Re: [Qemu-devel] [PATCH] cpu: smp_wmb before lauching cpus.

[Jan Kiszka]

On 2012-07-05 12:10, liu ping fan wrote:
> On Thu, Jul 5, 2012 at 2:46 PM, Jan Kiszka <address@hidden> wrote:
>> On 2012-07-05 04:18, Liu Ping Fan wrote:
>>> Vcpu state must be set completely before receiving INIT-IPI,SIPI
>>>
>>> Signed-off-by: Liu Ping Fan <address@hidden>
>>> ---
>>>  kvm.h |    1 +
>>>  1 files changed, 1 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/kvm.h b/kvm.h
>>> index 9c7b0ea..5b3c228 100644
>>> --- a/kvm.h
>>> +++ b/kvm.h
>>> @@ -198,6 +198,7 @@ static inline void 
>>> cpu_synchronize_post_init(CPUArchState *env)
>>>  {
>>>      if (kvm_enabled()) {
>>>          kvm_cpu_synchronize_post_init(env);
>>> +        smp_wmb();
>>>      }
>>>  }
>>>
>>>
>>
>> In theory, there should be no vcpu kick-off after this without some
>> locking operations involved that imply barriers. Did you see real
> 
> Yeah, but what if it is non-x86?

The locking I'm referring to is arch independent.

>> inconsistencies without this explicit one?

Again: Did you see real issues or is this based on static analysis?

Jan

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