> -----Original Message----- > From: linux-kernel-ow...@vger.kernel.org [mailto:linux-kernel- > ow...@vger.kernel.org] On Behalf Of Yang Zhang > Sent: Thursday, January 21, 2016 1:24 PM > To: Wu, Feng <feng...@intel.com>; pbonz...@redhat.com; > rkrc...@redhat.com > Cc: linux-kernel@vger.kernel.org; k...@vger.kernel.org > Subject: Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest- > priority interrupts > > On 2016/1/20 9:42, Feng Wu wrote: > > Use vector-hashing to deliver lowest-priority interrupts, As an > > example, modern Intel CPUs in server platform use this method to > > handle lowest-priority interrupts. > > > > Signed-off-by: Feng Wu <feng...@intel.com> > > --- > > bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic > *src, > > struct kvm_lapic_irq *irq, int *r, unsigned long *dest_map) > > { > > @@ -727,21 +743,51 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm > *kvm, struct kvm_lapic *src, > > > > dst = map->logical_map[cid]; > > > > - if (kvm_lowest_prio_delivery(irq)) { > > + if (!kvm_lowest_prio_delivery(irq)) > > + goto set_irq; > > + > > + if (!kvm_vector_hashing_enabled()) { > > int l = -1; > > for_each_set_bit(i, &bitmap, 16) { > > if (!dst[i]) > > continue; > > if (l < 0) > > l = i; > > - else if (kvm_apic_compare_prio(dst[i]->vcpu, > dst[l]->vcpu) < 0) > > + else if (kvm_apic_compare_prio(dst[i]->vcpu, > > + dst[l]->vcpu) < 0) > > l = i; > > } > > - > > bitmap = (l >= 0) ? 1 << l : 0; > > + } else { > > + int idx = 0; > > + unsigned int dest_vcpus = 0; > > + > > + dest_vcpus = hweight16(bitmap); > > + if (dest_vcpus == 0) > > + goto out; > > + > > + idx = kvm_vector_2_index(irq->vector, > > + dest_vcpus, &bitmap, 16); > > + > > + /* > > + * We may find a hardware disabled LAPIC here, if > that > > + * is the case, print out a error message once for each > > + * guest and return. > > + */ > > + if (!dst[idx-1] && > > + (kvm->arch.disabled_lapic_found == 0)) { > > + kvm->arch.disabled_lapic_found = 1; > > + printk(KERN_ERR > > + "Disabled LAPIC found during irq > injection\n"); > > + goto out; > > What does "goto out" mean? Inject successfully or fail? According the > value of ret which is set to ture here, it means inject successfully but > i = -1. >
Oh, I didn't notice 'ret' is initialized to true, I thought it was initialized to false like another function, I should add a "ret = false' here. We should failed to inject the interrupt since hardware disabled LAPIC is found. Thanks, Feng
