Re: [PATCH v3 5/7] vfio: move barmap to a separate function and export

[Donald Dutile]

On 11/21/25 11:39 AM, Alex Williamson wrote:
> On Fri, 21 Nov 2025 14:11:39 +0000
> <ankita@xxxxxxxxxx> wrote:
>
> > From: Ankit Agrawal <ankita@xxxxxxxxxx>
> >
> > Move the code to map the BAR to a separate function.
> >
> > This would be reused by the nvgrace-gpu module.
> >
> > Signed-off-by: Ankit Agrawal <ankita@xxxxxxxxxx>
> > ---
> >   drivers/vfio/pci/vfio_pci_core.c | 38 ++++++++++++++++++++++----------
> >   include/linux/vfio_pci_core.h    |  1 +
> >   2 files changed, 27 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> > index 29dcf78905a6..d1ff1c0aa727 100644
> > --- a/drivers/vfio/pci/vfio_pci_core.c
> > +++ b/drivers/vfio/pci/vfio_pci_core.c
> > @@ -1717,6 +1717,29 @@ static const struct vm_operations_struct vfio_pci_mmap_ops = {
> >   #endif
> >   };
> >   
> > +int vfio_pci_core_barmap(struct vfio_pci_core_device *vdev, unsigned int index)
> > +{
> > +	struct pci_dev *pdev = vdev->pdev;
> > +	int ret;
> > +
> > +	if (vdev->barmap[index])
> > +		return 0;
> > +
> > +	ret = pci_request_selected_regions(pdev,
> > +					   1 << index, "vfio-pci");
> > +	if (ret)
> > +		return ret;
> > +
> > +	vdev->barmap[index] = pci_iomap(pdev, index, 0);
> > +	if (!vdev->barmap[index]) {
> > +		pci_release_selected_regions(pdev, 1 << index);
> > +		return -ENOMEM;
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL_GPL(vfio_pci_core_barmap);
>
> Looks a lot like vfio_pci_core_setup_barmap() ;)
>
> Thanks,
> Alex
+1 ... and below ...
> > +
> >   int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma)
> >   {
> >   	struct vfio_pci_core_device *vdev =
> > @@ -1761,18 +1784,9 @@ int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma
> >   	 * Even though we don't make use of the barmap for the mmap,
> >   	 * we need to request the region and the barmap tracks that.
> >   	 */
> > -	if (!vdev->barmap[index]) {
> > -		ret = pci_request_selected_regions(pdev,
> > -						   1 << index, "vfio-pci");
> > -		if (ret)
> > -			return ret;
> > -
> > -		vdev->barmap[index] = pci_iomap(pdev, index, 0);
> > -		if (!vdev->barmap[index]) {
> > -			pci_release_selected_regions(pdev, 1 << index);
> > -			return -ENOMEM;
> > -		}
> > -	}
> > +	ret = vfio_pci_core_barmap(vdev, index);
> > +	if (ret)
> > +		return ret;
> >   
so, vfio_pci_core_mmap() should be calling vfio_pci_core_setup_barmap() vs. what it does above currently?

--Don

> >   	vma->vm_private_data = vdev;
> >   	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> > diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
> > index a097a66485b4..75f04d613e0c 100644
> > --- a/include/linux/vfio_pci_core.h
> > +++ b/include/linux/vfio_pci_core.h
> > @@ -121,6 +121,7 @@ ssize_t vfio_pci_core_write(struct vfio_device *core_vdev, const char __user *bu
> >   		size_t count, loff_t *ppos);
> >   vm_fault_t vfio_pci_map_pfn(struct vm_fault *vmf, unsigned long pfn,
> >   			    unsigned int order);
> > +int vfio_pci_core_barmap(struct vfio_pci_core_device *vdev, unsigned int index);
> >   int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma);
> >   void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count);
> >   int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf);