Re: [PATCH 4/5] vfio: Introduce vfio_device_ops.get_unmapped_area hook

Peter Xu
2025-06-17T16:47:53Z

On Tue, Jun 17, 2025 at 12:41:57PM -0300, Jason Gunthorpe wrote:
> On Tue, Jun 17, 2025 at 11:39:07AM -0400, Peter Xu wrote:
> >
> > +#ifdef CONFIG_ARCH_SUPPORTS_HUGE_PFNMAP
> > static unsigned long vfio_device_get_unmapped_area(struct file *file,
> > unsigned long addr,
> > unsigned long len,
> > @@ -1370,6 +1371,7 @@ static unsigned long vfio_device_get_unmapped_area(struct file *file,
> > return device->ops->get_unmapped_area(device, file, addr, len,
> > pgoff, flags);
> > }
> > +#endif
> >
> > const struct file_operations vfio_device_fops = {
> > .owner = THIS_MODULE,
> > @@ -1380,7 +1382,9 @@ const struct file_operations vfio_device_fops = {
> > .unlocked_ioctl = vfio_device_fops_unl_ioctl,
> > .compat_ioctl = compat_ptr_ioctl,
> > .mmap = vfio_device_fops_mmap,
> > +#ifdef CONFIG_ARCH_SUPPORTS_HUGE_PFNMAP
> > .get_unmapped_area = vfio_device_get_unmapped_area,
> > +#endif
> > };
>
> IMHO this also seems like something the core code should be dealing
> with and not putting weird ifdefs in drivers.

It may depend on whether we want to still do the fallbacks to
mm_get_unmapped_area(). I get your point in the other email but not yet
get a chance to reply. I'll try that out to see how it looks and reply
there.

--
Peter Xu