Re: [PATCH] vfio/fsl-mc: keep logical vm_pgoff in MMIO region mmap

[Ioana Ciornei]

On Thu, Sep 03, 2026 at 12:29:22PM +0300, Abdifatah Suruur wrote:
> vfio_fsl_mc_mmap_mmio() overwrites vma->vm_pgoff with the physical
> frame number of the MMIO region and passes it to remap_pfn_range().
> The VMA is inserted into the device file's mapping->i_mmap interval
> tree keyed by vm_pgoff, which VFIO expects to be the logical file
> offset: the core links every device mmap to the device inode's
> i_mapping precisely so that unmap_mapping_range() can revoke all
> mappings associated with a device (see vfio_device_cdev_open()).
> 
> With a raw PFN in vm_pgoff the interval tree entry lands in the wrong
> coordinate space and unmap_mapping_range() cannot find the VMA,
> leaving stale MMIO mappings behind any revocation attempt.  Keep
> vm_pgoff in the logical VFIO offset space, as vfio-pci does, and pass
> the physical PFN to remap_pfn_range() explicitly.
> 
> Fixes: 67247289688d4 ("vfio/fsl-mc: Allow userspace to MMAP fsl-mc device MMIO regions")
> Signed-off-by: Abdifatah Suruur <suruurism@xxxxxxxxx>

Reviewed-by: Ioana Ciornei <ioana.ciornei@xxxxxxx>