Re: [Xen-devel] [PATCH v8 2/2] xen/arm: trap guest WFI

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-04-22 at 18:42 +0100, Stefano Stabellini wrote:

> +static inline int _local_events_need_delivery(void)

Can we call this local_events_need_delivery_nomask or something to make
it clear why it is special (which the leading _ doesn't really do).

> +{
> +    struct pending_irq *p = irq_to_pending(current, 
> VGIC_IRQ_EVTCHN_CALLBACK);
> +
> +    /* XXX: if the first interrupt has already been delivered, we should
> +     * check whether any higher priority interrupts are in the
> +     * lr_pending queue or in the LR registers and return 1 only in that
> +     * case.
> +     * In practice the guest interrupt handler should run with
> +     * interrupts disabled so this shouldn't be a problem in the general
> +     * case.
> +     */
> +    if ( gic_events_need_delivery() )
> +        return 1;
> +
> +    if ( vcpu_info(current, evtchn_upcall_pending) &&
> +        !vcpu_info(current, evtchn_upcall_mask) &&

I don't think you need this upcall_mask check.

> +        list_empty(&p->inflight) )
> +        return 1;
> +
> +    return 0;
> +}
> +
>  static inline int local_events_need_delivery(void)
>  {
> -    /* TODO
> -     * return (vcpu_info(v, evtchn_upcall_pending) &&
> -                        !vcpu_info(v, evtchn_upcall_mask)); */
> +    struct cpu_user_regs *regs = guest_cpu_user_regs();
> +
> +    /* guest IRQs are masked */
> +    if ( (regs->cpsr & PSR_IRQ_MASK) )
>          return 0;
> +    return _local_events_need_delivery();
>  }
>  
>  int local_event_delivery_is_enabled(void);
>  
> -static inline void local_event_delivery_disable(void)
> -{
> -    /* TODO current->vcpu_info->evtchn_upcall_mask = 1; */
> -}
> -
>  static inline void local_event_delivery_enable(void)
>  {
>      /* TODO current->vcpu_info->evtchn_upcall_mask = 0; */

No reason to leave this TODO IMHO.

Ian.


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