[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <4A28172D.6010906@gmail.com>
Date: Thu, 04 Jun 2009 14:49:17 -0400
From: Gregory Haskins <gregory.haskins@...il.com>
To: "Michael S. Tsirkin" <mst@...hat.com>
CC: Avi Kivity <avi@...hat.com>, Gregory Haskins <ghaskins@...ell.com>,
linux-kernel@...r.kernel.org, agraf@...e.de, pmullaney@...ell.com,
pmorreale@...ell.com, anthony@...emonkey.ws, rusty@...tcorp.com.au,
netdev@...r.kernel.org, kvm@...r.kernel.org,
bhutchings@...arflare.com, andi@...stfloor.org, gregkh@...e.de,
herber@...dor.apana.org.au, chrisw@...s-sol.org,
shemminger@...tta.com
Subject: Re: [RFC PATCH v2 00/19] virtual-bus
Avi Kivity wrote:
> Gregory Haskins wrote:
>> Avi,
>>
>> Gregory Haskins wrote:
>>
>>> Todo:
>>> *) Develop some kind of hypercall registration mechanism for KVM so
>>> that
>>> we can use that as an integration point instead of directly hooking
>>> kvm hypercalls
>>>
>>
>> What would you like to see here? I now remember why I removed the
>> original patch I had for registration...it requires some kind of
>> discovery mechanism on its own. Note that this is hard, but I figured
>> it would make the overall series simpler if I didn't go this route and
>> instead just integrated with a statically allocated vector. That being
>> said, I have no problem adding this back in but figure we should discuss
>> the approach so I don't go down a rat-hole ;)
>>
>>
>
>
> One idea is similar to signalfd() or eventfd(). Provide a kvm ioctl
> that takes a gsi and returns an fd. Writes to the fd change the state
> of the line, possible triggering an interrupt. Another ioctl takes a
> hypercall number or pio port as well as an existing fd. Invocations
> of the hypercall or writes to the port write to the fd (using the same
> protocol as eventfd), so the other end can respond.
>
> The nice thing is that this can be used by both kernel and userspace
> components, and for kernel components, hypercalls can be either
> buffered or unbuffered.
And thus the "kvm-eventfd" (irqfd/iosignalfd) interface project was born. ;)
(Michael FYI: so I will be pushing a vbus-v4 series at some point in the
near future that is expressed in terms of irqfd/iosignalfd, per the
conversation above. The patches in v3 and earlier are more intrusive to
the KVM core than they will be in final form)
-Greg
Download attachment "signature.asc" of type "application/pgp-signature" (267 bytes)
Powered by blists - more mailing lists