From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alex Williamson <alex.williamson@redhat.com>
Subject: Re: kvm PCI assignment & VFIO ramblings
Date: Mon, 01 Aug 2011 10:40:46 -0600
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Cc: kvm@vger.kernel.org, Anthony Liguori <anthony@codemonkey.ws>,
	David Gibson <dwg@au1.ibm.com>,
	Paul Mackerras <pmac@au1.ibm.com>,
	Alexey Kardashevskiy <aik@au1.ibm.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Return-path: <linux-pci-owner@vger.kernel.org>
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Sender: linux-pci-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

On Sun, 2011-07-31 at 08:21 +1000, Benjamin Herrenschmidt wrote:
> On Sat, 2011-07-30 at 09:58 +1000, Benjamin Herrenschmidt wrote:
> > Hi folks !
> > 
> > So I promised Anthony I would try to summarize some of the comments &
> > issues we have vs. VFIO after we've tried to use it for PCI pass-through
> > on POWER. It's pretty long, there are various items with more or less
> > impact, some of it is easily fixable, some are API issues, and we'll
> > probably want to discuss them separately, but for now here's a brain
> > dump.
> > 
> > David, Alexei, please make sure I haven't missed anything :-)
> 
> And I think I have :-)
> 
>   * Config space
> 
> VFIO currently handles that as a byte stream. It's quite gross to be
> honest and it's not right. You shouldn't lose access size information
> between guest and host when performing real accesses.
> 
> Some config space registers can have side effects and not respecting
> access sizes can be nasty.

It's a bug, let's fix it.

Alex