On Mon, 27 Oct 2025 14:21:56 -0700 Mukesh R <[email protected]> wrote:
> Hi Alex, > > This regards vfio passthru support on hyperv running linux as dom0 aka > root. At a high level, cloud hypervisor uses vfio for set up as usual, > then maps the mmio ranges via the hyperv linux driver ioctls. > > Over a year ago, when working on this I had used vm_pgoff to get the pfn > for the mmio, that was 5.15 and early 6.x kernels. Now that I am porting > to 6.18 for upstreaming, I noticed: > > commit aac6db75a9fc > Author: Alex Williamson <[email protected]> > vfio/pci: Use unmap_mapping_range() > > changed the behavior and vm_pgoff is no longer holding the pfn. In light > of that, I wondered if the following minor change, making vma_to_pfn() > public (after renaming it), would be acceptable to you. How do you know the device is using vfio_pci_core_mmap() with these semantics for vm_pgoff versus something like nvgrace_gpu_mmap() that uses vm_pgoff more like you're expecting? vma_to_pfn() is specific to the vfio-pci-core semantics, it's not portable to expose for other use cases. Thanks, Alex
