diff --git a/hw/cxl/cxl-host-stubs.c b/hw/cxl/cxl-host-stubs.c
index e0d5ec8ad5..cae4afcdde 100644
--- a/hw/cxl/cxl-host-stubs.c
+++ b/hw/cxl/cxl-host-stubs.c
@@ -10,5 +10,6 @@
 
 void cxl_fmws_link_targets(CXLState *stat, Error **errp) {};
 void cxl_machine_init(Object *obj, CXLState *state) {};
+void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp) {};
 
 const MemoryRegionOps cfmws_ops;
diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c
index 8e7738a65b..efa14908d8 100644
--- a/hw/cxl/cxl-host.c
+++ b/hw/cxl/cxl-host.c
@@ -20,6 +20,7 @@
 #include "hw/pci/pci_bridge.h"
 #include "hw/pci/pci_host.h"
 #include "hw/pci/pcie_port.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
 
 static void cxl_fixed_memory_window_config(CXLState *cxl_state,
                                            CXLFixedMemoryWindowOptions *object,
@@ -280,3 +281,22 @@ void cxl_machine_init(Object *obj, CXLState *state)
     object_property_set_description(obj, "cxl-fmw",
                                     "CXL Fixed Memory Windows (array)");
 }
+
+void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp)
+{
+    /* Walk the pci busses looking for pxb busses to hook up */
+    if (bus) {
+        QLIST_FOREACH(bus, &bus->child, sibling) {
+            if (!pci_bus_is_root(bus)) {
+                continue;
+            }
+            if (pci_bus_is_cxl(bus)) {
+                if (!state->is_enabled) {
+                    error_setg(errp, "CXL host bridges present, but cxl=off");
+                    return;
+                }
+                pxb_cxl_hook_up_registers(state, bus, errp);
+            }
+        }
+    }
+}
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 6cecd74d58..9f48d02739 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -37,6 +37,7 @@
 #include "hw/ide.h"
 #include "hw/pci/pci.h"
 #include "hw/pci/pci_bus.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
 #include "hw/nvram/fw_cfg.h"
 #include "hw/timer/hpet.h"
 #include "hw/firmware/smbios.h"
@@ -735,6 +736,8 @@ void pc_machine_done(Notifier *notifier, void *data)
     MachineState *ms = MACHINE(pcms);
 
     if (ms->cxl_devices_state) {
+        cxl_hook_up_pxb_registers(pcms->bus, ms->cxl_devices_state,
+                                  &error_fatal);
         cxl_fmws_link_targets(ms->cxl_devices_state, &error_fatal);
     }
 
diff --git a/hw/pci-bridge/meson.build b/hw/pci-bridge/meson.build
index b6d26a03d5..fdbe2e07c5 100644
--- a/hw/pci-bridge/meson.build
+++ b/hw/pci-bridge/meson.build
@@ -3,7 +3,8 @@ pci_ss.add(files('pci_bridge_dev.c'))
 pci_ss.add(when: 'CONFIG_I82801B11', if_true: files('i82801b11.c'))
 pci_ss.add(when: 'CONFIG_IOH3420', if_true: files('ioh3420.c'))
 pci_ss.add(when: 'CONFIG_PCIE_PORT', if_true: files('pcie_root_port.c', 'gen_pcie_root_port.c', 'pcie_pci_bridge.c'))
-pci_ss.add(when: 'CONFIG_PXB', if_true: files('pci_expander_bridge.c'))
+pci_ss.add(when: 'CONFIG_PXB', if_true: files('pci_expander_bridge.c'),
+                               if_false: files('pci_expander_bridge_stubs.c'))
 pci_ss.add(when: 'CONFIG_XIO3130', if_true: files('xio3130_upstream.c', 'xio3130_downstream.c'))
 pci_ss.add(when: 'CONFIG_CXL', if_true: files('cxl_root_port.c'))
 
@@ -13,3 +14,5 @@ pci_ss.add(when: 'CONFIG_DEC_PCI', if_true: files('dec.c'))
 pci_ss.add(when: 'CONFIG_SIMBA', if_true: files('simba.c'))
 
 softmmu_ss.add_all(when: 'CONFIG_PCI', if_true: pci_ss)
+
+softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('pci_expander_bridge_stubs.c'))
diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
index 02032360f5..c9e817aa58 100644
--- a/hw/pci-bridge/pci_expander_bridge.c
+++ b/hw/pci-bridge/pci_expander_bridge.c
@@ -17,6 +17,7 @@
 #include "hw/pci/pci_host.h"
 #include "hw/qdev-properties.h"
 #include "hw/pci/pci_bridge.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
 #include "hw/cxl/cxl.h"
 #include "qemu/range.h"
 #include "qemu/error-report.h"
@@ -186,25 +187,38 @@ static const TypeInfo pxb_host_info = {
 
 static void pxb_cxl_realize(DeviceState *dev, Error **errp)
 {
-    MachineState *ms = MACHINE(qdev_get_machine());
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     CXLHost *cxl = PXB_CXL_HOST(dev);
     CXLComponentState *cxl_cstate = &cxl->cxl_cstate;
     struct MemoryRegion *mr = &cxl_cstate->crb.component_registers;
-    hwaddr offset;
 
     cxl_component_register_block_init(OBJECT(dev), cxl_cstate,
                                       TYPE_PXB_CXL_HOST);
     sysbus_init_mmio(sbd, mr);
+}
 
