drm/i915/gvt: introudce intel_vgpu_reset_resource() to reset vgpu resource state

This patch introudces a new function intel_vgpu_reset_resource() to
reset allocated vgpu resources by intel_vgpu_alloc_resource(). So far
we only need clear the fence registers. The function _clear_vgpu_fence()
will reset both virtual and physical fence registers to 0.
Signed-off-by: Changbin Du <changbin.du@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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

@@ -158,6 +158,14 @@ void intel_vgpu_write_fence(struct intel_vgpu *vgpu,
 	POSTING_READ(fence_reg_lo);
 }
 
+static void _clear_vgpu_fence(struct intel_vgpu *vgpu)
+{
+	int i;
+
+	for (i = 0; i < vgpu_fence_sz(vgpu); i++)
+		intel_vgpu_write_fence(vgpu, i, 0);
+}
+
 static void free_vgpu_fence(struct intel_vgpu *vgpu)
 {
 	struct intel_gvt *gvt = vgpu->gvt;
@@ -171,9 +179,9 @@ static void free_vgpu_fence(struct intel_vgpu *vgpu)
 	intel_runtime_pm_get(dev_priv);
 
 	mutex_lock(&dev_priv->drm.struct_mutex);
+	_clear_vgpu_fence(vgpu);
 	for (i = 0; i < vgpu_fence_sz(vgpu); i++) {
 		reg = vgpu->fence.regs[i];
-		intel_vgpu_write_fence(vgpu, i, 0);
 		list_add_tail(&reg->link,
 			      &dev_priv->mm.fence_list);
 	}
@@ -201,13 +209,14 @@ static int alloc_vgpu_fence(struct intel_vgpu *vgpu)
 			continue;
 		list_del(pos);
 		vgpu->fence.regs[i] = reg;
-		intel_vgpu_write_fence(vgpu, i, 0);
 		if (++i == vgpu_fence_sz(vgpu))
 			break;
 	}
 	if (i != vgpu_fence_sz(vgpu))
 		goto out_free_fence;
 
+	_clear_vgpu_fence(vgpu);
+
 	mutex_unlock(&dev_priv->drm.struct_mutex);
 	intel_runtime_pm_put(dev_priv);
 	return 0;
@@ -306,6 +315,22 @@ void intel_vgpu_free_resource(struct intel_vgpu *vgpu)
 	free_resource(vgpu);
 }
 
+/**
+ * intel_vgpu_reset_resource - reset resource state owned by a vGPU
+ * @vgpu: a vGPU
+ *
+ * This function is used to reset resource state owned by a vGPU.
+ *
+ */
+void intel_vgpu_reset_resource(struct intel_vgpu *vgpu)
+{
+	struct drm_i915_private *dev_priv = vgpu->gvt->dev_priv;
+
+	intel_runtime_pm_get(dev_priv);
+	_clear_vgpu_fence(vgpu);
+	intel_runtime_pm_put(dev_priv);
+}
+
 /**
  * intel_alloc_vgpu_resource - allocate HW resource for a vGPU
  * @vgpu: vGPU

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

@@ -323,6 +323,7 @@ struct intel_vgpu_creation_params {
 
 int intel_vgpu_alloc_resource(struct intel_vgpu *vgpu,
 			      struct intel_vgpu_creation_params *param);
+void intel_vgpu_reset_resource(struct intel_vgpu *vgpu);
 void intel_vgpu_free_resource(struct intel_vgpu *vgpu);
 void intel_vgpu_write_fence(struct intel_vgpu *vgpu,
 	u32 fence, u64 value);