Re: nmi is broken?

[Avi Kivity <avi@redhat.com>]

On 05/03/2011 01:37 PM, Jan Kiszka wrote:
> >
> >  Yes.  Unfortunately that is very vendor and model specific.  The
> >  architectural PMU is supported, but that is only available on Intel.
>
> Is it supposed to have any practical value already? I did not yet find a
> magic -cpu switch to let Linux detect anything, not to speak of perf or
> watchdog support.

On the guest side it is supported for the watchdog 
(arch/x86/kernel/cpu/perfctr-watchdog.c, look for 
X86_FEATURE_ARCH_PERFMON).  It's also mentioned in perf_event_intel.c, 
but I don't know if it will work without the other PMU features being 
present.

> >
> >  Perhaps we could emulate the architectural PMU on AMD as well, and make
> >  the detection code in the guest vendor agnostic.  Since it's based on a
> >  cpuid bit, it should be safe.
> >
>
> We may only make Linux happy this way, no?

I would argue that if a feature is discoverable by a cpuid bit it 
shouldn't need to be qualified by vendor.  No idea how other OSes work 
this out (or even if they make use of the architectural PMU).

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