qemu: implement <target chassisNr='n'/> subelement/attribute of <controller>

This uses the new subelement/attribute in two ways:

1) If a "pci-bridge" pci controller has no chassisNr attribute, it
will automatically be set to the controller's index as soon as the
controller's PCI address is known (during
qemuDomainAssignPCIAddresses()).

2) when creating the commandline for a pci-bridge device, chassisNr
will be used to set qemu's chassis_nr option (rather than the previous
practice of hard-coding it to the controller's index).

src/qemu/qemu_command.c

@@ -2276,6 +2276,8 @@ qemuDomainAssignPCIAddresses(virDomainDefPtr def,
                 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;
+                    if (options->chassisNr == -1)
+                        options->chassisNr = cont->idx;
                     break;
                 case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
                     if (options->modelName == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE)
@@ -4656,7 +4658,8 @@ qemuBuildControllerDevStr(virDomainDefPtr domainDef,
         switch (def->model) {
         case VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE:
             if (def->opts.pciopts.modelName
-                == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE) {
+                == VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE ||
+                def->opts.pciopts.chassisNr == -1) {
                 virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                                _("autogenerated pci-bridge options not set"));
                 goto error;
@@ -4684,7 +4687,8 @@ qemuBuildControllerDevStr(virDomainDefPtr domainDef,
                 goto error;
             }
             virBufferAsprintf(&buf, "%s,chassis_nr=%d,id=%s",
-                              modelName, def->idx, def->info.alias);
+                              modelName, def->opts.pciopts.chassisNr,
+                              def->info.alias);
             break;
         case VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE:
             if (def->opts.pciopts.modelName

tests/qemuxml2argvdata/qemuxml2argv-q35.args

@@ -2,7 +2,7 @@ LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \
 /usr/libexec/qemu-kvm -S -M q35 -m 2048 -smp 2 -nographic -nodefaults \
 -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c \
 -device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1e \
--device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x1 \
+-device pci-bridge,chassis_nr=56,id=pci.2,bus=pci.1,addr=0x1 \
 -drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-sata0-0-0 \
 -device ide-drive,bus=ide.0,drive=drive-sata0-0-0,id=sata0-0-0 \
 -vga qxl -global qxl-vga.ram_size=67108864 -global qxl-vga.vram_size=33554432