Re: [Qemu-devel] [PATCH 4/5] kvm-i8259: support "info pic" and "info irq"

[Philippe Mathieu-Daudé]

On 12/10/2017 03:38 AM, Peter Xu wrote:
> Let's leverage the i8259 common code for kvm-i8259 too.
> 
> I think it's still possible that stats can lost when i8259 is in kernel
> and meanwhile when irqfd is used, e.g., by vfio or vhost devices.
> However that should be rare IMHO since they should be using MSIs mostly
> if they really want performance (that's why people use vhost and device
> assignment), and no old INTx should be used.  As long as the INTx users
> are emulated in QEMU the stats will be correct.
> 
> For "info pic", it should be always accurate since we fetch kvm regs
> before dump.
> 
> More importantly, it's just too simple to do this now - it's only 10+
> LOC to gain this feature.
> 
> Signed-off-by: Peter Xu <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  hw/i386/kvm/i8259.c    | 8 ++++++++
>  hw/intc/i8259_common.c | 1 +
>  2 files changed, 9 insertions(+)
> 
> diff --git a/hw/i386/kvm/i8259.c b/hw/i386/kvm/i8259.c
> index 11d1b726b6..57abe091b0 100644
> --- a/hw/i386/kvm/i8259.c
> +++ b/hw/i386/kvm/i8259.c
> @@ -111,6 +111,7 @@ static void kvm_pic_set_irq(void *opaque, int irq, int 
> level)
>  {
>      int delivered;
>  
> +    pic_stat_update_irq(irq, level);
>      delivered = kvm_set_irq(kvm_state, irq, level);
>      apic_report_irq_delivered(delivered);
>  }
> @@ -139,12 +140,15 @@ static void kvm_i8259_class_init(ObjectClass *klass, 
> void *data)
>      KVMPICClass *kpc = KVM_PIC_CLASS(klass);
>      PICCommonClass *k = PIC_COMMON_CLASS(klass);
>      DeviceClass *dc = DEVICE_CLASS(klass);
> +    InterruptStatsProviderClass *ic = INTERRUPT_STATS_PROVIDER_CLASS(klass);
>  
>      dc->reset     = kvm_pic_reset;
>      kpc->parent_realize = dc->realize;
>      dc->realize   = kvm_pic_realize;
>      k->pre_save   = kvm_pic_get;
>      k->post_load  = kvm_pic_put;
> +    ic->get_statistics = pic_get_statistics;
> +    ic->print_info = pic_print_info;
>  }
>  
>  static const TypeInfo kvm_i8259_info = {
> @@ -153,6 +157,10 @@ static const TypeInfo kvm_i8259_info = {
>      .instance_size = sizeof(PICCommonState),
>      .class_init = kvm_i8259_class_init,
>      .class_size = sizeof(KVMPICClass),
> +    .interfaces = (InterfaceInfo[]) {
> +        { TYPE_INTERRUPT_STATS_PROVIDER },
> +        { }
> +    },
>  };
>  
>  static void kvm_pic_register_types(void)
> diff --git a/hw/intc/i8259_common.c b/hw/intc/i8259_common.c
> index a3caddeefb..7efd2e8012 100644
> --- a/hw/intc/i8259_common.c
> +++ b/hw/intc/i8259_common.c
> @@ -132,6 +132,7 @@ void pic_print_info(InterruptStatsProvider *obj, Monitor 
> *mon)
>  {
>      PICCommonState *s = PIC_COMMON(obj);
>  
> +    pic_dispatch_pre_save(s);
>      monitor_printf(mon, "pic%d: irr=%02x imr=%02x isr=%02x hprio=%d "
>                     "irq_base=%02x rr_sel=%d elcr=%02x fnm=%d\n",
>                     s->master ? 0 : 1, s->irr, s->imr, s->isr, 
> s->priority_add,
>