On Wed, Mar 25, 2015 at 04:44:48PM +1100, David Gibson wrote:
> On Mon, Mar 23, 2015 at 07:06:00PM +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.
> >
> > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
> > ---
> > hw/ppc/spapr.c | 78
> > ++++++++++++++++++++++++++++++++++++++++++++++-
> > linux-headers/linux/kvm.h | 1 +
> > target-ppc/kvm.c | 7 +++++
> > target-ppc/kvm_ppc.h | 6 ++++
> > 4 files changed, 91 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index b48994b..7b8784d 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -1468,6 +1468,12 @@ static void spapr_cpu_init(PowerPCCPU *cpu)
> > qemu_register_reset(spapr_cpu_reset, cpu);
> > }
> >
> > +static void spapr_cpu_destroy(PowerPCCPU *cpu)
> > +{
> > + xics_cpu_destroy(spapr->icp, cpu);
> > + qemu_unregister_reset(spapr_cpu_reset, cpu);
> > +}
> > +
> > /* pSeries LPAR / sPAPR hardware init */
> > static void ppc_spapr_init(MachineState *machine)
> > {
> > @@ -1880,6 +1886,18 @@ static void spapr_cpu_hotplug_add(DeviceState *dev,
> > CPUState *cs, Error **errp)
> > }
> > }
> >
> > +static void spapr_cpu_hotplug_remove(DeviceState *dev, CPUState *cs,
> > + Error **errp)
> > +{
> > + PowerPCCPU *cpu = POWERPC_CPU(cs);
> > + int id = ppc_get_vcpu_dt_id(cpu);
> > + sPAPRDRConnector *drc =
> > + spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, id);
> > + sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> > +
> > + drck->detach(drc, dev, NULL, NULL, errp);
> > +}
> > +
> > static void spapr_cpu_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> > Error **errp)
> > {
> > @@ -1911,6 +1929,51 @@ static void spapr_cpu_plug(HotplugHandler
> > *hotplug_dev, DeviceState *dev,
> > return;
> > }
> >
> > +static int spapr_cpu_unplug(Object *obj, void *opaque)
> > +{
> > + Error **errp = opaque;
> > + DeviceState *dev = DEVICE(obj);
> > + 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);
> > +
> > + spapr_cpu_destroy(cpu);
>
> I may be misunderstanding something here, but don't you need to signal
> the removal to the guest (and get its ack) before you "physically"
> remove the cpu?
Oh yes, I should move this call to spapr_cpu_release().
>
> > + /*
> > + * 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);
> > +
> > + spapr_cpu_hotplug_remove(dev, cs, errp);
> > + if (*errp) {
> > + return -1;
> > + }
> > + spapr_hotplug_req_remove_event(drc);
> > +
> > + return 0;
> > +}
> > +
> > +static int spapr_cpu_core_unplug(Object *obj, void *opaque)
> > +{
> > + Error **errp = opaque;
> > +
> > + object_child_foreach(obj, spapr_cpu_unplug, errp);
> > + return 0;
> > +}
> > +
> > +static void spapr_cpu_socket_unplug(HotplugHandler *hotplug_dev,
> > + DeviceState *dev, Error **errp)
> > +{
> > + object_child_foreach(OBJECT(dev), spapr_cpu_core_unplug, errp);
> > +}
> > +
> > static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
> > DeviceState *dev, Error **errp)
> > {
> > @@ -1926,10 +1989,21 @@ static void
> > spapr_machine_device_plug(HotplugHandler *hotplug_dev,
> > }
> > }
> >
> > +static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
> > + DeviceState *dev, Error **errp)
> > +{
> > + if (object_dynamic_cast(OBJECT(dev), TYPE_CPU_SOCKET)) {
> > + if (dev->hotplugged && spapr->dr_cpu_enabled) {
> > + spapr_cpu_socket_unplug(hotplug_dev, dev, errp);
> > + }
> > + }
> > +}
> > +
> > static HotplugHandler *spapr_get_hotpug_handler(MachineState *machine,
> > DeviceState *dev)
> > {
> > - if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> > + if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) ||
> > + object_dynamic_cast(OBJECT(dev), TYPE_CPU_SOCKET)) {
> > return HOTPLUG_HANDLER(machine);
> > }
> > return NULL;
> > @@ -1953,6 +2027,8 @@ static void spapr_machine_class_init(ObjectClass *oc,
> > void *data)
> > mc->has_dynamic_sysbus = true;
> > mc->get_hotplug_handler = spapr_get_hotpug_handler;
> > hc->plug = spapr_machine_device_plug;
> > + hc->unplug = spapr_machine_device_unplug;
> > +
> > smc->dr_phb_enabled = false;
> > smc->dr_cpu_enabled = false;
> > smc->dr_lmb_enabled = false;
> > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> > index 12045a1..0c1be07 100644
> > --- a/linux-headers/linux/kvm.h
> > +++ b/linux-headers/linux/kvm.h
> > @@ -761,6 +761,7 @@ struct kvm_ppc_smmu_info {
> > #define KVM_CAP_PPC_FIXUP_HCALL 103
> > #define KVM_CAP_PPC_ENABLE_HCALL 104
> > #define KVM_CAP_CHECK_EXTENSION_VM 105
> > +#define KVM_CAP_SPAPR_REUSE_VCPU 107
>
> Updates to linux-headers/ are usually put into their own patch for
> safety (along with an indication of what kernel commit the additions
> came from).
>
> > #ifdef KVM_CAP_IRQ_ROUTING
> >
> > diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> > index 1edf2b5..ee23bf6 100644
> > --- a/target-ppc/kvm.c
> > +++ b/target-ppc/kvm.c
> > @@ -72,6 +72,7 @@ static int cap_ppc_watchdog;
> > static int cap_papr;
> > static int cap_htab_fd;
> > static int cap_fixup_hcalls;
> > +static int cap_spapr_reuse_vcpu;
>
> AFAICT nothing in this patch checks this variable. Does it belong in
> this patch?
This is some remnant of an old approach I was trying. It got left out
by mistake and sorry that you had to review this part.
I will clean this up in the next post.
Regards,
Bharata.
