On Fri, Nov 20, 2015 at 06:24:38PM +0530, Bharata B Rao wrote:
> Support hot removal of CPU for sPAPR guests by sending the hot unplug
> notification to the guest via EPOW interrupt. Release the vCPU object
> after CPU hot unplug so that vCPU fd can be parked and reused.
>
> Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
> ---
> hw/ppc/spapr.c | 71
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 71 insertions(+)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 4434d45..6dca553 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2401,11 +2401,82 @@ static void spapr_machine_device_plug(HotplugHandler
> *hotplug_dev,
> }
> }
>
> +static void spapr_cpu_destroy(PowerPCCPU *cpu)
> +{
> + sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> +
> + xics_cpu_destroy(spapr->icp, cpu);
> + qemu_unregister_reset(spapr_cpu_reset, cpu);
> +}
> +
> +static void spapr_cpu_release(DeviceState *dev, void *opaque)
I'd prefer to see this called "core_release" since "cpu" doesn't make
it clear that it's acting on a whole core.
> +{
> + CPUState *cs;
> + int i;
> + int id = ppc_get_vcpu_dt_id(POWERPC_CPU(CPU(dev)));
> +
> + for (i = id; i < id + smp_threads; i++) {
> + CPU_FOREACH(cs) {
> + PowerPCCPU *cpu = POWERPC_CPU(cs);
> +
> + if (i == ppc_get_vcpu_dt_id(cpu)) {
> + spapr_cpu_destroy(cpu);
> + cpu_remove(cs);
> + }
> + }
> + }
> +}
> +
> +static int spapr_cpu_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
> + Error **errp)
> +{
> + CPUState *cs = CPU(dev);
> + PowerPCCPU *cpu = POWERPC_CPU(cs);
> + int id = ppc_get_vcpu_dt_id(cpu);
> + int smt = kvmppc_smt_threads();
> + sPAPRDRConnector *drc =
> + spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, id);
> + sPAPRDRConnectorClass *drck;
> + Error *local_err = NULL;
> +
> + /*
> + * SMT threads return from here, only main thread (core) will
> + * continue and signal hot unplug event to the guest.
> + */
> + if ((id % smt) != 0) {
> + return 0;
> + }
> + g_assert(drc);
> +
> + drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> + drck->detach(drc, dev, spapr_cpu_release, NULL, &local_err);
> + if (local_err) {
> + error_propagate(errp, local_err);
> + return -1;
> + }
> +
> + /*
> + * In addition to hotplugged CPUs, send the hot-unplug notification
> + * interrupt to the guest for coldplugged CPUs started via -device
> + * option too.
> + */
> + spapr_hotplug_req_remove_by_index(drc);
> + return 0;
> +}
> +
> static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
> DeviceState *dev, Error **errp)
> {
> + sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(qdev_get_machine());
> +
> if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> error_setg(errp, "Memory hot unplug not supported by sPAPR");
> + } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> + if (!smc->dr_cpu_enabled) {
> + error_setg(errp, "CPU hot unplug not supported on this machine");
> + return;
> + }
> + spapr_cpu_unplug(hotplug_dev, dev, errp);
> }
> }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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