Re: Ping: [PATCH v3] x86/CPUID: shrink max_{,sub}leaf fields according to actual leaf contents

[Jan Beulich <jbeulich@suse.com>]

On 22.04.2021 14:34, Paul Durrant wrote:
> On 22/04/2021 12:38, Jan Beulich wrote:
>> On 16.04.2021 15:16, Jan Beulich wrote:
>>> Zapping leaf data for out of range leaves is just one half of it: To
>>> avoid guests (bogusly or worse) inferring information from mere leaf
>>> presence, also shrink maximum indicators such that the respective
>>> trailing entry is not all blank (unless of course it's the initial
>>> subleaf of a leaf that's not the final one).
>>>
>>> This is also in preparation of bumping the maximum basic leaf we
>>> support, to ensure guests not getting exposed related features won't
>>> observe a change in behavior.
>>>
>>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>
>> First of all - I'm sorry Paul, I forgot to Cc you on the original
>> submission.
>>
> 
> Ok. I did notice some discussion but wasn't really paying attention.
> 
>> May I ask for an ack or otherwise for the Viridian part of this?
>> Please be sure, however, that you have seen the earlier discussion,
>> also on v2, as Roger is questioning whether the Viridian change
>> here wouldn't better be dropped.
>>
> 
> I confess that I'm not a fan of the recursive calls and I do agree with 
> Roger that limiting the leaves simply because they have zero values is 
> probably not the right thing to do and it could lead to issues with 
> Windows. I think, to be on the safe side, it's best to leave the 
> viridian code as-is.

Okay. In which case I have all needed acks, and the remaining part of
the change can go in.

Jan