diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 7d99ab35833c..c1558cf071b8 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -22,7 +22,6 @@ int pci_domain_nr(struct pci_bus *);
 int pci_proc_domain(struct pci_bus *);
 
 #define ZPCI_BUS_NR			0	/* default bus number */
-#define ZPCI_DEVFN			0	/* default device number */
 
 #define ZPCI_NR_DMA_SPACES		1
 #define ZPCI_NR_DEVICES			CONFIG_PCI_NR_FUNCTIONS
@@ -110,6 +109,7 @@ struct zpci_bus {
 	struct resource		bus_resource;
 	int			pchid;
 	int			domain_nr;
+	bool			multifunction;
 	enum pci_bus_speed	max_bus_speed;
 };
 
@@ -117,6 +117,7 @@ struct zpci_bus {
 struct zpci_dev {
 	struct zpci_bus *zbus;
 	struct list_head entry;		/* list of all zpci_devices, needed for hotplug, etc. */
+	struct list_head bus_next;
 	struct kref kref;
 	struct hotplug_slot hotplug_slot;
 
@@ -129,7 +130,8 @@ struct zpci_dev {
 	u8		pft;		/* pci function type */
 	u8		port;
 	u8		rid_available	: 1;
-	u8		reserved	: 7;
+	u8		has_hp_slot	: 1;
+	u8		reserved	: 6;
 	unsigned int	devfn;		/* DEVFN part of the RID*/
 
 	struct mutex lock;
@@ -253,7 +255,7 @@ static inline struct zpci_dev *to_zpci(struct pci_dev *pdev)
 {
 	struct zpci_bus *zbus = pdev->sysdata;
 
-	return zbus->function[ZPCI_DEVFN];
+	return zbus->function[pdev->devfn];
 }
 
 static inline struct zpci_dev *to_zpci_dev(struct device *dev)
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 41423dad881c..3f6670613c57 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -371,29 +371,17 @@ EXPORT_SYMBOL(pci_iounmap);
 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,
 		    int size, u32 *val)
 {
-	struct zpci_dev *zdev = get_zdev_by_bus(bus);
-	int ret;
+	struct zpci_dev *zdev = get_zdev_by_bus(bus, devfn);
 
-	if (!zdev || devfn != ZPCI_DEVFN)
-		ret = -ENODEV;
-	else
-		ret = zpci_cfg_load(zdev, where, val, size);
-
-	return ret;
+	return (zdev) ? zpci_cfg_load(zdev, where, val, size) : -ENODEV;
 }
 
 static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,
 		     int size, u32 val)
 {
-	struct zpci_dev *zdev = get_zdev_by_bus(bus);
-	int ret;
+	struct zpci_dev *zdev = get_zdev_by_bus(bus, devfn);
 
-	if (!zdev || devfn != ZPCI_DEVFN)
-		ret = -ENODEV;
-	else
-		ret = zpci_cfg_store(zdev, where, val, size);
-
-	return ret;
+	return (zdev) ? zpci_cfg_store(zdev, where, val, size) : -ENODEV;
 }
 
 static struct pci_ops pci_root_ops = {
@@ -708,12 +696,12 @@ int zpci_create_device(struct zpci_dev *zdev)
 	if (rc)
 		goto out_disable;
 
-	zpci_init_slot(zdev);
 	return 0;
 
 out_disable:
 	if (zdev->state == ZPCI_FN_STATE_ONLINE)
 		zpci_disable_device(zdev);
+
 out_destroy_iommu:
 	zpci_destroy_iommu(zdev);
 out:
@@ -727,18 +715,25 @@ void zpci_release_device(struct kref *kref)
 {
 	struct zpci_dev *zdev = container_of(kref, struct zpci_dev, kref);
 
+	if (zdev->zbus->bus) {
+		struct pci_dev *pdev;
+
+		pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
+		if (pdev)
+			pci_stop_and_remove_bus_device_locked(pdev);
+	}
+
 	switch (zdev->state) {
 	case ZPCI_FN_STATE_ONLINE:
 	case ZPCI_FN_STATE_CONFIGURED:
 		zpci_disable_device(zdev);
 		fallthrough;
 	case ZPCI_FN_STATE_STANDBY:
-		if (zdev->zbus) {
+		if (zdev->has_hp_slot)
 			zpci_exit_slot(zdev);
-			zpci_cleanup_bus_resources(zdev);
-			zpci_bus_device_unregister(zdev);
-			zpci_destroy_iommu(zdev);
-		}
+		zpci_cleanup_bus_resources(zdev);
+		zpci_bus_device_unregister(zdev);
+		zpci_destroy_iommu(zdev);
 		fallthrough;
 	default:
 		break;
diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
index b4fefc69c461..542c6b8f56df 100644
--- a/arch/s390/pci/pci_bus.c
+++ b/arch/s390/pci/pci_bus.c
@@ -62,14 +62,16 @@ static void zpci_bus_release(struct kref *kref)
 {
 	struct zpci_bus *zbus = container_of(kref, struct zpci_bus, kref);
 
