On Tue, Apr 28, 2020 at 10:54:55AM -0600, Alex Williamson wrote: > static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma) > { > struct vfio_pci_device *vdev = device_data; > @@ -1253,8 +1323,14 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma) > vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); > vma->vm_pgoff = (pci_resource_start(pdev, index) >> PAGE_SHIFT) + pgoff; > > + vma->vm_ops = &vfio_pci_mmap_ops; > + > +#if 1 > + return 0; > +#else > return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, > - req_len, vma->vm_page_prot); > + vma->vm_end - vma->vm_start, vma->vm_page_prot); The remap_pfn_range here is what tells get_user_pages this is a non-struct page mapping: vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; Which has to be set when the VMA is created, they shouldn't be modified during fault. Also the vma code above looked a little strange to me, if you do send something like this cc me and I can look at it. I did some work like this for rdma a while ago.. Jason