diff --git a/hw/intc/s390_flic.c b/hw/intc/s390_flic.c
index bef4caf980..711c11454f 100644
--- a/hw/intc/s390_flic.c
+++ b/hw/intc/s390_flic.c
@@ -21,11 +21,14 @@
 
 S390FLICState *s390_get_flic(void)
 {
-    S390FLICState *fs;
+    static S390FLICState *fs;
 
-    fs = S390_FLIC_COMMON(object_resolve_path(TYPE_KVM_S390_FLIC, NULL));
     if (!fs) {
-        fs = S390_FLIC_COMMON(object_resolve_path(TYPE_QEMU_S390_FLIC, NULL));
+        fs = S390_FLIC_COMMON(object_resolve_path(TYPE_KVM_S390_FLIC, NULL));
+        if (!fs) {
+            fs = S390_FLIC_COMMON(object_resolve_path(TYPE_QEMU_S390_FLIC,
+                                                      NULL));
+        }
     }
     return fs;
 }
diff --git a/hw/s390x/ccw-device.c b/hw/s390x/ccw-device.c
index 28ea20440e..fb8d640a7e 100644
--- a/hw/s390x/ccw-device.c
+++ b/hw/s390x/ccw-device.c
@@ -11,11 +11,51 @@
 #include "qemu/osdep.h"
 #include "ccw-device.h"
 
+static void ccw_device_refill_ids(CcwDevice *dev)
+{
+    SubchDev *sch = dev->sch;
+
+    assert(sch);
+
+    dev->dev_id.cssid = sch->cssid;
+    dev->dev_id.ssid = sch->ssid;
+    dev->dev_id.devid = sch->devno;
+    dev->dev_id.valid = true;
+
+    dev->subch_id.cssid = sch->cssid;
+    dev->subch_id.ssid = sch->ssid;
+    dev->subch_id.devid = sch->schid;
+    dev->subch_id.valid = true;
+}
+
+static void ccw_device_realize(CcwDevice *dev, Error **errp)
+{
+    ccw_device_refill_ids(dev);
+}
+
+static Property ccw_device_properties[] = {
+    DEFINE_PROP_CSS_DEV_ID("devno", CcwDevice, devno),
+    DEFINE_PROP_CSS_DEV_ID_RO("dev_id", CcwDevice, dev_id),
+    DEFINE_PROP_CSS_DEV_ID_RO("subch_id", CcwDevice, subch_id),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void ccw_device_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    CCWDeviceClass *k = CCW_DEVICE_CLASS(klass);
+
+    k->realize = ccw_device_realize;
+    k->refill_ids = ccw_device_refill_ids;
+    dc->props = ccw_device_properties;
+}
+
 static const TypeInfo ccw_device_info = {
     .name = TYPE_CCW_DEVICE,
     .parent = TYPE_DEVICE,
     .instance_size = sizeof(CcwDevice),
     .class_size = sizeof(CCWDeviceClass),
+    .class_init = ccw_device_class_init,
     .abstract = true,
 };
 
diff --git a/hw/s390x/ccw-device.h b/hw/s390x/ccw-device.h
index 59ba01b6c5..89c8e5dff7 100644
--- a/hw/s390x/ccw-device.h
+++ b/hw/s390x/ccw-device.h
@@ -19,12 +19,19 @@ typedef struct CcwDevice {
     DeviceState parent_obj;
     SubchDev *sch;
     /* <cssid>.<ssid>.<device number> */
-    CssDevId bus_id;
+    /* The user-set busid of the virtual ccw device. */
+    CssDevId devno;
+    /* The actual busid of the virtual ccw device. */
+    CssDevId dev_id;
+    /* The actual busid of the virtual subchannel. */
+    CssDevId subch_id;
 } CcwDevice;
 
 typedef struct CCWDeviceClass {
     DeviceClass parent_class;
     void (*unplug)(HotplugHandler *, DeviceState *, Error **);
+    void (*realize)(CcwDevice *, Error **);
+    void (*refill_ids)(CcwDevice *);
 } CCWDeviceClass;
 
 static inline CcwDevice *to_ccw_dev_fast(DeviceState *d)
diff --git a/hw/s390x/css-bridge.c b/hw/s390x/css-bridge.c
index 9a7f7ee60c..b54ac01d37 100644
--- a/hw/s390x/css-bridge.c
+++ b/hw/s390x/css-bridge.c
@@ -107,6 +107,9 @@ VirtualCssBus *virtual_css_bus_init(void)
     /* Enable hotplugging */
     qbus_set_hotplug_handler(bus, dev, &error_abort);
 
