Re: [PATCH v4 5/8] mips/cps: Use start-powered-off CPUState property

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 8/18/20 1:03 PM, Philippe Mathieu-Daudé wrote:
> On 8/18/20 9:26 AM, Philippe Mathieu-Daudé wrote:
>> On 8/18/20 5:33 AM, Thiago Jung Bauermann wrote:
>>> Instead of setting CPUState::halted to 1 in main_cpu_reset(), 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/mips/cps.c | 16 ++++++++++++----
>>>  1 file changed, 12 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/hw/mips/cps.c b/hw/mips/cps.c
>>> index 615e1a1ad2..be85357dc0 100644
>>> --- a/hw/mips/cps.c
>>> +++ b/hw/mips/cps.c
>>> @@ -52,9 +52,6 @@ static void main_cpu_reset(void *opaque)
>>>      CPUState *cs = CPU(cpu);
>>>  
>>>      cpu_reset(cs);
>>> -
>>> -    /* All VPs are halted on reset. Leave powering up to CPC. */
>>> -    cs->halted = 1;
>>>  }
>>>  
>>>  static bool cpu_mips_itu_supported(CPUMIPSState *env)
>>> @@ -76,7 +73,9 @@ static void mips_cps_realize(DeviceState *dev, Error **errp)
>>>      bool saar_present = false;
>>>  
>>>      for (i = 0; i < s->num_vp; i++) {
>>> -        cpu = MIPS_CPU(cpu_create(s->cpu_type));
>>> +        Error *err = NULL;
>>> +
>>> +        cpu = MIPS_CPU(object_new(s->cpu_type));
>>>  
>>>          /* Init internal devices */
>>>          cpu_mips_irq_init_cpu(cpu);
>>> @@ -89,7 +88,16 @@ static void mips_cps_realize(DeviceState *dev, Error **errp)
>>>              env->itc_tag = mips_itu_get_tag_region(&s->itu);
>>>              env->itu = &s->itu;
>>>          }
>>> +        /* All VPs are halted on reset. Leave powering up to CPC. */
>>> +        object_property_set_bool(OBJECT(cpu), "start-powered-off", true,
>>> +                                 &error_abort);
>>>          qemu_register_reset(main_cpu_reset, cpu);
>>> +
>>> +        if (!qdev_realize(DEVICE(cpu), NULL, &err)) {
>>> +            error_report_err(err);
>>> +            object_unref(OBJECT(cpu));
>>> +            exit(EXIT_FAILURE);
>>> +        }
>>
>> Here errp is available, so we can propagate the error to the caller:
>>
>>            if (!qdev_realize(DEVICE(cpu), NULL, errp)) {
> 
> Igor corrected me in the previous patch, to avoid leaking the
> reference this snippet misses:
> 
>                  object_unref(OBJECT(cpu));

Well this is simply:

              if (!qdev_realize_and_unref(DEVICE(cpu), NULL, errp)) {
> 
>>                return;
>>            }
>>
>> For example in hw/mips/boston.c:
>>
>>     object_initialize_child(OBJECT(machine), "cps", &s->cps, TYPE_MIPS_CPS);
>>     object_property_set_str(OBJECT(&s->cps), "cpu-type", machine->cpu_type,
>>                             &error_fatal);
>>     object_property_set_int(OBJECT(&s->cps), "num-vp", machine->smp.cpus,
>>                             &error_fatal);
>>     sysbus_realize(SYS_BUS_DEVICE(&s->cps), &error_fatal);
>>
>> This will be propagated here ---------------^^^^^^^^^^^^^
>>
>>>      }
>>>  
>>>      cpu = MIPS_CPU(first_cpu);
>>>
>