diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index e393022917326bf7b3c1c53b586854e1ebd5d30e..0276694b005fdc4e3565678397667f8080254e52 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -342,7 +342,7 @@ static void pc_xen_hvm_init(QEMUMachineInitArgs *args)
 
     pc_init_pci(args);
 
-    bus = pci_find_root_bus(0);
+    bus = pci_find_primary_bus();
     if (bus != NULL) {
         pci_create_simple(bus, -1, "xen-platform");
     }
diff --git a/hw/pci/pci-hotplug-old.c b/hw/pci/pci-hotplug-old.c
index a0b5558789a72304208ae8981ade867154418c17..7a47d6b0f00bec955d0693746e8c4efeb251cfe6 100644
--- a/hw/pci/pci-hotplug-old.c
+++ b/hw/pci/pci-hotplug-old.c
@@ -36,17 +36,23 @@
 #include "sysemu/blockdev.h"
 #include "qapi/error.h"
 
-static int pci_read_devaddr(Monitor *mon, const char *addr, int *domp,
+static int pci_read_devaddr(Monitor *mon, const char *addr,
                             int *busp, unsigned *slotp)
 {
+    int dom;
+
     /* strip legacy tag */
     if (!strncmp(addr, "pci_addr=", 9)) {
         addr += 9;
     }
-    if (pci_parse_devaddr(addr, domp, busp, slotp, NULL)) {
+    if (pci_parse_devaddr(addr, &dom, busp, slotp, NULL)) {
         monitor_printf(mon, "Invalid pci address\n");
         return -1;
     }
+    if (dom != 0) {
+        monitor_printf(mon, "Multiple PCI domains not supported, use device_add\n");
+        return -1;
+    }
     return 0;
 }
 
@@ -128,18 +134,22 @@ static int scsi_hot_add(Monitor *mon, DeviceState *adapter,
 
 int pci_drive_hot_add(Monitor *mon, const QDict *qdict, DriveInfo *dinfo)
 {
-    int dom, pci_bus;
+    int pci_bus;
     unsigned slot;
+    PCIBus *root = pci_find_primary_bus();
     PCIDevice *dev;
     const char *pci_addr = qdict_get_str(qdict, "pci_addr");
 
     switch (dinfo->type) {
     case IF_SCSI:
-        if (pci_read_devaddr(mon, pci_addr, &dom, &pci_bus, &slot)) {
+        if (!root) {
+            monitor_printf(mon, "no primary PCI bus\n");
+            goto err;
+        }
+        if (pci_read_devaddr(mon, pci_addr, &pci_bus, &slot)) {
             goto err;
         }
-        dev = pci_find_device(pci_find_root_bus(dom), pci_bus,
-                              PCI_DEVFN(slot, 0));
+        dev = pci_find_device(root, pci_bus, PCI_DEVFN(slot, 0));
         if (!dev) {
             monitor_printf(mon, "no pci device with address %s\n", pci_addr);
             goto err;
@@ -275,16 +285,22 @@ void pci_device_hot_add(Monitor *mon, const QDict *qdict)
 
 static int pci_device_hot_remove(Monitor *mon, const char *pci_addr)
 {
+    PCIBus *root = pci_find_primary_bus();
     PCIDevice *d;
-    int dom, bus;
+    int bus;
     unsigned slot;
     Error *local_err = NULL;
 
-    if (pci_read_devaddr(mon, pci_addr, &dom, &bus, &slot)) {
+    if (!root) {
+        monitor_printf(mon, "no primary PCI bus\n");
+        return -1;
+    }
+
+    if (pci_read_devaddr(mon, pci_addr, &bus, &slot)) {
         return -1;
     }
 
-    d = pci_find_device(pci_find_root_bus(dom), bus, PCI_DEVFN(slot, 0));
+    d = pci_find_device(root, bus, PCI_DEVFN(slot, 0));
     if (!d) {
         monitor_printf(mon, "slot %d empty\n", slot);
         return -1;
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index adf4da5b95a6ebd1110be649cf94e7566e4adef8..fc99e3bf69bb5985cec6b34b67562d827b9a0d3e 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -246,12 +246,12 @@ static void pci_host_bus_register(int domain, PCIBus *bus)
     QLIST_INSERT_HEAD(&host_buses, host, next);
 }
 
-PCIBus *pci_find_root_bus(int domain)
+PCIBus *pci_find_primary_bus(void)
 {
     struct PCIHostBus *host;
 
     QLIST_FOREACH(host, &host_buses, next) {
-        if (host->domain == domain) {
+        if (host->domain == 0) {
             return host->bus;
         }
     }
@@ -583,20 +583,31 @@ int pci_parse_devaddr(const char *addr, int *domp, int *busp,
 
 PCIBus *pci_get_bus_devfn(int *devfnp, const char *devaddr)
 {
+    PCIBus *root = pci_find_primary_bus();
     int dom, bus;
     unsigned slot;
 
+    if (!root) {
+        fprintf(stderr, "No primary PCI bus\n");
+        return NULL;
+    }
+
     if (!devaddr) {
         *devfnp = -1;
-        return pci_find_bus_nr(pci_find_root_bus(0), 0);
+        return pci_find_bus_nr(root, 0);
     }
 
     if (pci_parse_devaddr(devaddr, &dom, &bus, &slot, NULL) < 0) {
         return NULL;
     }
 
+    if (dom != 0) {
+        fprintf(stderr, "No support for non-zero PCI domains\n");
+        return NULL;
+    }
+
     *devfnp = PCI_DEVFN(slot, 0);
-    return pci_find_bus_nr(pci_find_root_bus(dom), bus);
+    return pci_find_bus_nr(root, bus);
 }
 
 static void pci_init_cmask(PCIDevice *dev)
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index b5edef832ec4fe18ec068bed49b7ebb8fbc6f1a2..7b89d8810632aee550e4f6993c596bcafe9beed6 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -389,7 +389,7 @@ int pci_bus_num(PCIBus *s);
 void pci_for_each_device(PCIBus *bus, int bus_num,
                          void (*fn)(PCIBus *bus, PCIDevice *d, void *opaque),
                          void *opaque);
-PCIBus *pci_find_root_bus(int domain);
+PCIBus *pci_find_primary_bus(void);
 int pci_find_domain(const PCIBus *bus);
 PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn);
 int pci_qdev_find_device(const char *id, PCIDevice **pdev);