target/arm: cortex-a7 and cortex-a15 have pmus

cortex-a7 and cortex-a15 have pmus (PMUv2) and they advertise
them in ID_DFR0. Let's allow them to function. This also enables
the pmu cpu property to work with these cpu types, i.e. we can
now do '-cpu cortex-a15,pmu=off' to remove the pmu.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190322162333.17159-3-drjones@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/cpu.c

@@ -1109,6 +1109,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
 #endif
     } else {
         cpu->id_aa64dfr0 &= ~0xf00;
+        cpu->id_dfr0 &= ~(0xf << 24);
         cpu->pmceid0 = 0;
         cpu->pmceid1 = 0;
     }
@@ -1744,6 +1745,7 @@ static void cortex_a7_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_CBAR_RO);
     set_feature(&cpu->env, ARM_FEATURE_EL2);
     set_feature(&cpu->env, ARM_FEATURE_EL3);
+    set_feature(&cpu->env, ARM_FEATURE_PMU);
     cpu->kvm_target = QEMU_KVM_ARM_TARGET_CORTEX_A7;
     cpu->midr = 0x410fc075;
     cpu->reset_fpsid = 0x41023075;
@@ -1789,6 +1791,7 @@ static void cortex_a15_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_CBAR_RO);
     set_feature(&cpu->env, ARM_FEATURE_EL2);
     set_feature(&cpu->env, ARM_FEATURE_EL3);
+    set_feature(&cpu->env, ARM_FEATURE_PMU);
     cpu->kvm_target = QEMU_KVM_ARM_TARGET_CORTEX_A15;
     cpu->midr = 0x412fc0f1;
     cpu->reset_fpsid = 0x410430f0;