Re: [libvirt] [PATCH 3/4] Explicitly represent balloon device in XML and handle PCI address

From: Daniel P. Berrange <dan(a)berrange.com&gt; To allow compatability with older QEMU PCI device slot assignment it is neccessary to explicitly track the balloon device in the XML. This introduces a new device <memballoon model='virtio|xen'/>

It can also have a PCI address, auto-assigned if neccessary. The memballoon will be automatically added to all Xen and QEMU guests by default.

* docs/schemas/domain.rng: Add <memballoon> element * src/conf/domain_conf.c, src/conf/domain_conf.h: parsing and formatting for memballoon device. Always add a memory balloon device to Xen/QEMU if none exists in XML * src/libvirt_private.syms: Export memballoon model APIs * src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Honour the PCI device address in memory balloon device * tests/*: Update to test new functionality

@@ -4634,6 +4685,41 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps, VIR_FREE(nodes); } + /* analysis of the memballoon devices */ + def->memballoon = NULL; + if ((n = virXPathNodeSet("./devices/memballoon", ctxt, &nodes)) < 0) { + virDomainReportError(VIR_ERR_INTERNAL_ERROR, + "%s", _("cannot extract memballoon devices")); + goto error; + } + if (n > 1) { + virDomainReportError (VIR_ERR_INTERNAL_ERROR, + "%s", _("only a single memballoon device is supported")); + goto error; + } + if (n > 0) { + virDomainMemballoonDefPtr memballoon = + virDomainMemballoonDefParseXML(nodes[0], flags); + if (!memballoon) + goto error; + + def->memballoon = memballoon; + VIR_FREE(nodes); + } else { + if (def->virtType == VIR_DOMAIN_VIRT_XEN || + def->virtType == VIR_DOMAIN_VIRT_QEMU || + def->virtType == VIR_DOMAIN_VIRT_KQEMU || + def->virtType == VIR_DOMAIN_VIRT_KVM) { + virDomainMemballoonDefPtr memballoon; + if (VIR_ALLOC(memballoon) < 0) + goto no_memory; + memballoon->model = def->virtType == VIR_DOMAIN_VIRT_XEN ? + VIR_DOMAIN_MEMBALLOON_MODEL_XEN : + VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO; + def->memballoon = memballoon; + } + }

+ if (def->memballoon) { + if (def->memballoon->model != VIR_DOMAIN_MEMBALLOON_MODEL_VIRTIO) { + qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("Memory balloon device type '%s' is not supported by this version of qemu"), + virDomainMemballoonModelTypeToString(def->memballoon->model)); + goto error;