+    css_register_io_adapters(CSS_IO_ADAPTER_VIRTIO, true, false,
+                             &error_abort);
+
     return cbus;
  }
 
diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 37caa98195..c03bb20bc9 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -47,7 +47,6 @@ typedef struct IoAdapter {
     uint32_t id;
     uint8_t type;
     uint8_t isc;
-    QTAILQ_ENTRY(IoAdapter) sibling;
 } IoAdapter;
 
 typedef struct ChannelSubSys {
@@ -61,7 +60,7 @@ typedef struct ChannelSubSys {
     uint64_t chnmon_area;
     CssImage *css[MAX_CSSID + 1];
     uint8_t default_cssid;
-    QTAILQ_HEAD(, IoAdapter) io_adapters;
+    IoAdapter *io_adapters[CSS_IO_ADAPTER_TYPE_NUMS][MAX_ISC + 1];
     QTAILQ_HEAD(, IndAddr) indicator_addresses;
 } ChannelSubSys;
 
@@ -72,7 +71,6 @@ static ChannelSubSys channel_subsys = {
     .do_crw_mchk = true,
     .crws_lost = false,
     .chnmon_active = false,
-    .io_adapters = QTAILQ_HEAD_INITIALIZER(channel_subsys.io_adapters),
     .indicator_addresses =
         QTAILQ_HEAD_INITIALIZER(channel_subsys.indicator_addresses),
 };
@@ -155,44 +153,67 @@ int css_create_css_image(uint8_t cssid, bool default_image)
     return 0;
 }
 
-int css_register_io_adapter(uint8_t type, uint8_t isc, bool swap,
-                            bool maskable, uint32_t *id)
+uint32_t css_get_adapter_id(CssIoAdapterType type, uint8_t isc)
 {
+    if (type >= CSS_IO_ADAPTER_TYPE_NUMS || isc > MAX_ISC ||
+        !channel_subsys.io_adapters[type][isc]) {
+        return -1;
+    }
+
+    return channel_subsys.io_adapters[type][isc]->id;
+}
+
+/**
+ * css_register_io_adapters: Register I/O adapters per ISC during init
+ *
+ * @swap: an indication if byte swap is needed.
+ * @maskable: an indication if the adapter is subject to the mask operation.
+ * @errp: location to store error information.
+ */
+void css_register_io_adapters(CssIoAdapterType type, bool swap, bool maskable,
+                              Error **errp)
+{
+    uint32_t id;
+    int ret, isc;
     IoAdapter *adapter;
-    bool found = false;
-    int ret;
     S390FLICState *fs = s390_get_flic();
     S390FLICStateClass *fsc = S390_FLIC_COMMON_GET_CLASS(fs);
 
