Re: [Qemu-devel] Re: [PATCH] fix smp with tcg mode and --enable-io-thread

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/23/2010 02:42 AM, Jan Kiszka wrote:
> Jan Kiszka wrote:
>    
>> Marcelo Tosatti wrote:
>>      
>>> On Mon, Jun 21, 2010 at 10:58:32PM +0200, Jan Kiszka wrote:
>>>        
>>>> Jan Kiszka wrote:
>>>>          
>>>>> Marcelo Tosatti wrote:
>>>>>            
>>>>>> Clear exit_request when iothread grabs the global lock.
>>>>>>
>>>>>> Signed-off-by: Marcelo Tosatti<mtosatti@redhat.com>
>>>>>>
>>>>>> diff --git a/cpu-exec.c b/cpu-exec.c
>>>>>> index 026980a..74cb973 100644
>>>>>> --- a/cpu-exec.c
>>>>>> +++ b/cpu-exec.c
>>>>>> @@ -236,10 +236,8 @@ int cpu_exec(CPUState *env1)
>>>>>>       asm("");
>>>>>>       env = env1;
>>>>>>
>>>>>> -    if (exit_request) {
>>>>>> +    if (exit_request)
>>>>>>           env->exit_request = 1;
>>>>>> -        exit_request = 0;
>>>>>> -    }
>>>>>>              
>>>>> Coding style...
>>>>>
>>>>>            
>>>>>>
>>>>>>   #if defined(TARGET_I386)
>>>>>>       if (!kvm_enabled()) {
>>>>>> diff --git a/cpus.c b/cpus.c
>>>>>> index fcd0f09..ef1ab22 100644
>>>>>> --- a/cpus.c
>>>>>> +++ b/cpus.c
>>>>>> @@ -598,6 +598,7 @@ void qemu_mutex_lock_iothread(void)
>>>>>>           }
>>>>>>           qemu_mutex_unlock(&qemu_fair_mutex);
>>>>>>       }
>>>>>> +   exit_request = 0;
>>>>>>   }
>>>>>>
>>>>>>   void qemu_mutex_unlock_iothread(void)
>>>>>>
>>>>>>
>>>>>>              
>>>>> I looked into this a bit as well, and that's what I also have in my
>>>>> queue.
>>>>>
>>>>> But things are still widely broken: pause_all_vcpus and run_on_cpu as
>>>>> there is no guarantee that all VCPUs regularly call into
>>>>> qemu_wait_io_event. Also breakpoints don't work, not only in SMP mode.
>>>>>            
>>> This fixes pause for me:
>>>
>>>        
>> Partially. It caused regressions on the SMP scheduling without the early
>> loop exit in my patch. I will break up my changes later today and post
>> them as series.
>>      
> After fixing the APIC/IOAPIC fallouts, the series is almost done.
> Unfortunately, host&guest debugging is totally broken for
> CONFIG_IOTHREAD (I also noticed that [1] is still not merged).

Did it not get applied to uq/master or has there just not been a merge 
request yet?

Regards,

Anthony LIguori

>   I will
> try to fix this first as it may require some more refactorings.
>
> Jan
>
> [1] http://thread.gmane.org/gmane.comp.emulators.kvm.devel/52718
>
>