From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32838) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cWiIg-00079Y-3T for qemu-devel@nongnu.org; Thu, 26 Jan 2017 06:33:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cWiIc-0004om-WC for qemu-devel@nongnu.org; Thu, 26 Jan 2017 06:33:10 -0500 Date: Thu, 26 Jan 2017 12:32:58 +0100 From: Igor Mammedov Message-ID: <20170126123258.2d34fe95@Igors-MacBook-Pro.local> In-Reply-To: <1466145399-32209-16-git-send-email-david@gibson.dropbear.id.au> References: <1466145399-32209-1-git-send-email-david@gibson.dropbear.id.au> <1466145399-32209-16-git-send-email-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PULL 15/18] spapr: CPU hot unplug support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: peter.maydell@linaro.org, agraf@suse.de, aik@ozlabs.ru, bharata@linux.vnet.ibm.com, mdroth@linux.vnet.ibm.com, qemu-ppc@nongnu.org, qemu-devel@nongnu.org On Fri, 17 Jun 2016 16:36:36 +1000 David Gibson wrote: > From: Bharata B Rao > > Remove the CPU core device by removing the underlying CPU thread devices. > Hot removal of CPU for sPAPR guests is achieved by sending the hot unplug > notification to the guest. Release the vCPU object after CPU hot unplug so > that vCPU fd can be parked and reused. > > Signed-off-by: Bharata B Rao > Signed-off-by: David Gibson [...] Bharata, Here is some notes I've made while auditing spapr cpu hotplug code. spapr_core_release() should be spapr_core_unrealize() except of machine related spapr->cores[cc->core_id / smt] = NULL; which should go to spapr_core_unplug() > +static void spapr_core_release(DeviceState *dev, void *opaque) > +{ > + sPAPRCPUCore *sc = SPAPR_CPU_CORE(OBJECT(dev)); > + const char *typename = object_class_get_name(sc->cpu_class); > + size_t size = object_type_get_instance_size(typename); > + sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine()); > + sPAPRCPUCore *core = SPAPR_CPU_CORE(OBJECT(dev)); > + CPUCore *cc = CPU_CORE(dev); > + int smt = kvmppc_smt_threads(); > + int i; > + > + for (i = 0; i < cc->nr_threads; i++) { > + void *obj = sc->threads + i * size; > + DeviceState *dev = DEVICE(obj); > + CPUState *cs = CPU(dev); > + PowerPCCPU *cpu = POWERPC_CPU(cs); > + > + spapr_cpu_destroy(cpu); > + cpu_remove_sync(cs); > + object_unparent(obj); > + } > + > + spapr->cores[cc->core_id / smt] = NULL; > + > + g_free(core->threads); > + object_unparent(OBJECT(dev)); > +} > + spapr_core_[un]plug() functions belong to machine code and should be in hw/ppc/spapr.c > +void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev, > + Error **errp) > +{ > + sPAPRCPUCore *core = SPAPR_CPU_CORE(OBJECT(dev)); > + PowerPCCPU *cpu = POWERPC_CPU(core->threads); > + int id = ppc_get_vcpu_dt_id(cpu); > + sPAPRDRConnector *drc = > + spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, id); > + sPAPRDRConnectorClass *drck; > + Error *local_err = NULL; > + > + g_assert(drc); > + > + drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc); > + drck->detach(drc, dev, spapr_core_release, NULL, &local_err); Could you explain call flow during cpu unplug? My expectations were that unplug_request() handler asks for CPU removal and unplug() handler removes CPU. It's obviously messed up somehow. > + if (local_err) { > + error_propagate(errp, local_err); > + return; > + } > + > + spapr_hotplug_req_remove_by_index(drc); > +} > + > void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > Error **errp) > { > diff --git a/include/hw/ppc/spapr_cpu_core.h b/include/hw/ppc/spapr_cpu_core.h > index 7cb0515..1c9b319 100644 > --- a/include/hw/ppc/spapr_cpu_core.h > +++ b/include/hw/ppc/spapr_cpu_core.h > @@ -31,4 +31,6 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > char *spapr_get_cpu_core_type(const char *model); > void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > Error **errp); > +void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev, > + Error **errp); > #endif