Re: iommu/amd: Initialize IOMMU Private Address (IPA) space mapping region

[Suthikulpanit, Suravee]

On 3/31/2026 12:12 PM, Weinan Liu wrote:
> > diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
> > @@ -2198,6 +2202,10 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
> >   	if (check_feature(FEATURE_PPR) && amd_iommu_alloc_ppr_log(iommu))
> >   		return -ENOMEM;
> >   
> > +	ret = amd_viommu_init(iommu);
> > +	if (ret)
> > +		pr_err("Failed to initialize vIOMMU.\n");
>
> Should amd_iommu_viommu be set to false if vIOMMU initialization fails?
> Currently, the following logic will indicate that vIOMMU is enabled even if the
> initialization process does not succeed:
>
>   	if (iommu->cap & (1UL << IOMMU_CAP_NPCACHE)) {
>   		pr_info("Using strict mode due to virtualization\n");
>   		iommu_set_dma_strict();
> @@ -2291,6 +2299,9 @@ static void print_iommu_info(void)
>   		if (check_feature2(FEATURE_SEVSNPIO_SUP))
>   			pr_cont(" SEV-TIO");
>   
> +		if (check_feature(FEATURE_VIOMMU))
> +			pr_cont(" vIOMMU");
> +
>   		pr_cont("\n");
>   	}
>   
> @@ -2303,6 +2314,8 @@ static void print_iommu_info(void)
>   		pr_info("V2 page table enabled (Paging mode : %d level)\n",
>   			amd_iommu_gpt_level);
>   	}
> +	if (amd_iommu_viommu)
> +		pr_info("AMD-Vi: vIOMMU enabled\n");
>   }

Good point. I'll fix this in V2.

Thanks,
Suravee