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
WARNING: multiple messages have this Message-ID (diff)
From: agraf@suse.de (Alexander Graf)
To: linux-arm-kernel@lists.infradead.org
Subject: [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
next prev parent reply other threads:[~2016-09-22 12:23 UTC|newest]
Thread overview: 34+ 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 ` 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 ` 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 11:14 ` Alexander Graf
2016-09-19 14:48 ` Marc Zyngier
2016-09-19 14:48 ` Marc Zyngier
2016-09-19 17:39 ` Alexander Graf
2016-09-19 17:39 ` Alexander Graf
2016-09-20 9:21 ` Marc Zyngier
2016-09-20 9:21 ` Marc Zyngier
2016-09-20 9:26 ` Alexander Graf
2016-09-20 9:26 ` Alexander Graf
2016-09-20 9:39 ` Marc Zyngier
2016-09-20 9:39 ` Marc Zyngier
2016-09-20 10:05 ` Alexander Graf
2016-09-20 10:05 ` Alexander Graf
2016-09-20 10:28 ` Marc Zyngier
2016-09-20 10:28 ` Marc Zyngier
2016-09-20 12:22 ` Alexander Graf
2016-09-20 12:22 ` Alexander Graf
2016-09-20 12:37 ` Marc Zyngier
2016-09-20 12:37 ` Marc Zyngier
2016-09-20 14:31 ` Alexander Graf
2016-09-20 14:31 ` Alexander Graf
2016-09-20 16:42 ` Marc Zyngier
2016-09-20 16:42 ` Marc Zyngier
2016-09-22 11:17 ` Alexander Graf
2016-09-22 11:17 ` Alexander Graf
2016-09-22 12:32 ` Alexander Graf [this message]
2016-09-22 12:32 ` Alexander Graf
2016-09-22 12:35 ` Marc Zyngier
2016-09-22 12:35 ` Marc Zyngier
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