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Re: [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices |
Date: |
Mon, 28 May 2012 16:15:24 +0300 |
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 <address@hidden>
> >
> > 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