Daniel P. Berrangé, Jan 29, 2024 at 20:29: > On Thu, Jan 25, 2024 at 08:22:14AM +0100, Anthony Harivel wrote: > > diff --git a/docs/specs/rapl-msr.rst b/docs/specs/rapl-msr.rst > > new file mode 100644 > > index 000000000000..04d27c198fc0 > > --- /dev/null > > +++ b/docs/specs/rapl-msr.rst > > @@ -0,0 +1,133 @@ > > +================ > > +RAPL MSR support > > +================ > > > + > > +Current Limitations > > +------------------- > > + > > +- Works only on Intel host CPUs because AMD CPUs are using different MSR > > + addresses. > > The privileged helper program is validating an allow list of MSRs. > > If those MSRs are only correct on Intel hosts, then the validation > is incomplete, and it could be allowing unprivileged processes on > AMD hosts to access forbidden MSRS whose address happen to clash > with the Intel RAPL MSRs. > > IOW, the privileged helper needs to call cpuid() and validate that > the current host vendor is Intel. > > I suspect we also need a feature check of some kind to validate > that the intel processor supports this features, since old ones > definitely didn't, and we shouldn't assume all future ones will > either. >
To validate that the processor supports the RAPL feature I propose to check this on the Host: $ cat /sys/class/powercap/intel-rapl/enabled 1 The only down side is that INTEL RAPL drivers needs to be mounted then. We don't need it because we directly read the MSRs. Regards, Anthony
