On Fri, 2021-12-10 at 14:03 +0100, Paolo Bonzini wrote: > 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. Yes exactly! but no need to scan IRR here since irr_pending is already true at that point anyway - it is always true while avic is enabled. Best regards, Maxim Levitsky > > Paolo > > and if the avic errata is present, reduce slightly > > the chances of it happening.
