Re: [Qemu-devel] [PATCH 03/16] introduce resume_vcpu(), for single CPU

["Andreas Färber" <afaerber@suse.de>]

Am 22.04.2013 13:45, schrieb Igor Mammedov:
> On Mon, 22 Apr 2013 13:59:17 +0300
> Gleb Natapov <gleb@redhat.com> wrote:
> 
>> On Mon, Apr 22, 2013 at 12:54:04PM +0200, Igor Mammedov wrote:
>>> On Mon, 22 Apr 2013 13:40:02 +0300
>>> Gleb Natapov <gleb@redhat.com> wrote:
>>>
>>>> On Tue, Apr 16, 2013 at 12:12:43AM +0200, Igor Mammedov wrote:
>>>>> ... also add stub for it, to make possible to use it in qom/cpu.c,
>>>>> which is shared with user emulators.
>>>>>
>>>>> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
>>>>> ---
>>>>> Note:
>>>>>   it will be re-used from qom/cpu.c by hotpluged CPU
>>>>> ---
>>>>>  cpus.c              | 11 ++++++++---
>>>>>  include/qom/cpu.h   |  9 +++++++++
>>>>>  stubs/Makefile.objs |  1 +
>>>>>  stubs/cpus.c        |  5 +++++
>>>>>  4 files changed, 23 insertions(+), 3 deletions(-)
>>>>>  create mode 100644 stubs/cpus.c
>>>>>
>>>>> diff --git a/cpus.c b/cpus.c
>>>>> index c15ff6c..c347db5 100644
>>>>> --- a/cpus.c
>>>>> +++ b/cpus.c
>>>>> @@ -993,6 +993,13 @@ void pause_all_vcpus(void)
>>>>>      }
>>>>>  }
>>>>>  
>>>>> +void resume_vcpu(CPUState *cpu)
>>>>> +{
>>>>> +    cpu->stop = false;
>>>>> +    cpu->stopped = false;
>>>>> +    qemu_cpu_kick(cpu);
>>>>> +}
>>>>> +
>>>>>  void resume_all_vcpus(void)
>>>>>  {
>>>>>      CPUArchState *penv = first_cpu;
>>>>> @@ -1000,9 +1007,7 @@ void resume_all_vcpus(void)
>>>>>      qemu_clock_enable(vm_clock, true);
>>>>>      while (penv) {
>>>>>          CPUState *pcpu = ENV_GET_CPU(penv);
>>>>> -        pcpu->stop = false;
>>>>> -        pcpu->stopped = false;
>>>>> -        qemu_cpu_kick(pcpu);
>>>>> +        resume_vcpu(pcpu);
>>>>>          penv = penv->next_cpu;
>>>>>      }
>>>>>  }
>>>>> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
>>>>> index 3664a1b..6ce6f10 100644
>>>>> --- a/include/qom/cpu.h
>>>>> +++ b/include/qom/cpu.h
>>>>> @@ -256,5 +256,14 @@ void cpu_interrupt(CPUState *cpu, int mask);
>>>>>   */
>>>>>  void cpu_reset_interrupt(CPUState *cpu, int mask);
>>>>>  
>>>>> +/**
>>>>> + * resume_vcpu:
>>>>> + * @cpu: The CPU to resume.
>>>>> + *
>>>>> + * Resumes CPU, i.e. puts CPU into runable state.
>>>>> + * KVM requires extra call cpu_synchronize_post_init() to make
>>>>> + * KVM's CPU instance runable.
>>>>> + */
>>>> Can you elaborate on this a bit. Why is it needed and why is it relevant
>>>> for this function?
>>> If running in KVM mode and resume_vcpu() is called without
>>> cpu_synchronize_post_init(), then CPU instance in KVM will be
>>> left in UNCONFIGURED state. I've added comment here to document 
>>> that resume_vcpu() isn't enough to make CPU run-able in case of KVM.
>>>
>> But this really relevant only during vcpu creation after that
>> resume_vcpu() should just work. My be have launch_vcpu() function that
> Agreed, it's applicable only during CPU creation.
> 
>> does the right thing and add assert to resume_vcpu() if it is called on
>> vcpu that is not launched yet. In other words made the dependency clear
>> in the code, not comment.
> Would dropping this comment, suffice
> and re-factoring to use launch_vcpu() done later?

Either way I had request cpu_... naming for CPUState functions on IRC.
Could be a follow-up cleanup.

Andreas

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