Re: [PATCH v4 4/8] ppc/e500: Use start-powered-off CPUState property

[Thiago Jung Bauermann]

Hello Philippe,

Thanks for your review.

Philippe Mathieu-Daudé <philmd@redhat.com> writes:

> On 8/18/20 9:22 AM, Philippe Mathieu-Daudé wrote:
>> On 8/18/20 5:33 AM, Thiago Jung Bauermann wrote:
>>> Instead of setting CPUState::halted to 1 in ppce500_cpu_reset_sec(), use
>>> the start-powered-off property which makes cpu_common_reset() initialize it
>>> to 1 in common code.
>>>
>>> Also change creation of CPU object from cpu_create() to object_new() and
>>> qdev_realize() because cpu_create() realizes the CPU and it's not possible
>>> to set a property after the object is realized.
>>>
>>> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
>>> ---
>>>  hw/ppc/e500.c | 19 +++++++++++++++----
>>>  1 file changed, 15 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
>>> index ab9884e315..0077aca74d 100644
>>> --- a/hw/ppc/e500.c
>>> +++ b/hw/ppc/e500.c
>>> @@ -704,9 +704,6 @@ static void ppce500_cpu_reset_sec(void *opaque)
>>>
>>>      cpu_reset(cs);
>>>
>>> -    /* Secondary CPU starts in halted state for now. Needs to change when
>>> -       implementing non-kernel boot. */
>>> -    cs->halted = 1;
>>>      cs->exception_index = EXCP_HLT;
>>>  }
>>>
>>> @@ -864,8 +861,9 @@ void ppce500_init(MachineState *machine)
>>>          PowerPCCPU *cpu;
>>>          CPUState *cs;
>>>          qemu_irq *input;
>>> +        Error *err = NULL;
>>>
>>> -        cpu = POWERPC_CPU(cpu_create(machine->cpu_type));
>>> +        cpu = POWERPC_CPU(object_new(machine->cpu_type));
>>>          env = &cpu->env;
>>>          cs = CPU(cpu);
>>>
>>> @@ -897,6 +895,19 @@ void ppce500_init(MachineState *machine)
>>>          } else {
>>>              /* Secondary CPUs */
>>>              qemu_register_reset(ppce500_cpu_reset_sec, cpu);
>>> +
>>> +            /*
>>> +             * Secondary CPU starts in halted state for now. Needs to 
>>> change
>>> +             * when implementing non-kernel boot.
>>> +             */
>>> +            object_property_set_bool(OBJECT(cs), "start-powered-off", true,
>>> +                                     &error_abort);
>>
>> [*]
>>
>>> +        }
>>> +
>>> +        if (!qdev_realize(DEVICE(cs), NULL, &err)) {
>>> +            error_report_err(err);
>>> +            object_unref(OBJECT(cs));
>>> +            exit(EXIT_FAILURE);
>>>          }
>>
>> The last 4 lines are equivalent to:
>>
>>            qdev_realize(DEVICE(cs), NULL, &error_fatal)) {
>
> I meant:
>
>              qdev_realize(DEVICE(cs), NULL, &error_fatal);

Ah! Thanks for pointing it out. I'll use that (along with
qdev_realize_and_unref()).

>
>>
>> This is also the preferred form, as we can not propagate errors
>> from the machine_init() handler.
>>
>> Since you use &error_abort in [*], maybe you want to use it here too.

I think &error_fatal is better since it preserves the behavior from
cpu_create().

--
Thiago Jung Bauermann
IBM Linux Technology Center