Subject: Re: [bug report]: iommu WARNING is observed on powerpc system during pci enumeration at boot up

From: Nicolin Chen <[email-masked]>
Date: Mon, 9 Mar 2026 11:48:44 -0700

On Mon, Mar 09, 2026 at 11:27:42PM +0530, Nilay Shroff wrote:
> Looking at the warning it seems that this is a regression caused due to
> commit a75b2be249d6 ("iommu: Add iommu_driver_get_domain_for_dev() helper").
> 
> Any help from the iommu expert would be appreciated. Though I am not expert,
> it seems the following patch help fix this warning (I encourage the iommu
> developers to confirm and/or take this forward) :
> 
> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
> index 0ce71310b7d9..d122e8447831 100644
> --- a/arch/powerpc/kernel/iommu.c
> +++ b/arch/powerpc/kernel/iommu.c
> @@ -1159,7 +1159,7 @@ spapr_tce_platform_iommu_attach_dev(struct iommu_domain *platform_domain,
>                                     struct device *dev,
>                                     struct iommu_domain *old)
>  {
> -       struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> +       struct iommu_domain *domain = iommu_driver_get_domain_for_dev(dev);
>         struct iommu_table_group *table_group;
>         struct iommu_group *grp;
> 
> 
> Please let me know if any further information is needed.

Yea, that should be the fix.

Please submit a "PATCH rc" with:

Fixes: a75b2be249d6 ("iommu: Add iommu_driver_get_domain_for_dev() helper")
Cc: [email-masked]

Thanks!
Nicolin