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From: pbonzini@redhat.com (Paolo Bonzini)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6] KVM: arm/arm64: Route vtimer events to user space
Date: Fri, 23 Sep 2016 14:46:48 +0200	[thread overview]
Message-ID: <55ac71d8-7e92-aa57-9856-5fc48a7f8357@redhat.com> (raw)
In-Reply-To: <D82BA95A-A89E-46EB-93D2-197DF44433EC@suse.de>



On 23/09/2016 14:36, Alexander Graf wrote:
>>>
>>> +        if ((ret == 1) && timer_ret) {
>>> +            /*
>>> +             * We have to exit straight away to ensure that we only
>>> +             * ever notify user space once about a level change
>>> +             */
>>
>> Is this really a requirement?  It complicates the logic noticeably.
> 
> The alternative would be to track the state on ioctl entry, which
> Christoffer disliked :).

Ok, I see.  Maybe he's convinced by the ugly code. :)

It's not an architectural concept, it's a KVM API concept.  Tracking the
state on entry just the equivalent of making this vmexit edge-triggered
(both rising and falling edge).

Paolo

      parent reply	other threads:[~2016-09-23 12:46 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-23 11:07 [PATCH v6] KVM: arm/arm64: Route vtimer events to user space Alexander Graf
2016-09-23 12:11 ` Paolo Bonzini
2016-09-23 12:40   ` Christoffer Dall
2016-09-23 14:42     ` Paolo Bonzini
     [not found]   ` <D82BA95A-A89E-46EB-93D2-197DF44433EC@suse.de>
2016-09-23 12:46     ` Paolo Bonzini [this message]

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