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Groups > linux.kernel > #1314371
| From | "rkrcmar@redhat.com" <rkrcmar@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts |
| Date | 2016-01-21 18:30 +0100 |
| Message-ID | <qTrdy-8tf-31@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> |
| Organization | linux.* mail to news gateway |
2016-01-21 05:33+0000, Wu, Feng:
>> From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
>> owner@vger.kernel.org] On Behalf Of Yang Zhang
>> On 2016/1/20 9:42, Feng Wu wrote:
>> > + /*
>> > + * 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
(true actually means that fast path did the job and slow path isn't
needed.)
>> i = -1.
(I think there isn't a practical difference between *r=-1 and *r=0.)
> 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.
'ret = true' is the better one. We know that the interrupt is not
deliverable [1], so there's no point in trying to deliver with the slow
path. We behave similarly when the interrupt targets a single disabled
APIC.
---
1: Well ... it's possible that slowpath would deliver it thanks to
different handling of disabled APICs, but it's undefined behavior,
so it doesn't matter matter if we don't try.
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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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