conf: restrict where dmi-to-pci-bridge can be connected

libvirt had allowed a dmi-to-pci-bridge to be plugged in anywhere a
normal PCIe endpoint can be connected, but this is wrong - it will
only work if it's plugged into pcie-root (the PCIe root complex) or a
pcie-expander-bus (the qemu device pxb-pcie). This patch adjusts the
connection flags accordingly.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1363648

src/conf/domain_addr.c

@@ -58,15 +58,17 @@ virDomainPCIControllerModelToConnectType(virDomainControllerModelPCI model)
          */
         return VIR_PCI_CONNECT_TYPE_PCI_DEVICE;
 
-    case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
     case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS:
-        /* dmi-to-pci-bridge and pcie-expander-bus are treated like
+        /* pcie-expander-bus is treated like a standard PCIe endpoint
-         * PCIe devices (the part of pcie-expander-bus that is plugged
+         * device (the part of pcie-expander-bus that is plugged in
-         * in isn't the expander bus itself, but a companion device
+         * isn't the expander bus itself, but a companion device used
-         * used for setting it up).
+         * for setting it up).
          */
         return VIR_PCI_CONNECT_TYPE_PCIE_DEVICE;
 
+    case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
+        return VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE;
+
     case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT:
         return VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT;
 
@@ -133,6 +135,8 @@ virDomainPCIAddressFlagsCompatible(virPCIDeviceAddressPtr addr,
             connectStr = "pci-switch-upstream-port";
         } else if (devFlags & VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_DOWNSTREAM_PORT) {
             connectStr = "pci-switch-downstream-port";
+        } else if (devFlags & VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE) {
+            connectStr = "dmi-to-pci-bridge";
         } else {
             /* this should never happen. If it does, there is a
              * bug in the code that sets the flag bits for devices.
@@ -259,8 +263,9 @@ virDomainPCIAddressBusSetModel(virDomainPCIAddressBusPtr bus,
          * user config *and* the particular device being attached also
          * allows it.
          */
-        bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_DEVICE
+        bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_DEVICE |
-                      | VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT);
+                      VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT |
+                      VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE);
         bus->minSlot = 1;
         bus->maxSlot = VIR_PCI_ADDRESS_SLOT_LAST;
         break;
@@ -291,8 +296,11 @@ virDomainPCIAddressBusSetModel(virDomainPCIAddressBusPtr bus,
         bus->maxSlot = VIR_PCI_ADDRESS_SLOT_LAST;
         break;
     case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS:
-        /* single slot, no hotplug, only accepts pcie-root-port */
+        /* single slot, no hotplug, only accepts pcie-root-port or
-        bus->flags = VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT;
+         * dmi-to-pci-bridge
+         */
+        bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT |
+                      VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE);
         bus->minSlot = 0;
         bus->maxSlot = 0;
         break;

src/conf/domain_addr.h

@@ -40,6 +40,7 @@ typedef enum {
    VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT = 1 << 3,
    VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_UPSTREAM_PORT = 1 << 4,
    VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_DOWNSTREAM_PORT = 1 << 5,
+   VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE = 1 << 6,
 } virDomainPCIConnectFlags;
 
 /* a combination of all bits that describe the type of connections
@@ -49,7 +50,8 @@ typedef enum {
    (VIR_PCI_CONNECT_TYPE_PCI_DEVICE | VIR_PCI_CONNECT_TYPE_PCIE_DEVICE | \
     VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_UPSTREAM_PORT | \
     VIR_PCI_CONNECT_TYPE_PCIE_SWITCH_DOWNSTREAM_PORT | \
-    VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT)
+    VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT | \
+    VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE)
 
 /* combination of all bits that could be used to connect a normal
  * endpoint device (i.e. excluding the connection possible between an

tests/qemuxml2argvdata/qemuxml2argv-q35-dmi-bad-address1.xml

@@ -0,0 +1,31 @@
+<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='pci' index='0' model='pcie-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>
+    <controller type='pci' index='3' model='pcie-root-port'/>
+    <controller type='pci' index='4' model='dmi-to-pci-bridge'>
+      <address type='pci' bus='2' slot='3'/>
+    </controller>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/qemuxml2argvdata/qemuxml2argv-q35-dmi-bad-address2.xml

@@ -0,0 +1,39 @@
+<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='sda' bus='sata'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='pci' index='0' model='pcie-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>
+    <controller type='pci' index='3' model='pcie-root-port'/>
+    <controller type='pci' index='4' model='dmi-to-pci-bridge'>
+      <address type='pci' bus='3'/>
+    </controller>
+    <video>
+      <model type='qxl' ram='65536' vram='32768' vgamem='8192' heads='1'/>
+    </video>
+    <memballoon model='none'/>
+  </devices>
+</domain>

tests/qemuxml2argvtest.c

@@ -1632,6 +1632,14 @@ mymain(void)
             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("q35-dmi-bad-address1",
+                        QEMU_CAPS_DEVICE_PCI_BRIDGE,
+                        QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+                        QEMU_CAPS_DEVICE_IOH3420);
+    DO_TEST_PARSE_ERROR("q35-dmi-bad-address2",
+                        QEMU_CAPS_DEVICE_PCI_BRIDGE,
+                        QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE,
+                        QEMU_CAPS_DEVICE_IOH3420);
     DO_TEST("q35-pm-disable",
             QEMU_CAPS_DEVICE_PCI_BRIDGE,
             QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE, QEMU_CAPS_ICH9_AHCI,