Re: [PATCH v10 06/50] x86/sev: Add the host SEV-SNP initialization support

[Borislav Petkov]

On Tue, Nov 07, 2023 at 03:21:29PM -0600, Kalra, Ashish wrote:
> No, this is not correct as this will always enable SNP support on
> IOMMU even when SNP support is not supported and enabled on the
> platform,

You see that we set or clear X86_FEATURE_SEV_SNP depending on support,
right?

Which means, you need to test that bit in amd_iommu_snp_enable() first.

> And isn't IOMMU driver always going to be built-in and isn't it part of the
> platform support (not arch code, but surely platform specific code)?
> (IOMMU enablement is requirement for SNP).

Read the note again about the fragile ordering in my previous mail.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette