spapr: convert boot CPUs into CPU core devices

Introduce sPAPRMachineClass.dr_cpu_enabled to indicate support for
CPU core hotplug. Initialize boot time CPUs as core deivces and prevent
topologies that result in partially filled cores. Both of these are done
only if CPU core hotplug is supported.

Note: An unrelated change in the call to xics_system_init() is done
in this patch as it makes sense to use the local variable smt introduced
in this patch instead of kvmppc_smt_threads() call here.

TODO: We derive sPAPR core type by looking at -cpu <model>. However
we don't take care of "compat=" feature yet for boot time as well
as hotplug CPUs.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 58 insertions, 0 deletions

diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 2e24e3999c..d747c26982 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -63,6 +63,64 @@ void spapr_cpu_init(sPAPRMachineState *spapr, PowerPCCPU *cpu, Error **errp)
     qemu_register_reset(spapr_cpu_reset, cpu);
 }
 
+/*
+ * Return the sPAPR CPU core type for @model which essentially is the CPU
+ * model specified with -cpu cmdline option.
+ */
+char *spapr_get_cpu_core_type(const char *model)
+{
+    char *core_type;
+    gchar **model_pieces = g_strsplit(model, ",", 2);
+
+    core_type = g_strdup_printf("%s-%s", model_pieces[0], TYPE_SPAPR_CPU_CORE);
+    g_strfreev(model_pieces);
+    return core_type;
+}
+
+void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
+                         Error **errp)
+{
+    MachineState *machine = MACHINE(OBJECT(hotplug_dev));
+    sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
+    int spapr_max_cores = max_cpus / smp_threads;
+    int index;
+    int smt = kvmppc_smt_threads();
+    Error *local_err = NULL;
+    CPUCore *cc = CPU_CORE(dev);
+    char *base_core_type = spapr_get_cpu_core_type(machine->cpu_model);
+    const char *type = object_get_typename(OBJECT(dev));
+
+    if (strcmp(base_core_type, type)) {
+        error_setg(&local_err, "CPU core type should be %s", base_core_type);
+        goto out;
+    }
+
+    if (cc->nr_threads != smp_threads) {
+        error_setg(&local_err, "threads must be %d", smp_threads);
+        goto out;
+    }
+
+    if (cc->core_id % smt) {
+        error_setg(&local_err, "invalid core id %d\n", cc->core_id);
+        goto out;
+    }
+
+    index = cc->core_id / smt;
+    if (index < 0 || index >= spapr_max_cores) {
+        error_setg(&local_err, "core id %d out of range", cc->core_id);
+        goto out;
+    }
+
+    if (spapr->cores[index]) {
+        error_setg(&local_err, "core %d already populated", cc->core_id);
+        goto out;
+    }
+
+out:
+    g_free(base_core_type);
+    error_propagate(errp, local_err);
+}
+
 static int spapr_cpu_core_realize_child(Object *child, void *opaque)
 {
     Error **errp = opaque;