Re: [PATCH 1/3] Make kvm_apic_set_irq() deliver all kinds of interrupts.

[Marcelo Tosatti <mtosatti@redhat.com>]

Hi Gleb,

On Wed, Mar 04, 2009 at 03:30:11PM +0200, Gleb Natapov wrote:
> Get rid of ioapic_inj_irq() and ioapic_inj_nmi() functions.
> 
> Signed-off-by: Gleb Natapov <gleb@redhat.com>
> ---
> 
> index afc59b2..d58268f 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -196,20 +196,30 @@ int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
>  }
>  EXPORT_SYMBOL_GPL(kvm_lapic_find_highest_irr);
>  
> -int kvm_apic_set_irq(struct kvm_vcpu *vcpu, u8 vec, u8 trig)
> +static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
> +			     int vector, int level, int trig_mode);
> +
> +int kvm_apic_set_irq(struct kvm_vcpu *vcpu, u8 vec, u8 dmode, u8 trig)
>  {
>  	struct kvm_lapic *apic = vcpu->arch.apic;
> +	int lapic_dmode;
>  
> -	if (!apic_test_and_set_irr(vec, apic)) {
> -		/* a new pending irq is set in IRR */
> -		if (trig)
> -			apic_set_vector(vec, apic->regs + APIC_TMR);
> -		else
> -			apic_clear_vector(vec, apic->regs + APIC_TMR);
> -		kvm_vcpu_kick(apic->vcpu);
> -		return 1;
> +	switch(dmode) {
> +		case IOAPIC_LOWEST_PRIORITY:
> +			lapic_dmode = APIC_DM_LOWEST;
> +			break;
> +		case IOAPIC_FIXED:
> +			lapic_dmode = APIC_DM_FIXED;
> +			break;
> +		case IOAPIC_NMI:
> +			lapic_dmode = APIC_DM_NMI;
> +			break;
> +		default:
> +			printk(KERN_DEBUG"Ignoring delivery mode %d\n", dmode);
> +			return 0;
> +			break;
>  	}
> -	return 0;
> +	return __apic_accept_irq(apic, lapic_dmode, vec, 1, trig);

The FIXED/LOWEST handling in __apic_accept_irqs is not as straightforward
as the old kvm_apic_set_irq. Perhaps replace

                orig_irr = apic_test_and_set_irr(vector, apic);
                if (orig_irr && trig_mode) {
                        apic_debug("level trig mode repeatedly for vector %d",
                                   vector);
                        break;
                }

                if (trig_mode) {
                        apic_debug("level trig mode for vector %d", vector);
                        apic_set_vector(vector, apic->regs + APIC_TMR);
                } else
                        apic_clear_vector(vector, apic->regs + APIC_TMR);

                kvm_vcpu_kick(vcpu);

With the old 

> -     if (!apic_test_and_set_irr(vec, apic)) {
> -             /* a new pending irq is set in IRR */
> -             if (trig)
> -                     apic_set_vector(vec, apic->regs + APIC_TMR);
> -             else
> -                     apic_clear_vector(vec, apic->regs + APIC_TMR);
> -             kvm_vcpu_kick(apic->vcpu);

Note they are slightly different. The first version will update APIC_TMR
even if the IRR was already set, for trig_mode == 0.

Otherwise looks very nice, I've updated Sheng's "KVM: Merge
kvm_ioapic_get_delivery_bitmask into kvm_get_intr_delivery_bitmask", 
so please rebase against that.

git://git.kernel.org/pub/scm/linux/kernel/git/marcelo/kvm.git kvm-devel
branch, will push in a few minutes.