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

Suthikulpanit, Suravee
2022-06-22T07:33:47Z

On 6/22/2022 12:50 AM, Peter Gonda wrote:
> On Tue, Jun 21, 2022 at 11:45 AM Kalra, Ashish <Ashish.Kalra@amd.com> 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