On 08/06/2011 01:39 PM, Christoffer Dall wrote:
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 * 2
FIQ: (vcpu_index * 2) + 1
This is documented in Documentation/kvm/api.txt.
The effect of the ioctl is simply to simply raise/lower the
corresponding virt_irq 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 causing an idle VCPU to become active again.
Note x86 starts out with a default configuration and allows updating it
via KVM_SET_GSI_ROUTING. You may need this in the future if you decide
to implement an irq controller in the kernel.
+static int kvm_arch_vm_ioctl_irq_line(struct kvm *kvm,
+ struct kvm_irq_level *irq_level)
+{
+ u32 mask;
+ unsigned int vcpu_idx;
+ struct kvm_vcpu *vcpu;
+
+ vcpu_idx = irq_level->irq / 2;
+ if (vcpu_idx>= KVM_MAX_VCPUS)
+ return -EINVAL;
+
+ vcpu = kvm_get_vcpu(kvm, vcpu_idx);
+ if (!vcpu)
+ return -EINVAL;
+
+ switch (irq_level->irq % 2) {
+ case KVM_ARM_IRQ_LINE:
+ mask = HCR_VI;
+ break;
+ case KVM_ARM_FIQ_LINE:
+ mask = HCR_VF;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ trace_kvm_irq_line(irq_level->irq % 2, irq_level->level, vcpu_idx);
Please reuse trace_kvm_set_irq(). You can decode vcpu/type in a
trace-cmd plugin.
+
+ if (irq_level->level) {
+ vcpu->arch.virt_irq |= mask;
+ vcpu->arch.wait_for_interrupts = 0;
+ } else
+ vcpu->arch.virt_irq&= ~mask;
+
This seems to be non-smp-safe? Do you need atomic ops and barriers
here? And a wakeup?
Unlike KVM_INTERRUPT, KVM_IRQ_LINE is designed to be used asynchronously
wrt the vcpu.
+ return 0;
+}
+
long kvm_arch_vcpu_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -312,8 +349,21 @@ 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)
{
- printk(KERN_ERR "kvm_arch_vm_ioctl: Unsupported ioctl (%d)\n", ioctl);
- 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:
+ kvm_err(-EINVAL, "Unsupported ioctl (%d)", ioctl);
Please remove for the final code, we don't want a user spamming the
kernel log.
+ return -EINVAL;
+ }
}
--
error compiling committee.c: too many arguments to function
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