-    *id = 0;
-    QTAILQ_FOREACH(adapter, &channel_subsys.io_adapters, sibling) {
-        if ((adapter->type == type) && (adapter->isc == isc)) {
-            *id = adapter->id;
-            found = true;
-            ret = 0;
+    /*
+     * Disallow multiple registrations for the same device type.
+     * Report an error if registering for an already registered type.
+     */
+    if (channel_subsys.io_adapters[type][0]) {
+        error_setg(errp, "Adapters for type %d already registered", type);
+    }
+
+    for (isc = 0; isc <= MAX_ISC; isc++) {
+        id = (type << 3) | isc;
+        ret = fsc->register_io_adapter(fs, id, isc, swap, maskable);
+        if (ret == 0) {
+            adapter = g_new0(IoAdapter, 1);
+            adapter->id = id;
+            adapter->isc = isc;
+            adapter->type = type;
+            channel_subsys.io_adapters[type][isc] = adapter;
+        } else {
+            error_setg_errno(errp, -ret, "Unexpected error %d when "
+                             "registering adapter %d", ret, id);
             break;
         }
-        if (adapter->id >= *id) {
-            *id = adapter->id + 1;
+    }
+
+    /*
+     * No need to free registered adapters in kvm: kvm will clean up
+     * when the machine goes away.
+     */
+    if (ret) {
+        for (isc--; isc >= 0; isc--) {
+            g_free(channel_subsys.io_adapters[type][isc]);
+            channel_subsys.io_adapters[type][isc] = NULL;
         }
     }
-    if (found) {
-        goto out;
-    }
-    adapter = g_new0(IoAdapter, 1);
-    ret = fsc->register_io_adapter(fs, *id, isc, swap, maskable);
-    if (ret == 0) {
-        adapter->id = *id;
-        adapter->isc = isc;
-        adapter->type = type;
-        QTAILQ_INSERT_TAIL(&channel_subsys.io_adapters, adapter, sibling);
-    } else {
-        g_free(adapter);
-        fprintf(stderr, "Unexpected error %d when registering adapter %d\n",
-                ret, *id);
-    }
-out:
-    return ret;
+
 }
 
 static void css_clear_io_interrupt(uint16_t subchannel_id,
@@ -1894,6 +1915,13 @@ PropertyInfo css_devid_propinfo = {
     .set = set_css_devid,
 };
 
+PropertyInfo css_devid_ro_propinfo = {
+    .name = "str",
+    .description = "Read-only identifier of an I/O device in the channel "
+                   "subsystem, example: fe.1.23ab",
+    .get = get_css_devid,
+};
+
 SubchDev *css_create_virtual_sch(CssDevId bus_id, Error **errp)
 {
     uint16_t schid = 0;
diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 69b0291e8a..a8a1bab50a 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -23,15 +23,17 @@
 #include "hw/pci/msi.h"
 #include "qemu/error-report.h"
 
-/* #define DEBUG_S390PCI_BUS */
-#ifdef DEBUG_S390PCI_BUS
-#define DPRINTF(fmt, ...) \
-    do { fprintf(stderr, "S390pci-bus: " fmt, ## __VA_ARGS__); } while (0)
-#else
-#define DPRINTF(fmt, ...) \
-    do { } while (0)
+#ifndef DEBUG_S390PCI_BUS
+#define DEBUG_S390PCI_BUS  0
 #endif
 
+#define DPRINTF(fmt, ...)                                         \
+    do {                                                          \
+        if (DEBUG_S390PCI_BUS) {                                  \
+            fprintf(stderr, "S390pci-bus: " fmt, ## __VA_ARGS__); \
+        }                                                         \
+    } while (0)
+
 S390pciState *s390_get_phb(void)
 {
     static S390pciState *phb;
@@ -579,6 +581,9 @@ static int s390_pcihost_init(SysBusDevice *dev)
     s->bus_no = 0;
     QTAILQ_INIT(&s->pending_sei);
     QTAILQ_INIT(&s->zpci_devs);
+
+    css_register_io_adapters(CSS_IO_ADAPTER_PCI, true, false, &error_abort);
+
     return 0;
 }
 
diff --git a/hw/s390x/s390-pci-bus.h b/hw/s390x/s390-pci-bus.h
index dcbf4820c9..cf142a3e68 100644
--- a/hw/s390x/s390-pci-bus.h
+++ b/hw/s390x/s390-pci-bus.h
@@ -30,7 +30,6 @@
 #define FH_MASK_INDEX    0x0000ffff
 #define FH_SHM_VFIO      0x00010000
 #define FH_SHM_EMUL      0x00020000
-#define S390_PCIPT_ADAPTER 2
 #define ZPCI_MAX_FID 0xffffffff
 #define ZPCI_MAX_UID 0xffff
 #define UID_UNDEFINED 0
diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index d2a8c0a083..314a9cbad4 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -20,15 +20,17 @@
 #include "qemu/error-report.h"
 #include "sysemu/hw_accel.h"
 
-/* #define DEBUG_S390PCI_INST */
-#ifdef DEBUG_S390PCI_INST
-#define DPRINTF(fmt, ...) \
-    do { fprintf(stderr, "s390pci-inst: " fmt, ## __VA_ARGS__); } while (0)
-#else
-#define DPRINTF(fmt, ...) \
-    do { } while (0)
+#ifndef DEBUG_S390PCI_INST
+#define DEBUG_S390PCI_INST  0
 #endif
 
+#define DPRINTF(fmt, ...)                                          \
+    do {                                                           \
+        if (DEBUG_S390PCI_INST) {                                  \
+            fprintf(stderr, "s390pci-inst: " fmt, ## __VA_ARGS__); \
+        }                                                          \
+    } while (0)
+
 static void s390_set_status_code(CPUS390XState *env,
                                  uint8_t r, uint64_t status_code)
 {
@@ -731,12 +733,10 @@ int pcistb_service_call(S390CPU *cpu, uint8_t r1, uint8_t r3, uint64_t gaddr,
 static int reg_irqs(CPUS390XState *env, S390PCIBusDevice *pbdev, ZpciFib fib)
 {
     int ret, len;
+    uint8_t isc = FIB_DATA_ISC(ldl_p(&fib.data));
 
-    ret = css_register_io_adapter(S390_PCIPT_ADAPTER,
-                                  FIB_DATA_ISC(ldl_p(&fib.data)), true, false,
-                                  &pbdev->routes.adapter.adapter_id);
-    assert(ret == 0);
-
+    pbdev->routes.adapter.adapter_id = css_get_adapter_id(
+                                       CSS_IO_ADAPTER_PCI, isc);
     pbdev->summary_ind = get_indicator(ldq_p(&fib.aisb), sizeof(uint64_t));
     len = BITS_TO_LONGS(FIB_DATA_NOI(ldl_p(&fib.data))) * sizeof(unsigned long);
     pbdev->indicator = get_indicator(ldq_p(&fib.aibv), len);
@@ -755,7 +755,7 @@ static int reg_irqs(CPUS390XState *env, S390PCIBusDevice *pbdev, ZpciFib fib)
     pbdev->routes.adapter.summary_offset = FIB_DATA_AISBO(ldl_p(&fib.data));
     pbdev->routes.adapter.ind_addr = ldq_p(&fib.aibv);
     pbdev->routes.adapter.ind_offset = FIB_DATA_AIBVO(ldl_p(&fib.data));
-    pbdev->isc = FIB_DATA_ISC(ldl_p(&fib.data));
+    pbdev->isc = isc;
     pbdev->noi = FIB_DATA_NOI(ldl_p(&fib.data));
     pbdev->sum = FIB_DATA_SUM(ldl_p(&fib.data));
 
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 40914fde6f..04bd0ebe40 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -113,12 +113,13 @@ static void ccw_init(MachineState *machine)
     s390_sclp_init();
     s390_memory_init(machine->ram_size);
 
+    s390_flic_init();
+
     /* get a BUS */
     css_bus = virtual_css_bus_init();
     s390_init_ipl_dev(machine->kernel_filename, machine->kernel_cmdline,
                       machine->initrd_filename, "s390-ccw.img",
                       "s390-netboot.img", true);
-    s390_flic_init();
 
     dev = qdev_create(NULL, TYPE_S390_PCI_HOST_BRIDGE);
     object_property_add_child(qdev_get_machine(), TYPE_S390_PCI_HOST_BRIDGE,
@@ -336,6 +337,9 @@ static const TypeInfo ccw_machine_info = {
     }                                                                         \
     type_init(ccw_machine_register_##suffix)
 
