Re: [PATCH] x86/mm/mem_encrypt: Disable all instrumentation for SME early boot code

From: Gary R Hook
Date: Mon Apr 29 2019 - 17:24:03 EST


On 4/29/19 3:51 PM, Borislav Petkov wrote:
> [CAUTION: External Email]
>
> On Mon, Apr 29, 2019 at 08:16:07PM +0000, Gary R Hook wrote:
>> Yes, option 4 would be a combination of using a local copy of strncmp()
>
> Why the local copy?

Seemed suitable, since it's tiny. But I'm not married to the idea.

>
>> and disabling instrumentation (KASAN, KCOV, whatever) for
>> arch/x86/lib/cmdline.c when SME is enabled.
>
> I think this should suffice. You only disable instrumentation when
> CONFIG_AMD_MEM_ENCRYPT=y and not do any local copies but use the generic
> functions.

Okay, super. I'll post a v2 that does that.

Do we want to document the subordinate functions in their respective
source files so that a future editor would (hopefully) be made aware of
this use?

grh