From: Alex Williamson <alex.williamson@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: mst@redhat.com, gleb@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 0/6] kvm: level irqfd support
Date: Thu, 16 Aug 2012 10:45:55 -0600 [thread overview]
Message-ID: <1345135555.4683.480.camel@ul30vt.home> (raw)
In-Reply-To: <502D2099.7050800@redhat.com>
On Thu, 2012-08-16 at 19:32 +0300, Avi Kivity wrote:
> On 08/11/2012 01:37 AM, Alex Williamson wrote:
> > v8:
> >
> > Trying a new approach. Nobody seems to like the internal IRQ
> > source ID object and the interactions it implies between irqfd
> > and eoifd, so let's get rid of it. Instead, simply expose
> > IRQ source IDs to userspace. This lets the user be in charge
> > of freeing them or hanging onto a source ID for later use. They
> > can also detach and re-attach components at will. It also opens
> > up the possibility that userspace might want to use each IRQ
> > source ID for more than one GSI (and avoids the kernel needing
> > to manage that). Per suggestions, EOIFD is now IRQ_ACKFD.
> >
> > I really wanted to add a de-assert-only option to irqfd so the
> > irq_ackfd could be fed directly into an irqfd, but I'm dependent
> > on the ordering of de-assert _then_ signal an eventfd. Keeping
> > that ordering doesn't seem to be possible, especially since irqfd
> > uses a workqueue, if I attempt to make that connection. Thanks,
>
> I can't say I'm happy with exposing irq source IDs. It's true that they
> correspond to a physical entity so they can't be said to be an
> implementation detail, but adding more ABIs has a cost and I can't say
> that I see another user for this.
>
> Can you provide a link to the combined irqfd+ackfd implementation? I'm
> inclined now to go for the simplest solution possible.
As soon as I write it :) Keeping lists to handle the one-to-many
deassert-to-notify will notch up the complexity, but it'll be
interesting to see how it compares. Thanks,
Alex
prev parent reply other threads:[~2012-08-16 16:45 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-10 22:37 [PATCH v8 0/6] kvm: level irqfd support Alex Williamson
2012-08-10 22:37 ` [PATCH v8 1/6] kvm: Allow filtering of acked irqs Alex Williamson
2012-08-15 12:27 ` Michael S. Tsirkin
2012-08-15 16:47 ` Alex Williamson
2012-08-15 19:24 ` Michael S. Tsirkin
2012-08-10 22:37 ` [PATCH v8 2/6] kvm: Expose IRQ source IDs to userspace Alex Williamson
2012-08-15 12:59 ` Michael S. Tsirkin
2012-08-15 17:05 ` Alex Williamson
2012-08-10 22:37 ` [PATCH v8 3/6] kvm: Add IRQ source ID option to KVM_IRQFD Alex Williamson
2012-08-15 13:49 ` Michael S. Tsirkin
2012-08-15 17:08 ` Alex Williamson
2012-08-10 22:37 ` [PATCH v8 4/6] kvm: Add assert-only " Alex Williamson
2012-08-10 22:37 ` [PATCH v8 5/6] kvm: KVM_IRQ_ACKFD Alex Williamson
2012-08-15 14:05 ` Michael S. Tsirkin
2012-08-15 17:17 ` Alex Williamson
2012-08-10 22:37 ` [PATCH v8 6/6] kvm: Add de-assert option to KVM_IRQ_ACKFD Alex Williamson
2012-08-15 14:11 ` Michael S. Tsirkin
2012-08-15 17:24 ` Alex Williamson
2012-08-15 14:28 ` [PATCH v8 0/6] kvm: level irqfd support Michael S. Tsirkin
2012-08-15 17:36 ` Alex Williamson
2012-08-15 19:22 ` Michael S. Tsirkin
2012-08-15 19:59 ` Alex Williamson
2012-08-16 12:34 ` Alex Williamson
2012-08-16 12:53 ` Michael S. Tsirkin
2012-08-16 16:29 ` Avi Kivity
2012-08-16 16:36 ` Michael S. Tsirkin
2012-08-16 16:39 ` Avi Kivity
2012-08-16 16:54 ` Michael S. Tsirkin
2012-08-16 16:54 ` Avi Kivity
2012-08-16 17:01 ` Michael S. Tsirkin
2012-08-16 16:37 ` Alex Williamson
2012-08-16 16:32 ` Avi Kivity
2012-08-16 16:45 ` Alex Williamson [this message]
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