Re: [PATCH 0/3] arch/x86: Optionally flush L1D on context switch

From: Thomas Gleixner
Date: Thu Apr 02 2020 - 17:45:14 EST


Josh Poimboeuf <jpoimboe@xxxxxxxxxx> writes:
> On Thu, Apr 02, 2020 at 08:35:46PM +0000, Singh, Balbir wrote:
>> Yes, that CVE the motivation, the mitigation for CVE-2020-0550 does suggest
>> flushing the cache on context switch. But in general, as we begin to find more
>> ways of evicting data or snopping data, a generic mechanism is more useful and
>> that is why I am making it an opt-in.
>
> Ok. I think it would be a good idea to expand on that justification
> more precisely in the commit message. That would help both reviewers of
> the code and users of the new option understand what level of paranoia
> they're opting in to :-)

The commit message is mostly useful for reviewers and people who have to
do code archeaology.

Documentation/admin-guide/hw-vuln/ has plenty of space to host a
document with explanations. paranoia.rst comes to my mind. :)

Thanks,

tglx