On Fri, Feb 26, 2016 at 02:51:41PM +1100, David Gibson wrote:
> On Thu, Feb 25, 2016 at 09:52:40PM +0530, Bharata B Rao wrote:
> > Set up device tree entries for the hotplugged CPU core and use the
> > exising EPOW event infrastructure to send CPU hotplug notification to
> > the guest.
> >
> > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
> > ---
> > hw/ppc/spapr.c | 136
> > ++++++++++++++++++++++++++++++++++++++++++++++++-
> > hw/ppc/spapr_events.c | 3 ++
> > hw/ppc/spapr_rtas.c | 24 +++++++++
> > include/hw/ppc/spapr.h | 1 +
> > 4 files changed, 163 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > index 1f0d232..780cd00 100644
> > --- a/hw/ppc/spapr.c
> > +++ b/hw/ppc/spapr.c
> > @@ -603,6 +603,18 @@ static void spapr_populate_cpu_dt(CPUState *cs, void
> > *fdt, int offset,
> > size_t page_sizes_prop_size;
> > uint32_t vcpus_per_socket = smp_threads * smp_cores;
> > uint32_t pft_size_prop[] = {0, cpu_to_be32(spapr->htab_shift)};
> > + sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(qdev_get_machine());
> > + sPAPRDRConnector *drc;
> > + sPAPRDRConnectorClass *drck;
> > + int drc_index;
> > +
> > + if (smc->dr_cpu_enabled) {
> > + drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, index);
> > + g_assert(drc);
> > + drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> > + drc_index = drck->get_index(drc);
> > + _FDT((fdt_setprop_cell(fdt, offset, "ibm,my-drc-index",
> > drc_index)));
> > + }
> >
> > /* Note: we keep CI large pages off for now because a 64K capable guest
> > * provisioned with large pages might otherwise try to map a qemu
> > @@ -987,6 +999,16 @@ static void spapr_finalize_fdt(sPAPRMachineState
> > *spapr,
> > _FDT(spapr_drc_populate_dt(fdt, 0, NULL,
> > SPAPR_DR_CONNECTOR_TYPE_LMB));
> > }
> >
> > + if (smc->dr_cpu_enabled) {
> > + int offset = fdt_path_offset(fdt, "/cpus");
> > + ret = spapr_drc_populate_dt(fdt, offset, NULL,
> > + SPAPR_DR_CONNECTOR_TYPE_CPU);
> > + if (ret < 0) {
> > + fprintf(stderr, "Couldn't set up CPU DR device tree
> > properties\n");
> > + exit(1);
> > + }
> > + }
> > +
> > _FDT((fdt_pack(fdt)));
> >
> > if (fdt_totalsize(fdt) > FDT_MAX_SIZE) {
> > @@ -1759,6 +1781,7 @@ static void ppc_spapr_init(MachineState *machine)
> > char *filename;
> > int spapr_cores = smp_cpus / smp_threads;
> > int spapr_max_cores = max_cpus / smp_threads;
> > + int smt = kvmppc_smt_threads();
> >
> > msi_supported = true;
> >
> > @@ -1813,6 +1836,15 @@ static void ppc_spapr_init(MachineState *machine)
> > spapr_validate_node_memory(machine, &error_fatal);
> > }
> >
> > + if (smc->dr_cpu_enabled) {
> > + for (i = 0; i < spapr_max_cores; i++) {
> > + sPAPRDRConnector *drc =
> > + spapr_dr_connector_new(OBJECT(spapr),
> > + SPAPR_DR_CONNECTOR_TYPE_CPU, i *
> > smt);
> > + qemu_register_reset(spapr_drc_reset, drc);
> > + }
> > + }
> > +
> > /* init CPUs */
> > if (machine->cpu_model == NULL) {
> > machine->cpu_model = kvm_enabled() ? "host" : "POWER7";
> > @@ -2247,6 +2279,88 @@ out:
> > error_propagate(errp, local_err);
> > }
> >
> > +static void *spapr_populate_hotplug_cpu_dt(DeviceState *dev, CPUState *cs,
> > + int *fdt_offset,
> > + sPAPRMachineState *spapr)
> > +{
> > + PowerPCCPU *cpu = POWERPC_CPU(cs);
> > + DeviceClass *dc = DEVICE_GET_CLASS(cs);
> > + int id = ppc_get_vcpu_dt_id(cpu);
> > + void *fdt;
> > + int offset, fdt_size;
> > + char *nodename;
> > +
> > + fdt = create_device_tree(&fdt_size);
