KVM: Expose a version 2 architectural PMU to a guests

Use perf_events to emulate an architectural PMU, version 2.

Based on PMU version 1 emulation by Avi Kivity.

[avi: adjust for cpuid.c]
[jan: fix anonymous field initialization for older gcc]

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/cpuid.c

@@ -45,6 +45,8 @@ void kvm_update_cpuid(struct kvm_vcpu *vcpu)
 		else
 			apic->lapic_timer.timer_mode_mask = 1 << 17;
 	}
+
+	kvm_pmu_cpuid_update(vcpu);
 }
 
 static int is_efer_nx(void)