Re: [Xen-devel] [PATCH v4 2/6] xen/arm: track the state of guest IRQs

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2013-12-11 at 19:07 +0000, Stefano Stabellini wrote:
> @@ -916,6 +910,36 @@ static void maintenance_interrupt(int irq, void *dev_id, 
> struct cpu_user_regs *r
>              cpu = p->desc->arch.eoi_cpu;
>              pirq = p->desc->irq;
>          }
> +        if ( test_bit(GIC_IRQ_GUEST_PENDING, &p->status) &&
> +             test_bit(GIC_IRQ_GUEST_ENABLED, &p->status))
> +        {
> +            BUG_ON(!list_empty(&p->lr_queue));
> +
> +            list_for_each_entry ( iter, &v->arch.vgic.lr_pending, lr_queue )
> +            {
> +                if ( iter->priority > p->priority )
> +                {
> +                    list_add_tail(&p->lr_queue, &iter->lr_queue);
> +                    goto out;
> +                }
> +            }
> +            list_add_tail(&p->lr_queue, &v->arch.vgic.lr_pending);
> +out:

Is there really no helper function for all that? It looks very similar
to the tail of gic_set_guest_irq.

> +            set_int = 1;
> +        }
> +
> +        clear_bit(GIC_IRQ_GUEST_VISIBLE, &p->status);
> +
> +        if ( !list_empty(&v->arch.vgic.lr_pending) ) {
> +            p2 = list_entry(v->arch.vgic.lr_pending.next, typeof(*p2), 
> lr_queue);
> +            gic_set_lr(i, p2->irq, GICH_LR_PENDING, p2->priority);
> +            list_del_init(&p2->lr_queue);
> +            set_bit(i, &this_cpu(lr_mask));
> +            set_int = 1;
> +        }
> +        spin_unlock_irq(&gic.lock);
> +
> +        spin_lock_irq(&v->arch.vgic.lock);
>          list_del_init(&p->inflight);
>          spin_unlock_irq(&v->arch.vgic.lock);
>  
> @@ -931,6 +955,12 @@ static void maintenance_interrupt(int irq, void *dev_id, 
> struct cpu_user_regs *r
>  
>          i++;
>      }
> +    if ( !set_int )
> +    {
> +        spin_lock_irq(&gic.lock);

Dropping the lock and then retaking it here is a bit of a suspicious
pattern -- what if something changes in the interim?

Ian.


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel