On Fri, Dec 04, 2015 at 08:42:06AM +0100, Ingo Molnar wrote: > > * Borislav Petkov <[email protected]> wrote: > > > From: Borislav Petkov <[email protected]> > > > > qemu/kvm doesn't support RAPL and RAPL doesn't have a CPUID feature bit > > so check whether we're in a guest instead. > > So when a hypervisor starts supporting RAPL we'll disable the driver > erroneously? > > Isn't there any better method to detect RAPL support? > > So in particular in drivers/powercap/intel_rapl.c there's an enumerated list > of > CPU models, which is used via a x86_match_cpu() call. That's still not ideal > (it > does not work on hypervisors for example), but even better would be to detect > RAPL > support in some other fashion, that does not rely on us statically > enumerating CPU > models that support it.
RAPL isn't enumerated, the best we could do is attempt to write to one of the writable MSRs and see if that 'works'. Also, yuck @ powercap/intel_rapl.c for doing rdmsr_on_cpu() + wrmsr_on_cpu() all over the place. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