+#define CCW_COMPAT_2_9 \
+        HW_COMPAT_2_9
+
 #define CCW_COMPAT_2_8 \
         HW_COMPAT_2_8 \
         {\
@@ -402,14 +406,26 @@ static const TypeInfo ccw_machine_info = {
             .value    = "0",\
         },
 
+static void ccw_machine_2_10_instance_options(MachineState *machine)
+{
+}
+
+static void ccw_machine_2_10_class_options(MachineClass *mc)
+{
+}
+DEFINE_CCW_MACHINE(2_10, "2.10", true);
+
 static void ccw_machine_2_9_instance_options(MachineState *machine)
 {
+    ccw_machine_2_10_instance_options(machine);
 }
 
 static void ccw_machine_2_9_class_options(MachineClass *mc)
 {
+    ccw_machine_2_10_class_options(mc);
+    SET_MACHINE_COMPAT(mc, CCW_COMPAT_2_9);
 }
-DEFINE_CCW_MACHINE(2_9, "2.9", true);
+DEFINE_CCW_MACHINE(2_9, "2.9", false);
 
 static void ccw_machine_2_8_instance_options(MachineState *machine)
 {
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 00b3bde4e9..f376381b9c 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -616,10 +616,9 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
                 dev->routes.adapter.ind_offset = ind_bit;
                 dev->routes.adapter.summary_offset = 7;
                 cpu_physical_memory_unmap(thinint, hw_len, 0, hw_len);
-                ret = css_register_io_adapter(CSS_IO_ADAPTER_VIRTIO,
-                                              dev->thinint_isc, true, false,
-                                              &dev->routes.adapter.adapter_id);
-                assert(ret == 0);
+                dev->routes.adapter.adapter_id = css_get_adapter_id(
+                                                 CSS_IO_ADAPTER_VIRTIO,
+                                                 dev->thinint_isc);
                 sch->thinint_active = ((dev->indicators != NULL) &&
                                        (dev->summary_indicator != NULL));
                 sch->curr_status.scsw.count = ccw.count - len;
@@ -680,7 +679,8 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
 {
     VirtIOCCWDeviceClass *k = VIRTIO_CCW_DEVICE_GET_CLASS(dev);
     CcwDevice *ccw_dev = CCW_DEVICE(dev);
-    SubchDev *sch = css_create_virtual_sch(ccw_dev->bus_id, errp);
+    CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
+    SubchDev *sch = css_create_virtual_sch(ccw_dev->devno, errp);
     Error *err = NULL;
 
     if (!sch) {
@@ -689,8 +689,7 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
     if (!virtio_ccw_rev_max(dev) && dev->force_revision_1) {
         error_setg(&err, "Invalid value of property max_rev "
                    "(is %d expected >= 1)", virtio_ccw_rev_max(dev));
-        error_propagate(errp, err);
-        return;
+        goto out_err;
     }
 
     sch->driver_data = dev;
@@ -705,7 +704,7 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
 
     trace_virtio_ccw_new_device(
         sch->cssid, sch->ssid, sch->schid, sch->devno,
-        ccw_dev->bus_id.valid ? "user-configured" : "auto-configured");
+        ccw_dev->devno.valid ? "user-configured" : "auto-configured");
 
     if (!kvm_eventfds_enabled()) {
         dev->flags &= ~VIRTIO_CCW_FLAG_USE_IOEVENTFD;
@@ -713,13 +712,23 @@ static void virtio_ccw_device_realize(VirtioCcwDevice *dev, Error **errp)
 
     if (k->realize) {
         k->realize(dev, &err);
+        if (err) {
+            goto out_err;
+        }
     }
+
+    ck->realize(ccw_dev, &err);
     if (err) {
-        error_propagate(errp, err);
-        css_subch_assign(sch->cssid, sch->ssid, sch->schid, sch->devno, NULL);
-        ccw_dev->sch = NULL;
-        g_free(sch);
+        goto out_err;
     }
+
+    return;
+
+out_err:
+    error_propagate(errp, err);
+    css_subch_assign(sch->cssid, sch->ssid, sch->schid, sch->devno, NULL);
+    ccw_dev->sch = NULL;
+    g_free(sch);
 }
 