> > + nodename = g_strdup_printf("%s@%x", dc->fw_name, id);
> > + offset = fdt_add_subnode(fdt, 0, nodename);
> > +
> > + spapr_populate_cpu_dt(cs, fdt, offset, spapr);
> > + g_free(nodename);
> > +
> > + *fdt_offset = offset;
> > + return fdt;
> > +}
> > +
> > +static void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> > + Error **errp)
> > +{
> > + sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(qdev_get_machine());
> > + sPAPRMachineState *ms = SPAPR_MACHINE(qdev_get_machine());
> > + sPAPRCPUCore *core = SPAPR_CPU_CORE(OBJECT(dev));
> > + PowerPCCPU *cpu = &core->threads[0];
> > + CPUState *cs = CPU(cpu);
> > + 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;
> > + void *fdt = NULL;
> > + int fdt_offset = 0;
> > +
> > + if (!smc->dr_cpu_enabled) {
> > + /*
> > + * This is a cold plugged CPU core but the machine doesn't support
> > + * DR. So skip the hotplug path ensuring that the core is brought
> > + * up online with out an associated DR connector.
> > + */
> > + return;
> > + }
> > +
> > + g_assert(drc);
> > +
> > + /*
> > + * Setup CPU DT entries only for hotplugged CPUs. For boot time or
> > + * coldplugged CPUs DT entries are setup in spapr_finalize_fdt().
> > + */
> > + if (dev->hotplugged) {
> > + fdt = spapr_populate_hotplug_cpu_dt(dev, cs, &fdt_offset, ms);
> > + dev->hotplugged = true;
> > + }
> > +
> > + drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> > + drck->attach(drc, dev, fdt, fdt_offset, !dev->hotplugged, &local_err);
> > + if (local_err) {
> > + g_free(fdt);
> > + error_propagate(errp, local_err);
> > + return;
> > + }
> > +
> > + if (dev->hotplugged) {
> > + /*
> > + * Send hotplug notification interrupt to the guest only in case
> > + * of hotplugged CPUs.
> > + */
> > + spapr_hotplug_req_add_by_index(drc);
> > + } else {
> > + /*
> > + * Set the right DRC states for cold plugged CPU.
> > + */
> > + drck->set_allocation_state(drc, SPAPR_DR_ALLOCATION_STATE_USABLE);
> > + drck->set_isolation_state(drc,
> > SPAPR_DR_ISOLATION_STATE_UNISOLATED);
> > + }
> > + return;
> > +}
> > +
> > static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
> > DeviceState *dev, Error **errp)
> > {
> > @@ -2291,8 +2405,25 @@ static void spapr_machine_device_plug(HotplugHandler
> > *hotplug_dev,
> > } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> > CPUState *cs = CPU(dev);
> > PowerPCCPU *cpu = POWERPC_CPU(cs);
> > + int i;
> > +
> > + if (!smc->dr_cpu_enabled && dev->hotplugged) {
> > + error_setg(errp, "CPU hotplug not supported for this machine");
> > + return;
> > + }
> > +
> > + /* Set NUMA node for the added CPUs */
> > + for (i = 0; i < nb_numa_nodes; i++) {
> > + if (test_bit(cs->cpu_index, numa_info[i].node_cpu)) {
> > + cs->numa_node = i;
> > + break;
> > + }
> > + }
> >
> > spapr_cpu_init(ms, cpu, errp);
> > + spapr_cpu_reset(cpu);
>
> It looks to me like all of this setup should be either in the last
> patch, or in this one, not split between them.
The way I have done the functional split is like this:
- Introduce the spapr-cpu-core device as the 2nd patch in the series
- The previous patch converts the boot CPU initialization into
spapr-cpu-core creation. So until this point, we can just boot a guest
with this CPUs created as core devices.
- Then this patch adds the bits needed to actually perform a device_add
operation of core device.
But I am open to re-arrange things if you feel it is necessary.
