Re: [PATCH v10 03/32] ARM: vGIC: move irq_to_pending() calls under the VGIC VCPU lock

[Stefano Stabellini <sstabellini@kernel.org>]

On Tue, 6 Jun 2017, Andre Przywara wrote:
> Maybe we should consider to merge this one for 4.9 still,
> as currently enabling the ITS in .config and running it on an ITS
> machine will fail to boot Dom0.

Here, you are talking about this patch, patch #3, right?

Although it should be "safe", it touches a lot of common code. I think
it is too risky to commit it now to fix an experimental feature. I would
rather wait until it is committed to staging in the 4.10 dev window,
then backport it.

 

> >> -        if ( p->desc != NULL )
> >> +        desc = p->desc;
> >> +        spin_unlock_irqrestore(&v_target->arch.vgic.lock, flags);
> >> +
> >> +        if ( desc != NULL )
> >>          {
> >> -            spin_lock_irqsave(&p->desc->lock, flags);
> >> -            p->desc->handler->disable(p->desc);
> >> -            spin_unlock_irqrestore(&p->desc->lock, flags);
> >> +            spin_lock_irqsave(&desc->lock, flags);
> >> +            desc->handler->disable(desc);
> >> +            spin_unlock_irqrestore(&desc->lock, flags);
> >>          }
> >>          i++;
> >>      }
> >> @@ -349,9 +368,9 @@ void vgic_enable_irqs(struct vcpu *v, uint32_t r,
> >> int n)
> >>      while ( (i = find_next_bit(&mask, 32, i)) < 32 ) {
> >>          irq = i + (32 * n);
> >>          v_target = vgic_get_target_vcpu(v, irq);
> >> +        spin_lock_irqsave(&v_target->arch.vgic.lock, flags);
> >>          p = irq_to_pending(v_target, irq);
> >>          set_bit(GIC_IRQ_GUEST_ENABLED, &p->status);
> >> -        spin_lock_irqsave(&v_target->arch.vgic.lock, flags);
> >>          if ( !list_empty(&p->inflight) &&
> >> !test_bit(GIC_IRQ_GUEST_VISIBLE, &p->status) )
> >>              gic_raise_guest_irq(v_target, irq, p->priority);
> >>          spin_unlock_irqrestore(&v_target->arch.vgic.lock, flags);
> >> @@ -460,7 +479,7 @@ void vgic_clear_pending_irqs(struct vcpu *v)
> >>  void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int virq)
> >>  {
> >>      uint8_t priority;
> >> -    struct pending_irq *iter, *n = irq_to_pending(v, virq);
> >> +    struct pending_irq *iter, *n;
> >>      unsigned long flags;
> >>      bool running;
> >>
> >> @@ -468,6 +487,8 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned
> >> int virq)
> >>
> >>      spin_lock_irqsave(&v->arch.vgic.lock, flags);
> >>
> >> +    n = irq_to_pending(v, virq);
> >> +
> >>      /* vcpu offline */
> >>      if ( test_bit(_VPF_down, &v->pause_flags) )
> >>      {
> >>

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