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SubjectRe: [PATCH] vfio: Add an ioctl to reset the device
On Tue, 19 Apr 2011 14:32:59 -0600 Alex Williamson wrote:

> When using VFIO to assign a device to a guest, we want to make sure
> the device is quiesced on VM reset to stop all DMA within the guest
> mapped memory. Add an ioctl which just calls pci_reset_function()
> and returns whether it succeeds.
>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
>
> We've recently needed to add this functionality for current KVM
> based device assignment, VFIO should provide a way to do this too.
> An example of it being used in the Qemu VFIO driver can be found
> here:
>
> https://github.com/awilliam/qemu-vfio/blob/vfio/hw/vfio.c
>
> drivers/vfio/vfio_main.c | 4 ++++
> include/linux/vfio.h | 3 +++
> 2 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> index 7e427fc..b9bb692 100644
> --- a/drivers/vfio/vfio_main.c
> +++ b/drivers/vfio/vfio_main.c
> @@ -490,6 +490,10 @@ static long vfio_unl_ioctl(struct file *filep,
> ret = vfio_irq_eoi_eventfd(vdev, fd);
> break;
>
> + case VFIO_RESET_FUNCTION:
> + ret = pci_reset_function(vdev->pdev);
> + break;
> +
> default:
> return -EINVAL;
> }
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index f07d8fe..47d9bb9 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -215,6 +215,9 @@ struct vfio_dma_map {
> /* Re-enable INTx via eventfd */
> #define VFIO_IRQ_EOI_EVENTFD _IOW(';', 110, int)
>
> +/* Reset PCI function */
> +#define VFIO_RESET_FUNCTION _IO(';', 111)
> +
> /*
> * Reads, writes, and mmaps determine which PCI BAR (or config space)
> * from the high level bits of the file offset

I can't find include/linux/vfio.h in linux-next or mainline git, but
ioctls need to be documented in Documentation/ioctl/ioctl-number.txt....
---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

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