qemu: auto-add pcie-root-port/dmi-to-pci-bridge controllers as needed

Previously libvirt would only add pci-bridge devices automatically
when an address was requested for a device that required a legacy PCI
slot and none was available. This patch expands that support to
dmi-to-pci-bridge (which is needed in order to add a pci-bridge on a
machine with a pcie-root), and pcie-root-port (which is needed to add
a hotpluggable PCIe device). It does *not* automatically add
pcie-switch-upstream-ports or pcie-switch-downstream-ports (and
currently there are no plans for that).

Given the existing code to auto-add pci-bridge devices, automatically
adding pcie-root-ports is fairly straightforward. The
dmi-to-pci-bridge support is a bit tricky though, for a few reasons:

1) Although the only reason to add a dmi-to-pci-bridge is so that
   there is a reasonable place to plug in a pci-bridge controller,
   most of the time it's not the presence of a pci-bridge *in the
   config* that triggers the requirement to add a dmi-to-pci-bridge.
   Rather, it is the presence of a legacy-PCI device in the config,
   which triggers auto-add of a pci-bridge, which triggers auto-add of
   a dmi-to-pci-bridge (this is handled in
   virDomainPCIAddressSetGrow() - if there's a request to add a
   pci-bridge we'll check if there is a suitable bus to plug it into;
   if not, we first add a dmi-to-pci-bridge).

2) Once there is already a single dmi-to-pci-bridge on the system,
   there won't be a need for any more, even if it's full, as long as
   there is a pci-bridge with an open slot - you can also plug
   pci-bridges into existing pci-bridges. So we have to make sure we
   don't add a dmi-to-pci-bridge unless there aren't any
   dmi-to-pci-bridges *or* any pci-bridges.

3) Although it is strongly discouraged, it is legal for a pci-bridge
   to be directly plugged into pcie-root, and we don't want to
   auto-add a dmi-to-pci-bridge if there is already a pci-bridge
   that's been forced directly into pcie-root.

Although libvirt will now automatically create a dmi-to-pci-bridge
when it's needed, the code still remains for now that forces a
dmi-to-pci-bridge on all domains with pcie-root (in
qemuDomainDefAddDefaultDevices()). That will be removed in a future
patch.

For now, the pcie-root-ports are added one to a slot, which is a bit
wasteful and means it will fail after 31 total PCIe devices (30 if
there are also some PCI devices), but helps keep the changeset down
for this patch. A future patch will have 8 pcie-root-ports sharing the
functions on a single slot.

src/conf/domain_addr.c

@@ -82,6 +82,36 @@ virDomainPCIControllerModelToConnectType(virDomainControllerModelPCI model)
     return 0;
 }
 
+
+static int
+virDomainPCIControllerConnectTypeToModel(virDomainPCIConnectFlags flags)
+{
+    if (flags & VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT)
+        return VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT;
+
+    if (flags & VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_UPSTREAM_PORT)
+        return VIR_DOMAIN_CONTROLLER_MODEL_PCIE_SWITCH_UPSTREAM_PORT;
+
+    if (flags & VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_DOWNSTREAM_PORT)
+        return VIR_DOMAIN_CONTROLLER_MODEL_PCIE_SWITCH_DOWNSTREAM_PORT;
+
+    if (flags & VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE)
+        return VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE;
+
+    if (flags & VIR_PCI_CONNECT_TYPE_PCI_EXPANDER_BUS)
+        return VIR_DOMAIN_CONTROLLER_MODEL_PCI_EXPANDER_BUS;
+
+    if (flags & VIR_PCI_CONNECT_TYPE_PCIE_EXPANDER_BUS)
+        return VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS;
+
+    if (flags & VIR_PCI_CONNECT_TYPE_PCI_BRIDGE)
+        return VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE;
+
+    /* some connect types don't correspond to a controller model */
+    return -1;
+}
+
+
 bool
 virDomainPCIAddressFlagsCompatible(virPCIDeviceAddressPtr addr,
                                    const char *addrStr,
@@ -334,10 +364,7 @@ virDomainPCIAddressBusSetModel(virDomainPCIAddressBusPtr bus,
 }
 
