Re: [Qemu-devel] [PATCH v6 08/11] target-ppc: Introduce PowerPC specific CPU core device

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Wed, Jan 13, 2016 at 10:44:07AM +1100, Alexey Kardashevskiy wrote:
> On 01/08/2016 05:55 PM, Bharata B Rao wrote:
> >CPU core device is a container of CPU thread devices.  CPU hotplug is
> >performed at the granularity of CPU core device. When hotplugged, CPU core
> >creates CPU thread devices.
> >
> >Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> >---
> >  hw/ppc/Makefile.objs      |  1 +
> >  hw/ppc/cpu-core.c         | 69 +++++++++++++++++++++++++++++++++++++++++++++++
> >  include/hw/ppc/cpu-core.h | 22 +++++++++++++++
> >  3 files changed, 92 insertions(+)
> >  create mode 100644 hw/ppc/cpu-core.c
> >  create mode 100644 include/hw/ppc/cpu-core.h
> >
> >diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
> >index c1ffc77..a6b7cfb 100644
> >--- a/hw/ppc/Makefile.objs
> >+++ b/hw/ppc/Makefile.objs
> >@@ -21,3 +21,4 @@ obj-$(CONFIG_E500) += e500.o mpc8544ds.o e500plat.o
> >  obj-$(CONFIG_E500) += mpc8544_guts.o ppce500_spin.o
> >  # PowerPC 440 Xilinx ML507 reference board.
> >  obj-$(CONFIG_XILINX) += virtex_ml507.o
> >+obj-y += cpu-core.o
> >diff --git a/hw/ppc/cpu-core.c b/hw/ppc/cpu-core.c
> >new file mode 100644
> >index 0000000..c5c6188
> >--- /dev/null
> >+++ b/hw/ppc/cpu-core.c
> >@@ -0,0 +1,69 @@
> >+/*
> >+ * CPU core device, acts as container of CPU thread devices.
> >+ *
> >+ * Copyright (C) 2015 Bharata B Rao <bharata@linux.vnet.ibm.com>
> >+ *
> >+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
> >+ * See the COPYING file in the top-level directory.
> >+ */
> >+#include "hw/ppc/cpu-core.h"
> >+#include "hw/boards.h"
> >+#include <sysemu/cpus.h>
> >+#include "qemu/error-report.h"
> >+
> >+static int ppc_cpu_core_realize_child(Object *child, void *opaque)
> >+{
> >+    Error **errp = opaque;
> >+
> >+    object_property_set_bool(child, true, "realized", errp);
> >+    if (*errp) {
> >+        return 1;
> >+    }
> >+
> >+    return 0;
> >+}
> >+
> >+static void ppc_cpu_core_realize(DeviceState *dev, Error **errp)
> >+{
> >+    object_child_foreach(OBJECT(dev), ppc_cpu_core_realize_child, errp);
> >+}
> >+
> >+static void ppc_cpu_core_class_init(ObjectClass *oc, void *data)
> >+{
> >+    DeviceClass *dc = DEVICE_CLASS(oc);
> >+
> >+    dc->realize = ppc_cpu_core_realize;
> >+}
> >+
> >+static void ppc_cpu_core_instance_init(Object *obj)
> >+{
> >+    int i;
> >+    CPUState *cpu;
> >+    MachineState *machine = MACHINE(qdev_get_machine());
> >+
> >+    /* Create as many CPU threads as specified in the topology */
> >+    for (i = 0; i < smp_threads; i++) {
> >+        cpu = cpu_generic_init(TYPE_POWERPC_CPU, machine->cpu_model);
> >+        if (!cpu) {
> >+            error_report("Unable to find CPU definition: %s\n",
> >+                          machine->cpu_model);
> >+            exit(EXIT_FAILURE);
> >+        }
> >+        object_property_add_child(obj, "thread[*]", OBJECT(cpu), &error_abort);
> >+        object_unref(OBJECT(cpu));
> >+    }
> >+}
> >+
> >+static const TypeInfo ppc_cpu_core_type_info = {
> >+    .name = TYPE_POWERPC_CPU_CORE,
> >+    .parent = TYPE_DEVICE,
> >+    .class_init = ppc_cpu_core_class_init,
> >+    .instance_init = ppc_cpu_core_instance_init,
> 
> 
> Out of curiosity - why not .realize (and return Error instead of exit())?
> I'd think this is the recommended approach now for QOM.

This is an error during object creation and hence we don't have any
other option but to exit. I guess I should use error_setg(&error_fatal, )
instead of exit().

Note that realize time errors are being handled in
.realize (ppc_cpu_core_realize) already.

Regards,
Bharata.