Re: [Xen-devel] [RFC PATCH 24/49] ARM: new VGIC: Add IRQ sync/flush framework

[Julien Grall <julien.grall@xxxxxxx>]

Hi Andre,

On 09/02/18 14:39, Andre Przywara wrote:
> +/* Requires the VCPU's ap_list_lock to be held. */
> +static void vgic_flush_lr_state(struct vcpu *vcpu)
> +{
> +    struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> +    struct vgic_irq *irq;
> +    int count = 0;
> +
> +    ASSERT(spin_is_locked(&vgic_cpu->ap_list_lock));
> +
> +    if ( compute_ap_list_depth(vcpu) > gic_get_nr_lrs() )
> +        vgic_sort_ap_list(vcpu);
> +
> +    list_for_each_entry( irq, &vgic_cpu->ap_list_head, ap_list )
> +    {
> +        spin_lock(&irq->irq_lock);
> +
> +        if ( unlikely(vgic_target_oracle(irq) != vcpu) )
> +            goto next;
> +
> +        /*
> +         * If we get an SGI with multiple sources, try to get
> +         * them in all at once.
> +         */
> +        do
> +        {
> +            vgic_populate_lr(vcpu, irq, count++);
> +        } while ( irq->source && count < gic_get_nr_lrs() );
> +
> +next:
> +        spin_unlock(&irq->irq_lock);
> +
> +        if ( count == gic_get_nr_lrs() )
> +        {
> +            if ( !list_is_last(&irq->ap_list, &vgic_cpu->ap_list_head) )
> +                vgic_set_underflow(vcpu);
> +            break;
> +        }
> +    }
> +
> +    vcpu->arch.vgic_cpu.used_lrs = count;
> +
> +    /* Nuke remaining LRs */
> +    for ( ; count < gic_get_nr_lrs(); count++)
> +        vgic_clear_lr(vcpu, count);
Why do you need to nuke the LRs here, don't you always zero them when 
clearing it?
Cheers,

--
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel