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From: Alexander Graf <agraf@suse.de>
To: Marc Zyngier <marc.zyngier@arm.com>, kvmarm@lists.cs.columbia.edu
Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	pbonzini@redhat.com
Subject: Re: [PATCH v4 2/2] KVM: arm/arm64: Route vtimer events to user space
Date: Thu, 22 Sep 2016 14:32:26 +0200	[thread overview]
Message-ID: <57E3CF5A.3050608@suse.de> (raw)
In-Reply-To: <57E0FF95.7040305@arm.com>

On 09/20/2016 11:21 AM, Marc Zyngier wrote:
> On 19/09/16 18:39, Alexander Graf wrote:
>>
>> On 19.09.16 16:48, Marc Zyngier wrote:
>>
>>>> +
>>>> +		/*
>>>> +		 * So we can just explicitly mask or unmask the IRQ, gaining
>>>> +		 * more compatibility with oddball irq controllers.
>>>> +		 */
>>>> +		if (phys_active)
>>>> +			disable_percpu_irq(host_vtimer_irq);
>>>> +		else
>>>> +			enable_percpu_irq(host_vtimer_irq, 0);
>>> Since you are now targeting random irqchips (as opposed to a GIC
>>> specifically), what guarantees that the timer is a per-cpu IRQ?
>> This is the host interrupt controller - and we're already using percpu
>> irqs on it :). Also as it happens the RPi has them percpu (anything else
>> wouldn't make sense...).
> Not really. The RPi is faking percpu interrupts just to have some level
> of compatibility with the host arch timer driver. But nonetheless, if
> you're opening the code to something else than a GIC, then you should
> check that the interrupt you're getting is percpu.

This should already be covered by request_percpu_irq() in 
kvm_timer_hyp_init(), no?


Alex

  parent reply	other threads:[~2016-09-22 12:23 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-19 11:14 [PATCH v4 0/2] KVM: ARM: Enable vtimers with user space gic Alexander Graf
2016-09-19 11:14 ` [PATCH v4 1/2] KVM: arm/arm64: Add vcpu ENABLE_CAP functionality Alexander Graf
2016-09-19 11:14 ` [PATCH v4 2/2] KVM: arm/arm64: Route vtimer events to user space Alexander Graf
2016-09-19 14:48   ` Marc Zyngier
2016-09-19 17:39     ` Alexander Graf
2016-09-20  9:21       ` Marc Zyngier
2016-09-20  9:26         ` Alexander Graf
2016-09-20  9:39           ` Marc Zyngier
2016-09-20 10:05             ` Alexander Graf
2016-09-20 10:28               ` Marc Zyngier
2016-09-20 12:22                 ` Alexander Graf
2016-09-20 12:37                   ` Marc Zyngier
2016-09-20 14:31                     ` Alexander Graf
2016-09-20 16:42                       ` Marc Zyngier
2016-09-22 11:17                         ` Alexander Graf
2016-09-22 12:32         ` Alexander Graf [this message]
2016-09-22 12:35           ` Marc Zyngier

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