Messages in this thread | | | Date | Tue, 1 Mar 2022 18:10:28 +0100 | Subject | Re: [PATCH MANUALSEL 5.10 1/2] KVM: x86: lapic: don't touch irr_pending in kvm_apic_update_apicv when inhibiting it | From | Paolo Bonzini <> |
| |
On 2/22/22 15:05, Sasha Levin wrote: > From: Maxim Levitsky <mlevitsk@redhat.com> > > [ Upstream commit 755c2bf878607dbddb1423df9abf16b82205896f ] > > 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> > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > arch/x86/kvm/lapic.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 677d21082454f..d484269a390bc 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -2292,7 +2292,12 @@ 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); > } > }
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo
| |