Re: [Xen-devel] [RFC PATCH 26/49] ARM: new VGIC: Implement vgic_vcpu_pending_irq

[Julien Grall <julien.grall@xxxxxxx>]

On 02/26/2018 04:25 PM, Andre Przywara wrote:
> Hi,
>
> On 26/02/18 15:55, Julien Grall wrote:
> > Hi,
> >
> > On 02/26/2018 03:29 PM, Andre Przywara wrote:
> > > On 13/02/18 16:35, Julien Grall wrote:
> > > > > diff --git a/xen/arch/arm/vgic/vgic.c b/xen/arch/arm/vgic/vgic.c
> > > > > index f4f2a04a60..9e7fb1edcb 100644
> > > > > --- a/xen/arch/arm/vgic/vgic.c
> > > > > +++ b/xen/arch/arm/vgic/vgic.c
> > > > > @@ -646,6 +646,38 @@ void gic_inject(void)
> > > > >         vgic_restore_state(current);
> > > > >     }
> > > > >     +static int vgic_vcpu_pending_irq(struct vcpu *vcpu)
> > > > > +{
> > > > > +    struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> > > > > +    struct vgic_irq *irq;
> > > > > +    bool pending = false;
> > > > > +    unsigned long flags;
> > > > > +
> > > > > +    if ( !vcpu->domain->arch.vgic.enabled )
> > > > > +        return false;
> > > > > +
> > > > > +    spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
> > > > > +
> > > > > +    list_for_each_entry(irq, &vgic_cpu->ap_list_head, ap_list)
> > > > > +    {
> > > > > +        spin_lock(&irq->irq_lock);
> > > > > +        pending = irq_is_pending(irq) && irq->enabled;
> > > > > +        spin_unlock(&irq->irq_lock);
> > > > > +
> > > > > +        if ( pending )
> > > > > +            break;
> > > > > +    }
> > > > > +
> > > > > +    spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
> > > > > +
> > > > > +    return pending;
> > > > > +}
> > > > > +
> > > > > +int gic_events_need_delivery(void)
> > > > You probably want to rename that function or just expose
> > > > vgic_vcpu_pending_irq().
> > > Rename to what? I need both functions: vgic_vcpu_pending_irq() is also
> > > called by vgic_kick_vcpus() (later in the series).
> > > And gic_events_need_delivery(void) is the interface that the arch code
> > > expects. Shall I rename this there? To what?
> > Let me start with it is a bit odd to have a function name 'gic_*' in the
> > virtual GIC code. So at least renaming to vgic_events_need_delivery
> > would be an improvement.
> >
> > Regarding the interface itself, it is ARM specific and not set in stone.
> > It would not be too bad to use vgic_vcpu_pending_irq(current). Is there
> > any reason for not doing that?
> Not really, but I am a bit reluctant to change too much original Xen
> code, don't want to step on anyone's toes ;-)
The original code is going to get kill at some point. So better use name 
that makes sense in the new context. It is quite similar to the 
gic_inject change.
> But if that's fine with you, I am OK with the renaming - though it adds
> yet another patch ;-)
The end goal is a better world, so the number of patches does not matter 
here :).
If you put them at the beginning, we can merge them right away.

Cheers,

--
Julien Grall

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