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Re: [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices
From: |
Benjamin Herrenschmidt |
Subject: |
Re: [Qemu-devel] [RFC PATCH] vfio: add fixup for broken PCI devices |
Date: |
Fri, 25 May 2012 18:28:38 +1000 |
On Fri, 2012-05-25 at 17:35 +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.
I think we should create a new quirk category... call it pci_fixup_reset
or something like that, which is responsible for blasting the thing into
submission when ownership changes.
We'll need these for more than just USB I suspect.
Cheers,
Ben.
> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> ---
> 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 |