Gleb Natapov wrote on 2013-04-11:
> On Wed, Apr 10, 2013 at 09:22:20PM +0800, Yang Zhang wrote:
>> From: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>>
>> Current interrupt coalescing logci which only used by RTC has conflict
>> with Posted Interrupt.
>> This patch introduces a new mechinism to use eoi to track interrupt:
>> When delivering an interrupt to vcpu, the pending_eoi set to number of
>> vcpu that received the interrupt. And decrease it when each vcpu writing
>> eoi. No subsequent RTC interrupt can deliver to vcpu until all vcpus
>> write eoi.
>>
>> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
>> ---
>> virt/kvm/ioapic.c | 39 ++++++++++++++++++++++++++++++++++++++-
>> 1 files changed, 38 insertions(+), 1 deletions(-)
>> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
>> index a49fcd5..aeac154 100644
>> --- a/virt/kvm/ioapic.c
>> +++ b/virt/kvm/ioapic.c
>> @@ -147,6 +147,26 @@ static void kvm_rtc_eoi_tracking_restore_all(struct
> kvm_ioapic *ioapic)
>> __rtc_irq_eoi_tracking_restore_one(vcpu);
>> }
>> +static void rtc_irq_eoi(struct kvm_ioapic *ioapic, struct kvm_vcpu *vcpu)
>> +{
>> + if (test_and_clear_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map))
>> + --ioapic->rtc_status.pending_eoi;
>> +
>> + WARN_ON(ioapic->rtc_status.pending_eoi < 0);
>> +}
>> +
>> +static bool rtc_irq_check_coalesced(struct kvm_ioapic *ioapic, int irq,
>> + bool line_status)
>> +{
>> + if (irq != RTC_GSI || !line_status)
>> + return false;
> Please move the check from rtc_irq_check_coalesced() to
> kvm_ioapic_set_irq() like this: if (irq == RTC_GSI && line_status &&
> rtc_irq_check_coalesced(ioapic, irq, line_status)) ....
>
> I was going to fix it myself while applying, but since there will be
> new posted interrupt series anyway you can as well fix this one too.
You mean fix it and send out it with posted interrupt series? Or just rebase the posted interrupt series on the top of this fix, but needn't to send out it?
>
>> +
>> + if (ioapic->rtc_status.pending_eoi > 0)
>> + return true; /* coalesced */
>> +
>> + return false;
>> +}
>> +
>> static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx,
>> bool line_status)
>> {
>> @@ -260,6 +280,7 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq,
> bool line_status)
>> {
>> union kvm_ioapic_redirect_entry *entry = &ioapic->redirtbl[irq];
>> struct kvm_lapic_irq irqe;
>> + int ret;
>>
>> ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
>> "vector=%x trig_mode=%x\n",
>> @@ -275,7 +296,15 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int
> irq, bool line_status)
>> irqe.level = 1;
>> irqe.shorthand = 0;
>> - return kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL);
>> + if (irq == RTC_GSI && line_status) {
>> + BUG_ON(ioapic->rtc_status.pending_eoi != 0);
>> + ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe,
>> + ioapic->rtc_status.dest_map);
>> + ioapic->rtc_status.pending_eoi = ret;
>> + } else
>> + ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL);
>> +
>> + return ret;
>> }
>>
>> int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
>> @@ -299,6 +328,11 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int
> irq, int irq_source_id,
>> ret = 1;
>> } else {
>> int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
>> +
>> + if (rtc_irq_check_coalesced(ioapic, irq, line_status)) {
>> + ret = 0; /* coalesced */
>> + goto out;
>> + }
>> ioapic->irr |= mask;
>> if ((edge && old_irr != ioapic->irr) ||
>> (!edge && !entry.fields.remote_irr))
>> @@ -306,6 +340,7 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq,
> int irq_source_id,
>> else ret = 0; /* report coalesced interrupt */ } +out:
>> trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
>> spin_unlock(&ioapic->lock);
>> @@ -333,6 +368,8 @@ static void __kvm_ioapic_update_eoi(struct kvm_vcpu
> *vcpu,
>> if (ent->fields.vector != vector)
>> continue;
>> + if (i == RTC_GSI)
>> + rtc_irq_eoi(ioapic, vcpu);
>> /*
>> * We are dropping lock while calling ack notifiers because ack
>> * notifier callbacks for assigned devices call into IOAPIC
>> --
>> 1.7.1
>
> --
> Gleb.
Best regards,
Yang
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
