diff --git a/hw/char/serial-pci.c b/hw/char/serial-pci.c
index 467c3b4f9ae733b29dc16419c56f5ae818bfcd34..653064fadf0852fe938a1769fd2e5e66371ac9c5 100644
--- a/hw/char/serial-pci.c
+++ b/hw/char/serial-pci.c
@@ -48,6 +48,8 @@ typedef struct PCIMultiSerialState {
     uint8_t      prog_if;
 } PCIMultiSerialState;
 
+static void multi_serial_pci_exit(PCIDevice *dev);
+
 static void serial_pci_realize(PCIDevice *dev, Error **errp)
 {
     PCISerialState *pci = DO_UPCAST(PCISerialState, dev, dev);
@@ -89,32 +91,33 @@ static void multi_serial_pci_realize(PCIDevice *dev, Error **errp)
     PCIMultiSerialState *pci = DO_UPCAST(PCIMultiSerialState, dev, dev);
     SerialState *s;
     Error *err = NULL;
-    int i;
+    int i, nr_ports = 0;
 
     switch (pc->device_id) {
     case 0x0003:
-        pci->ports = 2;
+        nr_ports = 2;
         break;
     case 0x0004:
-        pci->ports = 4;
+        nr_ports = 4;
         break;
     }
-    assert(pci->ports > 0);
-    assert(pci->ports <= PCI_SERIAL_MAX_PORTS);
+    assert(nr_ports > 0);
+    assert(nr_ports <= PCI_SERIAL_MAX_PORTS);
 
     pci->dev.config[PCI_CLASS_PROG] = pci->prog_if;
     pci->dev.config[PCI_INTERRUPT_PIN] = 0x01;
-    memory_region_init(&pci->iobar, OBJECT(pci), "multiserial", 8 * pci->ports);
+    memory_region_init(&pci->iobar, OBJECT(pci), "multiserial", 8 * nr_ports);
     pci_register_bar(&pci->dev, 0, PCI_BASE_ADDRESS_SPACE_IO, &pci->iobar);
     pci->irqs = qemu_allocate_irqs(multi_serial_irq_mux, pci,
-                                   pci->ports);
+                                   nr_ports);
 
-    for (i = 0; i < pci->ports; i++) {
+    for (i = 0; i < nr_ports; i++) {
         s = pci->state + i;
         s->baudbase = 115200;
         serial_realize_core(s, &err);
         if (err != NULL) {
             error_propagate(errp, err);
+            multi_serial_pci_exit(dev);
             return;
         }
         s->irq = pci->irqs[i];
@@ -122,6 +125,7 @@ static void multi_serial_pci_realize(PCIDevice *dev, Error **errp)
         memory_region_init_io(&s->io, OBJECT(pci), &serial_io_ops, s,
                               pci->name[i], 8);
         memory_region_add_subregion(&pci->iobar, 8 * i, &s->io);
+        pci->ports++;
     }
 }