Re: [PATCH 2/2] KVM: x86: fix edge EOI and IOAPIC reconfig race

From	Paolo Bonzini <pbonzini@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/2] KVM: x86: fix edge EOI and IOAPIC reconfig race
Date	2015-10-07 11:30 +0200
Message-ID	<qgTcS-DX-23@gated-at.bofh.it> (permalink)
References	<pX13j-4V5-3@gated-at.bofh.it> <pX13k-4V5-23@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 13/08/2015 15:46, Radim Krčmář wrote:
> +	if (kvm_x86_ops->sync_pir_to_irr(vcpu))
> +		kvm_make_request(KVM_REQ_EVENT, vcpu);
> +

The call to sync_pir_to_irr belongs more in vcpu_scan_ioapic, I think.

More importantly, I think that KVM_REQ_EVENT is a latent bug for
kvm_vcpu_ioctl_get_lapic as well, so the call to kvm_make_request should
go in vmx_sync_pir_to_irr or in a new kvm_sync_pir_to_irr wrapper.

> +			    (e->fields.trig_mode == IOAPIC_EDGE_TRIG &&
> +			     kvm_apic_pending_eoi(vcpu, e->fields.vector)))

Should we test again here that kvm_irq_has_notifier(ioapic->kvm,
KVM_IRQCHIP_IOAPIC, index), to avoid unnecessarily marking other
edge-triggered interrupts?

Paolo
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Re: [PATCH 2/2] KVM: x86: fix edge EOI and IOAPIC reconfig race Paolo Bonzini <pbonzini@redhat.com> - 2015-10-07 11:30 +0200
  Re: [PATCH 2/2] KVM: x86: fix edge EOI and IOAPIC reconfig race Radim Krčmář <rkrcmar@redhat.com> - 2015-10-07 17:10 +0200

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