[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v5 04/10] xen/arm: support HW interrupts, do not request maintenance_interrupts
On Tue, 1 Apr 2014, Ian Campbell wrote: > On Mon, 2014-03-24 at 18:49 +0000, Stefano Stabellini wrote: > > > > +static void gic_clear_one_lr(struct vcpu *v, int i) > > +{ > > + struct pending_irq *p; > > + uint32_t lr; > > + int irq; > > + bool_t inflight; > > + > > + ASSERT(!local_irq_is_enabled()); > > + ASSERT(spin_is_locked(&v->arch.vgic.lock)); > [...] > > + if ( !inflight ) > > + { > > + spin_lock(&v->arch.vgic.lock); > > Aren't you recursively taking this lock here? > > In principal could you remove the requirement for the caller to hold > this lock as long as you took it just before p = irq_to_pending(v, irq); > and released it on each iteration? (I'm not at all sure of that, just > wondering) Yes, you are right. I had already fixed this problem in v6 (already sent to the list). I didn't realize this problem because the spin_lock goes away with a later patch. > > + list_del_init(&p->inflight); > > + spin_unlock(&v->arch.vgic.lock); > > + } > > + } > > +} > > + > > +void gic_clear_lrs(struct vcpu *v) > > +{ > > + int i = 0; > > + unsigned long flags; > > + > > + spin_lock_irqsave(&v->arch.vgic.lock, flags); > > + > > + while ((i = find_next_bit((const unsigned long *) &this_cpu(lr_mask), > > + nr_lrs, i)) < nr_lrs) { > > + gic_clear_one_lr(v, i); > > + i++; > > + } > > + > > + spin_unlock_irqrestore(&v->arch.vgic.lock, flags); > > +} > > + > > static void gic_restore_pending_irqs(struct vcpu *v) > > { > > int i; > [...] > > > + /* > > + * The maintenance interrupt handler doesn't do anything anymore, but > > "This is a dummy interrupt handler." (We don't care about "anymore" once > this is applied OK > > + * receiving the interrupt is going to cause gic_inject to be called on > > Receiving... (because of the full stop I added above) > > > @@ -1642,6 +1647,11 @@ asmlinkage void leave_hypervisor_tail(void) > > } > > } > > > > +static void enter_hypervisor_head(void) > > +{ > > + gic_clear_lrs(current); > > +} > > Just put it before the first use and avoid the need for the forward > declaration. OK _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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