Re: KVM PMU virtualization

Avi Kivity
2010-02-26T14:12:32Z

On 02/26/2010 04:07 PM, Jes Sorensen wrote:
> On 02/26/10 14:27, Ingo Molnar wrote:
>>
>> * Jes Sorensen<Jes.Sorensen@redhat.com> wrote:
>>> You certainly cannot emulate the Core2 on a P4. The Core2 is Perfmon
>>> v2,
>>> whereas Nehalem and Atom are v3 if I remember correctly. [...]
>>
>> Of course you can emulate a good portion of it, as long as there's perf
>> support on the host side for P4.
>
> Actually P4 is pretty uninteresting in this discussion due to the lack
> of VMX support, it's the same issue for Nehalem vs Core2. The problem
> is the same though, we cannot tell the guest that yes P4 has this
> event, but no, we are going to feed you bogus data.

The Pentium D which is a P4 derivative has vmx support. However it is
so slow I'm fine with ignoring it for this feature.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.