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

[Will Deacon <will.deacon@xxxxxxx>]

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@xxxxxxx> 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!

Will
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