-	pci_lock_rescan_remove();
-	pci_stop_root_bus(zbus->bus);
+	if (zbus->bus) {
+		pci_lock_rescan_remove();
+		pci_stop_root_bus(zbus->bus);
 
-	zpci_free_domain(zbus->domain_nr);
-	pci_free_resource_list(&zbus->resources);
+		zpci_free_domain(zbus->domain_nr);
+		pci_free_resource_list(&zbus->resources);
 
-	pci_remove_root_bus(zbus->bus);
-	pci_unlock_rescan_remove();
+		pci_remove_root_bus(zbus->bus);
+		pci_unlock_rescan_remove();
+	}
 
 	spin_lock(&zbus_list_lock);
 	list_del(&zbus->bus_next);
@@ -82,6 +84,23 @@ static void zpci_bus_put(struct zpci_bus *zbus)
 	kref_put(&zbus->kref, zpci_bus_release);
 }
 
+static struct zpci_bus *zpci_bus_get(int pchid)
+{
+	struct zpci_bus *zbus;
+
+	spin_lock(&zbus_list_lock);
+	list_for_each_entry(zbus, &zbus_list, bus_next) {
+		if (pchid == zbus->pchid) {
+			kref_get(&zbus->kref);
+			goto out_unlock;
+		}
+	}
+	zbus = NULL;
+out_unlock:
+	spin_unlock(&zbus_list_lock);
+	return zbus;
+}
+
 static struct zpci_bus *zpci_bus_alloc(int pchid)
 {
 	struct zpci_bus *zbus;
@@ -107,10 +126,61 @@ static struct zpci_bus *zpci_bus_alloc(int pchid)
 	return zbus;
 }
 
+static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
+{
+	struct pci_bus *bus;
+	struct resource_entry *window, *n;
+	struct resource *res;
+	struct pci_dev *pdev;
+	int rc;
+
+	bus = zbus->bus;
+	if (!bus)
+		return -EINVAL;
+
+	pdev = pci_get_slot(bus, zdev->devfn);
+	if (pdev) {
+		/* Device is already known. */
+		pci_dev_put(pdev);
+		return 0;
+	}
+
+	rc = zpci_init_slot(zdev);
+	if (rc)
+		return rc;
+	zdev->has_hp_slot = 1;
+
+	resource_list_for_each_entry_safe(window, n, &zbus->resources) {
+		res = window->res;
+		pci_bus_add_resource(bus, res, 0);
+	}
+
+	pdev = pci_scan_single_device(bus, zdev->devfn);
+	if (pdev) {
+		pdev->multifunction = 1;
+		pci_bus_add_device(pdev);
+	}
+
+	return 0;
+}
+
+static void zpci_bus_add_devices(struct zpci_bus *zbus)
+{
+	int i;
+
+	for (i = 1; i < ZPCI_FUNCTIONS_PER_BUS; i++)
+		if (zbus->function[i])
+			zpci_bus_add_device(zbus, zbus->function[i]);
+
+	pci_lock_rescan_remove();
+	pci_bus_add_devices(zbus->bus);
+	pci_unlock_rescan_remove();
+}
+
 int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
 {
-	struct zpci_bus *zbus;
-	int rc;
+	struct zpci_bus *zbus = NULL;
+	int rc = -EBADF;
 
 	if (zpci_nb_devices == ZPCI_NR_DEVICES) {
 		pr_warn("Adding PCI function %08x failed because the configured limit of %d is reached\n",
@@ -119,25 +189,65 @@ int zpci_bus_device_register(struct zpci_dev *zdev, struct pci_ops *ops)
 	}
 	zpci_nb_devices++;
 
-	if (zdev->devfn != ZPCI_DEVFN)
+	if (zdev->devfn >= ZPCI_FUNCTIONS_PER_BUS)
 		return -EINVAL;
 
-	zbus = zpci_bus_alloc(zdev->pchid);
-	if (!zbus)
-		return -ENOMEM;
+	if (!s390_pci_no_rid && zdev->rid_available)
+		zbus = zpci_bus_get(zdev->pchid);
+
+	if (!zbus) {
+		zbus = zpci_bus_alloc(zdev->pchid);
+		if (!zbus)
+			return -ENOMEM;
+	}
 
 	zdev->zbus = zbus;
-	zbus->function[ZPCI_DEVFN] = zdev;
+	if (zbus->function[zdev->devfn]) {
+		pr_err("devfn %04x is already assigned\n", zdev->devfn);
+		goto error; /* rc already set */
+	}
+	zbus->function[zdev->devfn] = zdev;
 
 	zpci_setup_bus_resources(zdev, &zbus->resources);
-	zbus->max_bus_speed = zdev->max_bus_speed;
 
