[libvirt] [RFC PATCH] Cannot set persistent config mem/vcpu above live maxmem/maxvcpu

I submitted bug https://bugzilla.redhat.com/show_bug.cgi?id=1038363 for being unable to raise the persistent mem/vcpu values above a live domain’s maxmem/maxvcpu values (rather than the persistent maxmem/maxvcpu values). I was asked to submit my patch here for a wider review. For memory, check the newmem value against mem.max_baloon of the live def for non-persistent changes, or mem.max_baloon of the persistent def for persistent changes. Same theory for setting vcpus/maxvcpus. --- a/libvirt0/libvirt-1.1.1/src/qemu/qemu_driver.c +++ b/libvirt0/libvirt-1.1.1/src/qemu/qemu_driver.c @@ -2236,13 +2236,13 @@ static int qemuDomainSetMemoryFlags(virDomainPtr dom, unsigned long newmem, } else { /* resize the current memory */ - if (newmem > vm->def->mem.max_balloon) { - virReportError(VIR_ERR_INVALID_ARG, "%s", - _("cannot set memory higher than max memory")); - goto endjob; - } - if (flags & VIR_DOMAIN_AFFECT_LIVE) { + if (newmem > vm->def->mem.max_balloon) { + virReportError(VIR_ERR_INVALID_ARG, "%s", + _("cannot set memory higher than max memory")); + goto endjob; + } + priv = vm->privateData; qemuDomainObjEnterMonitor(driver, vm); r = qemuMonitorSetBalloon(priv->mon, newmem); @@ -2262,6 +2262,12 @@ static int qemuDomainSetMemoryFlags(virDomainPtr dom, unsigned long newmem, } if (flags & VIR_DOMAIN_AFFECT_CONFIG) { + if (newmem > persistentDef->mem.max_balloon) { + virReportError(VIR_ERR_INVALID_ARG, "%s", + _("cannot set memory higher than max memory")); + goto endjob; + } + sa_assert(persistentDef); persistentDef->mem.cur_balloon = newmem; ret = virDomainSaveConfig(cfg->configDir, persistentDef); @@ -4160,6 +4166,7 @@ qemuDomainSetVcpusFlags(virDomainPtr dom, unsigned int nvcpus, virDomainDefPtr persistentDef; int ret = -1; bool maximum; + unsigned int maxvcpus; virQEMUDriverConfigPtr cfg = NULL; virCapsPtr caps = NULL; qemuAgentCPUInfoPtr cpuinfo = NULL; @@ -4207,11 +4214,12 @@ qemuDomainSetVcpusFlags(virDomainPtr dom, unsigned int nvcpus, goto endjob; } - if (!maximum && nvcpus > vm->def->maxvcpus) { + maxvcpus = (flags & VIR_DOMAIN_AFFECT_LIVE) ? vm->def->maxvcpus : persistentDef->maxvcpus; + if (!maximum && nvcpus > maxvcpus) { virReportError(VIR_ERR_INVALID_ARG, _("requested vcpus is greater than max allowable" " vcpus for the domain: %d > %d"), - nvcpus, vm->def->maxvcpus); + nvcpus, maxvcpus); goto endjob; }