On 10/27/25 19:17, Alex Williamson wrote: > 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 gpu mmap will not come thru this ioctl path into the hyperv driver. > 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, Ok. Will think of alternate way, just thought would check before going that route. Thanks, -Mukesh > > Alex
