Maybe the patch have a risk to break the process of lapic.just avoid
a IPI between the cpu core asap.
Thanks
YiLi
2012/12/4 yi li <yilikernel@xxxxxxxxx>:
> The cpu inject the interrupt to vcpu which vcpu->cpu is the same as it.
> And it maybe avoid a IPI between the cpu core.
>
> Signed-off-by: Yi Li <yilikernel@xxxxxxxxx>
>
> --- linux/virt/kvm/irq_comm.c 2012-12-04 10:14:57.711024619 +0800
> +++ linux/virt/kvm/irq_comm.c 2012-12-04 11:01:27.728859597 +0800
> @@ -64,9 +64,10 @@ inline static bool kvm_is_dm_lowest_prio
> int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
> struct kvm_lapic_irq *irq)
> {
> - int i, r = -1;
> + int i, cpu, r = -1;
> struct kvm_vcpu *vcpu, *lowest = NULL;
>
> + cpu = get_cpu();
> if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
> kvm_is_dm_lowest_prio(irq)) {
> printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
> @@ -89,13 +90,17 @@ int kvm_irq_delivery_to_apic(struct kvm
> r = 0;
> r += kvm_apic_set_irq(vcpu, irq);
> } else if (kvm_lapic_enabled(vcpu)) {
> - if (!lowest)
> + if(vcpu->cpu == cpu) {
> + lowest = vcpu;
> + break;
> + }
> + else if (!lowest)
> lowest = vcpu;
> else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
> lowest = vcpu;
> }
> }
> -
> + put_cpu();
> if (lowest)
> r = kvm_apic_set_irq(lowest, irq);
>
>
> YiLi
> Thanks
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