drm/i915/gvt: Introduce vGPU submission ops

Introduce vGPU submission ops to support easy switching submission mode
of one vGPU between different OSes.
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>

drivers/gpu/drm/i915/gvt/execlist.c

@@ -548,7 +548,7 @@ static void clean_workloads(struct intel_vgpu *vgpu, unsigned long engine_mask)
 	}
 }
 
-void intel_vgpu_clean_execlist(struct intel_vgpu *vgpu)
+void clean_execlist(struct intel_vgpu *vgpu)
 {
 	enum intel_engine_id i;
 	struct intel_engine_cs *engine;
@@ -564,7 +564,7 @@ void intel_vgpu_clean_execlist(struct intel_vgpu *vgpu)
 	}
 }
 
-int intel_vgpu_init_execlist(struct intel_vgpu *vgpu)
+int init_execlist(struct intel_vgpu *vgpu)
 {
 	enum intel_engine_id i;
 	struct intel_engine_cs *engine;
@@ -586,3 +586,9 @@ void intel_vgpu_reset_execlist(struct intel_vgpu *vgpu,
 	for_each_engine_masked(engine, dev_priv, engine_mask, tmp)
 		init_vgpu_execlist(vgpu, engine->id);
 }
+
+const struct intel_vgpu_submission_ops intel_vgpu_execlist_submission_ops = {
+	.name = "execlist",
+	.init = init_execlist,
+	.clean = clean_execlist,
+};

drivers/gpu/drm/i915/gvt/gvt.h

@@ -142,6 +142,17 @@ struct vgpu_sched_ctl {
 	int weight;
 };
 
+enum {
+	INTEL_VGPU_EXECLIST_SUBMISSION = 1,
+	INTEL_VGPU_GUC_SUBMISSION,
+};
+
+struct intel_vgpu_submission_ops {
+	const char *name;
+	int (*init)(struct intel_vgpu *vgpu);
+	void (*clean)(struct intel_vgpu *vgpu);
+};
+
 struct intel_vgpu_submission {
 	struct intel_vgpu_execlist execlist[I915_NUM_ENGINES];
 	struct list_head workload_q_head[I915_NUM_ENGINES];
@@ -152,6 +163,9 @@ struct intel_vgpu_submission {
 	DECLARE_BITMAP(tlb_handle_pending, I915_NUM_ENGINES);
 	void *ring_scan_buffer[I915_NUM_ENGINES];
 	int ring_scan_buffer_size[I915_NUM_ENGINES];
+	const struct intel_vgpu_submission_ops *ops;
+	int virtual_submission_interface;
+	bool active;
 };
 
 struct intel_vgpu {

drivers/gpu/drm/i915/gvt/handlers.c

@@ -1471,9 +1471,11 @@ static int elsp_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 static int ring_mode_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 		void *p_data, unsigned int bytes)
 {
+	struct intel_vgpu_submission *s = &vgpu->submission;
 	u32 data = *(u32 *)p_data;
 	int ring_id = render_mmio_to_ring_id(vgpu->gvt, offset);
 	bool enable_execlist;
+	int ret;
 
 	write_vreg(vgpu, offset, p_data, bytes);
 
@@ -1495,8 +1497,18 @@ static int ring_mode_mmio_write(struct intel_vgpu *vgpu, unsigned int offset,
 				(enable_execlist ? "enabling" : "disabling"),
 				ring_id);
 
-		if (enable_execlist)
-			intel_vgpu_start_schedule(vgpu);
+		if (!enable_execlist)
+			return 0;
+
+		if (s->active)
+			return 0;
+
+		ret = intel_vgpu_select_submission_ops(vgpu,
+				INTEL_VGPU_EXECLIST_SUBMISSION);
+		if (ret)
+			return ret;
+
+		intel_vgpu_start_schedule(vgpu);
 	}
 	return 0;
 }

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -884,6 +884,7 @@ void intel_vgpu_clean_submission(struct intel_vgpu *vgpu)
 {
 	struct intel_vgpu_submission *s = &vgpu->submission;
 
