Re: [Qemu-devel] [PATCH] ipmi: do not take/drop iothread lock

[Corey Minyard <cminyard@mvista.com>]

On 01/26/2016 10:21 AM, Michael S. Tsirkin wrote:
> On Tue, Jan 26, 2016 at 05:15:53PM +0100, Paolo Bonzini wrote:
>> This is not necessary and actually causes a hang; it was probably copied
>> and pasted from KVM code, that is one of the very few places that run
>> outside iothread lock.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Makes sense. I wonder how hard would it be to have a test to catch this.

The IPMI side would be easy for me, but I don't know how to handle 
catching the NMI.

-corey

>> ---
>>   hw/ipmi/ipmi.c | 2 --
>>   1 file changed, 2 deletions(-)
>>
>> diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
>> index 52aba1e..fcba0ca 100644
>> --- a/hw/ipmi/ipmi.c
>> +++ b/hw/ipmi/ipmi.c
>> @@ -50,9 +50,7 @@ static int ipmi_do_hw_op(IPMIInterface *s, enum ipmi_op op, int checkonly)
>>           if (checkonly) {
>>               return 0;
>>           }
>> -        qemu_mutex_lock_iothread();
>>           qmp_inject_nmi(NULL);
>> -        qemu_mutex_unlock_iothread();
>>           return 0;
>>   
>>       case IPMI_POWERCYCLE_CHASSIS:
>> -- 
>> 2.5.0