Re: [PATCH Part2 v6 02/49] iommu/amd: Introduce function to check SEV-SNP support

[Suthikulpanit, Suravee]

On 6/22/2022 12:50 AM, Peter Gonda wrote:
> On Tue, Jun 21, 2022 at 11:45 AM Kalra, Ashish <Ashish.Kalra@xxxxxxx> wrote:
> > [AMD Official Use Only - General]
> >
> > Hello Peter,
> >
> > > > +bool iommu_sev_snp_supported(void)
> > > > +{
> > > > +       struct amd_iommu *iommu;
> > > > +
> > > > +       /*
> > > > +        * The SEV-SNP support requires that IOMMU must be enabled, and is
> > > > +        * not configured in the passthrough mode.
> > > > +        */
> > > > +       if (no_iommu || iommu_default_passthrough()) {
> > > > +               pr_err("SEV-SNP: IOMMU is either disabled or
> > > > + configured in passthrough mode.\n");
> >
> > > Like below could this say something like snp support is disabled because of iommu settings.
> >
> > Here we may need to be more precise with the error information indicating why SNP is not enabled.
> > Please note that this patch may actually become part of the IOMMU + SNP patch series, where
> > additional checks are done, for example, not enabling SNP if IOMMU v2 page tables are enabled,
> > so precise error information will be useful here.
>
> I agree we should be more precise. I just thought we should explicitly
> state something like: "SEV-SNP: IOMMU is either disabled or configured
> in passthrough mode, SNP cannot be supported".

I can update this in the other patch series here

https://lists.linuxfoundation.org/pipermail/iommu/2022-June/066399.html

Thank you,
Suravee