cvs commit: src/sys/amd64/amd64 mp_machdep.c src/sys/i386/i386 mp_machdep.c

[Colin Percival]

Kris Kennaway wrote:
> Colin Percival wrote:
>> To quote core@, whom I agree with on this point:
>>   We think this decision should be revisited once at least one of the
>>   following occur: new crypto code is made available by crypto vendors to
>>   address cache-related attacks, or sufficient work is performed on
>>   scheduling and protection mechanisms to prevent the attack from being
>>   exploited.
>>
>> When I have time, I'm working on a cryptographic library ...
> 
> Sounds possibly infeasible and at the very least a long way off.  Is it
> appropriate to continue to leave hyperthreading disabled for the
> indefinite future pending the completion of a library you hope to one
> day write?

You seem to be ignoring the second half of core's criteria for revisiting
this decision: "or sufficient work is performed on scheduling and protection
mechanisms to prevent the attack from being exploited".  This certainly
seems to be the route which involves less work -- but since my expertise is
in cryptography rather than schedulers, I can only work on the cryptographic
option.

Colin Percival