Re: [PATCH] vfio: fix VFIO_IOMMU_UNMAP_DMA when end of range would overflow u64

Jason Gunthorpe
2025-10-06T22:50:42Z

On Mon, Oct 06, 2025 at 09:29:07AM -0700, Alex Mastro wrote:
> On Mon, Oct 06, 2025 at 09:16:18AM -0300, Jason Gunthorpe wrote:
> > This doesn't seem complete though, if the range ends at the ULONG_MAX
> > then these are not working either:
> >
> > if (start < dma->iova + dma->size) {
> >
> > ?
> >
> > And I see a few more instances like that eg in
> > vfio_iova_dirty_bitmap(), vfio_dma_do_unmap(), vfio_iommu_replay()
>
> You are right. There are several places which would need to be fixed to handle
> mappings which lie against the end of the addressable range. At least these
> would need to be vetted:

Could we block right at the ioctl inputs that end at ULONG_MAX? Maybe
that is a good enough fix?

Jason