Re: [libvirt] [PATCH 4/7] qemu: Fix coldplug of vcpus

On Wed, Sep 21, 2016 at 01:49:56PM +0200, Peter Krempa wrote: > virDomainDefSetVcpus was not designed to handle coldplug of vcpus now > that we can set state of vcpus individually. > > Introduce qemuDomainSetVcpusConfig that properly handles state changes > of vcpus when coldplugging so that invalid configurations are not > created. > > Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1375939 > --- > src/qemu/qemu_driver.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 53 insertions(+), 2 deletions(-) > > diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c > index e29180d..336673d 100644 > --- a/src/qemu/qemu_driver.c > +++ b/src/qemu/qemu_driver.c > @@ -4898,6 +4898,58 @@ qemuDomainSetVcpusLive(virQEMUDriverPtr driver, > } > > > +/** > + * qemuDomainSetVcpusConfig: > + * @def: config/offline definition of a domain > + * @nvcpus: target vcpu count > + * > + * Properly handle cold(un)plug of vcpus: > + * - plug in inactive vcpus/uplug active rather than rewriting state > + * - fix hotpluggable state > + */ > +static void > +qemuDomainSetVcpusConfig(virDomainDefPtr def, > + unsigned int nvcpus) > +{ > + virDomainVcpuDefPtr vcpu; > + size_t curvcpus = virDomainDefGetVcpus(def); > + size_t maxvcpus = virDomainDefGetVcpusMax(def); > + size_t i; > + > + > + if (curvcpus == nvcpus) > + return; > + > + if (curvcpus < nvcpus) { > + for (i = 0; i < maxvcpus; i++) { > + vcpu = virDomainDefGetVcpu(def, i); > + > + if (!vcpu || vcpu->online) > + continue; vcpu == NULL should not happen because virDomainDefGetVcpu() checks if (i >= maxvcpus)