On Mon, Apr 08, 2013 at 10:17:49PM +0800, Yang Zhang wrote:
> From: Yang Zhang <yang.z.zh...@intel.com>
>
> 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.zh...@intel.com>
> ---
> virt/kvm/ioapic.c | 41 ++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 40 insertions(+), 1 deletions(-)
>
> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
> index 8d1f662..197ef97 100644
> --- a/virt/kvm/ioapic.c
> +++ b/virt/kvm/ioapic.c
> @@ -149,6 +149,29 @@ static void kvm_rtc_eoi_tracking_restore_all(struct
> kvm_ioapic *ioapic)
> __rtc_irq_eoi_tracking_restore_one(vcpu, vector);
> }
>
> +static void rtc_irq_ack_eoi(struct kvm_ioapic *ioapic, struct kvm_vcpu *vcpu,
> + int irq)
rtc_irq_eoi() drop ack. We sometimes call EOI ack, but putting ack and
eoi in the name is to much.
> +{
> + if (irq != RTC_GSI)
> + return;
> +
Lets move the check to the caller:
if (i == RTC_GSI)
rtc_irq_eoi()
> + 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(struct kvm_ioapic *ioapic, int irq, bool
> line_status)
rtc_irq_check_coalesced()
> +{
> + if (irq != RTC_GSI || !line_status)
> + return false;
> +
> + 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)
> {
> @@ -262,6 +285,7 @@ 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",
> @@ -277,7 +301,15 @@ 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,
> @@ -301,6 +333,11 @@ 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(ioapic, irq, line_status)) {
> + ret = 0; /* coalesced */
> + goto out;
> + }
> ioapic->irr |= mask;
> if ((edge && old_irr != ioapic->irr) ||
> (!edge && !entry.fields.remote_irr))
> @@ -308,6 +345,7 @@ 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);
>
> @@ -335,6 +373,7 @@ static void __kvm_ioapic_update_eoi(struct kvm_vcpu *vcpu,
> if (ent->fields.vector != vector)
> continue;
>
> + rtc_irq_ack_eoi(ioapic, vcpu, i);
> /*
> * We are dropping lock while calling ack notifiers because ack
> * notifier callbacks for assigned devices call into IOAPIC
> --
> 1.7.1
--
Gleb.
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