Re: [Qemu-devel] [PATCH v3 1/2] move vm_start to cpus.c

[Paolo Bonzini <pbonzini@redhat.com>]

On 25/01/2017 18:53, Claudio Imbrenda wrote:
> On 25/01/17 11:21, Paolo Bonzini wrote:
>>
>>
>> On 28/10/2016 19:15, Claudio Imbrenda wrote:
>>> * moves the call to qemu_clock_enable away from resume_all_vcpus, and
>>>   add an explicit call to it before each instance of resume_all_vcpus
>>>   in the code.
>>
>> This change adds useless duplication, and isn't matched by a similar
>> change to pause_all_vcpus.  You need to justify it; I suppose it is
>> because the next patch will not call resume_all_cpus?
> 
> Actually it is because the next patch used to call resume_all_vcpus, and
> we didn't want it to restart the clock too. But then I ended up not
> using resume_all_vcpus.
> 
> And now I have actually no idea why we didn't want to restart the clock.
> Maybe we should? After all some CPUs are running. I can patch
> gdb_continue_partial to check if any CPU was actually restarted, and if
> so start the clock.
> 
> So in the end it should still be correct, but the changes would be kept
> small.

Yeah, this sounds like a good solution.  Thanks!

Paolo

>> Most of the callers of pause_all_vcpus/resume_all_vcpus don't let timers
>> run, so the clock need not be disabled and enabled.  Maybe the right
>> places to call qemu_clock_enable are cpu_disable_ticks and
>> cpu_enable_ticks?  That should work for you.
>>
>> In that case, please make the first patch the qemu_clock_enable
>> movement; the second patch the introduction of vm_prepare_start; the
>> third patch the gdbstub change.
>>
>>> diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h
>>> index 3728a1e..5fa074b 100644
>>> --- a/include/sysemu/cpus.h
>>> +++ b/include/sysemu/cpus.h
>>> @@ -5,6 +5,7 @@
>>>  bool qemu_in_vcpu_thread(void);
>>>  void qemu_init_cpu_loop(void);
>>>  void resume_all_vcpus(void);
>>> +void resume_some_vcpus(CPUState **cpus);
>>>  void pause_all_vcpus(void);
>>>  void cpu_stop_current(void);
>>>  void cpu_ticks_init(void);
>>
>> This function doesn't exist.
> 
> oops.
> 
> 
> Claudio
>