Re: [PATCH v5 21/21] KVM: ARM64: Add a new kvm ARM PMU device

[Shannon Zhao <shannon.zhao@linaro.org>]

On 2015/12/7 21:56, Marc Zyngier wrote:
>> +static int kvm_arm_pmu_set_attr(struct kvm_device *dev,
>> >+				struct kvm_device_attr *attr)
>> >+{
>> >+	switch (attr->group) {
>> >+	case KVM_DEV_ARM_PMU_GRP_IRQ: {
>> >+		int __user *uaddr = (int __user *)(long)attr->addr;
>> >+		int reg;
>> >+
>> >+		if (get_user(reg, uaddr))
>> >+			return -EFAULT;
>> >+
>> >+		if (reg < VGIC_NR_SGIS || reg >= VGIC_NR_PRIVATE_IRQS)
>> >+			return -EINVAL;
>> >+
>> >+		return kvm_arm_pmu_set_irq(dev->kvm, reg);
> What prevents the IRQ to be changed while the VM is already running?
> This should probably be a one-shot thing (change it once, be denied
> other changes).

So add a helper like vgic_initialized to check whether vPMU is initialized?

Thanks,
-- 
Shannon