>
> > + } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
> > + spapr_core_plug(hotplug_dev, dev, errp);
> > }
> > }
> >
> > @@ -2308,7 +2439,8 @@ static HotplugHandler
> > *spapr_get_hotpug_handler(MachineState *machine,
> > DeviceState *dev)
> > {
> > if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) ||
> > - object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> > + object_dynamic_cast(OBJECT(dev), TYPE_CPU) ||
> > + object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
> > return HOTPLUG_HANDLER(machine);
> > }
> > return NULL;
> > @@ -2352,6 +2484,7 @@ static void spapr_machine_class_init(ObjectClass *oc,
> > void *data)
> > mc->cpu_index_to_socket_id = spapr_cpu_index_to_socket_id;
> >
> > smc->dr_lmb_enabled = true;
> > + smc->dr_cpu_enabled = true;
> > fwc->get_dev_path = spapr_get_fw_dev_path;
> > nc->nmi_monitor_handler = spapr_nmi;
> > }
> > @@ -2431,6 +2564,7 @@ static void
> > spapr_machine_2_5_class_options(MachineClass *mc)
> >
> > spapr_machine_2_6_class_options(mc);
> > smc->use_ohci_by_default = true;
> > + smc->dr_cpu_enabled = false;
> > SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_5);
> > }
> >
> > diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
> > index f5eac4b..e50bb16 100644
> > --- a/hw/ppc/spapr_events.c
> > +++ b/hw/ppc/spapr_events.c
> > @@ -437,6 +437,9 @@ static void spapr_hotplug_req_event(uint8_t hp_id,
> > uint8_t hp_action,
> > case SPAPR_DR_CONNECTOR_TYPE_LMB:
> > hp->hotplug_type = RTAS_LOG_V6_HP_TYPE_MEMORY;
> > break;
> > + case SPAPR_DR_CONNECTOR_TYPE_CPU:
> > + hp->hotplug_type = RTAS_LOG_V6_HP_TYPE_CPU;
> > + break;
> > default:
> > /* we shouldn't be signaling hotplug events for resources
> > * that don't support them
> > diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> > index b7c5ebd..cc0369e 100644
> > --- a/hw/ppc/spapr_rtas.c
> > +++ b/hw/ppc/spapr_rtas.c
> > @@ -34,6 +34,7 @@
> >
> > #include "hw/ppc/spapr.h"
> > #include "hw/ppc/spapr_vio.h"
> > +#include "hw/ppc/ppc.h"
> > #include "qapi-event.h"
> > #include "hw/boards.h"
> >
> > @@ -161,6 +162,27 @@ static void rtas_query_cpu_stopped_state(PowerPCCPU
> > *cpu_,
> > rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
> > }
> >
> > +/*
> > + * Set the timebase offset of the CPU to that of first CPU.
> > + * This helps hotplugged CPU to have the correct timebase offset.
> > + */
> > +static void spapr_cpu_update_tb_offset(PowerPCCPU *cpu)
> > +{
> > + PowerPCCPU *fcpu = POWERPC_CPU(first_cpu);
> > +
> > + cpu->env.tb_env->tb_offset = fcpu->env.tb_env->tb_offset;
> > +}
> > +
> > +static void spapr_cpu_set_endianness(PowerPCCPU *cpu)
> > +{
> > + PowerPCCPU *fcpu = POWERPC_CPU(first_cpu);
> > + PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(fcpu);
> > +
> > + if (!pcc->interrupts_big_endian(fcpu)) {
> > + cpu->env.spr[SPR_LPCR] |= LPCR_ILE;
> > + }
> > +}
> > +
>
> Any particular reason for doing these things at rtas_start_cpu() time,
> but other initialization at plug time? Could you consolidate it to
> one place or the other?
Those board specific things that are needed to be done have been consolidated
into spapr_cpu_init() which will be called from the plug handler. We have
discussed this earlier at:
https://lists.nongnu.org/archive/html/qemu-devel/2015-02/msg04399.html
It has been a while but there was a good reason why setting endianness
here rather than in plug handler is necessary. W/o this LE hotplug on guests
wouldn't work, I will dig up and come back on what exactly necessiated
this change.
Regards,
Bharata.
