diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 11d2f7d05f9191afd9510bc8b078ac6bf95caac2..a76dd27fb2e819330d384021d2eab8ba6a5a6836 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -1268,7 +1268,6 @@ static bool is_ri_cb_valid(struct runtime_instr_cb *cb)
 		cb->pc == 1 &&
 		cb->qc == 0 &&
 		cb->reserved2 == 0 &&
-		cb->key == PAGE_DEFAULT_KEY &&
 		cb->reserved3 == 0 &&
 		cb->reserved4 == 0 &&
 		cb->reserved5 == 0 &&
@@ -1330,7 +1329,11 @@ static int s390_runtime_instr_set(struct task_struct *target,
 		kfree(data);
 		return -EINVAL;
 	}
-
+	/*
+	 * Override access key in any case, since user space should
+	 * not be able to set it, nor should it care about it.
+	 */
+	ri_cb.key = PAGE_DEFAULT_KEY >> 4;
 	preempt_disable();
 	if (!target->thread.ri_cb)
 		target->thread.ri_cb = data;
diff --git a/arch/s390/kernel/runtime_instr.c b/arch/s390/kernel/runtime_instr.c
index 125c7f6e87150d526a60c9e23b99c47bad1aae2b..1788a5454b6fc7a3a64b621b9b1880e35d6b705d 100644
--- a/arch/s390/kernel/runtime_instr.c
+++ b/arch/s390/kernel/runtime_instr.c
@@ -57,7 +57,7 @@ static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
 	cb->k = 1;
 	cb->ps = 1;
 	cb->pc = 1;
-	cb->key = PAGE_DEFAULT_KEY;
+	cb->key = PAGE_DEFAULT_KEY >> 4;
 	cb->v = 1;
 }
 
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 3902c9f6f2d63dd011f9e1c3244f062ed1d182cc..4b62d6b550246ddf20c8cd72dcabebfb6e8e2075 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -672,6 +672,19 @@ int zpci_disable_device(struct zpci_dev *zdev)
 }
 EXPORT_SYMBOL_GPL(zpci_disable_device);
 
+void zpci_remove_device(struct zpci_dev *zdev)
+{
+	struct zpci_bus *zbus = zdev->zbus;
+	struct pci_dev *pdev;
+
+	pdev = pci_get_slot(zbus->bus, zdev->devfn);
+	if (pdev) {
+		if (pdev->is_virtfn)
+			return zpci_remove_virtfn(pdev, zdev->vfn);
+		pci_stop_and_remove_bus_device_locked(pdev);
+	}
+}
+
 int zpci_create_device(struct zpci_dev *zdev)
 {
 	int rc;
@@ -716,13 +729,8 @@ 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);
-	}
+	if (zdev->zbus->bus)
+		zpci_remove_device(zdev);
 
 	switch (zdev->state) {
 	case ZPCI_FN_STATE_ONLINE:
diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
index 642a993846889935749280ad0b87d94c7b61841b..5967f30141563705e66067efc87c6d452e9b5fb3 100644
--- a/arch/s390/pci/pci_bus.c
+++ b/arch/s390/pci/pci_bus.c
@@ -132,13 +132,14 @@ static int zpci_bus_link_virtfn(struct pci_dev *pdev,
 {
 	int rc;
 
-	virtfn->physfn = pci_dev_get(pdev);
 	rc = pci_iov_sysfs_link(pdev, virtfn, vfid);
-	if (rc) {
-		pci_dev_put(pdev);
-		virtfn->physfn = NULL;
+	if (rc)
 		return rc;
-	}
+
+	virtfn->is_virtfn = 1;
+	virtfn->multifunction = 0;
+	virtfn->physfn = pci_dev_get(pdev);
+
 	return 0;
 }
 
@@ -151,9 +152,9 @@ static int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
 	int vfid = vfn - 1; /* Linux' vfid's start at 0 vfn at 1*/
 	int rc = 0;
 
-	virtfn->is_virtfn = 1;
-	virtfn->multifunction = 0;
-	WARN_ON(vfid < 0);
+	if (!zbus->multifunction)
+		return 0;
+
 	/* If the parent PF for the given VF is also configured in the
 	 * instance, it must be on the same zbus.
 	 * We can then identify the parent PF by checking what
@@ -165,11 +166,17 @@ static int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
 		zdev = zbus->function[i];
 		if (zdev && zdev->is_physfn) {
 			pdev = pci_get_slot(zbus->bus, zdev->devfn);
+			if (!pdev)
+				continue;
 			cand_devfn = pci_iov_virtfn_devfn(pdev, vfid);
 			if (cand_devfn == virtfn->devfn) {
 				rc = zpci_bus_link_virtfn(pdev, virtfn, vfid);
+				/* balance pci_get_slot() */
+				pci_dev_put(pdev);
 				break;
 			}
+			/* balance pci_get_slot() */
+			pci_dev_put(pdev);
 		}
 	}
 	return rc;
@@ -178,12 +185,23 @@ static int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
 static inline int zpci_bus_setup_virtfn(struct zpci_bus *zbus,
 		struct pci_dev *virtfn, int vfn)
 {
-	virtfn->is_virtfn = 1;
-	virtfn->multifunction = 0;
 	return 0;
 }
 #endif
 