+	intel_vgpu_select_submission_ops(vgpu, 0);
 	i915_gem_context_put(s->shadow_ctx);
 	kmem_cache_destroy(s->workloads);
 }
@@ -935,6 +936,58 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
 	return ret;
 }
 
+/**
+ * intel_vgpu_select_submission_ops - select virtual submission interface
+ * @vgpu: a vGPU
+ * @interface: expected vGPU virtual submission interface
+ *
+ * This function is called when guest configures submission interface.
+ *
+ * Returns:
+ * Zero on success, negative error code if failed.
+ *
+ */
+int intel_vgpu_select_submission_ops(struct intel_vgpu *vgpu,
+				     unsigned int interface)
+{
+	struct intel_vgpu_submission *s = &vgpu->submission;
+	const struct intel_vgpu_submission_ops *ops[] = {
+		[INTEL_VGPU_EXECLIST_SUBMISSION] =
+			&intel_vgpu_execlist_submission_ops,
+	};
+	int ret;
+
+	if (WARN_ON(interface >= ARRAY_SIZE(ops)))
+		return -EINVAL;
+
+	if (s->active) {
+		s->ops->clean(vgpu);
+		s->active = false;
+		gvt_dbg_core("vgpu%d: de-select ops [ %s ] \n",
+				vgpu->id, s->ops->name);
+	}
+
+	if (interface == 0) {
+		s->ops = NULL;
+		s->virtual_submission_interface = 0;
+		gvt_dbg_core("vgpu%d: no submission ops\n", vgpu->id);
+		return 0;
+	}
+
+	ret = ops[interface]->init(vgpu);
+	if (ret)
+		return ret;
+
+	s->ops = ops[interface];
+	s->virtual_submission_interface = interface;
+	s->active = true;
+
+	gvt_dbg_core("vgpu%d: activate ops [ %s ]\n",
+			vgpu->id, s->ops->name);
+
+	return 0;
+}
+
 /**
  * intel_vgpu_destroy_workload - destroy a vGPU workload
  * @vgpu: a vGPU

drivers/gpu/drm/i915/gvt/scheduler.h

@@ -141,6 +141,12 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu);
 
 void intel_vgpu_clean_submission(struct intel_vgpu *vgpu);
 
+int intel_vgpu_select_submission_ops(struct intel_vgpu *vgpu,
+				     unsigned int interface);
+
+extern const struct intel_vgpu_submission_ops
+intel_vgpu_execlist_submission_ops;
+
 struct intel_vgpu_workload *
 intel_vgpu_create_workload(struct intel_vgpu *vgpu, int ring_id,
 			   struct execlist_ctx_descriptor_format *desc);

drivers/gpu/drm/i915/gvt/vgpu.c

@@ -255,7 +255,6 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)
 	idr_remove(&gvt->vgpu_idr, vgpu->id);
 	intel_vgpu_clean_sched_policy(vgpu);
 	intel_vgpu_clean_submission(vgpu);
-	intel_vgpu_clean_execlist(vgpu);
 	intel_vgpu_clean_display(vgpu);
 	intel_vgpu_clean_opregion(vgpu);
 	intel_vgpu_clean_gtt(vgpu);
@@ -371,26 +370,20 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
 	if (ret)
 		goto out_clean_gtt;
 
-	ret = intel_vgpu_init_execlist(vgpu);
-	if (ret)
-		goto out_clean_display;
-
 	ret = intel_vgpu_setup_submission(vgpu);
 	if (ret)
-		goto out_clean_execlist;
+		goto out_clean_display;
 
 	ret = intel_vgpu_init_sched_policy(vgpu);
 	if (ret)
-		goto out_clean_shadow_ctx;
+		goto out_clean_submission;
 
 	mutex_unlock(&gvt->lock);
 
 	return vgpu;
 
-out_clean_shadow_ctx:
+out_clean_submission:
 	intel_vgpu_clean_submission(vgpu);
-out_clean_execlist:
-	intel_vgpu_clean_execlist(vgpu);
 out_clean_display:
 	intel_vgpu_clean_display(vgpu);
 out_clean_gtt: