Allow to memory map the MMIO regions of the device so userspace can directly access them. Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx> --- drivers/vfio/platform/vfio_platform.c | 40 ++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c index c66afbc..1515175 100644 --- a/drivers/vfio/platform/vfio_platform.c +++ b/drivers/vfio/platform/vfio_platform.c @@ -57,6 +57,11 @@ static int vfio_platform_regions_init(struct vfio_platform_device *vdev) vdev->region[i].size = resource_size(res); vdev->region[i].flags = VFIO_REGION_INFO_FLAG_READ | VFIO_REGION_INFO_FLAG_WRITE; + /* Only regions addressed with PAGE granularity may be MMAPed + * securely. */ + if (!(vdev->region[i].addr & ~PAGE_MASK) + && !(vdev->region[i].size & ~PAGE_MASK)) + vdev->region[i].flags |= VFIO_REGION_INFO_FLAG_MMAP; } vdev->num_regions = cnt; @@ -276,7 +281,40 @@ err: static int vfio_platform_mmap(void *device_data, struct vm_area_struct *vma) { - return -EINVAL; + struct vfio_platform_device *vdev = device_data; + unsigned int index; + u64 req_len, pgoff, req_start; + struct vfio_platform_region region; + + index = vma->vm_pgoff >> (VFIO_PLATFORM_OFFSET_SHIFT - PAGE_SHIFT); + + if (vma->vm_end < vma->vm_start) + return -EINVAL; + if ((vma->vm_flags & VM_SHARED) == 0) + return -EINVAL; + if (index >= vdev->num_regions) + return -EINVAL; + if (vma->vm_start & ~PAGE_MASK) + return -EINVAL; + if (vma->vm_end & ~PAGE_MASK) + return -EINVAL; + + region = vdev->region[index]; + + req_len = vma->vm_end - vma->vm_start; + pgoff = vma->vm_pgoff & + ((1U << (VFIO_PLATFORM_OFFSET_SHIFT - PAGE_SHIFT)) - 1); + req_start = pgoff << PAGE_SHIFT; + + if (region.size < PAGE_SIZE || req_start + req_len > region.size) + return -EINVAL; + + vma->vm_private_data = vdev; + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + vma->vm_pgoff = (region.addr >> PAGE_SHIFT) + pgoff; + + return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, + req_len, vma->vm_page_prot); } static const struct vfio_device_ops vfio_platform_ops = { -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html