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

[Paul Durrant <xadimgnik@xxxxxxxxx>]

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@xxxxxxxx>
> 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.
  Paul