Re: [RFC Part1 PATCH v3 07/17] x86/mm: Include SEV for encryption memory attribute changes

Borislav Petkov
2017-07-27T14:58:41Z

On Mon, Jul 24, 2017 at 02:07:47PM -0500, Brijesh Singh wrote:
> From: Tom Lendacky <thomas.lendacky-5C7GfCeVMHo@public.gmane.org>
>
> The current code checks only for sme_active() when determining whether
> to perform the encryption attribute change. Include sev_active() in this
> check so that memory attribute changes can occur under SME and SEV.
>
> Signed-off-by: Tom Lendacky <thomas.lendacky-5C7GfCeVMHo@public.gmane.org>
> Signed-off-by: Brijesh Singh <brijesh.singh-5C7GfCeVMHo@public.gmane.org>
> ---
> arch/x86/mm/pageattr.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
> index dfb7d65..b726b23 100644
> --- a/arch/x86/mm/pageattr.c
> +++ b/arch/x86/mm/pageattr.c
> @@ -1781,8 +1781,8 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
> unsigned long start;
> int ret;
>
> - /* Nothing to do if the SME is not active */
> - if (!sme_active())
> + /* Nothing to do if SME and SEV are not active */
> + if (!sme_active() && !sev_active())

This is the second place which does

if (!SME && !SEV)

I wonder if, instead of sprinking those, we should have a

if (mem_enc_active())

or so which unifies all those memory encryption logic tests and makes
the code more straightforward for readers who don't have to pay
attention to SME vs SEV ...

Just a thought.

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
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