Re: [PATCH vfio 08/11] vfio/pci: Expose vfio_pci_core_setup_barmap()

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

On Thu, 21 Sep 2023 15:40:37 +0300
Yishai Hadas <yishaih@nvidia.com> wrote:

> Expose vfio_pci_core_setup_barmap() to be used by drivers.
> 
> This will let drivers to mmap a BAR and re-use it from both vfio and the
> driver when it's applicable.
> 
> This API will be used in the next patches by the vfio/virtio coming
> driver.
> 
> Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
> ---
>  drivers/vfio/pci/vfio_pci_core.c | 25 +++++++++++++++++++++++++
>  drivers/vfio/pci/vfio_pci_rdwr.c | 28 ++--------------------------
>  include/linux/vfio_pci_core.h    |  1 +
>  3 files changed, 28 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index 1929103ee59a..b56111ed8a8c 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -684,6 +684,31 @@ void vfio_pci_core_disable(struct vfio_pci_core_device *vdev)
>  }
>  EXPORT_SYMBOL_GPL(vfio_pci_core_disable);
>  
> +int vfio_pci_core_setup_barmap(struct vfio_pci_core_device *vdev, int bar)
> +{
> +	struct pci_dev *pdev = vdev->pdev;
> +	void __iomem *io;
> +	int ret;
> +
> +	if (vdev->barmap[bar])
> +		return 0;
> +
> +	ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
> +	if (ret)
> +		return ret;
> +
> +	io = pci_iomap(pdev, bar, 0);
> +	if (!io) {
> +		pci_release_selected_regions(pdev, 1 << bar);
> +		return -ENOMEM;
> +	}
> +
> +	vdev->barmap[bar] = io;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(vfio_pci_core_setup_barmap);

Not to endorse the rest of this yet, but minimally _GPL, same for the
following patch.  Thanks,

Alex

> +
>  void vfio_pci_core_close_device(struct vfio_device *core_vdev)
>  {
>  	struct vfio_pci_core_device *vdev =
> diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
> index e27de61ac9fe..6f08b3ecbb89 100644
> --- a/drivers/vfio/pci/vfio_pci_rdwr.c
> +++ b/drivers/vfio/pci/vfio_pci_rdwr.c
> @@ -200,30 +200,6 @@ static ssize_t do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
>  	return done;
>  }
>  
> -static int vfio_pci_setup_barmap(struct vfio_pci_core_device *vdev, int bar)
> -{
> -	struct pci_dev *pdev = vdev->pdev;
> -	int ret;
> -	void __iomem *io;
> -
> -	if (vdev->barmap[bar])
> -		return 0;
> -
> -	ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
> -	if (ret)
> -		return ret;
> -
> -	io = pci_iomap(pdev, bar, 0);
> -	if (!io) {
> -		pci_release_selected_regions(pdev, 1 << bar);
> -		return -ENOMEM;
> -	}
> -
> -	vdev->barmap[bar] = io;
> -
> -	return 0;
> -}
> -
>  ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
>  			size_t count, loff_t *ppos, bool iswrite)
>  {
> @@ -262,7 +238,7 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
>  		}
>  		x_end = end;
>  	} else {
> -		int ret = vfio_pci_setup_barmap(vdev, bar);
> +		int ret = vfio_pci_core_setup_barmap(vdev, bar);
>  		if (ret) {
>  			done = ret;
>  			goto out;
> @@ -438,7 +414,7 @@ int vfio_pci_ioeventfd(struct vfio_pci_core_device *vdev, loff_t offset,
>  		return -EINVAL;
>  #endif
>  
> -	ret = vfio_pci_setup_barmap(vdev, bar);
> +	ret = vfio_pci_core_setup_barmap(vdev, bar);
>  	if (ret)
>  		return ret;
>  
> diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
> index 562e8754869d..67ac58e20e1d 100644
> --- a/include/linux/vfio_pci_core.h
> +++ b/include/linux/vfio_pci_core.h
> @@ -127,6 +127,7 @@ int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf);
>  int vfio_pci_core_enable(struct vfio_pci_core_device *vdev);
>  void vfio_pci_core_disable(struct vfio_pci_core_device *vdev);
>  void vfio_pci_core_finish_enable(struct vfio_pci_core_device *vdev);
> +int vfio_pci_core_setup_barmap(struct vfio_pci_core_device *vdev, int bar);
>  pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
>  						pci_channel_state_t state);
>  

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