v3: - Remove the output struct sizing code that copied out zeroed fields at the end of the struct. Alex pointed out that new fields (or repurposing a field that was previously reserved) must be guarded by a flag and this means userspace won't access those fields when they are absent. v2: - Rebased onto https://github.com/awilliam/linux-vfio.git next to get the vfio_iommu_type1_info pad field [Kevin] - Fixed min(minsz, sizeof(dmabuf)) -> min(dmabuf.argsz, sizeof(dmabuf)) [Jason, Kevin] - Squashed Patch 3 (vfio_iommu_type1_info) into Patch 1 since it is trivial now that the padding field is already there. Jason Gunthorpe <jgg@xxxxxxxxxx> pointed out that u64 VFIO ioctl struct fields have architecture-dependent alignment. iommufd already uses __aligned_u64 to avoid this problem. See the __aligned_u64 typedef in <uapi/linux/types.h> for details on why it is a good idea for kernel<->user interfaces. This series modifies the VFIO ioctl structs to use __aligned_u64. Some of the changes preserve the existing memory layout on all architectures, so I put them together into the first patch. The remaining patches are for structs where explanation is necessary about why changing the memory layout does not break the uapi. Stefan Hajnoczi (3): vfio: trivially use __aligned_u64 for ioctl structs vfio: use __aligned_u64 in struct vfio_device_gfx_plane_info vfio: use __aligned_u64 in struct vfio_device_ioeventfd include/uapi/linux/vfio.h | 26 ++++++++++++++------------ drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +- samples/vfio-mdev/mbochs.c | 2 +- samples/vfio-mdev/mdpy.c | 2 +- 4 files changed, 17 insertions(+), 15 deletions(-) -- 2.41.0
