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KVM: x86: lapic: don't touch irr_pending in kvm_apic_update_apicv when inhibiting it

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kvm_apic_update_apicv is called when AVIC is still active, thus IRR bits
can be set by the CPU after it is called, and don't cause the irr_pending
to be set to true.

Also logic in avic_kick_target_vcpu doesn't expect a race with this
function so to make it simple, just keep irr_pending set to true and
let the next interrupt injection to the guest clear it.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220207155447.840194-9-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Maxim Levitsky 2022-02-07 17:54:25 +02:00 • committed by Paolo Bonzini
parent 2b0ecccb55
commit 755c2bf878
1 changed files with 6 additions and 1 deletions
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7
arch/x86/kvm/lapic.c
View file

@ -2306,7 +2306,12 @@ void kvm_apic_update_apicv(struct kvm_vcpu *vcpu)
apic->irr_pending = true;
apic->isr_count = 1;
} else {
apic->irr_pending = (apic_search_irr(apic) != -1);
/*
* Don't clear irr_pending, searching the IRR can race with
* updates from the CPU as APICv is still active from hardware's
* perspective. The flag will be cleared as appropriate when
* KVM injects the interrupt.
*/
apic->isr_count = count_vectors(apic->regs + APIC_ISR);
}
}