diff --git a/hw/intc/s390_flic.c b/hw/intc/s390_flic.c
index 7dc8c7d..2b56835 100644
--- a/hw/intc/s390_flic.c
+++ b/hw/intc/s390_flic.c
@@ -44,10 +44,26 @@ void s390_flic_init(void)
     }
 }
 
+static int qemu_s390_register_io_adapter(S390FLICState *fs, uint32_t id,
+                                         uint8_t isc, bool swap,
+                                         bool is_maskable)
+{
+    /* nothing to do */
+    return 0;
+}
+
+static void qemu_s390_flic_class_init(ObjectClass *oc, void *data)
+{
+    S390FLICStateClass *fsc = S390_FLIC_COMMON_CLASS(oc);
+
+    fsc->register_io_adapter = qemu_s390_register_io_adapter;
+}
+
 static const TypeInfo qemu_s390_flic_info = {
     .name          = TYPE_QEMU_S390_FLIC,
     .parent        = TYPE_S390_FLIC_COMMON,
     .instance_size = sizeof(QEMUS390FLICState),
+    .class_init    = qemu_s390_flic_class_init,
 };
 
 static const TypeInfo s390_flic_common_info = {
diff --git a/hw/intc/s390_flic_kvm.c b/hw/intc/s390_flic_kvm.c
index 70c1710..cc4072e 100644
--- a/hw/intc/s390_flic_kvm.c
+++ b/hw/intc/s390_flic_kvm.c
@@ -151,6 +151,33 @@ static int __get_all_irqs(KVMS390FLICState *flic,
     return r;
 }
 
+static int kvm_s390_register_io_adapter(S390FLICState *fs, uint32_t id,
+                                        uint8_t isc, bool swap,
+                                        bool is_maskable)
+{
+    struct kvm_s390_io_adapter adapter = {
+        .id = id,
+        .isc = isc,
+        .maskable = is_maskable,
+        .swap = swap,
+    };
+    KVMS390FLICState *flic = KVM_S390_FLIC(fs);
+    int r, ret;
+    struct kvm_device_attr attr = {
+        .group = KVM_DEV_FLIC_ADAPTER_REGISTER,
+        .addr = (uint64_t)&adapter,
+    };
+
+    if (!kvm_check_extension(kvm_state, KVM_CAP_IRQ_ROUTING)) {
+        return -ENOSYS;
+    }
+
+    r = ioctl(flic->fd, KVM_SET_DEVICE_ATTR, &attr);
+
+    ret = r ? -errno : 0;
+    return ret;
+}
+
 /**
  * kvm_flic_save - Save pending floating interrupts
  * @f: QEMUFile containing migration state
@@ -304,10 +331,12 @@ static void kvm_s390_flic_reset(DeviceState *dev)
 static void kvm_s390_flic_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
+    S390FLICStateClass *fsc = S390_FLIC_COMMON_CLASS(oc);
 
     dc->realize = kvm_s390_flic_realize;
     dc->unrealize = kvm_s390_flic_unrealize;
     dc->reset = kvm_s390_flic_reset;
+    fsc->register_io_adapter = kvm_s390_register_io_adapter;
 }
 
 static const TypeInfo kvm_s390_flic_info = {
diff --git a/hw/s390x/css.c b/hw/s390x/css.c
index 122cc7e..2678e44 100644
--- a/hw/s390x/css.c
+++ b/hw/s390x/css.c
@@ -16,6 +16,7 @@
 #include "ioinst.h"
 #include "css.h"
 #include "trace.h"
+#include "hw/s390x/s390_flic.h"
 
 typedef struct CrwContainer {
     CRW crw;
@@ -39,6 +40,13 @@ typedef struct CssImage {
     ChpInfo chpids[MAX_CHPID + 1];
 } CssImage;
 
+typedef struct IoAdapter {
+    uint32_t id;
+    uint8_t type;
+    uint8_t isc;
+    QTAILQ_ENTRY(IoAdapter) sibling;
+} IoAdapter;
+
 typedef struct ChannelSubSys {
     QTAILQ_HEAD(, CrwContainer) pending_crws;
     bool do_crw_mchk;
@@ -49,6 +57,7 @@ typedef struct ChannelSubSys {
     uint64_t chnmon_area;
     CssImage *css[MAX_CSSID + 1];
     uint8_t default_cssid;
+    QTAILQ_HEAD(, IoAdapter) io_adapters;
 } ChannelSubSys;
 
 static ChannelSubSys *channel_subsys;
@@ -69,6 +78,46 @@ 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)
+{
+    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;
+            break;
+        }
+        if (adapter->id >= *id) {
+            *id = adapter->id + 1;
+        }
+    }
+    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;
+}
+
 uint16_t css_build_subchannel_id(SubchDev *sch)
 {
     if (channel_subsys->max_cssid > 0) {
@@ -1235,6 +1284,7 @@ static void css_init(void)
     channel_subsys->do_crw_mchk = true;
     channel_subsys->crws_lost = false;
     channel_subsys->chnmon_active = false;
+    QTAILQ_INIT(&channel_subsys->io_adapters);
 }
 machine_init(css_init);
 
diff --git a/hw/s390x/css.h b/hw/s390x/css.h
index 220169e..6586106 100644
--- a/hw/s390x/css.h
+++ b/hw/s390x/css.h
@@ -98,4 +98,8 @@ void css_generate_sch_crws(uint8_t cssid, uint8_t ssid, uint16_t schid,
                            int hotplugged, int add);
 void css_generate_chp_crws(uint8_t cssid, uint8_t chpid);
 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);
 #endif
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 1cb4e2c..e3b7120 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -522,6 +522,10 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
                 dev->thinint_isc = thinint->isc;
                 dev->ind_bit = thinint->ind_bit;
                 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->adapter_id);
+                assert(ret == 0);
                 sch->thinint_active = ((dev->indicators != 0) &&
                                        (dev->summary_indicator != 0));
                 sch->curr_status.scsw.count = ccw.count - len;
diff --git a/hw/s390x/virtio-ccw.h b/hw/s390x/virtio-ccw.h
index 4393e44..0b70b91 100644
--- a/hw/s390x/virtio-ccw.h
+++ b/hw/s390x/virtio-ccw.h
@@ -85,6 +85,7 @@ struct VirtioCcwDevice {
     bool ioeventfd_disabled;
     uint32_t flags;
     uint8_t thinint_isc;
+    uint32_t adapter_id;
     /* Guest provided values: */
     hwaddr indicators;
     hwaddr indicators2;
diff --git a/include/hw/s390x/s390_flic.h b/include/hw/s390x/s390_flic.h
index 3bc60fd..83913ec 100644
--- a/include/hw/s390x/s390_flic.h
+++ b/include/hw/s390x/s390_flic.h
@@ -32,6 +32,8 @@ typedef struct S390FLICState {
 typedef struct S390FLICStateClass {
     DeviceClass parent_class;
 
+    int (*register_io_adapter)(S390FLICState *fs, uint32_t id, uint8_t isc,
+                               bool swap, bool maskable);
 } S390FLICStateClass;
 
 #define TYPE_KVM_S390_FLIC "s390-flic-kvm"
