On Fri, Mar 14, 2014 at 6:56 AM, Andi Kleen <a...@linux.intel.com> wrote: > On Fri, Mar 14, 2014 at 09:44:29AM +0100, Peter Zijlstra wrote: >> On Thu, Mar 13, 2014 at 12:36:26PM -0700, Venkatesh Srinivas wrote: >> > CPUs which should support the RAPL counters according to >> > Family/Model/Stepping may still issue #GP when attempting to access >> > the RAPL MSRs. This may happen when Linux is running under KVM and >> > we are passing-through host F/M/S data, for example. Use rdmsrl_safe >> > to first access the RAPL_POWER_UNIT MSR; if this fails, do not >> > attempt to use this PMU. >> >> This kvm thing is getting tedious :-( > > It sounds bogus to me too, VMs are supposed to return 0 > on reading unknown MSRs, no #GP.
The Intel ISR section for RDMSR seems to say: "Specifying a reserved or unimplemented MSR address in ECX will also cause a general protection exception". >From a guest's perspective, MSR_RAPL_POWER_UNIT is unimplemented; kvm matches this behavior. Thanks, -- vs; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
