Index: sys/compat/linuxkpi/common/include/linux/pci.h
===================================================================
--- sys/compat/linuxkpi/common/include/linux/pci.h
+++ sys/compat/linuxkpi/common/include/linux/pci.h
@@ -458,6 +458,47 @@
 	return (0);
 }
 
+static inline bool
+pci_is_root_bus(struct pci_bus *pbus)
+{
+
+	return (pbus->self == NULL);
+}
+
+static inline struct pci_dev *
+pci_upstream_bridge(struct pci_dev *pdev)
+{
+
+	if (pci_is_root_bus(pdev->bus))
+		return (NULL);
+
+	/*
+	 * If we do not have a (proper) "upstream bridge" set, e.g., we point
+	 * to ourselves or to nothing, try to handle this case on the fly
+	 * like we do for pcie_find_root_port().
+	 */
+	if (pdev == pdev->bus->self || pdev->bus->self == NULL) {
+		device_t bridge;
+
+		bridge = device_get_parent(pdev->dev.bsddev);
+		if (bridge == NULL)
+			return (pdev->bus->self);
+		bridge = device_get_parent(bridge);
+		if (bridge == NULL)
+			return (pdev->bus->self);
+		if (device_get_devclass(device_get_parent(bridge)) !=
+		    devclass_find("pci"))
+			return (pdev->bus->self);
+
+		/*
+		 * "bridge" is a PCI-to-PCI bridge.  Create a Linux pci_dev
+		 * for it so it can be returned.
+		 */
+		pdev->bus->self = lkpinew_pci_dev(bridge);
+	}
+	return (pdev->bus->self);
+}
+
 static inline struct pci_devres *
 lkpi_pci_devres_get_alloc(struct pci_dev *pdev)
 {
@@ -1379,13 +1420,6 @@
 	return (0);
 }
 
-static inline bool
-pci_is_root_bus(struct pci_bus *pbus)
-{
-
-	return (pbus->self == NULL);
-}
-
 struct pci_dev *lkpi_pci_get_domain_bus_and_slot(int domain,
     unsigned int bus, unsigned int devfn);
 #define	pci_get_domain_bus_and_slot(domain, bus, devfn)	\
Index: sys/compat/linuxkpi/common/src/linux_pci.c
===================================================================
--- sys/compat/linuxkpi/common/src/linux_pci.c
+++ sys/compat/linuxkpi/common/src/linux_pci.c
@@ -278,6 +278,11 @@
 	pdev->class = pci_get_class(dev);
 	pdev->revision = pci_get_revid(dev);
 	pdev->bus = malloc(sizeof(*pdev->bus), M_DEVBUF, M_WAITOK | M_ZERO);
+	/*
+	 * This should be the upstream bridge; pci_upstream_bridge()
+	 * handles that case on demand as otherwise we'll shadow the
+	 * entire PCI hierarchy.
+	 */
 	pdev->bus->self = pdev;
 	pdev->bus->number = pci_get_bus(dev);
 	pdev->bus->domain = pci_get_domain(dev);
@@ -301,6 +306,8 @@
 	pdev = to_pci_dev(dev);
 	if (pdev->root != NULL)
 		pci_dev_put(pdev->root);
+	if (pdev->bus->self != pdev)
+		pci_dev_put(pdev->bus->self);
 	free(pdev->bus, M_DEVBUF);
 	free(pdev, M_DEVBUF);
 }