From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Wanpeng Li <kernellwp@gmail.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
kvm <kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
Wanpeng Li <wanpeng.li@hotmail.com>
Subject: Re: [PATCH v2 4/4] KVM: LAPIC: Don't silently accept bad vectors
Date: Fri, 13 Oct 2017 19:36:21 +0200 [thread overview]
Message-ID: <20171013173620.GB16116@flask> (raw)
In-Reply-To: <CANRm+CzDrw6-8+wDXon5bCbfTCg8MdCbnAsahNXEJuZdQn=C8A@mail.gmail.com>
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 ...
next prev parent reply other threads:[~2017-10-13 17:36 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-29 1:04 [PATCH v2 0/4] KVM: LAPIC: Rework lapic timer to behave more like real-hardware Wanpeng Li
2017-09-29 1:04 ` [PATCH v2 1/4] KVM: LAPIC: Fix lapic timer mode transition Wanpeng Li
2017-10-03 17:05 ` Radim Krčmář
2017-10-04 1:45 ` Wanpeng Li
2017-10-04 13:21 ` Radim Krčmář
2017-10-04 13:50 ` Wanpeng Li
2017-10-04 14:02 ` Wanpeng Li
2017-09-29 1:04 ` [PATCH v2 2/4] KVM: LAPIC: Keep timer running when switching between one-shot and periodic mode Wanpeng Li
2017-10-03 17:06 ` Radim Krčmář
2017-10-04 1:46 ` Wanpeng Li
2017-10-04 13:33 ` Radim Krčmář
2017-10-04 13:57 ` Wanpeng Li
2017-09-29 1:04 ` [PATCH v2 3/4] KVM: LAPIC: Apply change to TDCR right away to the timer Wanpeng Li
2017-10-03 17:28 ` Radim Krčmář
2017-10-04 1:59 ` Wanpeng Li
2017-10-04 12:43 ` Radim Krčmář
2017-09-29 1:04 ` [PATCH v2 4/4] KVM: LAPIC: Don't silently accept bad vectors Wanpeng Li
2017-10-03 17:53 ` Radim Krčmář
2017-10-04 7:56 ` Wanpeng Li
2017-10-04 12:01 ` Radim Krčmář
2017-10-04 14:16 ` Wanpeng Li
2017-10-04 14:44 ` Radim Krčmář
2017-10-13 1:17 ` Wanpeng Li
2017-10-13 17:36 ` Radim Krčmář [this message]
2017-10-13 20:31 ` Radim Krčmář
2017-10-15 2:41 ` Wanpeng Li
2017-10-05 10:57 ` [PATCH v2 0/4] KVM: LAPIC: Rework lapic timer to behave more like real-hardware Wanpeng Li
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