On 06/15/2012 10:08 PM, Christoffer Dall wrote:
> From: Christoffer Dall <cdall at cs.columbia.edu>
>
> Userspace can inject IRQs and FIQs through the KVM_IRQ_LINE VM ioctl.
> This ioctl is used since the sematics are in fact two lines that can be
> either raised or lowered on the VCPU - the IRQ and FIQ lines.
>
> KVM needs to know which VCPU it must operate on and whether the FIQ or
> IRQ line is raised/lowered. Hence both pieces of information is packed
> in the kvm_irq_level->irq field. The irq fild value will be:
> IRQ: vcpu_index << 1
> FIQ: (vcpu_index << 1) | 1
>
> This is documented in Documentation/kvm/api.txt.
>
> The effect of the ioctl is simply to simply raise/lower the
> corresponding irq_line field on the VCPU struct, which will cause the
> world-switch code to raise/lower virtual interrupts when running the
> guest on next switch. The wait_for_interrupt flag is also cleared for
> raised IRQs or FIQs causing an idle VCPU to become active again. CPUs
> in guest mode are kicked to make sure they refresh their interrupt status.
>
> +static int kvm_arch_vm_ioctl_irq_line(struct kvm *kvm,
> + struct kvm_irq_level *irq_level)
> +{
> + int mask;
> + unsigned int vcpu_idx;
> + struct kvm_vcpu *vcpu;
> + unsigned long old, new, *ptr;
> +
> + vcpu_idx = irq_level->irq >> 1;
> + if (vcpu_idx >= KVM_MAX_VCPUS)
> + return -EINVAL;
> +
> + vcpu = kvm_get_vcpu(kvm, vcpu_idx);
> + if (!vcpu)
> + return -EINVAL;
> +
> + if ((irq_level->irq & 1) == KVM_ARM_IRQ_LINE)
> + mask = HCR_VI;
> + else /* KVM_ARM_FIQ_LINE */
> + mask = HCR_VF;
> +
> + trace_kvm_set_irq(irq_level->irq, irq_level->level, 0);
> +
> + ptr = (unsigned long *)&vcpu->arch.irq_lines;
> + do {
> + old = ACCESS_ONCE(*ptr);
> + if (irq_level->level)
> + new = old | mask;
> + else
> + new = old & ~mask;
> +
> + if (new == old)
> + return 0; /* no change */
> + } while (cmpxchg(ptr, old, new) != old);
Isn't this a complicated
if (level)
set_bit()
else
clear_bit()
?
> +
> + /*
> + * The vcpu irq_lines field was updated, wake up sleeping VCPUs and
> + * trigger a world-switch round on the running physical CPU to set the
> + * virtual IRQ/FIQ fields in the HCR appropriately.
> + */
> + kvm_vcpu_kick(vcpu);
No need to wake when the line is asserted so you can make this
conditional on level.
> +
> + return 0;
> +}
> +
> long kvm_arch_vcpu_ioctl(struct file *filp,
> unsigned int ioctl, unsigned long arg)
> {
> @@ -298,7 +345,20 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
> long kvm_arch_vm_ioctl(struct file *filp,
> unsigned int ioctl, unsigned long arg)
> {
> - return -EINVAL;
> + struct kvm *kvm = filp->private_data;
> + void __user *argp = (void __user *)arg;
> +
> + switch (ioctl) {
> + case KVM_IRQ_LINE: {
> + struct kvm_irq_level irq_event;
> +
> + if (copy_from_user(&irq_event, argp, sizeof irq_event))
> + return -EFAULT;
> + return kvm_arch_vm_ioctl_irq_line(kvm, &irq_event);
> + }
> + default:
> + return -EINVAL;
> + }
> }
Should be in common code guarded by the define introduced previously.
--
error compiling committee.c: too many arguments to function
