Re: [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices

["Michael S. Tsirkin" <mst@redhat.com>]

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?
If yes need to address that not just vfio.

> ---
>  drivers/vfio/pci/vfio_pci.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 1e5315c..6e7c12d 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -88,6 +88,8 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
>  {
>  	int bar;
>  
> +	pci_fixup_device(pci_fixup_final, vdev->pdev);
> +
>  	pci_disable_device(vdev->pdev);
>  
>  	vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
> -- 
> 1.7.7.3