+void pcibios_bus_add_device(struct pci_dev *pdev)
+{
+	struct zpci_dev *zdev = to_zpci(pdev);
+
+	/*
+	 * With pdev->no_vf_scan the common PCI probing code does not
+	 * perform PF/VF linking.
+	 */
+	if (zdev->vfn)
+		zpci_bus_setup_virtfn(zdev->zbus, pdev, zdev->vfn);
+
+}
+
 static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
 {
 	struct pci_bus *bus;
@@ -214,20 +232,10 @@ static int zpci_bus_add_device(struct zpci_bus *zbus, struct zpci_dev *zdev)
 	}
 
 	pdev = pci_scan_single_device(bus, zdev->devfn);
-	if (pdev) {
-		if (!zdev->is_physfn) {
-			rc = zpci_bus_setup_virtfn(zbus, pdev, zdev->vfn);
-			if (rc)
-				goto failed_with_pdev;
-		}
+	if (pdev)
 		pci_bus_add_device(pdev);
-	}
-	return 0;
 
-failed_with_pdev:
-	pci_stop_and_remove_bus_device(pdev);
-	pci_dev_put(pdev);
-	return rc;
+	return 0;
 }
 
 static void zpci_bus_add_devices(struct zpci_bus *zbus)
diff --git a/arch/s390/pci/pci_bus.h b/arch/s390/pci/pci_bus.h
index 89be3c354b7bcadfdead28b6f0d817d0d9eb8d3c..4972433df4581ab5acbbf5b33ac55e6b7db99375 100644
--- a/arch/s390/pci/pci_bus.h
+++ b/arch/s390/pci/pci_bus.h
@@ -29,3 +29,16 @@ static inline struct zpci_dev *get_zdev_by_bus(struct pci_bus *bus,
 
 	return (devfn >= ZPCI_FUNCTIONS_PER_BUS) ? NULL : zbus->function[devfn];
 }
+
+#ifdef CONFIG_PCI_IOV
+static inline void zpci_remove_virtfn(struct pci_dev *pdev, int vfn)
+{
+
+	pci_lock_rescan_remove();
+	/* Linux' vfid's start at 0 vfn at 1 */
+	pci_iov_remove_virtfn(pdev->physfn, vfn - 1);
+	pci_unlock_rescan_remove();
+}
+#else /* CONFIG_PCI_IOV */
+static inline void zpci_remove_virtfn(struct pci_dev *pdev, int vfn) {}
+#endif /* CONFIG_PCI_IOV */
diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index fdebd286f40236d80939cff20c5d55b417e3fc9b..9a3a291cad43244feca43b05c2ad7896a38dded7 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -92,6 +92,9 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 			ret = clp_add_pci_device(ccdf->fid, ccdf->fh, 1);
 			break;
 		}
+		/* the configuration request may be stale */
+		if (zdev->state != ZPCI_FN_STATE_STANDBY)
+			break;
 		zdev->fh = ccdf->fh;
 		zdev->state = ZPCI_FN_STATE_CONFIGURED;
 		ret = zpci_enable_device(zdev);
@@ -118,7 +121,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 		if (!zdev)
 			break;
 		if (pdev)
-			pci_stop_and_remove_bus_device_locked(pdev);
+			zpci_remove_device(zdev);
 
 		ret = zpci_disable_device(zdev);
 		if (ret)
@@ -137,7 +140,7 @@ static void __zpci_event_availability(struct zpci_ccdf_avail *ccdf)
 			/* Give the driver a hint that the function is
 			 * already unusable. */
 			pdev->error_state = pci_channel_io_perm_failure;
-			pci_stop_and_remove_bus_device_locked(pdev);
+			zpci_remove_device(zdev);
 		}
 
 		zdev->state = ZPCI_FN_STATE_STANDBY;
diff --git a/drivers/pci/hotplug/s390_pci_hpc.c b/drivers/pci/hotplug/s390_pci_hpc.c
index b59f84918fe060058d0f74c0e89fa39491b4f8d6..c9e790c74051f6215b7c8f1057234f2a169ee965 100644
--- a/drivers/pci/hotplug/s390_pci_hpc.c
+++ b/drivers/pci/hotplug/s390_pci_hpc.c
@@ -83,21 +83,19 @@ static int disable_slot(struct hotplug_slot *hotplug_slot)
 	struct zpci_dev *zdev = container_of(hotplug_slot, struct zpci_dev,
 					     hotplug_slot);
 	struct pci_dev *pdev;
-	struct zpci_bus *zbus = zdev->zbus;
 	int rc;
 
 	if (!zpci_fn_configured(zdev->state))
 		return -EIO;
 
-	pdev = pci_get_slot(zbus->bus, zdev->devfn);
-	if (pdev) {
-		if (pci_num_vf(pdev))
-			return -EBUSY;
-
-		pci_stop_and_remove_bus_device_locked(pdev);
+	pdev = pci_get_slot(zdev->zbus->bus, zdev->devfn);
+	if (pdev && pci_num_vf(pdev)) {
 		pci_dev_put(pdev);
+		return -EBUSY;
 	}
 
+	zpci_remove_device(zdev);
+
 	rc = zpci_disable_device(zdev);
 	if (rc)
 		return rc;
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 94edbb33d0d1fa7db7c93c8fe6702b7c30eebb8e..aca022239b333e6eabe0904ef4e7b6e77c00a84d 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -677,6 +677,11 @@ static int slow_eval_known_fn(struct subchannel *sch, void *data)
 		rc = css_evaluate_known_subchannel(sch, 1);
 		if (rc == -EAGAIN)
 			css_schedule_eval(sch->schid);
+		/*
+		 * The loop might take long time for platforms with lots of
+		 * known devices. Allow scheduling here.
+		 */
+		cond_resched();
 	}
 	return 0;
 }