Re: [PATCH 1/3] vfio/pci: Set VFIO_PCI_OFFSET_SHIFT to 48

Jason Gunthorpe
2026-02-12T14:17:40Z

On Thu, Feb 12, 2026 at 03:02:15PM +0100, Julian Ruess wrote:
> Extend VFIO_PCI_OFFSET_SHIFT to 48 to use the vfio-pci
> VFIO_PCI_OFFSET_TO_INDEX() mechanism with the 256 TiB pseudo-BAR 0 of
> the ISM device on s390. This bar is never mapped.

Woah, this is dangerous, the size was selected to fit within a pgoff
of a 32bit system.. Does this entirely break vfio on 32 bit?

Jason