On Tue, Jun 26, 2018 at 05:22:29PM +0300, Kirill A. Shutemov wrote:
> Pages encrypted with different encryption keys are not subject to KSM
Perhaps not allowed instead of subject?
> merge. Otherwise it would cross security boundary.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> ---
> include/linux/mm.h | 7 +++++++
> mm/ksm.c | 3 +++
> 2 files changed, 10 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index ebf4bd8bd0bf..406a28cadfcf 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1548,6 +1548,13 @@ static inline int vma_keyid(struct vm_area_struct *vma)
> }
> #endif
>
> +#ifndef page_keyid
> +static inline int page_keyid(struct page *page)
> +{
> + return 0;
> +}
> +#endif
> +
> #ifdef CONFIG_SHMEM
> /*
> * The vma_is_shmem is not inline because it is used only by slow
> diff --git a/mm/ksm.c b/mm/ksm.c
> index a6d43cf9a982..1bd7b9710e29 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -1214,6 +1214,9 @@ static int try_to_merge_one_page(struct vm_area_struct *vma,
> if (!PageAnon(page))
> goto out;
>
> + if (page_keyid(page) != page_keyid(kpage))
> + goto out;
> +
> /*
> * We need the page lock to read a stable PageSwapCache in
> * write_protect_page(). We use trylock_page() instead of
> --
> 2.18.0
>
