Implement struct vfio_pci_regops for alias regions. Where it implements the mmap ops. When mmap is called on these regions it translates the vm_pgoff to match the aliased region. Then it calls the required mmap for the target region. It updates the vm_page_prot afterwards with the requested flags. The call path would be: vfio_pci_core_mmap (index >= VFIO_PCI_NUM_REGIONS) vfio_pci_alias_region_mmap (update vm_pgoff) vfio_pci_core_mmap For now no more information is needed more than the aliased index. So we use region->data to save the aliased index number. Note: Alias regions can't alias another alias. Signed-off-by: Mahmoud Adam --- drivers/vfio/pci/vfio_pci_core.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 04b93bd55a5c2..962d3eda1ea9f 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -1528,6 +1528,33 @@ static int vfio_pci_core_feature_token(struct vfio_device *device, u32 flags, return 0; } +static int vfio_pci_alias_region_mmap(struct vfio_pci_core_device *vdev, + struct vfio_pci_region *region, + struct vm_area_struct *vma) +{ + unsigned int alias_index = (uintptr_t) region->data; + unsigned long vm_pgoff; + int ret; + + /* change the pgoff to the corresponding alias */ + vm_pgoff = alias_index << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT); + vm_pgoff |= vma->vm_pgoff & + ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1); + vma->vm_pgoff = vm_pgoff; + + ret = vdev->vdev.ops->mmap(&vdev->vdev, vma); + + /* overwrite prot with the alias flags */ + if (region->flags & VFIO_REGION_INFO_FLAG_WC) + vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); + + return ret; +} + +struct vfio_pci_regops vfio_pci_alias_region_ops = { + .mmap = vfio_pci_alias_region_mmap, +}; + int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, void __user *arg, size_t argsz) { -- 2.47.3 Amazon Web Services Development Center Germany GmbH Tamara-Danz-Str. 13 10243 Berlin Geschaeftsfuehrung: Christian Schlaeger Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B Sitz: Berlin Ust-ID: DE 365 538 597