Re: perf uncore & lkvm woes

["Yan, Zheng" <zheng.z.yan@linux.intel.com>]

On 08/19/2012 05:55 PM, Avi Kivity wrote:
> On 08/17/2012 09:56 AM, Peter Zijlstra wrote:
>> On Fri, 2012-08-17 at 09:40 +0800, Yan, Zheng wrote:
>>>
>>> Peter, do I need to submit a patch disables uncore on virtualized CPU?
>>>
>> I think Avi prefers the method where KVM 'fakes' the MSRs and we have to
>> detect if the MSRs actually work or not.
> 
> s/we have/we don't have/.
> 
>>
>> If you're willing to have a go at that, please do so. If you're not sure
>> how to do the KVM part, I'm sure Avi and/or Gleb can help you out.
> 
> Certainly, please see kvm_pmu_get_msr() and kvm_pmu_set_msr().
> 
> The approach is that if an msr write can be emulated correctly (for
> example, it disables a counter) then we let it proceed; if it cannot be
> emulated correctly (for example it enables a counter that we cannot
> emulate), then we ignore it, but print out a message that tells the user
> that we're faking something that may cause the guest to malfunction.
> 
> 

Anyone knows how to detect if the kernel is running on virtualized CPU?

Regards
Yan, Zheng