up prior to the first execution. */
-
-	execlists_init_reg_state(vaddr + LRC_STATE_PN * PAGE_SIZE,
-				 ctx, engine, ring);
+	regs = vaddr + LRC_STATE_PN * PAGE_SIZE;
+	execlists_init_reg_state(regs, ctx, engine, ring);
+	if (!engine->default_state) {
+		regs[CTX_CONTEXT_CONTROL+1] |=
+			_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT);
+	}
 
 	i915_gem_object_unpin_map(ctx_obj);
 
@@ -2250,7 +2258,6 @@ static int execlists_context_deferred_alloc(struct i915_gem_context *ctx,
 
 	ce->ring = ring;
 	ce->state = vma;
-	ce->initialised |= engine->init_context == NULL;
 
 	return 0;
 
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 47fadf8da84e..3e5c296cd8bc 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1368,7 +1368,7 @@ static int context_pin(struct i915_gem_context *ctx)
 	 * on an active context (which by nature is already on the GPU).
 	 */
 	if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
-		ret = i915_gem_object_set_to_gtt_domain(vma->obj, false);
+		ret = i915_gem_object_set_to_gtt_domain(vma->obj, true);
 		if (ret)
 			return ret;
 	}
@@ -1383,11 +1383,34 @@ alloc_context_vma(struct intel_engine_cs *engine)
 	struct drm_i915_private *i915 = engine->i915;
 	struct drm_i915_gem_object *obj;
 	struct i915_vma *vma;
+	int err;
 
 	obj = i915_gem_object_create(i915, engine->context_size);
 	if (IS_ERR(obj))
 		return ERR_CAST(obj);
 
+	if (engine->default_state) {
+		void *defaults, *vaddr;
+
+		vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
+		if (IS_ERR(vaddr)) {
+			err = PTR_ERR(vaddr);
+			goto err_obj;
+		}
+
+		defaults = i915_gem_object_pin_map(engine->default_state,
+						   I915_MAP_WB);
+		if (IS_ERR(defaults)) {
+			err = PTR_ERR(defaults);
+			goto err_map;
+		}
+
+		memcpy(vaddr, defaults, engine->context_size);
+
+		i915_gem_object_unpin_map(engine->default_state);
+		i915_gem_object_unpin_map(obj);
+	}
+
 	/*
 	 * Try to make the context utilize L3 as well as LLC.
 	 *
@@ -1409,10 +1432,18 @@ alloc_context_vma(struct intel_engine_cs *engine)
 	}
 
 	vma = i915_vma_instance(obj, &i915->ggtt.base, NULL);
-	if (IS_ERR(vma))
-		i915_gem_object_put(obj);
+	if (IS_ERR(vma)) {
+		err = PTR_ERR(vma);
+		goto err_obj;
+	}
 
 	return vma;
+
+err_map:
+	i915_gem_object_unpin_map(obj);
+err_obj:
+	i915_gem_object_put(obj);
+	return ERR_PTR(err);
 }
 
 static struct intel_ring *
@@ -1449,16 +1480,6 @@ intel_ring_context_pin(struct intel_engine_cs *engine,
 		ce->state->obj->pin_global++;
 	}
 
-	/* The kernel context is only used as a placeholder for flushing the
-	 * active context. It is never used for submitting user rendering and
-	 * as such never requires the golden render context, and so we can skip
-	 * emitting it when we switch to the kernel context. This is required
-	 * as during eviction we cannot allocate and pin the renderstate in
-	 * order to initialise the context.
-	 */
-	if (i915_gem_context_is_kernel(ctx))
-		ce->initialised = true;
-
 	i915_gem_context_get(ctx);
 
 out:
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 69ad875fd011..1d752b9a3065 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -303,6 +303,7 @@ struct intel_engine_cs {
 	struct intel_ring *buffer;
 	struct intel_timeline *timeline;
 
+	struct drm_i915_gem_object *default_state;
 	struct intel_render_state *render_state;
 
 	atomic_t irq_count;
-- 
2.15.0



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