 static int virtio_ccw_exit(VirtioCcwDevice *dev)
@@ -1261,12 +1270,17 @@ static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
 {
     VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d);
     CcwDevice *ccw_dev = CCW_DEVICE(d);
+    CCWDeviceClass *ck = CCW_DEVICE_GET_CLASS(ccw_dev);
     SubchDev *s = ccw_dev->sch;
     VirtIODevice *vdev = virtio_ccw_get_vdev(s);
     int len;
 
     s->driver_data = dev;
     subch_device_load(s, f);
+    /* Re-fill subch_id after loading the subchannel states.*/
+    if (ck->refill_ids) {
+        ck->refill_ids(ccw_dev);
+    }
     len = qemu_get_be32(f);
     if (len != 0) {
         dev->indicators = get_indicator(qemu_get_be64(f), len);
@@ -1293,9 +1307,9 @@ static int virtio_ccw_load_config(DeviceState *d, QEMUFile *f)
     dev->thinint_isc = qemu_get_byte(f);
     dev->revision = qemu_get_be32(f);
     if (s->thinint_active) {
-        return css_register_io_adapter(CSS_IO_ADAPTER_VIRTIO,
-                                       dev->thinint_isc, true, false,
-                                       &dev->routes.adapter.adapter_id);
+        dev->routes.adapter.adapter_id = css_get_adapter_id(
+                                         CSS_IO_ADAPTER_VIRTIO,
+                                         dev->thinint_isc);
     }
 
     return 0;
@@ -1354,7 +1368,6 @@ static void virtio_ccw_device_unplugged(DeviceState *d)
 /**************** Virtio-ccw Bus Device Descriptions *******************/
 
 static Property virtio_ccw_net_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1383,7 +1396,6 @@ static const TypeInfo virtio_ccw_net = {
 };
 
 static Property virtio_ccw_blk_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1412,7 +1424,6 @@ static const TypeInfo virtio_ccw_blk = {
 };
 
 static Property virtio_ccw_serial_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1441,7 +1452,6 @@ static const TypeInfo virtio_ccw_serial = {
 };
 
 static Property virtio_ccw_balloon_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1470,7 +1480,6 @@ static const TypeInfo virtio_ccw_balloon = {
 };
 
 static Property virtio_ccw_scsi_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1500,7 +1509,6 @@ static const TypeInfo virtio_ccw_scsi = {
 
 #ifdef CONFIG_VHOST_SCSI
 static Property vhost_ccw_scsi_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
                        VIRTIO_CCW_MAX_REV),
     DEFINE_PROP_END_OF_LIST(),
@@ -1538,7 +1546,6 @@ static void virtio_ccw_rng_instance_init(Object *obj)
 }
 
 static Property virtio_ccw_rng_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1567,7 +1574,6 @@ static const TypeInfo virtio_ccw_rng = {
 };
 
 static Property virtio_ccw_crypto_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
                     VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1694,7 +1700,6 @@ static const TypeInfo virtio_ccw_bus_info = {
 
 #ifdef CONFIG_VIRTFS
 static Property virtio_ccw_9p_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_BIT("ioeventfd", VirtioCcwDevice, flags,
             VIRTIO_CCW_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
@@ -1743,7 +1748,6 @@ static const TypeInfo virtio_ccw_9p_info = {
 #ifdef CONFIG_VHOST_VSOCK
 
 static Property vhost_vsock_ccw_properties[] = {
-    DEFINE_PROP_CSS_DEV_ID("devno", VirtioCcwDevice, parent_obj.bus_id),
     DEFINE_PROP_UINT32("max_revision", VirtioCcwDevice, max_rev,
                        VIRTIO_CCW_MAX_REV),
     DEFINE_PROP_END_OF_LIST(),
diff --git a/include/hw/compat.h b/include/hw/compat.h
index 5d5be91daf..846b90eb67 100644
--- a/include/hw/compat.h
+++ b/include/hw/compat.h
@@ -1,6 +1,9 @@
 #ifndef HW_COMPAT_H
 #define HW_COMPAT_H
 
