Re: [PATCH v4 07/14] KVM: ARM: Inject IRQs and FIQs from userspace

Christoffer Dall
2012-11-30T06:13:58Z

On Mon, Nov 19, 2012 at 11:21 AM, Will Deacon <will.deacon@arm.com> wrote:
> On Mon, Nov 19, 2012 at 04:09:06PM +0000, Christoffer Dall wrote:
>> On Mon, Nov 19, 2012 at 10:26 AM, Will Deacon <will.deacon@arm.com> wrote:
>> > On Mon, Nov 19, 2012 at 03:04:38PM +0000, Christoffer Dall wrote:
>> In all seriousness, I will unite myself with an alcoholic beverage one
>> of these evenings and try to see what I can do about it, maybe split
>> it up somehow, I'll give it a shot.
>
> So this might be to do with the way you've split up the patches (likely I'll
> have similar complaints against the vGIC code, but at least it will make
> sense there!)...
>
>> >> >> +int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level)
>> >> >> +{
>> >> >> + u32 irq = irq_level->irq;
>> >> >> + unsigned int irq_type, vcpu_idx, irq_num;
>> >> >> + int nrcpus = atomic_read(&kvm->online_vcpus);
>> >> >> + struct kvm_vcpu *vcpu = NULL;
>> >> >> + bool level = irq_level->level;
>> >> >> +
>> >> >> + irq_type = (irq >> KVM_ARM_IRQ_TYPE_SHIFT) & KVM_ARM_IRQ_TYPE_MASK;
>> >> >> + vcpu_idx = (irq >> KVM_ARM_IRQ_VCPU_SHIFT) & KVM_ARM_IRQ_VCPU_MASK;
>> >> >> + irq_num = (irq >> KVM_ARM_IRQ_NUM_SHIFT) & KVM_ARM_IRQ_NUM_MASK;
>> >> >> +
>> >> >> + trace_kvm_irq_line(irq_type, vcpu_idx, irq_num, irq_level->level);
>> >> >> +
>> >> >> + if (irq_type == KVM_ARM_IRQ_TYPE_CPU ||
>> >> >> + irq_type == KVM_ARM_IRQ_TYPE_PPI) {
>> >> >> + if (vcpu_idx >= nrcpus)
>> >> >> + return -EINVAL;
>> >> >> +
>> >> >> + vcpu = kvm_get_vcpu(kvm, vcpu_idx);
>> >> >> + if (!vcpu)
>> >> >> + return -EINVAL;
>> >> >> + }
>> >> >> +
>> >> >> + switch (irq_type) {
>> >> >> + case KVM_ARM_IRQ_TYPE_CPU:
>> >> >> + if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
>> >> >> + return -EINVAL;
>> >> >> +
>> >> >> + return vcpu_interrupt_line(vcpu, irq_num, level);
>> >> >> + }
>> >> >> +
>> >> >> + return -EINVAL;
>> >> >> +}
>
> This obviously doesn't handle PPIs, which is where the confusion lies. You
> can just as easily write it as:
>
> int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level)
> {
> u32 irq = irq_level->irq;
> unsigned int irq_type, vcpu_idx, irq_num;
> int nrcpus = atomic_read(&kvm->online_vcpus);
> struct kvm_vcpu *vcpu = NULL;
> bool level = irq_level->level;
>
> irq_type = (irq >> KVM_ARM_IRQ_TYPE_SHIFT) & KVM_ARM_IRQ_TYPE_MASK;
> vcpu_idx = (irq >> KVM_ARM_IRQ_VCPU_SHIFT) & KVM_ARM_IRQ_VCPU_MASK;
> irq_num = (irq >> KVM_ARM_IRQ_NUM_SHIFT) & KVM_ARM_IRQ_NUM_MASK;
>
> trace_kvm_irq_line(irq_type, vcpu_idx, irq_num, irq_level->level);
>
> if (irq_type != KVM_ARM_IRQ_TYPE_CPU)
> return -EINVAL;
>
> if (vcpu_idx >= nrcpus)
> return -EINVAL;
>
> vcpu = kvm_get_vcpu(kvm, vcpu_idx);
> if (!vcpu)
> return -EINVAL;
>
> if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
> return -EINVAL;
>
> return vcpu_interrupt_line(vcpu, irq_num, level);
> }
>
> Then add all the IRQ complexity in a later patch!
>
that was pretty constructive, I did just that. Thanks.