qemu: support new pci controller model "pci-expander-bus"

This is backed by the qemu device "pxb".

The pxb device always includes a pci-bridge that is at the bus number
of the pxb + 1.

busNr and <node> from the <target> subelement are used to set the
bus_nr and numa_node options for pxb.

During post-parse we validate that the domain's machinetype is
440fx-based (since the pxb device only works on 440fx-based machines),
and <node> also gets a sanity check to assure that the NUMA node
specified for the pxb (if any - it's optional) actually exists on the
guest.

src/qemu/qemu_command.c

@@ -2364,6 +2364,43 @@ qemuBuildControllerDevStr(const virDomainDef *domainDef,
                               modelName, def->opts.pciopts.chassisNr,
                               def->info.alias);
             break;
+        case VIR_DOMAIN_CONTROLLER_MODEL_PCI_EXPANDER_BUS:
+            if (def->opts.pciopts.modelName
+                == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE ||
+                def->opts.pciopts.busNr == -1) {
+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                               _("autogenerated pci-expander-bus options not set"));
+                goto error;
+            }
+
+            modelName = virDomainControllerPCIModelNameTypeToString(def->opts.pciopts.modelName);
+            if (!modelName) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("unknown pci-expander-bus model name value %d"),
+                               def->opts.pciopts.modelName);
+                goto error;
+            }
+            if (def->opts.pciopts.modelName
+                != VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_PXB) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("PCI controller model name '%s' "
+                                 "is not valid for a pci-expander-bus"),
+                               modelName);
+                goto error;
+            }
+            if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_PXB)) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                               _("the pxb controller "
+                                 "is not supported in this QEMU binary"));
+                goto error;
+            }
+            virBufferAsprintf(&buf, "%s,bus_nr=%d,id=%s",
+                              modelName, def->opts.pciopts.busNr,
+                              def->info.alias);
+            if (def->opts.pciopts.numaNode != -1)
+               virBufferAsprintf(&buf, ",numa_node=%d",
+                                 def->opts.pciopts.numaNode);
+            break;
         case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
             if (def->opts.pciopts.modelName
                 == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE) {

src/qemu/qemu_domain.c

@@ -1887,6 +1887,39 @@ qemuDomainDeviceDefPostParse(virDomainDeviceDefPtr dev,
             dev->data.panic->model = VIR_DOMAIN_PANIC_MODEL_ISA;
     }
 
+
+    if (dev->type == VIR_DOMAIN_DEVICE_CONTROLLER) {
+        virDomainControllerDefPtr cont = dev->data.controller;
+
+        if (cont->type == VIR_DOMAIN_CONTROLLER_TYPE_PCI &&
+            cont->model == VIR_DOMAIN_CONTROLLER_MODEL_PCI_EXPANDER_BUS) {
+
+            if (!qemuDomainMachineIsI440FX(def)) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                               _("pci-expander-bus controllers are only supported "
+                                 "on 440fx-based machinetypes"));
+                goto cleanup;
+            }
+
+            /* if a PCI expander bus has a NUMA node set, make sure
+             * that NUMA node is configured in the guest <cpu><numa>
+             * array. NUMA cell id's in this array are numbered
+             * from 0 .. size-1.
+             */
+            if ((int) virDomainNumaGetNodeCount(def->numa)
+                <= cont->opts.pciopts.numaNode) {
+                virReportError(VIR_ERR_XML_ERROR,
+                               _("pci-expander-bus with index %d is "
+                                 "configured for a NUMA node (%d) "
+                                 "not present in the domain's "
+                                 "<cpu><numa> array (%zu)"),
+                               cont->idx, cont->opts.pciopts.numaNode,
+                               virDomainNumaGetNodeCount(def->numa));
+                goto cleanup;
+            }
+        }
+    }
+
     ret = 0;
 
  cleanup:

src/qemu/qemu_domain_address.c

@@ -1373,6 +1373,8 @@ qemuDomainPCIControllerSetDefaultModelName(virDomainControllerDefPtr cont)
         *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_XIO3130_DOWNSTREAM;
         break;
     case VIR_DOMAIN_CONTROLLER_MODEL_PCI_EXPANDER_BUS:
+        *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_PXB;
+        break;
     case VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT:
     case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT:
     case VIR_DOMAIN_CONTROLLER_MODEL_PCI_LAST:
@@ -1381,6 +1383,74 @@ qemuDomainPCIControllerSetDefaultModelName(virDomainControllerDefPtr cont)
 }
 
 
+static int
+qemuDomainAddressFindNewBusNr(virDomainDefPtr def)
+{
+/* Try to find a nice default for busNr for a new pci-expander-bus.
+ * This is a bit tricky, since you need to satisfy the following:
+ *
+ * 1) There need to be enough unused bus numbers between busNr of this
+ *    bus and busNr of the next highest bus for the guest to assign a
+ *    unique bus number to each PCI bus that is a child of this
+ *    bus. Each PCI controller. On top of this, the pxb device (which
+ *    implements the pci-extender-bus) includes a pci-bridge within
+ *    it, and that bridge also uses one bus number (so each pxb device
+ *    requires at least 2 bus numbers).
+ *
+ * 2) There need to be enough bus numbers *below* this for all the
+ *    child controllers of the pci-expander-bus with the next lower
+ *    busNr (or the pci-root bus if there are no lower
+ *    pci-expander-buses).
+ *
+ * 3) If at all possible, we want to avoid needing to change the busNr
+ *    of a bus in the future, as that changes the guest's device ABI,
+ *    which could potentially lead to issues with a guest OS that is
+ *    picky about such things.
+ *
+ *  Due to the impossibility of predicting what might be added to the
+ *  config in the future, we can't make a foolproof choice, but since
+ *  a pci-expander-bus (pxb) has slots for 32 devices, and the only
+ *  practical use for it is to assign real devices on a particular
+ *  NUMA node in the host, it's reasonably safe to assume it should
+ *  never need any additional child buses (probably only a few of the
+ *  32 will ever be used). So for pci-expander-bus we find the lowest
+ *  existing busNr, and set this one to the current lowest - 2 (one
+ *  for the pxb, one for the intergrated pci-bridge), thus leaving the
+ *  maximum possible bus numbers available for other buses plugged
+ *  into pci-root (i.e. pci-bridges and other
+ *  pci-expander-buses). Anyone who needs more than 32 devices
+ *  descended from one pci-expander-bus should set the busNr manually
+ *  in the config.
+ *
+ *  There is room for more error checking here - in particular we
+ *  can/should determine the ultimate parent (root-bus) of each PCI
+ *  controller and determine if there is enough space for all the
+ *  buses within the current range allotted to the bus just prior to
+ *  this one.
+ */
+    size_t i;
+    int lowestBusNr = 256;
+
+    for (i = 0; i < def->ncontrollers; i++) {
+        if (def->controllers[i]->type == VIR_DOMAIN_CONTROLLER_TYPE_PCI) {
+            int thisBusNr = def->controllers[i]->opts.pciopts.busNr;
+
+            if (thisBusNr >= 0 && thisBusNr < lowestBusNr)
+                lowestBusNr = thisBusNr;
+        }
+    }
+
+    /* If we already have a busNR = 1, then we can't auto-assign (0 is
+     * the pci[e]-root, and the others may have been assigned
+     * purposefully).
+     */
+    if (lowestBusNr <= 2)
+        return -1;
+
+    return lowestBusNr - 2;
+}
+
+
 static int
 qemuDomainAssignPCIAddresses(virDomainDefPtr def,
                              virQEMUCapsPtr qemuCaps,
@@ -1509,6 +1579,18 @@ qemuDomainAssignPCIAddresses(virDomainDefPtr def,
                        options->port = addr->slot;
                     break;
                 case VIR_DOMAIN_CONTROLLER_MODEL_PCI_EXPANDER_BUS:
+                    if (options->busNr == -1)
+                        options->busNr = qemuDomainAddressFindNewBusNr(def);
+                    if (options->busNr == -1) {
+                        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                       _("No free busNr lower than current "
+                                         "lowest busNr is available to "
+                                         "auto-assign to bus %d. Must be "
+                                         "manually assigned"),
+                                       addr->bus);
+                        goto cleanup;
+                    }
+                    break;
                 case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
                 case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_SWITCH_UPSTREAM_PORT:
                 case VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT:

