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

Madhavan Srinivasan
2026-03-12T05:13:41Z

On 3/10/26 12:18 AM, Nicolin Chen wrote:
> 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:
Will pull this for my upcoming RC PR
https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20260310082129.3630996-1-nilay@linux.ibm.com/

Maddy
> Fixes: a75b2be249d6 ("iommu: Add iommu_driver_get_domain_for_dev() helper")
> Cc: stable@vger.kernel.org
>
> Thanks!
> Nicolin