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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jan Kiszka <jan.kiszka@web.de>
Cc: kvm@vger.kernel.org, Alexey Kardashevskiy <aik@ozlabs.ru>,
	qemu-devel@nongnu.org, Alex Graf <agraf@suse.de>,
	Alex Williamson <alex.williamson@redhat.com>,
	David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices
Date: Mon, 28 May 2012 16:15:24 +0300	[thread overview]
Message-ID: <20120528131524.GA22623@redhat.com> (raw)
In-Reply-To: <4FC3740A.4060801@web.de>

On Mon, May 28, 2012 at 02:48:10PM +0200, Jan Kiszka wrote:
> On 2012-05-28 14:44, Michael S. Tsirkin wrote:
> > On Fri, May 25, 2012 at 05:35:03PM +1000, Alexey Kardashevskiy wrote:
> >> Some adapters (like NEC PCI USB controller) do not flush their config
> >> on a sioftware reset and remember DMA config, etc.
> >>
> >> If we use such an adapter with QEMU, then crash QEMU (stop it with
> >> ctrl-A ctrl-X), and try to use it in QEMU again, it may start working
> >> immediately with previous config when pci_enable_device() is called
> >> on that PCI function.
> >>
> >> To eliminate such effect, some quirk should be called. The proposed
> >> pci_fixup_final does its job well for mentioned NEC PCI USB but not
> >> sure if it is 100% correct.
> >>
> >> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> > 
> > Won't current kvm device assignment be affected by this?
> 
> Would be surprising if not.
> 
> > If yes need to address that not just vfio.
> 
> A reason to solve this at PCI level?
> 
> Jan
> 

Sure, and I think this is what Benjamin Herren was suggesting.
I just wanted to add another reason.

-- 
MST

  reply	other threads:[~2012-05-28 13:15 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-25  7:35 [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices Alexey Kardashevskiy
2012-05-25  8:28 ` Benjamin Herrenschmidt
2012-05-25 12:24   ` Alex Williamson
2012-05-25 12:36     ` Benjamin Herrenschmidt
2012-05-28 12:44 ` Michael S. Tsirkin
2012-05-28 12:48   ` Jan Kiszka
2012-05-28 13:15     ` Michael S. Tsirkin [this message]
2012-06-06 23:17 ` Alex Williamson
2012-06-07  2:52   ` Benjamin Herrenschmidt
2012-06-07  3:56     ` Alex Williamson
2012-06-07  4:37       ` Benjamin Herrenschmidt
2012-06-22  8:16   ` Alexey Kardashevskiy
2012-08-17 14:28     ` Alexey Kardashevskiy
2012-08-21  2:31       ` Alex Williamson

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