Messages in this thread | | | Date | Fri, 13 Oct 2017 19:36:21 +0200 | From | Radim Krčmář <> | Subject | Re: [PATCH v2 4/4] KVM: LAPIC: Don't silently accept bad vectors |
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2017-10-13 09:17+0800, Wanpeng Li: > 2017-10-04 22:44 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>: > > 2017-10-04 22:16+0800, Wanpeng Li: > >> 2017-10-04 20:01 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>: > >> > 2017-10-04 15:56+0800, Wanpeng Li: > >> >> 2017-10-04 1:53 GMT+08:00 Radim Krčmář <rkrcmar@redhat.com>: > >> >> > 2017-09-28 18:04-0700, Wanpeng Li: > >> >> >> @@ -946,6 +965,11 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, > >> >> >> int result = 0; > >> >> >> struct kvm_vcpu *vcpu = apic->vcpu; > >> >> >> > >> >> >> + if (unlikely(vector < 16) && delivery_mode == APIC_DM_FIXED) { > >> >> >> + apic_error(apic, APIC_ESR_RECVILL); > >> >> > > >> >> > The error is also triggered if lowest priority is supported and tries to > >> >> > deliver an invalid vector. > >> >> > >> >> Could you point out this in SDM? :) > >> > > >> > In section 10.5.3 Error Handling: > >> > > >> > If the local APIC does not support the sending of lowest-priority IPIs > >> > and software writes the ICR to send a lowest-priority IPI with an > >> > illegal vector, the local APIC sets only the “redirectible IPI” error > >> > bit. > >> > > >> > Hence, if local APIC does support lowest-priority, then it throws the > >> > same error as fixed. (KVM does support lowest-priority.) > >> > >> Yeah, I read the section before but I misunderstand it. It seems that > >> the section means it just occurs when the local APIC does not support > >> the sending of lowest-priority IPIs? > > > > I think so. > > I see Virtualbox just captures Fixed delivery mode for error handling.
Hm, it doesn't even inject an error on destination of the lowest-priority interrupt and just drop it?
I can't interpret the SDM in any other way, though:
When an interrupt vector in the range of 0 to 15 is sent or received through the local APIC, the APIC indicates an illegal vector in its Error Status Register (see Section 10.5.3, “Error Handling”).
and we support lowest-priority interrupts, because if we didn't, then
The interrupt is not processed and hence the “Send Illegal Vector” bit is not set in the ESR.
I'll go for a quick bare-metal test ...
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