Re: [PATCH] Remove MSR_P6_{EVNTSEL0,PERFCTR0} from printk warning list.

[Avi Kivity <avi@redhat.com>]

On 07/01/2010 05:41 PM, Jes Sorensen wrote:
> On 07/01/10 16:38, Avi Kivity wrote:
>    
>> On 06/30/2010 05:27 PM, Jes.Sorensen@redhat.com wrote:
>>      
>>> From: Jes Sorensen<Jes.Sorensen@redhat.com>
>>>
>>> MSR_P6_EVNTSEL0 and MSR_P6_PERFCTR0 are used to probe for the P6 PMU
>>> for older family 6 CPUs, which is also the default in QEMU. Ie. per
>>> default we get the noise of these warnings in dmesg, confusing users
>>> for no reason.
>>>        
>> For the reason, see the comment above.  The guest may be trying to do
>> something with the counters and expect them to work.  Without the
>> warning we'd have no idea we are knowningly misemulating something.
>>      
> Saw it, which is why I only suggest we remove EVNTSEL0 and PERFCTR0 but
> not the others. If the guest is expecting normal operation it is likely
> to use more than just the first.
>    

Why is that?

> People are reporting these triggering in dmesg for both Linux and
> Windows guests btw.
>
> We could put them so the two in question only trigger with a debug flag
> or something like that?
>    

What values are the guests writing?  Are they really expecting this 
thing to work?

What would it take to emulate those counters?  They're supposed to be 
relatively simple, no?

-- 
error compiling committee.c: too many arguments to function