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

[Yishai Hadas <yishaih@xxxxxxxxxx>]

On 21/09/2023 19:35, Alex Williamson wrote:
> On Thu, 21 Sep 2023 15:40:37 +0300
> Yishai Hadas <yishaih@xxxxxxxxxx> 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@xxxxxxxxxx>
> > ---
> >   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

Sure, will change to EXPORT_SYMBOL_GPL as part of V1.

Yishai

> > +
> >   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);
> >