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Groups > linux.kernel > #1313925
| From | "Wu, Feng" <feng.wu@intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts |
| Date | 2016-01-21 06:50 +0100 |
| Message-ID | <qTgi6-LZ-3@gated-at.bofh.it> (permalink) |
| References | <qSQnE-8bo-19@gated-at.bofh.it> <qSQnF-8bo-51@gated-at.bofh.it> <qTfYK-Ea-5@gated-at.bofh.it> <qTg8q-Im-1@gated-at.bofh.it> <qTgi6-LZ-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
> -----Original Message-----
> From: Yang Zhang [mailto:yang.zhang.wz@gmail.com]
> Sent: Thursday, January 21, 2016 1:43 PM
> To: Wu, Feng <feng.wu@intel.com>; pbonzini@redhat.com;
> rkrcmar@redhat.com
> Cc: linux-kernel@vger.kernel.org; kvm@vger.kernel.org
> Subject: Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-
> priority interrupts
>
> On 2016/1/21 13:33, Wu, Feng wrote:
> >
> >
> >> -----Original Message-----
> >> From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
> >> owner@vger.kernel.org] On Behalf Of Yang Zhang
> >> Sent: Thursday, January 21, 2016 1:24 PM
> >> To: Wu, Feng <feng.wu@intel.com>; pbonzini@redhat.com;
> >> rkrcmar@redhat.com
> >> Cc: linux-kernel@vger.kernel.org; kvm@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.wu@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.
>
> I remember we have discussed that even the LAPIC is software disabled,
> it still can respond to some interrupts like INIT, NMI, SMI, and SIPI
> messages. Isn't current logic still problematically?
I don't think there are problems, here we only cover lowest-priority mode.
Thanks,
Feng
>
> --
> best regards
> yang
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[PATCH v3 0/4] VT-d posted-interrupts follow ups Feng Wu <feng.wu@intel.com> - 2016-01-20 03:10 +0100
[PATCH v3 4/4] KVM/VMX: Add host irq information in trace event when updating IRTE for posted interrupts Feng Wu <feng.wu@intel.com> - 2016-01-20 03:10 +0100
Re: [PATCH v3 4/4] KVM/VMX: Add host irq information in trace event when updating IRTE for posted interrupts Radim Krčmář <rkrcmar@redhat.com> - 2016-01-21 21:20 +0100
[PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Feng Wu <feng.wu@intel.com> - 2016-01-20 03:10 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 06:30 +0100
RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "Wu, Feng" <feng.wu@intel.com> - 2016-01-21 06:40 +0100
RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "Wu, Feng" <feng.wu@intel.com> - 2016-01-21 06:50 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 07:00 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 07:10 +0100
RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "Wu, Feng" <feng.wu@intel.com> - 2016-01-21 07:10 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-21 06:50 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "rkrcmar@redhat.com" <rkrcmar@redhat.com> - 2016-01-21 18:30 +0100
RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "Wu, Feng" <feng.wu@intel.com> - 2016-01-22 03:10 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Yang Zhang <yang.zhang.wz@gmail.com> - 2016-01-22 05:10 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "rkrcmar@redhat.com" <rkrcmar@redhat.com> - 2016-01-22 14:50 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Radim Krčmář <rkrcmar@redhat.com> - 2016-01-21 21:00 +0100
RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "Wu, Feng" <feng.wu@intel.com> - 2016-01-22 06:20 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Radim Krcmár <rkrcmar@redhat.com> - 2016-01-22 15:10 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Paolo Bonzini <pbonzini@redhat.com> - 2016-01-25 13:30 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Radim Krcmár <rkrcmar@redhat.com> - 2016-01-25 16:30 +0100
Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Paolo Bonzini <pbonzini@redhat.com> - 2016-01-25 17:20 +0100
RE: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts "Wu, Feng" <feng.wu@intel.com> - 2016-01-26 02:20 +0100
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