diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 0cddb86b51..3da0079770 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -1742,6 +1742,7 @@ qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
 {
     bool addDefaultUSB = true;
     int usbModel = -1; /* "default for machinetype" */
+    int pciRoot;       /* index within def->controllers */
     bool addImplicitSATA = false;
     bool addPCIRoot = false;
     bool addPCIeRoot = false;
@@ -1833,14 +1834,26 @@ qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
             def, VIR_DOMAIN_CONTROLLER_TYPE_SATA, 0, -1) < 0)
         goto cleanup;
 
+    pciRoot = virDomainControllerFind(def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 0);
+
     /* NB: any machine that sets addPCIRoot to true must also return
      * true from the function qemuDomainSupportsPCI().
      */
-    if (addPCIRoot &&
-        virDomainDefMaybeAddController(
-            def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 0,
-            VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT) < 0)
-        goto cleanup;
+    if (addPCIRoot) {
+        if (pciRoot >= 0) {
+            if (def->controllers[pciRoot]->model != VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT) {
+                virReportError(VIR_ERR_XML_ERROR,
+                               _("The PCI controller with index='0' must be "
+                                 "model='pci-root' for this machine type, "
+                                 "but model='%s' was found instead"),
+                               virDomainControllerModelPCITypeToString(def->controllers[pciRoot]->model));
+                goto cleanup;
+            }
+        } else if (!virDomainDefAddController(def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 0,
+                                              VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT)) {
+            goto cleanup;
+        }
+    }
 
     /* When a machine has a pcie-root, make sure that there is always
      * a dmi-to-pci-bridge controller added as bus 1, and a pci-bridge
@@ -1850,15 +1863,25 @@ qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
      * true from the function qemuDomainSupportsPCI().
      */
     if (addPCIeRoot) {
+        if (pciRoot >= 0) {
+            if (def->controllers[pciRoot]->model != VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT) {
+                virReportError(VIR_ERR_XML_ERROR,
+                               _("The PCI controller with index='0' must be "
+                                 "model='pcie-root' for this machine type, "
+                                 "but model='%s' was found instead"),
+                               virDomainControllerModelPCITypeToString(def->controllers[pciRoot]->model));
+                goto cleanup;
+            }
+        } else if (!virDomainDefAddController(def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 0,
+                                             VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT)) {
+            goto cleanup;
+        }
         if (virDomainDefMaybeAddController(
-                def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 0,
-                VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT) < 0 ||
+               def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 1,
+               VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE) < 0 ||
             virDomainDefMaybeAddController(
-                def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 1,
-                VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE) < 0 ||
-            virDomainDefMaybeAddController(
-                def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 2,
-                VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE) < 0) {
+               def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 2,
+               VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE) < 0) {
             goto cleanup;
         }
     }
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-440fx-wrong-root.xml b/tests/qemuxml2argvdata/qemuxml2argv-440fx-wrong-root.xml
new file mode 100644
index 0000000000..93fef08214
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-440fx-wrong-root.xml
@@ -0,0 +1,28 @@
+<domain type='qemu'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <title>A description of the test machine.</title>
+  <description>
+      A test of qemu&apos;s minimal configuration.
+      This test also tests the description and title elements.
+  </description>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-kvm</emulator>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pcie-root'/>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='virtio'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-q35-wrong-root.xml b/tests/qemuxml2argvdata/qemuxml2argv-q35-wrong-root.xml
new file mode 100644
index 0000000000..836de52a0c
--- /dev/null
+++ b/tests/qemuxml2argvdata/qemuxml2argv-q35-wrong-root.xml
@@ -0,0 +1,27 @@
+<domain type='qemu'>
+  <name>q35-test</name>
+  <uuid>11dbdcdd-4c3b-482b-8903-9bdb8c0a2774</uuid>
+  <memory unit='KiB'>2097152</memory>
+  <currentMemory unit='KiB'>2097152</currentMemory>
+  <vcpu placement='static' cpuset='0-1'>2</vcpu>
+  <os>
+    <type arch='x86_64' machine='q35'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-kvm</emulator>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='pci' index='1' model='dmi-to-pci-bridge'>
+      <model name='i82801b11-bridge'/>
+    </controller>
+    <controller type='pci' index='2' model='pci-bridge'>
+      <model name='pci-bridge'/>
+      <target chassisNr='56'/>
+    </controller>
+    <memballoon model='none'/>
+  </devices>
+</domain>
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index e41444d2a4..d1cfbecb9a 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -1554,6 +1554,15 @@ mymain(void)
             QEMU_CAPS_DEVICE_VIDEO_PRIMARY,
             QEMU_CAPS_VGA_QXL, QEMU_CAPS_DEVICE_QXL);
 
+    DO_TEST_PARSE_ERROR("q35-wrong-root",
+            QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+            QEMU_CAPS_ICH9_AHCI,
+            QEMU_CAPS_PCI_MULTIFUNCTION, QEMU_CAPS_ICH9_USB_EHCI1,
+            QEMU_CAPS_DEVICE_VIDEO_PRIMARY,
+            QEMU_CAPS_VGA_QXL, QEMU_CAPS_DEVICE_QXL);
+    DO_TEST_PARSE_ERROR("440fx-wrong-root", NONE);
+
     DO_TEST_FAILURE("pcie-root-port-too-many",
             QEMU_CAPS_DEVICE_PCI_BRIDGE,
             QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,