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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] [PATCH 05/11] qemu: MSI-X support functions
Date: Wed, 10 Jun 2009 15:39:05 +0100
References: <cover.1243253205.git.mst@redhat.com>
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	<20090610142508.GA28409@redhat.com>
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Carsten Otte <cotte@de.ibm.com>, kvm@vger.kernel.org, Rusty Russell <rusty@rustcorp.com.au>, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, Blue Swirl <blauwirbel@gmail.com>, Christian Borntraeger <borntraeger@de.ibm.com>, Avi Kivity <avi@redhat.com>

> > If we really need to avoid MSI-X capable devices then that should be done
> > explicity per-device. i.e. you have a different virtio-net device that
> > does not use MSI-X.
> >
> > Paul
>
> Why should it be done per-device?


Because otherwise you end up with the horrible hacks that you're currently 
tripping over: devices have to magically morph into a different device when 
you load a VM. That's seems just plain wrong to me. Loading a VM shouldn't not 
do anything that can't happen during normal operation.

Paul