-    offset = memory_region_size(mr) * ms->cxl_devices_state->next_mr_idx;
-    if (offset > memory_region_size(&ms->cxl_devices_state->host_mr)) {
+/*
+ * Host bridge realization has no means of knowning state associated
+ * with a particular machine. As such, it is nececssary to delay
+ * final setup of the host bridge register space until later in the
+ * machine bring up.
+ */
+void pxb_cxl_hook_up_registers(CXLState *cxl_state, PCIBus *bus, Error **errp)
+{
+    PXBDev *pxb =  PXB_CXL_DEV(pci_bridge_get_device(bus));
+    CXLHost *cxl = pxb->cxl.cxl_host_bridge;
+    CXLComponentState *cxl_cstate = &cxl->cxl_cstate;
+    struct MemoryRegion *mr = &cxl_cstate->crb.component_registers;
+    hwaddr offset;
+
+    offset = memory_region_size(mr) * cxl_state->next_mr_idx;
+    if (offset > memory_region_size(&cxl_state->host_mr)) {
         error_setg(errp, "Insufficient space for pxb cxl host register space");
         return;
     }
 
-    memory_region_add_subregion(&ms->cxl_devices_state->host_mr, offset, mr);
-    ms->cxl_devices_state->next_mr_idx++;
+    memory_region_add_subregion(&cxl_state->host_mr, offset, mr);
+    cxl_state->next_mr_idx++;
 }
 
 static void pxb_cxl_host_class_init(ObjectClass *class, void *data)
@@ -461,17 +475,11 @@ static const TypeInfo pxb_pcie_dev_info = {
 
 static void pxb_cxl_dev_realize(PCIDevice *dev, Error **errp)
 {
-    MachineState *ms = MACHINE(qdev_get_machine());
-
     /* A CXL PXB's parent bus is still PCIe */
     if (!pci_bus_is_express(pci_get_bus(dev))) {
         error_setg(errp, "pxb-cxl devices cannot reside on a PCI bus");
         return;
     }
-    if (!ms->cxl_devices_state || !ms->cxl_devices_state->is_enabled) {
-        error_setg(errp, "Machine does not have cxl=on");
-        return;
-    }
 
     pxb_dev_realize_common(dev, CXL, errp);
     pxb_dev_reset(DEVICE(dev));
diff --git a/hw/pci-bridge/pci_expander_bridge_stubs.c b/hw/pci-bridge/pci_expander_bridge_stubs.c
new file mode 100644
index 0000000000..b35180311f
--- /dev/null
+++ b/hw/pci-bridge/pci_expander_bridge_stubs.c
@@ -0,0 +1,14 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * Stubs for calls made from machines to handle the case where CONFIG_PXB
+ * is not enabled.
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
+#include "hw/cxl/cxl.h"
+
+void pxb_cxl_hook_up_registers(CXLState *state, PCIBus *bus, Error **errp) {};
diff --git a/include/hw/cxl/cxl_host.h b/include/hw/cxl/cxl_host.h
index 4d642a81fa..a1b662ce40 100644
--- a/include/hw/cxl/cxl_host.h
+++ b/include/hw/cxl/cxl_host.h
@@ -16,6 +16,7 @@
 
 void cxl_machine_init(Object *obj, CXLState *state);
 void cxl_fmws_link_targets(CXLState *stat, Error **errp);
+void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp);
 
 extern const MemoryRegionOps cfmws_ops;
 
diff --git a/include/hw/pci-bridge/pci_expander_bridge.h b/include/hw/pci-bridge/pci_expander_bridge.h
new file mode 100644
index 0000000000..0b3856d615
--- /dev/null
+++ b/include/hw/pci-bridge/pci_expander_bridge.h
@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef PCI_EXPANDER_BRIDGE_H
+#define PCI_EXPANDER_BRIDGE_H
+
+#include "hw/cxl/cxl.h"
+
+void pxb_cxl_hook_up_registers(CXLState *state, PCIBus *bus, Error **errp);
+
+#endif /* PCI_EXPANDER_BRIDGE_H */