Commit 09975b86 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/execlists: Disable preemption under GVT 



Preempt-to-busy uses a GPU semaphore to enforce an idle-barrier across
preemption, but mediated gvt does not fully support semaphores.

v2: Fiddle around with the flags and settle on using has-semaphores for
the core bits so that we retain the ability to preempt our own
semaphores.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Xiaolin Zhang <xiaolin.zhang@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190709091233.8573-1-chris@chris-wilson.co.uk
parent cfe7288c

drivers/gpu/drm/i915/gt/intel_engine_cs.c

+2 −2
Original line number Diff line number Diff line
@@ -829,6 +829,8 @@ int intel_engine_init_common(struct intel_engine_cs *engine) 
	struct drm_i915_private *i915 = engine->i915;

	int ret;



	engine->set_default_submission(engine);



	/* We may need to do things with the shrinker which

	 * require us to immediately switch back to the default

	 * context. This can cause a problem as pinning the
@@ -847,8 +849,6 @@ int intel_engine_init_common(struct intel_engine_cs *engine) 


	engine->emit_fini_breadcrumb_dw = ret;



	engine->set_default_submission(engine);



	return 0;



err_unpin:

drivers/gpu/drm/i915/gt/intel_lrc.c

+18 −6
Original line number Diff line number Diff line
@@ -306,6 +306,9 @@ static inline bool need_preempt(const struct intel_engine_cs *engine, 
{

	int last_prio;



	if (!intel_engine_has_semaphores(engine))

		return false;



	/*

	 * Check if the current priority hint merits a preemption attempt.

	 *
@@ -904,6 +907,9 @@ need_timeslice(struct intel_engine_cs *engine, const struct i915_request *rq) 
{

	int hint;



	if (!intel_engine_has_semaphores(engine))

		return false;



	if (list_is_last(&rq->sched.link, &engine->active.requests))

		return false;
@@ -2656,6 +2662,7 @@ static u32 *gen8_emit_fini_breadcrumb(struct i915_request *request, u32 *cs) 
	*cs++ = MI_USER_INTERRUPT;



	*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;

	if (intel_engine_has_semaphores(request->engine))

		cs = emit_preempt_busywait(request, cs);



	request->tail = intel_ring_offset(request, cs);
@@ -2680,6 +2687,7 @@ static u32 *gen8_emit_fini_breadcrumb_rcs(struct i915_request *request, u32 *cs) 
	*cs++ = MI_USER_INTERRUPT;



	*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;

	if (intel_engine_has_semaphores(request->engine))

		cs = emit_preempt_busywait(request, cs);



	request->tail = intel_ring_offset(request, cs);
@@ -2728,11 +2736,12 @@ void intel_execlists_set_default_submission(struct intel_engine_cs *engine) 
	engine->unpark = NULL;



	engine->flags |= I915_ENGINE_SUPPORTS_STATS;

	if (!intel_vgpu_active(engine->i915))

	if (!intel_vgpu_active(engine->i915)) {

		engine->flags |= I915_ENGINE_HAS_SEMAPHORES;

		if (HAS_LOGICAL_RING_PREEMPTION(engine->i915))

			engine->flags |= I915_ENGINE_HAS_PREEMPTION;

	}

}



static void execlists_destroy(struct intel_engine_cs *engine)

{
@@ -3419,7 +3428,6 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx, 
	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;



	/*

	 * The decision on whether to submit a request using semaphores
@@ -3516,8 +3524,12 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx, 
		ve->base.emit_fini_breadcrumb = sibling->emit_fini_breadcrumb;

		ve->base.emit_fini_breadcrumb_dw =

			sibling->emit_fini_breadcrumb_dw;



		ve->base.flags = sibling->flags;

	}



	ve->base.flags |= I915_ENGINE_IS_VIRTUAL;



	return &ve->context;



err_put:

drivers/gpu/drm/i915/gt/selftest_lrc.c

+6 −0
Original line number Diff line number Diff line
@@ -269,6 +269,9 @@ static int live_timeslice_preempt(void *arg) 
		enum intel_engine_id id;



		for_each_engine(engine, i915, id) {

			if (!intel_engine_has_preemption(engine))

				continue;



			memset(vaddr, 0, PAGE_SIZE);



			err = slice_semaphore_queue(engine, vma, count);
@@ -354,6 +357,9 @@ static int live_busywait_preempt(void *arg) 
		struct igt_live_test t;

		u32 *cs;



		if (!intel_engine_has_preemption(engine))

			continue;



		if (!intel_engine_can_store_dword(engine))

			continue;

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