+#define HW_COMPAT_2_9 \
+    /* empty */
+
 #define HW_COMPAT_2_8 \
     {\
         .driver   = "fw_cfg_mem",\
diff --git a/include/hw/s390x/css.h b/include/hw/s390x/css.h
index c96c862057..f1f0d7f07a 100644
--- a/include/hw/s390x/css.h
+++ b/include/hw/s390x/css.h
@@ -23,6 +23,8 @@
 #define MAX_CSSID 255
 #define MAX_CHPID 255
 
+#define MAX_ISC 7
+
 #define MAX_CIWS 62
 
 #define VIRTUAL_CSSID 0xfe
@@ -124,9 +126,15 @@ void css_generate_css_crws(uint8_t cssid);
 void css_clear_sei_pending(void);
 void css_adapter_interrupt(uint8_t isc);
 
-#define CSS_IO_ADAPTER_VIRTIO 1
-int css_register_io_adapter(uint8_t type, uint8_t isc, bool swap,
-                            bool maskable, uint32_t *id);
+typedef enum {
+    CSS_IO_ADAPTER_VIRTIO = 0,
+    CSS_IO_ADAPTER_PCI = 1,
+    CSS_IO_ADAPTER_TYPE_NUMS,
+} CssIoAdapterType;
+
+uint32_t css_get_adapter_id(CssIoAdapterType type, uint8_t isc);
+void css_register_io_adapters(CssIoAdapterType type, bool swap, bool maskable,
+                              Error **errp);
 
 #ifndef CONFIG_USER_ONLY
 SubchDev *css_find_subch(uint8_t m, uint8_t cssid, uint8_t ssid,
@@ -172,6 +180,11 @@ extern PropertyInfo css_devid_propinfo;
 #define DEFINE_PROP_CSS_DEV_ID(_n, _s, _f) \
     DEFINE_PROP(_n, _s, _f, css_devid_propinfo, CssDevId)
 
+extern PropertyInfo css_devid_ro_propinfo;
+
+#define DEFINE_PROP_CSS_DEV_ID_RO(_n, _s, _f) \
+    DEFINE_PROP(_n, _s, _f, css_devid_ro_propinfo, CssDevId)
+
 /**
  * Create a subchannel for the given bus id.
  *
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 1434d15315..ce461cc905 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -376,12 +376,12 @@ static void cpu_model_from_info(S390CPUModel *model, const CpuModelInfo *info,
 
 static void qdict_add_disabled_feat(const char *name, void *opaque)
 {
-    qdict_put((QDict *) opaque, name, qbool_from_bool(false));
+    qdict_put(opaque, name, qbool_from_bool(false));
 }
 
 static void qdict_add_enabled_feat(const char *name, void *opaque)
 {
-    qdict_put((QDict *) opaque, name, qbool_from_bool(true));
+    qdict_put(opaque, name, qbool_from_bool(true));
 }
 
 /* convert S390CPUDef into a static CpuModelInfo */
diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
index ac47154b83..1a249d8359 100644
--- a/target/s390x/kvm.c
+++ b/target/s390x/kvm.c
@@ -47,16 +47,16 @@
 #include "exec/memattrs.h"
 #include "hw/s390x/s390-virtio-ccw.h"
 
-/* #define DEBUG_KVM */
-
-#ifdef DEBUG_KVM
-#define DPRINTF(fmt, ...) \
-    do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
-#else
-#define DPRINTF(fmt, ...) \
-    do { } while (0)
+#ifndef DEBUG_KVM
+#define DEBUG_KVM  0
 #endif
 
+#define DPRINTF(fmt, ...) do {                \
+    if (DEBUG_KVM) {                          \
+        fprintf(stderr, fmt, ## __VA_ARGS__); \
+    }                                         \
+} while (0);
+
 #define kvm_vm_check_mem_attr(s, attr) \
     kvm_vm_check_attr(s, KVM_S390_VM_MEM_CTRL, attr)