tests/qemuxml2argvdata/qemuxml2argv-pci-expander-bus-bad-machine.xml

+<domain type='qemu'>
+  <name>expander-test</name>
+  <uuid>3ec6cbe1-b5a2-4515-b800-31a61855df41</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>16</vcpu>
+  <os>
+    <type arch='x86_64' machine='q35'>hvm</type>
+  </os>
+  <cpu>
+    <topology sockets='2' cores='4' threads='2'/>
+    <numa>
+      <cell cpus='0-7' memory='109550' unit='KiB'/>
+      <cell cpus='8-15' memory='109550' unit='KiB'/>
+    </numa>
+  </cpu>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <controller type='usb' index='0' model='none'/>
+    <controller type='ide' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='pci' index='1' model='pci-expander-bus'>
+      <model name='pxb'/>
+      <target busNr='254'>
+        <node>1</node>
+      </target>
+    </controller>
+    <controller type='pci' index='2' model='pci-expander-bus'>
+      <model name='pxb'/>
+    </controller>
+    <interface type='user'>
+      <mac address='52:54:00:f1:95:51'/>
+      <model type='rtl8139'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:5c:c6:1a'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:39:97:ac'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:45:28:cb'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:ee:b9:a8'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:a9:f7:17'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:df:2b:f3'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:78:94:b4'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:6b:9b:06'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:17:df:bc'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:3b:d0:51'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:8d:2d:17'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:a7:66:af'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:54:ab:d7'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:1f:99:90'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:c8:43:87'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:df:22:b2'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:d2:9a:47'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:86:05:e2'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:8c:1c:c2'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:48:58:92'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:99:e5:bf'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:b1:8c:25'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:60:e0:d0'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:37:00:6a'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:c7:c8:ad'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:4e:a7:cf'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:00:79:69'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:47:00:6f'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:2a:8c:8b'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:ec:d5:e3'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:7e:6e:c8'/>
+      <model type='e1000'/>
+    </interface>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
+    </memballoon>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-pci-expander-bus-bad-node.xml

+<domain type='qemu'>
+  <name>expander-test</name>
+  <uuid>3ec6cbe1-b5a2-4515-b800-31a61855df41</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>16</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-i440fx-2.5'>hvm</type>
+  </os>
+  <devices>
+    <emulator>/usr/bin/qemu-system-x86_64</emulator>
+    <controller type='usb' index='0' model='none'/>
+    <controller type='ide' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
+    </controller>
+    <controller type='pci' index='0' model='pci-root'/>
+    <controller type='pci' index='1' model='pci-expander-bus'>
+      <model name='pxb'/>
+      <target busNr='254'>
+        <node>1</node>
+      </target>
+    </controller>
+    <controller type='pci' index='2' model='pci-expander-bus'>
+      <model name='pxb'/>
+    </controller>
+    <interface type='user'>
+      <mac address='52:54:00:f1:95:51'/>
+      <model type='rtl8139'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:5c:c6:1a'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:39:97:ac'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:45:28:cb'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:ee:b9:a8'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:a9:f7:17'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:df:2b:f3'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:78:94:b4'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:6b:9b:06'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:17:df:bc'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:3b:d0:51'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:8d:2d:17'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:a7:66:af'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:54:ab:d7'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:1f:99:90'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:c8:43:87'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:df:22:b2'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:d2:9a:47'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:86:05:e2'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:8c:1c:c2'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:48:58:92'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:99:e5:bf'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:b1:8c:25'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:60:e0:d0'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:37:00:6a'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:c7:c8:ad'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:4e:a7:cf'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:00:79:69'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:47:00:6f'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:2a:8c:8b'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:ec:d5:e3'/>
+      <model type='e1000'/>
+    </interface>
+    <interface type='user'>
+      <mac address='52:54:00:7e:6e:c8'/>
+      <model type='e1000'/>
+    </interface>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
+    </memballoon>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-pci-expander-bus.args

