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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: kvm@vger.kernel.org, "Tian, Kevin" <kevin.tian@intel.com>,
	linux-kernel@vger.kernel.org,
	Alex Williamson <alex.williamson@redhat.com>
Subject: Re: [PATCH 1/4] vfio: trivially use __aligned_u64 for ioctl structs
Date: Mon, 14 Aug 2023 14:47:23 -0300	[thread overview]
Message-ID: <ZNpoq7emI19fApND@ziepe.ca> (raw)
In-Reply-To: <20230809210248.2898981-2-stefanha@redhat.com>

On Wed, Aug 09, 2023 at 05:02:45PM -0400, Stefan Hajnoczi wrote:
> 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@ziepe.ca>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  include/uapi/linux/vfio.h | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

  reply	other threads:[~2023-08-14 17:48 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-09 21:02 [PATCH 0/4] vfio: use __aligned_u64 for ioctl structs Stefan Hajnoczi
2023-08-09 21:02 ` [PATCH 1/4] vfio: trivially " Stefan Hajnoczi
2023-08-14 17:47   ` Jason Gunthorpe [this message]
2023-08-09 21:02 ` [PATCH 2/4] vfio: use __aligned_u64 in struct vfio_device_gfx_plane_info Stefan Hajnoczi
2023-08-10  3:22   ` Tian, Kevin
2023-08-10 14:24     ` Stefan Hajnoczi
2023-08-15 12:38     ` Stefan Hajnoczi
2023-08-14 17:50   ` Jason Gunthorpe
2023-08-15 12:38     ` Stefan Hajnoczi
2023-08-15 15:23   ` David Laight
2023-08-16 13:36     ` Stefan Hajnoczi
2023-08-09 21:02 ` [PATCH 3/4] vfio: use __aligned_u64 in struct vfio_iommu_type1_info Stefan Hajnoczi
2023-08-10  3:25   ` Tian, Kevin
2023-08-10 14:25     ` Stefan Hajnoczi
2023-08-14 17:52   ` Jason Gunthorpe
2023-08-09 21:02 ` [PATCH 4/4] vfio: use __aligned_u64 in struct vfio_device_ioeventfd Stefan Hajnoczi
2023-08-14 17:52   ` Jason Gunthorpe

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