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

Will Deacon
2012-11-19T16:21:43Z

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!

Will