[kvm-unit-tests PATCH v2 3/8] x86: skip PMU init when no PMU is advertised

[Giacomo Mazzola <gmazz@amazon.de>]

Guard pmu_init() behind CPUID checks: Intel's architectural PMU
version (CPUID 0xA EAX[7:0]) and AMD's PERFCTR_CORE feature bit.
Without a PMU, accessing performance counter MSRs triggers #GP.

Signed-off-by: Giacomo Mazzola <gmazz@amazon.de>
---
 lib/x86/setup.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index 09241b33..8c8b6e63 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -416,5 +416,7 @@ void bsp_rest_init(void)
 	bringup_aps();
 	enable_x2apic();
 	smp_init();
-	pmu_init();
+	if (this_cpu_property(X86_PROPERTY_PMU_VERSION) ||
+	    this_cpu_has(X86_FEATURE_PERFCTR_CORE))
+		pmu_init();
 }
-- 
2.47.3