The current code simply assumes Intel Arch PerfMon v2+ to have
the IA32_PERF_CAPABILITIES MSR; the SDM specifies that we should check
CPUID[1].ECX[15] (aka, FEATURE_PDCM) instead.
This was found by KVM which implements v2+ but didn't provide the
capabilities MSR. Change the code to DTRT; KVM will also implement the
MSR and return 0.
Cc: pbonzini@redhat.com
Reported-by: "Michael S. Tsirkin" <mst@redhat.com>
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140203132903.GI8874@twins.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
if (version > 1)
x86_pmu.num_counters_fixed = max((int)edx.split.num_counters_fixed, 3);
- /*
- * v2 and above have a perf capabilities MSR
- */
- if (version > 1) {
+ if (boot_cpu_has(X86_FEATURE_PDCM)) {
u64 capabilities;
rdmsrl(MSR_IA32_PERF_CAPABILITIES, capabilities);