Re: [RFT] Fix for unhandled msr c0000081 problems under Intel cpus

Ingo Molnar wrote:
> * Avi Kivity <avi@xxxxxxxxxxxx> wrote:
>
>   
>>> that did the trick. The only messages remaining are:
>>>
>>> kvm: unhandled wrmsr: 0xc1
>>> inject_general_protection: rip 0xc011b8ae
>>>
>>>  
>>>       
>> That's a performance counter.  What guest triggers it?
>>     
>
> a 32-bit Linux bzImage:
>
>   c011b8ae:       0f 30                   wrmsr
>
>  (gdb) list *0xc011b8ae
>  0xc011b8ae is in setup_apic_nmi_watchdog (include/asm/msr.h:36).
>  31      static inline void wrmsrl (unsigned long msr, unsigned long long val)
>  32      {
>  33              unsigned long lo, hi;
>  34              lo = (unsigned long) val;
>  35              hi = val >> 32;
>  36              wrmsr (msr, lo, hi);
>  37      }
>  38
>  39      /* wrmsr with exception handling */
>  40      #define wrmsr_safe(msr,a,b) ({ int ret__;                            
>   
>
> the guest also obviously crashes due to this #GPF.
>   

The wary ones use wrmsr_safe().

> [ 2.6.20-rc2-rt2 kernel of course ;-) ]
>
>   

Who's the caller?  I boot 2.6.18 variants regularly and they don't touch 
that msr.


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


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