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>

2 files changed, 121 insertions, 10 deletions

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index b04a3892ea..52e89afd15 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -66,6 +66,7 @@
 
 #include "hw/compat.h"
 #include "qemu/cutils.h"
+#include "hw/ppc/spapr_cpu_core.h"
 
 #include <libfdt.h>
 
@@ -1683,7 +1684,6 @@ static void ppc_spapr_init(MachineState *machine)
     const char *kernel_filename = machine->kernel_filename;
     const char *kernel_cmdline = machine->kernel_cmdline;
     const char *initrd_filename = machine->initrd_filename;
-    PowerPCCPU *cpu;
     PCIHostState *phb;
     int i;
     MemoryRegion *sysmem = get_system_memory();
@@ -1697,6 +1697,22 @@ static void ppc_spapr_init(MachineState *machine)
     long load_limit, fw_size;
     bool kernel_le = false;
     char *filename;
+    int smt = kvmppc_smt_threads();
+    int spapr_cores = smp_cpus / smp_threads;
+    int spapr_max_cores = max_cpus / smp_threads;
+
+    if (smc->dr_cpu_enabled) {
+        if (smp_cpus % smp_threads) {
+            error_report("smp_cpus (%u) must be multiple of threads (%u)",
+                         smp_cpus, smp_threads);
+            exit(1);
+        }
+        if (max_cpus % smp_threads) {
+            error_report("max_cpus (%u) must be multiple of threads (%u)",
+                         max_cpus, smp_threads);
+            exit(1);
+        }
+    }
 
     msi_nonbroken = true;
 
@@ -1743,8 +1759,7 @@ static void ppc_spapr_init(MachineState *machine)
 
     /* Set up Interrupt Controller before we create the VCPUs */
     spapr->icp = xics_system_init(machine,
-                                  DIV_ROUND_UP(max_cpus * kvmppc_smt_threads(),
-                                               smp_threads),
+                                  DIV_ROUND_UP(max_cpus * smt, smp_threads),
                                   XICS_IRQS, &error_fatal);
 
     if (smc->dr_lmb_enabled) {
@@ -1755,13 +1770,37 @@ static void ppc_spapr_init(MachineState *machine)
     if (machine->cpu_model == NULL) {
         machine->cpu_model = kvm_enabled() ? "host" : "POWER7";
     }
-    for (i = 0; i < smp_cpus; i++) {
-        cpu = cpu_ppc_init(machine->cpu_model);
-        if (cpu == NULL) {
-            error_report("Unable to find PowerPC CPU definition");
-            exit(1);
+
+    if (smc->dr_cpu_enabled) {
+        char *type = spapr_get_cpu_core_type(machine->cpu_model);
+
+        spapr->cores = g_new0(Object *, spapr_max_cores);
+        for (i = 0; i < spapr_cores; i++) {
+            int core_dt_id = i * smt;
+            Object *core;
+
+            if (!object_class_by_name(type)) {
+                error_report("Unable to find sPAPR CPU Core definition");
+                exit(1);
+            }
+
+            core  = object_new(type);
+            object_property_set_int(core, smp_threads, "nr-threads",
+                                    &error_fatal);
+            object_property_set_int(core, core_dt_id, CPU_CORE_PROP_CORE_ID,
+                                    &error_fatal);
+            object_property_set_bool(core, true, "realized", &error_fatal);
         }
-        spapr_cpu_init(spapr, cpu, &error_fatal);
+        g_free(type);
+    } else {
+        for (i = 0; i < smp_cpus; i++) {
+            PowerPCCPU *cpu = cpu_ppc_init(machine->cpu_model);
+            if (cpu == NULL) {
+                error_report("Unable to find PowerPC CPU definition");
+                exit(1);
+            }
+            spapr_cpu_init(spapr, cpu, &error_fatal);
+       }
     }
 
     if (kvm_enabled()) {
@@ -2227,10 +2266,19 @@ static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
     }
 }
 
+static void spapr_machine_device_pre_plug(HotplugHandler *hotplug_dev,
+                                          DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
+        spapr_core_pre_plug(hotplug_dev, dev, errp);
+    }
+}
+
 static HotplugHandler *spapr_get_hotpug_handler(MachineState *machine,
                                              DeviceState *dev)
 {
-    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) ||
+        object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
         return HOTPLUG_HANDLER(machine);
     }
     return NULL;
@@ -2269,11 +2317,13 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     mc->has_dynamic_sysbus = true;
     mc->pci_allow_0_address = true;
     mc->get_hotplug_handler = spapr_get_hotpug_handler;
+    hc->pre_plug = spapr_machine_device_pre_plug;
     hc->plug = spapr_machine_device_plug;
     hc->unplug = spapr_machine_device_unplug;
     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;
 }
@@ -2349,7 +2399,10 @@ static void spapr_machine_2_6_instance_options(MachineState *machine)
 
 static void spapr_machine_2_6_class_options(MachineClass *mc)
 {
+    sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
+
     spapr_machine_2_7_class_options(mc);
+    smc->dr_cpu_enabled = false;
     SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_6);
 }
 
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;