-	rc = zpci_bus_scan(zbus, (u16)zdev->uid, ops);
-	if (!rc)
-		return 0;
+	if (zbus->bus) {
+		if (!zbus->multifunction) {
+			WARN_ONCE(1, "zbus is not multifunction\n");
+			goto error_bus;
+		}
+		if (!zdev->rid_available) {
+			WARN_ONCE(1, "rid_available not set for multifunction\n");
+			goto error_bus;
+		}
+		rc = zpci_bus_add_device(zbus, zdev);
+		if (rc)
+			goto error_bus;
+	} else if (zdev->devfn == 0) {
+		if (zbus->multifunction && !zdev->rid_available) {
+			WARN_ONCE(1, "rid_available not set on function 0 for multifunction\n");
+			goto error_bus;
+		}
+		rc = zpci_bus_scan(zbus, (u16)zdev->uid, ops);
+		if (rc)
+			goto error_bus;
+		zpci_bus_add_devices(zbus);
+		rc = zpci_init_slot(zdev);
+		if (rc)
+			goto error_bus;
+		zdev->has_hp_slot = 1;
+		zbus->multifunction = zdev->rid_available;
+		zbus->max_bus_speed = zdev->max_bus_speed;
+	} else {
+		zbus->multifunction = 1;
+	}
 
+	return 0;
+
+error_bus:
+	zpci_nb_devices--;
+	zbus->function[zdev->devfn] = NULL;
+error:
 	pr_err("Adding PCI function %08x failed\n", zdev->fid);
-	zdev->zbus = NULL;
 	zpci_bus_put(zbus);
 	return rc;
 }
@@ -147,6 +257,6 @@ void zpci_bus_device_unregister(struct zpci_dev *zdev)
 	struct zpci_bus *zbus = zdev->zbus;
 
 	zpci_nb_devices--;
-	zbus->function[ZPCI_DEVFN] = NULL;
+	zbus->function[zdev->devfn] = NULL;
 	zpci_bus_put(zbus);
 }
diff --git a/arch/s390/pci/pci_bus.h b/arch/s390/pci/pci_bus.h
index c6aff42cc2cf..89be3c354b7b 100644
--- a/arch/s390/pci/pci_bus.h
+++ b/arch/s390/pci/pci_bus.h
@@ -22,9 +22,10 @@ void zpci_free_domain(int domain);
 int zpci_setup_bus_resources(struct zpci_dev *zdev,
 			     struct list_head *resources);
 
-static inline struct zpci_dev *get_zdev_by_bus(struct pci_bus *bus)
+static inline struct zpci_dev *get_zdev_by_bus(struct pci_bus *bus,
+					       unsigned int devfn)
 {
 	struct zpci_bus *zbus = bus->sysdata;
 
-	return zbus->function[ZPCI_DEVFN];
+	return (devfn >= ZPCI_FUNCTIONS_PER_BUS) ? NULL : zbus->function[devfn];
 }
diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index c296214f0a19..08e1d619398e 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -55,7 +55,7 @@ static void __zpci_event_error(struct zpci_ccdf_err *ccdf)
 	zpci_err_hex(ccdf, sizeof(*ccdf));
 
 	if (zdev)
-		pdev = pci_get_slot(zdev->zbus->bus, ZPCI_DEVFN);
+		pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
 
 	pr_err("%s: Event 0x%x reports an error for PCI function 0x%x\n",
 	       pdev ? pci_name(pdev) : "n/a", ccdf->pec, ccdf->fid);
@@ -81,7 +81,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 	int ret;
 
 	if (zdev && zdev->zbus && zdev->zbus->bus)
-		pdev = pci_get_slot(zdev->zbus->bus, ZPCI_DEVFN);
+		pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
 
 	zpci_err("avail CCDF:\n");
 	zpci_err_hex(ccdf, sizeof(*ccdf));
diff --git a/drivers/pci/hotplug/s390_pci_hpc.c b/drivers/pci/hotplug/s390_pci_hpc.c
index a9c9f05fe54b..1579ba895edf 100644
--- a/drivers/pci/hotplug/s390_pci_hpc.c
+++ b/drivers/pci/hotplug/s390_pci_hpc.c
@@ -66,7 +66,7 @@ static int enable_slot(struct hotplug_slot *hotplug_slot)
 	if (rc)
 		goto out_deconfigure;
 
-	pci_scan_slot(zbus->bus, ZPCI_DEVFN);
+	pci_scan_slot(zbus->bus, zdev->devfn);
 	pci_lock_rescan_remove();
 	pci_bus_add_devices(zbus->bus);
 	pci_unlock_rescan_remove();
@@ -89,7 +89,7 @@ static int disable_slot(struct hotplug_slot *hotplug_slot)
 	if (!zpci_fn_configured(zdev->state))
 		return -EIO;
 
-	pdev = pci_get_slot(zbus->bus, ZPCI_DEVFN);
+	pdev = pci_get_slot(zbus->bus, zdev->devfn);
 	if (pdev) {
 		pci_stop_and_remove_bus_device_locked(pdev);
 		pci_dev_put(pdev);
@@ -141,7 +141,7 @@ int zpci_init_slot(struct zpci_dev *zdev)
 
 	snprintf(name, SLOT_NAME_SIZE, "%08x", zdev->fid);
 	return pci_hp_register(&zdev->hotplug_slot, zbus->bus,
-			       ZPCI_DEVFN, name);
+			       zdev->devfn, name);
 }
 
 void zpci_exit_slot(struct zpci_dev *zdev)