+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/bin/qemu-system-x86_64 \
+-name expander-test \
+-S \
+-M pc-i440fx-2.5 \
+-m 214 \
+-smp 16 \
+-numa node,nodeid=0,cpus=0-7,mem=107 \
+-numa node,nodeid=1,cpus=8-15,mem=107 \
+-uuid 3ec6cbe1-b5a2-4515-b800-31a61855df41 \
+-nographic \
+-nodefaults \
+-monitor unix:/tmp/lib/domain--1-expander-test/monitor.sock,server,nowait \
+-no-acpi \
+-boot c \
+-device pxb,bus_nr=254,id=pci.1,numa_node=1,bus=pci.0,addr=0x3 \
+-device pxb,bus_nr=252,id=pci.2,bus=pci.0,addr=0x4 \
+-device rtl8139,vlan=0,id=net0,mac=52:54:00:f1:95:51,bus=pci.0,addr=0x5 \
+-net user,vlan=0,name=hostnet0 \
+-device e1000,vlan=1,id=net1,mac=52:54:00:5c:c6:1a,bus=pci.0,addr=0x7 \
+-net user,vlan=1,name=hostnet1 \
+-device e1000,vlan=2,id=net2,mac=52:54:00:39:97:ac,bus=pci.0,addr=0x8 \
+-net user,vlan=2,name=hostnet2 \
+-device e1000,vlan=3,id=net3,mac=52:54:00:45:28:cb,bus=pci.0,addr=0x9 \
+-net user,vlan=3,name=hostnet3 \
+-device e1000,vlan=4,id=net4,mac=52:54:00:ee:b9:a8,bus=pci.0,addr=0xa \
+-net user,vlan=4,name=hostnet4 \
+-device e1000,vlan=5,id=net5,mac=52:54:00:a9:f7:17,bus=pci.0,addr=0xb \
+-net user,vlan=5,name=hostnet5 \
+-device e1000,vlan=6,id=net6,mac=52:54:00:df:2b:f3,bus=pci.0,addr=0xc \
+-net user,vlan=6,name=hostnet6 \
+-device e1000,vlan=7,id=net7,mac=52:54:00:78:94:b4,bus=pci.0,addr=0xd \
+-net user,vlan=7,name=hostnet7 \
+-device e1000,vlan=8,id=net8,mac=52:54:00:6b:9b:06,bus=pci.0,addr=0xe \
+-net user,vlan=8,name=hostnet8 \
+-device e1000,vlan=9,id=net9,mac=52:54:00:17:df:bc,bus=pci.0,addr=0xf \
+-net user,vlan=9,name=hostnet9 \
+-device e1000,vlan=10,id=net10,mac=52:54:00:3b:d0:51,bus=pci.0,addr=0x10 \
+-net user,vlan=10,name=hostnet10 \
+-device e1000,vlan=11,id=net11,mac=52:54:00:8d:2d:17,bus=pci.0,addr=0x11 \
+-net user,vlan=11,name=hostnet11 \
+-device e1000,vlan=12,id=net12,mac=52:54:00:a7:66:af,bus=pci.0,addr=0x12 \
+-net user,vlan=12,name=hostnet12 \
+-device e1000,vlan=13,id=net13,mac=52:54:00:54:ab:d7,bus=pci.0,addr=0x13 \
+-net user,vlan=13,name=hostnet13 \
+-device e1000,vlan=14,id=net14,mac=52:54:00:1f:99:90,bus=pci.0,addr=0x14 \
+-net user,vlan=14,name=hostnet14 \
+-device e1000,vlan=15,id=net15,mac=52:54:00:c8:43:87,bus=pci.0,addr=0x15 \
+-net user,vlan=15,name=hostnet15 \
+-device e1000,vlan=16,id=net16,mac=52:54:00:df:22:b2,bus=pci.0,addr=0x16 \
+-net user,vlan=16,name=hostnet16 \
+-device e1000,vlan=17,id=net17,mac=52:54:00:d2:9a:47,bus=pci.0,addr=0x17 \
+-net user,vlan=17,name=hostnet17 \
+-device e1000,vlan=18,id=net18,mac=52:54:00:86:05:e2,bus=pci.0,addr=0x18 \
+-net user,vlan=18,name=hostnet18 \
+-device e1000,vlan=19,id=net19,mac=52:54:00:8c:1c:c2,bus=pci.0,addr=0x19 \
+-net user,vlan=19,name=hostnet19 \
+-device e1000,vlan=20,id=net20,mac=52:54:00:48:58:92,bus=pci.0,addr=0x1a \
+-net user,vlan=20,name=hostnet20 \
+-device e1000,vlan=21,id=net21,mac=52:54:00:99:e5:bf,bus=pci.0,addr=0x1b \
+-net user,vlan=21,name=hostnet21 \
+-device e1000,vlan=22,id=net22,mac=52:54:00:b1:8c:25,bus=pci.0,addr=0x1c \
+-net user,vlan=22,name=hostnet22 \
+-device e1000,vlan=23,id=net23,mac=52:54:00:60:e0:d0,bus=pci.0,addr=0x1d \
+-net user,vlan=23,name=hostnet23 \
+-device e1000,vlan=24,id=net24,mac=52:54:00:37:00:6a,bus=pci.0,addr=0x1e \
+-net user,vlan=24,name=hostnet24 \
+-device e1000,vlan=25,id=net25,mac=52:54:00:c7:c8:ad,bus=pci.0,addr=0x1f \
+-net user,vlan=25,name=hostnet25 \
+-device e1000,vlan=26,id=net26,mac=52:54:00:4e:a7:cf,bus=pci.1,addr=0x0 \
+-net user,vlan=26,name=hostnet26 \
+-device e1000,vlan=27,id=net27,mac=52:54:00:00:79:69,bus=pci.1,addr=0x1 \
+-net user,vlan=27,name=hostnet27 \
+-device e1000,vlan=28,id=net28,mac=52:54:00:47:00:6f,bus=pci.1,addr=0x2 \
+-net user,vlan=28,name=hostnet28 \
+-device e1000,vlan=29,id=net29,mac=52:54:00:2a:8c:8b,bus=pci.1,addr=0x3 \
+-net user,vlan=29,name=hostnet29 \
+-device e1000,vlan=30,id=net30,mac=52:54:00:ec:d5:e3,bus=pci.1,addr=0x4 \
+-net user,vlan=30,name=hostnet30 \
+-device e1000,vlan=31,id=net31,mac=52:54:00:7e:6e:c8,bus=pci.1,addr=0x5 \
+-net user,vlan=31,name=hostnet31 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6