 
-/* Ensure addr fits in the address set, by expanding it if needed.
- * This will only grow if the flags say that we need a normal
- * hot-pluggable PCI slot. If we need a different type of slot, it
- * will fail.
+/* Ensure addr fits in the address set, by expanding it if needed
  *
  * Return value:
  * -1 = OOM
@@ -351,32 +378,125 @@ virDomainPCIAddressSetGrow(virDomainPCIAddressSetPtr addrs,
 {
     int add;
     size_t i;
+    int model;
+    bool needDMIToPCIBridge = false;
 
     add = addr->bus - addrs->nbuses + 1;
-    i = addrs->nbuses;
     if (add <= 0)
         return 0;
 
-    /* auto-grow only works when we're adding plain PCI devices */
-    if (!(flags & VIR_PCI_CONNECT_TYPE_PCI_DEVICE)) {
-        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                       _("Cannot automatically add a new PCI bus for a "
-                         "device requiring a slot other than standard PCI."));
+    /* remember that the flags aren't for the type of controller that
+     * we want to add, they are the type of *device* that we want to
+     * plug in, and this function must decide on the appropriate
+     * controller to add in order to give us a slot for that device.
+     */
+
+    if (flags & VIR_PCI_CONNECT_TYPE_PCI_DEVICE) {
+        model = VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE;
+
+        /* if there aren't yet any buses that will accept a
+         * pci-bridge, and the caller is asking for one, we'll need to
+         * add a dmi-to-pci-bridge first.
+         */
+        needDMIToPCIBridge = true;
+        for (i = 0; i < addrs->nbuses; i++) {
+            if (addrs->buses[i].flags & VIR_PCI_CONNECT_TYPE_PCI_BRIDGE) {
+                needDMIToPCIBridge = false;
+                break;
+            }
+        }
+        if (needDMIToPCIBridge && add == 1) {
+            /* We need to add a single pci-bridge to provide the bus
+             * our legacy PCI device will be plugged into; however, we
+             * have also determined that there isn't yet any proper
+             * place to connect that pci-bridge we're about to add (on
+             * a system with pcie-root, that "proper place" would be a
+             * dmi-to-pci-bridge". So, to give the pci-bridge a place
+             * to connect, we increase the count of buses to add,
+             * while also incrementing the bus number in the address
+             * for the device (since the pci-bridge will now be at an
+             * index 1 higher than the caller had anticipated).
+             */
+            add++;
+            addr->bus++;
+        }
+    } else if (flags & VIR_PCI_CONNECT_TYPE_PCI_BRIDGE &&
+               addrs->buses[0].model == VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT) {
+        /* NB: if the root bus is pci-root, and we couldn't find an
+         * open place to connect a pci-bridge, then there is nothing
+         * we can do (since the only way to gain a new slot that
+         * accepts a pci-bridge is to add *a pci-bridge* (which is the
+         * reason we're here in the first place!)
+         */
+        model = VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE;
+    } else if (flags & (VIR_PCI_CONNECT_TYPE_PCIE_DEVICE |
+                        VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_UPSTREAM_PORT)) {
+        model = VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT;
+    } else {
+        /* The types of devices that we can't auto-add a controller for:
+         *
+         * VIR_CONNECT_TYPE_DMI_TO_PCI_BRIDGE &
+         * VIR_PCI_CONNECT_TYPE_ROOT_PORT - these can only plug into
+         *  pcie-root or pcie-expander-bus. By definition there is
+         *  only 1 pcie-root, and we don't support auto-adding
+         *  pcie-expander-bus (because it is intended for NUMA usage,
+         *  and we can't automatically decide which numa node to
+         *  associate it with)
+         *
+         * VIR_CONNECT_TYPE_PCIE_SWITCH_DOWNSTREAM_PORT - we ndon't
+         *  support this, because it can only plug into an
+         *  upstream-port, and the upstream port might need a
+         *  root-port; supporting this extra layer needlessly
+         *  complicates the code, and upstream/downstream ports are
+         *  outside the scope of our "automatic-bus-expansion" model
+         *  anyway.
+         *
+         * VIR_CONNECT_TYPE_PCI[E]_EXPANDER_BUS - these were created
+         *  to support guest awareness of the NUMA node placement of
+         *  devices on the host, and are also outside the scope of our
+         *  "automatic-bus-expansion".
+         *
+         * VIR_PCI_CONNECT_TYPE_PCI_BRIDGE (when the root bus is
+         *  pci-root) - see the comment above in the case that handles
+         *  adding a slot for pci-bridge to a guest with pcie-root.
+         *
+         */
+        int existingContModel = virDomainPCIControllerConnectTypeToModel(flags);
+
+        if (existingContModel >= 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("a PCI slot is needed to connect a PCI controller "
+                             "model='%s', but none is available, and it "
+                             "cannot be automatically added"),
+                           virDomainControllerModelPCITypeToString(existingContModel));
+        } else {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("Cannot automatically add a new PCI bus for a "
+                             "device with connect flags %.2x"), flags);
+        }
         return -1;
     }
 
+    i = addrs->nbuses;
+
     if (VIR_EXPAND_N(addrs->buses, addrs->nbuses, add) < 0)
         return -1;
 
-    for (; i < addrs->nbuses; i++) {
-        /* Any time we auto-add a bus, we will want a multi-slot
-         * bus. Currently the only type of bus we will auto-add is a
-         * pci-bridge, which is hot-pluggable and provides standard
-         * PCI slots.
+    if (needDMIToPCIBridge) {
+        /* first of the new buses is dmi-to-pci-bridge, the
+         * rest are of the requested type
          */
-        virDomainPCIAddressBusSetModel(&addrs->buses[i],
-                                       VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE);
+        if (virDomainPCIAddressBusSetModel(&addrs->buses[i++],
+                                           VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE) < 0) {
+            return -1;
+        }
     }
+
+    for (; i < addrs->nbuses; i++) {
+        if (virDomainPCIAddressBusSetModel(&addrs->buses[i], model) < 0)
+            return -1;
+    }
+
     return add;
 }
 

src/qemu/qemu_domain_address.c

@@ -911,27 +911,14 @@ qemuDomainPCIAddressSetCreate(virDomainDefPtr def,
 {
     virDomainPCIAddressSetPtr addrs;
     size_t i;
+    bool hasPCIeRoot = false;
+    virDomainControllerModelPCI defaultModel;
 
     if ((addrs = virDomainPCIAddressSetAlloc(nbuses)) == NULL)
         return NULL;
 
     addrs->dryRun = dryRun;
 
-    /* As a safety measure, set default model='pci-root' for first pci
-     * controller and 'pci-bridge' for all subsequent. After setting
-     * those defaults, then scan the config and set the actual model
-     * for all addrs[idx]->bus that already have a corresponding
-     * controller in the config.
-     *
-     */
-    if (nbuses > 0)
-        virDomainPCIAddressBusSetModel(&addrs->buses[0],
-                                       VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT);
-    for (i = 1; i < nbuses; i++) {
-        virDomainPCIAddressBusSetModel(&addrs->buses[i],
-                                       VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE);
-    }
-
     for (i = 0; i < def->ncontrollers; i++) {
         virDomainControllerDefPtr cont = def->controllers[i];
         size_t idx = cont->idx;
@@ -948,7 +935,42 @@ qemuDomainPCIAddressSetCreate(virDomainDefPtr def,
 
         if (virDomainPCIAddressBusSetModel(&addrs->buses[idx], cont->model) < 0)
             goto error;
-        }
+
+        if (cont->model == VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT)
+            hasPCIeRoot = true;
+    }
+
+    if (nbuses > 0 && !addrs->buses[0].model) {
+        /* This is just here to replicate a safety measure already in
+         * an older version of this code. In practice, the root bus
+         * should have already been added at index 0 prior to
+         * assigning addresses to devices.
+         */
+        if (virDomainPCIAddressBusSetModel(&addrs->buses[0],
+                                           VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT) < 0)
+            goto error;
+    }
+
+    /* Now fill in a reasonable model for all the buses in the set
+     * that don't yet have a corresponding controller in the domain
+     * config.
+     */
+    if (hasPCIeRoot)
+        defaultModel = VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT;
+    else
+        defaultModel = VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE;
+
+    for (i = 1; i < addrs->nbuses; i++) {
+
+        if (addrs->buses[i].model)
+            continue;
+
+        if (virDomainPCIAddressBusSetModel(&addrs->buses[i], defaultModel) < 0)
+            goto error;
+
+        VIR_DEBUG("Auto-adding <controller type='pci' model='%s' index='%zu'/>",
+                  virDomainControllerModelPCITypeToString(defaultModel), i);
+    }
 
     if (virDomainDeviceInfoIterate(def, qemuDomainCollectPCIAddress, addrs) < 0)
         goto error;

tests/qemuxml2argvdata/qemuxml2argv-q35-pcie-autoadd.args

+LC_ALL=C \
+PATH=/bin \
+HOME=/home/test \
+USER=test \
+LOGNAME=test \
+QEMU_AUDIO_DRV=none \
+/usr/libexec/qemu-kvm \
+-name q35-test \
+-S \
+-M q35 \
+-m 2048 \
+-smp 2,sockets=2,cores=1,threads=1 \
+-uuid 11dbdcdd-4c3b-482b-8903-9bdb8c0a2774 \
+-nographic \
+-nodefaults \
+-monitor unix:/tmp/lib/domain--1-q35-test/monitor.sock,server,nowait \
+-no-acpi \
+-boot c \
+-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e \
+-device ioh3420,port=0x10,chassis=2,id=pci.2,bus=pcie.0,addr=0x2 \
+-device ioh3420,port=0x18,chassis=3,id=pci.3,bus=pcie.0,addr=0x3 \
+-device ioh3420,port=0x20,chassis=4,id=pci.4,bus=pcie.0,addr=0x4 \
+-device ioh3420,port=0x28,chassis=5,id=pci.5,bus=pcie.0,addr=0x5 \
+-device ioh3420,port=0x30,chassis=6,id=pci.6,bus=pcie.0,addr=0x6 \
+-device ioh3420,port=0x38,chassis=7,id=pci.7,bus=pcie.0,addr=0x7 \
+-device ioh3420,port=0x40,chassis=8,id=pci.8,bus=pcie.0,addr=0x8 \
+-device ioh3420,port=0x48,chassis=9,id=pci.9,bus=pcie.0,addr=0x9 \
+-device ioh3420,port=0x50,chassis=10,id=pci.10,bus=pcie.0,addr=0xa \
+-device ioh3420,port=0x58,chassis=11,id=pci.11,bus=pcie.0,addr=0xb \
+-device ioh3420,port=0x60,chassis=12,id=pci.12,bus=pcie.0,addr=0xc \
+-device ioh3420,port=0x68,chassis=13,id=pci.13,bus=pcie.0,addr=0xd \
+-device ioh3420,port=0x70,chassis=14,id=pci.14,bus=pcie.0,addr=0xe \
+-device nec-usb-xhci,id=usb,bus=pci.7,addr=0x0 \
+-device virtio-scsi-pci,id=scsi0,bus=pci.6,addr=0x0 \
+-device virtio-serial-pci,id=virtio-serial0,bus=pci.5,addr=0x0 \
+-drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-virtio-disk1 \
+-device virtio-blk-pci,bus=pci.8,addr=0x0,drive=drive-virtio-disk1,\
+id=virtio-disk1 \
+-fsdev local,security_model=passthrough,id=fsdev-fs0,path=/export/to/guest \
+-device virtio-9p-pci,id=fs0,fsdev=fsdev-fs0,mount_tag=/import/from/host,\
+bus=pci.2,addr=0x0 \
+-netdev user,id=hostnet0 \
+-device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:11:22:33:44:55,bus=pci.3,\
+addr=0x0 \
+-netdev user,id=hostnet1 \
+-device e1000e,netdev=hostnet1,id=net1,mac=00:11:22:33:44:66,bus=pci.4,\
+addr=0x0 \
+-device virtio-input-host-pci,id=input0,evdev=/dev/input/event1234,bus=pci.11,\
+addr=0x0 \
+-device virtio-mouse-pci,id=input1,bus=pci.12,addr=0x0 \
+-device virtio-keyboard-pci,id=input2,bus=pci.13,addr=0x0 \
+-device virtio-tablet-pci,id=input3,bus=pci.14,addr=0x0 \
+-device virtio-gpu-pci,id=video0,bus=pcie.0,addr=0x1 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.9,addr=0x0 \
+-object rng-random,id=objrng0,filename=/dev/urandom \
+-device virtio-rng-pci,rng=objrng0,id=rng0,max-bytes=123,period=1234,\
+bus=pci.10,addr=0x0

tests/qemuxml2argvdata/qemuxml2argv-q35-pcie-autoadd.xml

+<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/libexec/qemu-kvm</emulator>
+    <controller type='virtio-serial'/>
+    <controller type='scsi' model='virtio-scsi'/>
+    <controller type='usb' model='nec-xhci'/>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='vdb' bus='virtio'/>
+    </disk>
+    <filesystem type='mount'>
+      <source dir='/export/to/guest'/>
+      <target dir='/import/from/host'/>
+    </filesystem>
+    <video>
+      <model type='virtio'/>
+    </video>
+    <interface type='user'>
+      <mac address='00:11:22:33:44:55'/>
+      <model type='virtio'/>
+    </interface>
+    <interface type='user'>
+      <mac address='00:11:22:33:44:66'/>
+      <model type='e1000e'/>
+    </interface>
+    <memballoon model='virtio'/>
+    <rng model='virtio'>
+      <rate bytes='123' period='1234'/>
+      <backend model='random'>/dev/urandom</backend>
+    </rng>
+    <input type='passthrough' bus='virtio'>
+      <source evdev='/dev/input/event1234'/>
+    </input>
+    <input type='mouse' bus='virtio'/>
+    <input type='keyboard' bus='virtio'/>
+    <input type='tablet' bus='virtio'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1820,6 +1820,30 @@ mymain(void)
             QEMU_CAPS_ICH9_USB_EHCI1,
             QEMU_CAPS_NEC_USB_XHCI,
             QEMU_CAPS_DEVICE_VIDEO_PRIMARY);
+    /* same as q35-pcie, but all PCI controllers are added automatically */
+    DO_TEST("q35-pcie-autoadd",
+            QEMU_CAPS_VIRTIO_PCI_DISABLE_LEGACY,
+            QEMU_CAPS_DEVICE_VIRTIO_RNG,
+            QEMU_CAPS_OBJECT_RNG_RANDOM,
+            QEMU_CAPS_NETDEV,
+            QEMU_CAPS_DEVICE_VIRTIO_NET,
+            QEMU_CAPS_DEVICE_VIRTIO_GPU,
+            QEMU_CAPS_VIRTIO_GPU_VIRGL,
+            QEMU_CAPS_VIRTIO_KEYBOARD,
+            QEMU_CAPS_VIRTIO_MOUSE,
+            QEMU_CAPS_VIRTIO_TABLET,
+            QEMU_CAPS_VIRTIO_INPUT_HOST,
+            QEMU_CAPS_VIRTIO_SCSI,
+            QEMU_CAPS_FSDEV,
+            QEMU_CAPS_FSDEV_WRITEOUT,
+            QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_IOH3420,
+            QEMU_CAPS_ICH9_AHCI,
+            QEMU_CAPS_PCI_MULTIFUNCTION,
+            QEMU_CAPS_ICH9_USB_EHCI1,
+            QEMU_CAPS_NEC_USB_XHCI,
+            QEMU_CAPS_DEVICE_VIDEO_PRIMARY);
     DO_TEST("pcie-root-port",
             QEMU_CAPS_DEVICE_PCI_BRIDGE,
             QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,

tests/qemuxml2xmloutdata/qemuxml2xmlout-q35-pcie-autoadd.xml

+<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/libexec/qemu-kvm</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'/>
+      <target dev='vdb' bus='virtio'/>
+      <address type='pci' domain='0x0000' bus='0x08' slot='0x00' function='0x0'/>
+    </disk>
+    <controller type='virtio-serial' index='0'>
+      <address type='pci' domain='0x0000' bus='0x05' slot='0x00' function='0x0'/>
+    </controller>
+    <controller type='scsi' index='0' model='virtio-scsi'>
+      <address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/>
+    </controller>
+    <controller type='usb' index='0' model='nec-xhci'>
+      <address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
+    </controller>
+    <controller type='sata' index='0'>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
+    </controller>
+    <controller type='pci' index='0' model='pcie-root'/>
+    <controller type='pci' index='1' model='dmi-to-pci-bridge'>
+      <model name='i82801b11-bridge'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x1e' function='0x0'/>
+    </controller>
+    <controller type='pci' index='2' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='2' port='0x10'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
+    </controller>
+    <controller type='pci' index='3' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='3' port='0x18'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
+    </controller>
+    <controller type='pci' index='4' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='4' port='0x20'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
+    </controller>
+    <controller type='pci' index='5' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='5' port='0x28'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
+    </controller>
+    <controller type='pci' index='6' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='6' port='0x30'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
+    </controller>
+    <controller type='pci' index='7' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='7' port='0x38'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
+    </controller>
+    <controller type='pci' index='8' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='8' port='0x40'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
+    </controller>
+    <controller type='pci' index='9' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='9' port='0x48'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
+    </controller>
+    <controller type='pci' index='10' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='10' port='0x50'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
+    </controller>
+    <controller type='pci' index='11' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='11' port='0x58'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/>
+    </controller>
+    <controller type='pci' index='12' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='12' port='0x60'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x0c' function='0x0'/>
+    </controller>
+    <controller type='pci' index='13' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='13' port='0x68'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x0d' function='0x0'/>
+    </controller>
+    <controller type='pci' index='14' model='pcie-root-port'>
+      <model name='ioh3420'/>
+      <target chassis='14' port='0x70'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x0e' function='0x0'/>
+    </controller>
+    <filesystem type='mount' accessmode='passthrough'>
+      <source dir='/export/to/guest'/>
+      <target dir='/import/from/host'/>
+      <address type='pci' domain='0x0000' bus='0x02' slot='0x00' function='0x0'/>
+    </filesystem>
+    <interface type='user'>
+      <mac address='00:11:22:33:44:55'/>
+      <model type='virtio'/>
+      <address type='pci' domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
+    </interface>
+    <interface type='user'>
+      <mac address='00:11:22:33:44:66'/>
+      <model type='e1000e'/>
+      <address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
+    </interface>
+    <input type='passthrough' bus='virtio'>
+      <source evdev='/dev/input/event1234'/>
+      <address type='pci' domain='0x0000' bus='0x0b' slot='0x00' function='0x0'/>
+    </input>
+    <input type='mouse' bus='virtio'>
+      <address type='pci' domain='0x0000' bus='0x0c' slot='0x00' function='0x0'/>
+    </input>
+    <input type='keyboard' bus='virtio'>
+      <address type='pci' domain='0x0000' bus='0x0d' slot='0x00' function='0x0'/>
+    </input>
+    <input type='tablet' bus='virtio'>
+      <address type='pci' domain='0x0000' bus='0x0e' slot='0x00' function='0x0'/>
+    </input>
+    <input type='mouse' bus='ps2'/>
+    <input type='keyboard' bus='ps2'/>
+    <video>
+      <model type='virtio' heads='1' primary='yes'/>
+      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
+    </video>
+    <memballoon model='virtio'>
+      <address type='pci' domain='0x0000' bus='0x09' slot='0x00' function='0x0'/>
+    </memballoon>
+    <rng model='virtio'>
+      <rate bytes='123' period='1234'/>
+      <backend model='random'>/dev/urandom</backend>
+      <address type='pci' domain='0x0000' bus='0x0a' slot='0x00' function='0x0'/>
+    </rng>
+  </devices>
+</domain>

tests/qemuxml2xmltest.c

@@ -741,7 +741,30 @@ mymain(void)
             QEMU_CAPS_ICH9_USB_EHCI1,
             QEMU_CAPS_NEC_USB_XHCI,
             QEMU_CAPS_DEVICE_VIDEO_PRIMARY);
-
+    /* same as q35-pcie, but all PCI controllers are added automatically */
+    DO_TEST("q35-pcie-autoadd",
+            QEMU_CAPS_VIRTIO_PCI_DISABLE_LEGACY,
+            QEMU_CAPS_DEVICE_VIRTIO_RNG,
+            QEMU_CAPS_OBJECT_RNG_RANDOM,
+            QEMU_CAPS_NETDEV,
+            QEMU_CAPS_DEVICE_VIRTIO_NET,
+            QEMU_CAPS_DEVICE_VIRTIO_GPU,
+            QEMU_CAPS_VIRTIO_GPU_VIRGL,
+            QEMU_CAPS_VIRTIO_KEYBOARD,
+            QEMU_CAPS_VIRTIO_MOUSE,
+            QEMU_CAPS_VIRTIO_TABLET,
+            QEMU_CAPS_VIRTIO_INPUT_HOST,
+            QEMU_CAPS_VIRTIO_SCSI,
+            QEMU_CAPS_FSDEV,
+            QEMU_CAPS_FSDEV_WRITEOUT,
+            QEMU_CAPS_DEVICE_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+            QEMU_CAPS_DEVICE_IOH3420,
+            QEMU_CAPS_ICH9_AHCI,
+            QEMU_CAPS_PCI_MULTIFUNCTION,
+            QEMU_CAPS_ICH9_USB_EHCI1,
+            QEMU_CAPS_NEC_USB_XHCI,
+            QEMU_CAPS_DEVICE_VIDEO_PRIMARY);
     DO_TEST("pcie-root",
             QEMU_CAPS_DEVICE_PCI_BRIDGE, QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
             QEMU_CAPS_DEVICE_IOH3420, QEMU_CAPS_ICH9_AHCI,