On Tue, Apr 07, 2015 at 04:45:17PM +1000, Alexey Kardashevskiy wrote:
> On 03/24/2015 12:36 AM, 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);
> >+
> >+ /*
> >+ * 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)) {
>
>
> What is this change for? I mean why is not it always socket-only? Commit log
> would not hurt here...
In the hot add case (do_device_add), the CPU socket device is realized first
which will realize the CPU core devices. Core devices will realize the CPU
thread devices. So the ->plug() operation happens as part of CPU thread devices
and hence hotplug_handler is returned only for TYPE_CPU.
However in case of hot remove, qdev_unplug() directly does ->unplug() and
hence I need to return the hotplug_handler for TYPE_CPU_SOCKET also.
This ensures that ->unplug() gets called for socket object where I take
care of recursively walking down the core and thread objects and unplugging
the CPU thread object eventually.
Regards,
Bharata.
