From: Paolo Bonzini <pbonzini@redhat.com>
To: "Zhang, Yang Z" <yang.z.zhang@intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"gleb@redhat.com" <gleb@redhat.com>,
"mtosatti@redhat.com" <mtosatti@redhat.com>,
"Zhang, Xiantao" <xiantao.zhang@intel.com>
Subject: Re: [PATCH v6 6/6] KVM: Use eoi to track RTC interrupt delivery status
Date: Fri, 29 Mar 2013 09:35:57 +0100 [thread overview]
Message-ID: <5155526D.6010405@redhat.com> (raw)
In-Reply-To: <A9667DDFB95DB7438FA9D7D576C3D87E099F6A3D@SHSMSX101.ccr.corp.intel.com>
Il 29/03/2013 04:25, Zhang, Yang Z ha scritto:
> Paolo Bonzini wrote on 2013-03-26:
>> Il 22/03/2013 06:24, Yang Zhang ha scritto:
>>> +static void rtc_irq_ack_eoi(struct kvm_vcpu *vcpu,
>>> + struct rtc_status *rtc_status, int irq)
>>> +{
>>> + if (irq != RTC_GSI)
>>> + return;
>>> +
>>> + if (test_and_clear_bit(vcpu->vcpu_id, rtc_status->dest_map))
>>> + --rtc_status->pending_eoi;
>>> +
>>> + WARN_ON(rtc_status->pending_eoi < 0);
>>> +}
>>
>> This is the only case where you're passing the struct rtc_status instead
>> of the struct kvm_ioapic. Please use the latter, and make it the first
>> argument.
>>
>>> @@ -244,7 +268,14 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int
>> irq)
>>> irqe.level = 1;
>>> irqe.shorthand = 0;
>>> - return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL);
>>> + if (irq == RTC_GSI) {
>>> + ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe,
>>> + ioapic->rtc_status.dest_map);
>>> + ioapic->rtc_status.pending_eoi = ret;
>>
>> I think you should either add a
>>
>> BUG_ON(ioapic->rtc_status.pending_eoi != 0);
>> or use "ioapic->rtc_status.pending_eoi += ret" (or both).
>>
> There may malicious guest to write EOI more than once. And the
> pending_eoi will be negative. But it should not be a bug. Just WARN_ON
> is enough. And we already do it in ack_eoi. So don't need to do
> duplicated thing here.
Even WARN_ON is too much if it is guest-triggerable. But then it is
better to make it "+=", I think.
Paolo
next prev parent reply other threads:[~2013-03-29 8:36 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-22 5:23 [PATCH v6 0/6] Use eoi to track RTC interrupt delivery status Yang Zhang
2013-03-22 5:24 ` [PATCH v6 1/6] KVM: Add vcpu info to ioapic_update_eoi() Yang Zhang
2013-03-22 5:24 ` [PATCH v6 2/6] KVM: Introduce struct rtc_status Yang Zhang
2013-03-22 5:24 ` [PATCH v6 3/6] KVM : Return destination vcpu on interrupt injection Yang Zhang
2013-03-22 7:05 ` Gleb Natapov
2013-03-22 7:50 ` Zhang, Yang Z
2013-03-22 7:57 ` Gleb Natapov
2013-03-22 5:24 ` [PATCH v6 4/6] KVM: Add reset/restore rtc_status support Yang Zhang
2013-03-26 14:04 ` Paolo Bonzini
2013-03-29 3:17 ` Zhang, Yang Z
2013-03-26 14:09 ` Paolo Bonzini
2013-03-29 3:19 ` Zhang, Yang Z
2013-03-22 5:24 ` [PATCH v6 5/6] KVM : Force vmexit with virtual interrupt delivery Yang Zhang
2013-03-22 5:24 ` [PATCH v6 6/6] KVM: Use eoi to track RTC interrupt delivery status Yang Zhang
2013-03-22 7:50 ` Gleb Natapov
2013-03-22 8:05 ` Zhang, Yang Z
2013-03-22 8:14 ` Gleb Natapov
2013-03-22 8:25 ` Zhang, Yang Z
2013-03-22 8:30 ` Gleb Natapov
2013-03-22 8:37 ` Zhang, Yang Z
2013-03-22 8:44 ` Gleb Natapov
2013-03-22 8:51 ` Zhang, Yang Z
2013-03-22 8:54 ` Gleb Natapov
2013-03-22 10:50 ` Zhang, Yang Z
2013-03-24 9:20 ` Gleb Natapov
2013-03-26 14:26 ` Paolo Bonzini
2013-03-26 14:14 ` Paolo Bonzini
2013-03-29 3:25 ` Zhang, Yang Z
2013-03-29 8:35 ` Paolo Bonzini [this message]
2013-03-29 8:42 ` Zhang, Yang Z
2013-04-02 13:08 ` Gleb Natapov
2013-04-03 0:21 ` Zhang, Yang Z
2013-04-03 4:03 ` Gleb Natapov
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