tests/qemuxml2argvtest.c

@@ -1562,6 +1562,16 @@ mymain(void)
             QEMU_CAPS_DEVICE_VIDEO_PRIMARY,
             QEMU_CAPS_VGA_QXL, QEMU_CAPS_DEVICE_QXL);
 
+    DO_TEST("pci-expander-bus",
+            QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_PXB);
+    DO_TEST_PARSE_ERROR("pci-expander-bus-bad-node",
+                        QEMU_CAPS_DEVICE_PCI_BRIDGE,
+                        QEMU_CAPS_DEVICE_PXB);
+    DO_TEST_PARSE_ERROR("pci-expander-bus-bad-machine",
+                        QEMU_CAPS_DEVICE_PCI_BRIDGE,
+                        QEMU_CAPS_DEVICE_PXB);
+
     DO_TEST("hostdev-scsi-lsi",
             QEMU_CAPS_VIRTIO_SCSI, QEMU_CAPS_SCSI_LSI,
             QEMU_CAPS_DEVICE_SCSI_GENERIC);

tests/qemuxml2xmloutdata/qemuxml2xmlout-pci-expander-bus.xml

@@ -35,6 +35,7 @@
     </controller>
     <controller type='pci' index='2' model='pci-expander-bus'>
       <model name='pxb'/>
+      <target busNr='252'/>
       <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
     </controller>
     <interface type='user'>