The RAPL MSR read path incorrectly validates CPU context when called
from the PMU subsystem:
if (atomic) {
if (unlikely(smp_processor_id() != cpu))
return -EIO;
rdmsrq(ra->reg.msr, ra->value);
}
This check fails for package-scoped MSRs like RAPL energy counters,
which are readable from any CPU within the package.
The perf tool avoids hitting this check by validating against
/sys/bus/event_source/devices/power/cpumask before opening events.
However, turbostat does not perform this validation and may attempt
reads from non-lead CPUs, causing the check to fail and return zero
power values.
Since package-scoped MSRs are architecturally accessible from any CPU
in the package, remove the CPU matching check.
Also rename 'atomic' to 'pmu_ctx' to clarify this indicates PMU context
where rdmsrq() can be used directly instead of rdmsrl_safe_on_cpu().
Fixes: 748d6ba43a ("powercap: intel_rapl: Enable MSR-based RAPL PMU support")
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Tested-by: Furquim Ulisses <ulisses.furquim@intel.com>
Reviewed-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/20260209234310.1440722-2-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Kuppuswamy Sathyanarayanan
7537bae8b6