From: Stefano Stabellini <sstabellini@kernel.org>
To: Julien Grall <julien.grall@arm.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
wei.chen@arm.com, steve.capper@arm.com, xen-devel@lists.xen.org,
shannon.zhao@linaro.org, shankerd@codeaurora.org
Subject: Re: [RFC 7/8] xen/arm: Allow DOM0 to set the irq type when ACPI is inuse
Date: Wed, 22 Jun 2016 12:49:07 +0100 (BST) [thread overview]
Message-ID: <alpine.DEB.2.10.1606221248530.2575@sstabellini-ThinkPad-X260> (raw)
In-Reply-To: <576A7A81.1020901@arm.com>
On Wed, 22 Jun 2016, Julien Grall wrote:
> > > @@ -356,6 +375,8 @@ void vgic_enable_irqs(struct vcpu *v, uint32_t r, int
> > > n)
> > > {
> > > irq_set_affinity(p->desc, cpumask_of(v_target->processor));
> > > spin_lock_irqsave(&p->desc->lock, flags);
> > > + if ( irq_type_set_by_domain(d) )
> > > + gic_set_irq_type(p->desc, __vgic_get_virq_type(v, irq));
> > > p->desc->handler->enable(p->desc);
> > > spin_unlock_irqrestore(&p->desc->lock, flags);
> > > }
> >
> > This is OK. But I am wondering if it wouldn't make sense to call
> > gic_set_irq_type when the guest actually writes to the virtual icfg?
>
> Hmmm it looks like that I forgot to explain in the commit message why I chose
> to call gic_set_irq_type here.
>
> Changing the value of Int_config is UNPREDICTABLE when the corresponding
> interrupt is not disabled (see 4.3.13 in ARM IHI 0048B.b).
>
> So calling gic_set_irq_type when the guest actualy writes to the virtual cfg
> would require to disable the IRQ before hand.
>
> Given that the behavior is UNPREDICTABLE, I chose to set the type before
> enabling the IRQ because the resulting code is simpler.
Ah, I see. Makes sense.
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next prev parent reply other threads:[~2016-06-22 11:49 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-07 16:48 [RFC 0/8] xen/arm: acpi: Support SPIs routing Julien Grall
2016-06-07 16:48 ` [RFC 1/8] xen/arm: gic: Consolidate the IRQ affinity set in a single place Julien Grall
2016-06-22 10:46 ` Stefano Stabellini
2016-06-07 16:48 ` [RFC 2/8] xen/arm: gic: Do not configure affinity for guest IRQ during routing Julien Grall
2016-06-22 10:54 ` Stefano Stabellini
2016-06-22 11:19 ` Julien Grall
2016-06-07 16:48 ` [RFC 3/8] xen/arm: gic: split set_irq_properties Julien Grall
2016-06-22 10:58 ` Stefano Stabellini
2016-06-07 16:48 ` [RFC 4/8] xen/arm: gic: set_type: Pass the type in parameter rather than in desc->arch.type Julien Grall
2016-06-22 11:25 ` Stefano Stabellini
2016-06-07 16:48 ` [RFC 5/8] xen/arm: gic: Document how gic_set_irq_type should be called Julien Grall
2016-06-22 11:00 ` Stefano Stabellini
2016-06-07 16:48 ` [RFC 6/8] Revert "xen/arm: warn the user that we cannot route SPIs to Dom0 on ACPI" Julien Grall
2016-06-22 11:01 ` Stefano Stabellini
2016-06-07 16:48 ` [RFC 7/8] xen/arm: Allow DOM0 to set the irq type when ACPI is inuse Julien Grall
2016-06-22 11:23 ` Stefano Stabellini
2016-06-22 11:46 ` Julien Grall
2016-06-22 11:49 ` Stefano Stabellini [this message]
2016-06-07 16:48 ` [RFC 8/8] xen/arm: acpi: route all unused IRQs to DOM0 Julien Grall
2016-06-22 11:44 ` Stefano Stabellini
2016-06-22 12:19 ` Julien Grall
2016-06-07 18:50 ` [RFC 0/8] xen/arm: acpi: Support SPIs routing Shanker Donthineni
2016-06-08 11:48 ` Shanker Donthineni
2016-06-08 11:49 ` Julien Grall
2016-06-08 12:11 ` Shanker Donthineni
2016-06-08 12:34 ` Julien Grall
2016-06-13 11:42 ` Julien Grall
2016-06-13 17:19 ` Shanker Donthineni
2016-06-13 17:20 ` Julien Grall
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