diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 11687e597a11..5a7ccbcc1b80 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -8823,15 +8823,13 @@ static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice *pci_dev)
     id->psd[0].enlat = cpu_to_le32(0x10);
     id->psd[0].exlat = cpu_to_le32(0x4);
 
-    if (n->subsys) {
-        id->cmic |= NVME_CMIC_MULTI_CTRL;
-        ctratt |= NVME_CTRATT_ENDGRPS;
+    id->cmic |= NVME_CMIC_MULTI_CTRL;
+    ctratt |= NVME_CTRATT_ENDGRPS;
 
-        id->endgidmax = cpu_to_le16(0x1);
+    id->endgidmax = cpu_to_le16(0x1);
 
-        if (n->subsys->endgrp.fdp.enabled) {
-            ctratt |= NVME_CTRATT_FDPS;
-        }
+    if (n->subsys->endgrp.fdp.enabled) {
+        ctratt |= NVME_CTRATT_FDPS;
     }
 
     id->ctratt = cpu_to_le32(ctratt);
@@ -8860,7 +8858,15 @@ static int nvme_init_subsys(NvmeCtrl *n, Error **errp)
     int cntlid;
 
     if (!n->subsys) {
-        return 0;
+        DeviceState *dev = qdev_new(TYPE_NVME_SUBSYS);
+
+        qdev_prop_set_string(dev, "nqn", n->params.serial);
+
+        if (!qdev_realize(dev, NULL, errp)) {
+            return -1;
+        }
+
+        n->subsys = NVME_SUBSYS(dev);
     }
 
     cntlid = nvme_subsys_register_ctrl(n, errp);
@@ -8950,17 +8956,15 @@ static void nvme_exit(PCIDevice *pci_dev)
 
     nvme_ctrl_reset(n, NVME_RESET_FUNCTION);
 
-    if (n->subsys) {
-        for (i = 1; i <= NVME_MAX_NAMESPACES; i++) {
-            ns = nvme_ns(n, i);
-            if (ns) {
-                ns->attached--;
-            }
+    for (i = 1; i <= NVME_MAX_NAMESPACES; i++) {
+        ns = nvme_ns(n, i);
+        if (ns) {
+            ns->attached--;
         }
-
-        nvme_subsys_unregister_ctrl(n->subsys, n);
     }
 
+    nvme_subsys_unregister_ctrl(n->subsys, n);
+
     g_free(n->cq);
     g_free(n->sq);
     g_free(n->aer_reqs);
diff --git a/hw/nvme/ns.c b/hw/nvme/ns.c
index 410df2959192..94cabc6a5b8d 100644
--- a/hw/nvme/ns.c
+++ b/hw/nvme/ns.c
@@ -727,25 +727,14 @@ static void nvme_ns_realize(DeviceState *dev, Error **errp)
     uint32_t nsid = ns->params.nsid;
     int i;
 
-    if (!n->subsys) {
-        /* If no subsys, the ns cannot be attached to more than one ctrl. */
-        ns->params.shared = false;
-        if (ns->params.detached) {
-            error_setg(errp, "detached requires that the nvme device is "
-                       "linked to an nvme-subsys device");
-            return;
-        }
-    } else {
-        /*
-         * If this namespace belongs to a subsystem (through a link on the
-         * controller device), reparent the device.
-         */
-        if (!qdev_set_parent_bus(dev, &subsys->bus.parent_bus, errp)) {
-            return;
-        }
-        ns->subsys = subsys;
-        ns->endgrp = &subsys->endgrp;
+    assert(subsys);
+
+    /* reparent to subsystem bus */
+    if (!qdev_set_parent_bus(dev, &subsys->bus.parent_bus, errp)) {
+        return;
     }
+    ns->subsys = subsys;
+    ns->endgrp = &subsys->endgrp;
 
     if (nvme_ns_setup(ns, errp)) {
         return;
@@ -753,7 +742,7 @@ static void nvme_ns_realize(DeviceState *dev, Error **errp)
 
     if (!nsid) {
         for (i = 1; i <= NVME_MAX_NAMESPACES; i++) {
-            if (nvme_ns(n, i) || nvme_subsys_ns(subsys, i)) {
+            if (nvme_subsys_ns(subsys, i)) {
                 continue;
             }
 
@@ -765,38 +754,29 @@ static void nvme_ns_realize(DeviceState *dev, Error **errp)
             error_setg(errp, "no free namespace id");
             return;
         }
-    } else {
-        if (nvme_ns(n, nsid) || nvme_subsys_ns(subsys, nsid)) {
-            error_setg(errp, "namespace id '%d' already allocated", nsid);
-            return;
-        }
+    } else if (nvme_subsys_ns(subsys, nsid)) {
+        error_setg(errp, "namespace id '%d' already allocated", nsid);
+        return;
     }
 
-    if (subsys) {
-        subsys->namespaces[nsid] = ns;
+    subsys->namespaces[nsid] = ns;
 
-        ns->id_ns.endgid = cpu_to_le16(0x1);
-        ns->id_ns_ind.endgrpid = cpu_to_le16(0x1);
+    ns->id_ns.endgid = cpu_to_le16(0x1);
+    ns->id_ns_ind.endgrpid = cpu_to_le16(0x1);
 
-        if (ns->params.detached) {
-            return;
-        }
+    if (ns->params.detached) {
+        return;
+    }
 
-        if (ns->params.shared) {
-            for (i = 0; i < ARRAY_SIZE(subsys->ctrls); i++) {
-                NvmeCtrl *ctrl = subsys->ctrls[i];
+    if (ns->params.shared) {
+        for (i = 0; i < ARRAY_SIZE(subsys->ctrls); i++) {
+            NvmeCtrl *ctrl = subsys->ctrls[i];
 
-                if (ctrl && ctrl != SUBSYS_SLOT_RSVD) {
-                    nvme_attach_ns(ctrl, ns);
-                }
+            if (ctrl && ctrl != SUBSYS_SLOT_RSVD) {
+                nvme_attach_ns(ctrl, ns);
             }
-
-            return;
         }
-
     }
-
-    nvme_attach_ns(n, ns);
 }
 
 static const Property nvme_ns_props[] = {
