# Re: \[PATCH v2 13/63\] iommu/amd: Use struct\_group() for memcpy() region

- From: Joerg Roedel \<joro@8bytes.org\>
- Date: 2021-08-18 11:34:33 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/08/1481627
- Thread: https://ratatoskr.run/linux-wireless/2021/08/1481188/t.md

```text
On Tue, Aug 17, 2021 at 11:04:43PM -0700, Kees Cook wrote:
> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memcpy(), memmove(), and memset(), avoid
> intentionally writing across neighboring fields.
> 
> Use struct_group() in struct ivhd_entry around members ext and hidh, so
> they can be referenced together. This will allow memcpy() and sizeof()
> to more easily reason about sizes, improve readability, and avoid future
> warnings about writing beyond the end of ext.
> 
> "pahole" shows no size nor member offset changes to struct ivhd_entry.
> "objdump -d" shows no object code changes.
> 
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Will Deacon <will@kernel.org>
> Cc: <redacted>
> Signed-off-by: Kees Cook <redacted>

Acked-by: Joerg Roedel <redacted>

```