arm64: KVM: PMU: Refactor pmu_*_el0_disabled

There is a lot of duplication in the pmu_*_el0_disabled helpers,
and as we're going to modify them shortly, let's move all the
common stuff in a single function.

No functional change.

Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>

arch/arm64/kvm/sys_regs.c

@@ -460,35 +460,32 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	vcpu_sys_reg(vcpu, PMCR_EL0) = val;
 }
 
-static bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu)
+static bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags)
 {
 	u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
+	bool enabled = (reg & flags) || vcpu_mode_priv(vcpu);
 
-	return !((reg & ARMV8_PMU_USERENR_EN) || vcpu_mode_priv(vcpu));
+	return !enabled;
+}
+
+static bool pmu_access_el0_disabled(struct kvm_vcpu *vcpu)
+{
+	return check_pmu_access_disabled(vcpu, ARMV8_PMU_USERENR_EN);
 }
 
 static bool pmu_write_swinc_el0_disabled(struct kvm_vcpu *vcpu)
 {
-	u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
+	return check_pmu_access_disabled(vcpu, ARMV8_PMU_USERENR_SW | ARMV8_PMU_USERENR_EN);
-
-	return !((reg & (ARMV8_PMU_USERENR_SW | ARMV8_PMU_USERENR_EN))
-		 || vcpu_mode_priv(vcpu));
 }
 
 static bool pmu_access_cycle_counter_el0_disabled(struct kvm_vcpu *vcpu)
 {
-	u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
+	return check_pmu_access_disabled(vcpu, ARMV8_PMU_USERENR_CR | ARMV8_PMU_USERENR_EN);
-
-	return !((reg & (ARMV8_PMU_USERENR_CR | ARMV8_PMU_USERENR_EN))
-		 || vcpu_mode_priv(vcpu));
 }
 
 static bool pmu_access_event_counter_el0_disabled(struct kvm_vcpu *vcpu)
 {
-	u64 reg = vcpu_sys_reg(vcpu, PMUSERENR_EL0);
+	return check_pmu_access_disabled(vcpu, ARMV8_PMU_USERENR_ER | ARMV8_PMU_USERENR_EN);
-
-	return !((reg & (ARMV8_PMU_USERENR_ER | ARMV8_PMU_USERENR_EN))
-		 || vcpu_mode_priv(vcpu));
 }
 
 static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,