Messages in this thread | | | Date | Fri, 10 Dec 2021 14:03:13 +0100 | Subject | Re: [PATCH 5/6] KVM: x86: never clear irr_pending in kvm_apic_update_apicv | From | Paolo Bonzini <> |
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On 12/10/21 13:47, Maxim Levitsky wrote: > If we scan vIRR here and see no bits, and*then* disable AVIC, > there is a window where the they could legit be turned on without any cpu errata, > and we will not have irr_pending == true, and thus the following > KVM_REQ_EVENT will make no difference.
Right.
> Not touching irr_pending and letting just the KVM_REQ_EVENT do the work > will work too,
Yeah, I think that's preferrable. irr_pending == true is a conservative setting that works; irr_pending will be evaluated again on the first call to apic_clear_irr and that's enough.
With that justification, you don't need to reorder the call to kvm_apic_update_apicv to be after kvm_x86_refresh_apicv_exec_ctrl.
Paolo
and if the avic errata is present, reduce slightly > the chances of it happening.
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