Re: [PATCH v2 3/4] arch/x86: Optionally flush L1D on context switch

[Thomas Gleixner]

"Singh, Balbir" <sblbir@xxxxxxxxxx> writes:
> On Tue, 2020-04-07 at 11:26 -0700, Kees Cook wrote:
>> On Mon, Apr 06, 2020 at 01:19:45PM +1000, Balbir Singh wrote:
>> > Add arch specific prctl()'s to opt-in to the L1D cache on context switch
>> > out, the existing mechanisms of tracking prev_mm via cpu_tlbstate is
>> > reused. cond_ibpb() is refactored and renamed into cond_mitigation().
>> 
>> I still think this should be a generic prctl(). If there is a strong
>> reason not to do this, can it be described in the commit log here?
>
> I can move to prctl() if that is what you prefer, the prctl() can then do arch
> specific things. I thought in my question around would other arch's like to do
> this, I did not hear anything specific, but I am happy to convert the
> interface over.

Yes, please. It's just a matter of time that other architectures find
this useful. L1D attacks are not restricted to x86 AFAICT.

Thanks,

        tglx