RE: [PATCH v4 14/23] iommufd: Add mmap interface

[Tian, Kevin]

> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Friday, May 16, 2025 12:47 AM
> 
> On Thu, May 08, 2025 at 08:02:35PM -0700, Nicolin Chen wrote:
> > +	/* vma->vm_pgoff carries an index to an mtree entry (immap) */
> > +	immap = mtree_load(&ictx->mt_mmap, vma->vm_pgoff);
> > +	if (!immap)
> > +		return -ENXIO;
> > +	if (length >> PAGE_SHIFT != immap->num_pfns)
> > +		return -ENXIO;
> 
> This needs to validate that vm_pgoff is at the start of the immap or
> num_pfns is the wrong thing to validate length against.
> 

vm_pgoff is the index into mtree. If it's wrong mtree_load() will
fail already?