Re: [PATCH v1 1/2] x86/retpoline: Add a function to clear the RETPOLINE_AMD feature

[Tom Lendacky]

On 1/9/2018 5:43 PM, Thomas Gleixner wrote:
> On Tue, 9 Jan 2018, Tom Lendacky wrote:
>> On 1/9/2018 5:09 PM, Thomas Gleixner wrote:
>>> On Tue, 9 Jan 2018, Tom Lendacky wrote:
>>>> On 1/9/2018 4:46 PM, Thomas Gleixner wrote:
>>>>> Urgh. That's an awful hack. why not do the obvious?
>>>>
>>>> My first attempt was very similar to your change below, but testing
>>>> showed that spectre_v2_check_boottime_disable() is called before the
>>>> X86_FEATURE_LFENCE_RDTSC can be set.  I can look at moving where the
>>>> X86_FEATURE_LFENCE_RDTSC is set, maybe into early_init_amd() or such
>>>> if you think that would be best.
>>>
>>> Wait, we can move the selection _AFTER_ identify_boot_cpu().
>>
>> Much cleaner.  Since it's just a single patch now, do you want me to
>> re-submit this after I test it or will you just pick this up as is?
>>
>> I did notice that the patch does change the behavior associated with
>> the command line options, though.  Not sure if that was intentional.
> 
> Yes. I noticed while looking at your issue that when AMD is selected on the
> command line then we have no support at all on intel. So I prefer to err
> out and enable the generic version.
> 
> If you can just polish it up with a changelog and resubmit after testing
> that would be appreciated as I'm steam blasting the IBRS stuff at the
> moment.

Will do.  I'll add your Signed-off-by when I submit it.

Thanks,
Tom

> 
> Thanks,
> 
> 	tglx
>