RE: [PATCH v2 1/3] vfio: trivially use __aligned_u64 for ioctl structs

Tian, Kevin
2023-09-11T06:07:05Z

> From: Stefan Hajnoczi <stefanha@redhat.com>
> Sent: Wednesday, August 30, 2023 2:27 AM
>
> u64 alignment behaves differently depending on the architecture and so
> <uapi/linux/types.h> offers __aligned_u64 to achieve consistent behavior
> in kernel<->userspace ABIs.
>
> There are structs in <uapi/linux/vfio.h> that can trivially be updated
> to __aligned_u64 because the struct sizes are multiples of 8 bytes.
> There is no change in memory layout on any CPU architecture and
> therefore this change is safe.
>
> The commits that follow this one handle the trickier cases where
> explanation about ABI breakage is necessary.
>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>