Re: [PATCH v7 33/36] x86/mm: Use proper encryption attributes with /dev/mem

[Borislav Petkov]

On Fri, Jun 16, 2017 at 01:56:07PM -0500, Tom Lendacky wrote:
> When accessing memory using /dev/mem (or /dev/kmem) use the proper
> encryption attributes when mapping the memory.
> 
> To insure the proper attributes are applied when reading or writing
> /dev/mem, update the xlate_dev_mem_ptr() function to use memremap()
> which will essentially perform the same steps of applying __va for
> RAM or using ioremap() for if not RAM.
> 
> To insure the proper attributes are applied when mmapping /dev/mem,
> update the phys_mem_access_prot() to call phys_mem_access_encrypted(),
> a new function which will check if the memory should be mapped encrypted
> or not. If it is not to be mapped encrypted then the VMA protection
> value is updated to remove the encryption bit.
> 
> Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
>  arch/x86/include/asm/io.h |    3 +++
>  arch/x86/mm/ioremap.c     |   18 +++++++++---------
>  arch/x86/mm/pat.c         |    3 +++
>  3 files changed, 15 insertions(+), 9 deletions(-)

Reviewed-by: Borislav Petkov <bp@xxxxxxx>

-- 
Regards/Gruss,
    Boris.

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