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Groups > linux.kernel > #1313932
| From | Yang Zhang <yang.zhang.wz@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v3 2/4] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts |
| Date | 2016-01-21 07:00 +0100 |
| Message-ID | <qTgrM-Pf-5@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <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> <qTgi6-LZ-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 2016/1/21 13:46, Wu, Feng wrote:
>
>
>> -----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.
Does Intel SDM said those interrupts cannot be delivered on
lowest-priority mode?
CC Jun.
Hi Jun,
Do you know whether INIT, NMI, SMI, and SIPI can be delivered through
lowest-priority mode? I didn't find SDM says no.
--
best regards
yang
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[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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