qemu: implement <model> subelement to <controller>

This patch provides qemu support for the contents of <model> in
<controller> for the two existing PCI controller types that need it
(i.e. the two controller types that are backed by a device that must
be specified on the qemu commandline):

1) pci-bridge - sets <model> name attribute default as "pci-bridge"

2) dmi-to-pci-bridge - sets <model> name attribute default as
   "i82801b11-bridge".

These both match current hardcoded practice.

The defaults are set at the end of qemuDomainAssignPCIAddresses().
This can't be done earlier because some of the options that will be
autogenerated need full PCI address info for the controller, and
because qemuDomainAssignPCIAddresses() might create extra controllers
which would need default settings added, and that hasn't yet been done
at the time the PostParse callbacks are being run.
qemuDomainAssignPCIAddresses() is still called prior to the XML being
written to disk, though, so the autogenerated defaults are persistent.

qemu capabilities bits aren't checked when the domain is defined, but
rather when the commandline is actually created (so the domain can
possibly be defined on a host that doesn't yet have support for the
given device, or a host different from the one where it will
eventually be run). When the commandline is being generated we compare
the modelName to known qemu device names implementing the given type
of controller, and check the capabilities bit for that device.

src/qemu/qemu_command.c

@@ -2260,11 +2260,33 @@ qemuDomainAssignPCIAddresses(virDomainDefPtr def,
                 virDomainControllerDefPtr cont = def->controllers[i];
                 int idx = cont->idx;
                 virDevicePCIAddressPtr addr;
+                virDomainPCIControllerOptsPtr options;
 
                 if (cont->type != VIR_DOMAIN_CONTROLLER_TYPE_PCI)
                     continue;
 
                 addr = &cont->info.addr.pci;
+                options = &cont->opts.pciopts;
+
+                /* set defaults for any other auto-generated config
+                 * options for this controller that haven't been
+                 * specified in config.
+                 */
+                switch ((virDomainControllerModelPCI)cont->model) {
+                case VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE:
+                    if (options->modelName == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE)
+                        options->modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_PCI_BRIDGE;
+                    break;
+                case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
+                    if (options->modelName == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE)
+                        options->modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_I82801B11_BRIDGE;
+                    break;
+                case VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT:
+                case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT:
+                case VIR_DOMAIN_CONTROLLER_MODEL_PCI_LAST:
+                    break;
+                }
+
                 /* check if every PCI bridge controller's ID is greater than
                  * the bus it is placed onto
                  */
@@ -4511,6 +4533,7 @@ qemuBuildControllerDevStr(virDomainDefPtr domainDef,
 {
     virBuffer buf = VIR_BUFFER_INITIALIZER;
     int model = def->model;
+    const char *modelName = NULL;
 
     if (def->type == VIR_DOMAIN_CONTROLLER_TYPE_SCSI) {
         if ((qemuSetSCSIControllerModel(domainDef, qemuCaps, &model)) < 0)
@@ -4632,17 +4655,67 @@ qemuBuildControllerDevStr(virDomainDefPtr domainDef,
         }
         switch (def->model) {
         case VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE:
-            virBufferAsprintf(&buf, "pci-bridge,chassis_nr=%d,id=%s",
-                              def->idx, def->info.alias);
+            if (def->opts.pciopts.modelName
+                == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE) {
+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                               _("autogenerated pci-bridge options not set"));
+                goto error;
+            }
+
+            modelName = virDomainControllerPCIModelNameTypeToString(def->opts.pciopts.modelName);
+            if (!modelName) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("unknown pci-bridge model name value %d"),
+                               def->opts.pciopts.modelName);
+                goto error;
+            }
+            if (def->opts.pciopts.modelName
+                != VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_PCI_BRIDGE) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("PCI controller model name '%s' "
+                                 "is not valid for a pci-bridge"),
+                               modelName);
+                goto error;
+            }
+            if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_PCI_BRIDGE)) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                               _("the pci-bridge controller "
+                                 "is not supported in this QEMU binary"));
+                goto error;
+            }
+            virBufferAsprintf(&buf, "%s,chassis_nr=%d,id=%s",
+                              modelName, def->idx, def->info.alias);
             break;
         case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
+            if (def->opts.pciopts.modelName
+                == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE) {
+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                               _("autogenerated dmi-to-pci-bridge options not set"));
+                goto error;
+            }
+
+            modelName = virDomainControllerPCIModelNameTypeToString(def->opts.pciopts.modelName);
+            if (!modelName) {
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("unknown dmi-to-pci-bridge model name value %d"),
+                               def->opts.pciopts.modelName);
+                goto error;
+            }
+            if (def->opts.pciopts.modelName
+                != VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_I82801B11_BRIDGE) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("PCI controller model name '%s' "
+                                 "is not valid for a dmi-to-pci-bridge"),
+                               modelName);
+                goto error;
+            }
             if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_DMI_TO_PCI_BRIDGE)) {
                 virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
-                               _("The dmi-to-pci-bridge (i82801b11-bridge) "
+                               _("the dmi-to-pci-bridge (i82801b11-bridge) "
                                  "controller is not supported in this QEMU binary"));
                 goto error;
             }
-            virBufferAsprintf(&buf, "i82801b11-bridge,id=%s", def->info.alias);
+            virBufferAsprintf(&buf, "%s,id=%s", modelName, def->info.alias);
             break;
         }
         break;