Libvirt Version: 0.9.8 Hi: I added a new api for qemu_driver. and both added libvirt.c and remote. I tested it and it worked well. the function of this new api was add a new field in xml config of domain. (I added it like qemudDomainSetMemoryFlags)at the same time, I added a new member to struct virDomainDef. then I tested xml config converted to virDomaindef and virDomainDef converted to xml config both well(just tested this new api). But there was a problem, if I change the memory size or cpu number then apply it with virtManager. the xml config was changed. but there is no field in the xml what I added. I guest the virDomainDef member in virDomainObjPtr wasn't update. I have no idea, can you give me some ideas? thanks! here is my code in qemu_driver.c: static int qemudDomainSetCustomOptions(virDomainPtr dom, char *opt) { struct qemud_driver *driver = dom->conn->privateData; virDomainObjPtr vm; virDomainDefPtr persistentDef = NULL; int ret = -1; qemuDriverLock(driver); vm = virDomainFindByUUID(&driver->domains, dom->uuid); qemuDriverUnlock(driver); if (!vm) { char uuidstr[VIR_UUID_STRING_BUFLEN]; virUUIDFormat(dom->uuid, uuidstr); qemuReportError(VIR_ERR_NO_DOMAIN, _("no domain with matching uuid '%s'"), uuidstr); goto cleanup; } if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0) goto cleanup; if (!vm->persistent) { qemuReportError(VIR_ERR_OPERATION_INVALID, "%s", _("cannot change persistent config of a transient domain")); goto endjob; } if (!(persistentDef = virDomainObjGetPersistentDef(driver->caps, vm))) goto endjob; sa_assert(persistentDef); persistentDef->running_mode = opt; ret = virDomainSaveConfig(driver->configDir, persistentDef); ret = 0; endjob: if (qemuDomainObjEndJob(driver, vm) == 0) vm = NULL; cleanup: if (vm) virDomainObjUnlock(vm); return ret; } xuanmao_001