On Mon, Mar 18, 2013 at 03:24:39PM +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 need_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 | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 67 insertions(+), 0 deletions(-)
>
> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
> index 7e47da8..8d498e5 100644
> --- a/virt/kvm/ioapic.c
> +++ b/virt/kvm/ioapic.c
> @@ -130,6 +130,48 @@ static void rtc_irq_get_dest_vcpu(struct kvm_ioapic *ioapic, int irq)
> kvm_get_dest_vcpu(ioapic->kvm, &irqe, ioapic->rtc_status.vcpu_map);
> }
>
> +static void rtc_irq_set_eoi(struct kvm_ioapic *ioapic, int irq)
> +{
> + union kvm_ioapic_redirect_entry *entry = &ioapic->redirtbl[irq];
> +
> + if (irq != 8)
> + return;
> +
> + if (likely(!bitmap_empty(ioapic->rtc_status.vcpu_map, KVM_MAX_VCPUS))) {
> + if (entry->fields.delivery_mode == APIC_DM_LOWEST)
> + ioapic->rtc_status.need_eoi = 1;
> + else {
> + int weight;
> + weight = bitmap_weight(ioapic->rtc_status.vcpu_map,
> + sizeof(ioapic->rtc_status.vcpu_map));
> + ioapic->rtc_status.need_eoi = weight;
> + }
> + }
> +}
Why two bitmaps are necessary? One should be enough.
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