diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index e11ebaf..a4a1b36 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -128,6 +128,23 @@
 }
 EXPORT_SYMBOL_GPL(pci_disable_ats);
 
+void pci_restore_ats_state(struct pci_dev *dev)
+{
+	u16 ctrl;
+
+	if (!pci_ats_enabled(dev))
+		return;
+	if (!pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS))
+		BUG();
+
+	ctrl = PCI_ATS_CTRL_ENABLE;
+	if (!dev->is_virtfn)
+		ctrl |= PCI_ATS_CTRL_STU(dev->ats->stu - PCI_ATS_MIN_STU);
+
+	pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
+}
+EXPORT_SYMBOL_GPL(pci_restore_ats_state);
+
 /**
  * pci_ats_queue_depth - query the ATS Invalidate Queue Depth
  * @dev: the PCI device