Re: [PATCH] vfio: Set PCI_DEV_FLAGS_ASSIGNED when assigning device to guest

[Alex Williamson <alex.williamson@redhat.com>]

On Thu, 2014-01-30 at 22:54 +0530, Bandan Das wrote:
> Some drivers such as ixgbe rely on pci_vfs_assigned() to prevent
> disabling sr-iov when vfs are still assigned during hotplug
> event or module removal. Set and unset PCI_DEV_FLAGS_ASSIGNED
> appropriately

This flag has always felt like a band-aide for KVM device assignment
because a device could be used without an actual driver attached to the
device.  vfio-pci is an actual driver, so why should it matter whether
the device is assigned or in use by ixgbevf or in use by pci-vfio?  It
seems like sr-iov shouldn't be disabled so long as either a driver or
this (needs to be deprecated) flag are set.  Thanks,

Alex

> ---
>  drivers/vfio/pci/vfio_pci.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 7ba0424..7cc7ed6 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -90,6 +90,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
>  		vdev->has_vga = true;
>  #endif
>  
> +	pdev->dev_flags |= PCI_DEV_FLAGS_ASSIGNED;
>  	return 0;
>  }
>  
> @@ -149,6 +150,7 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
>  				__func__, dev_name(&pdev->dev), ret);
>  	}
>  
> +	pdev->dev_flags &= ~PCI_DEV_FLAGS_ASSIGNED;
>  	pci_restore_state(pdev);
>  }
>