Re: [Qemu-devel] pert stat in KVM guest can not get LLC-loads hardware cache event

[Liang, Kan]

> 
> Dear KVM developers:
> I am trying use perf stat inside a VM to obtain some hardware cache
> performance counter values.
> The perf stat can report some numbers for L1 and TLB related counters. But
> for the LLC-loads and LLC-load-misses, the numbers are always 0. It seems
> that the these offcore events are not exposed to the guest.
> 
> Is this a bug in Qemu or KVM?
> 

There is no offcore virtualization support in KVM yet.
For you case, I guess you are using paravirt for guest, so it should be 0. 
Otherwise, you should get #GP in guest. 


> My testbed is
> 
> Host kernel: 3.12.26
> Qemu: 2.1.0
> CPU: Intel Ivy bridge 2620
> VM boosted by qemu, with -cpu host.
> 
> Thanks.
> 
> - Hui Kang