Re: [PATCH v2 3/5] virt: sevguest: Prep for kernel internal {get, get_ext}_report()

[Tom Lendacky]

On 8/14/23 18:24, Dan Williams wrote:
> Dionna Amalie Glaze wrote:
> > >          switch (ioctl) {
> > >          case SNP_GET_REPORT:
> > > -               ret = get_report(snp_dev, &input);
> > > +               ret = get_report(snp_dev, &input, SNP_UARG);
> > >                  break;
> > >          case SNP_GET_DERIVED_KEY:
> > >                  ret = get_derived_key(snp_dev, &input);
> > >                  break;
> >
> > Do we have an agreement around the continued existence of sev-guest
> > for supporting derived keys, is that similarly slated for the chopping
> > block, or is it left undecided?
> > It appears your choice to not include the uarg/karg extension here is
> > deliberate.
>
> I do want to understand the argument from James a bit more, but the
> exlcusion here was simply because there is currently no support for this
> concept from other vendors.
>
> That said, if it remains a vendor unique concept and continues getting
> suspicious looks from folks like James, it may indeed be something the
> kernel wants to jettison.

I'm not sure why we would want to jettison it. Just because other vendors 
don't have a key derivation function doesn't mean it can't be useful to 
customers that want to use it on AMD platforms.

Thanks,
Tom

> > >          case SNP_GET_EXT_REPORT:
> > > -               ret = get_ext_report(snp_dev, &input);
> > > +               ret = get_ext_report(snp_dev, &input, SNP_UARG);
> > >                  break;
> > >          default:
> > >                  break;
> >
> > Reviewed-by: Dionna Glaze <dionnaglaze@xxxxxxxxxx>
>
> Thanks for all your help on this!