Re: [PATCH 6.6.y 1/1] powerpc/pseries/iommu: Restore CONFIG_IOMMU_API dependency

[Madhavan Srinivasan <maddy@linux.ibm.com>]

On 11/6/26 4:54 AM, Stephen Brennan wrote:
> In stable v6.6.161 there is a build error with ppc64 when
> CONFIG_IOMMU_API is not enabled:
>
>      arch/powerpc/platforms/pseries/iommu.c: In function 'iommu_take_ownership':
>      arch/powerpc/platforms/pseries/iommu.c:69:25: error: 'struct iommu_table_ops' has no member named 'xchg_no_kill'
>         69 |         if (!tbl->it_ops->xchg_no_kill)
>      	  |                         ^~
>        AS      arch/powerpc/lib/copy_mc_64.o
>      arch/powerpc/platforms/pseries/iommu.c: At top level:
>      arch/powerpc/platforms/pseries/iommu.c:1787:37: error: 'spapr_tce_table_group_ops' defined but not used [-Werror=unused-variable]
>       1787 | static struct iommu_table_group_ops spapr_tce_table_group_ops = {
>      	  |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~
>      cc1: all warnings being treated as errors
>
> This is due to stable v6.6.161 commit 1e9dfe15404d ("powerpc/iommu: Move
> pSeries specific functions to pseries/iommu.c"). It was included as a
> stable-dep-of commit 8f70caad82e9 ("powerpc/pseries/iommu: IOMMU
> incorrectly marks MMIO range in DDW").
>
> It was backported without its associated fix: commit af199e6ca29c
> ("powerpc/pseries/iommu: Define spapr_tce_table_group_ops only with
> CONFIG_IOMMU_API").
>
> The code was supposed to only build under CONFIG_IOMMU_API, but the new
> location doesn't have this condition. Unfortunately, the fixing commit
> comes after a fairly large refactor, and doesn't apply on v6.16.161.
> Instead, apply the ifdefs where they would belong prior to the refactor.
Looks fine to me
Acked-by: Madhavan Srinivasan <maddy@linux.ibm.com>
> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
> ---
>   arch/powerpc/platforms/pseries/iommu.c | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 6a45e3e86f79b..a79927e870a87 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -54,6 +54,7 @@ enum {
>   	DDW_EXT_QUERY_OUT_SIZE = 2
>   };
>   
> +#ifdef CONFIG_IOMMU_API
>   static int iommu_take_ownership(struct iommu_table *tbl)
>   {
>   	unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
> @@ -104,6 +105,7 @@ static void iommu_release_ownership(struct iommu_table *tbl)
>   		spin_unlock(&tbl->pools[i].lock);
>   	spin_unlock_irqrestore(&tbl->large_pool.lock, flags);
>   }
> +#endif
>   
>   static struct iommu_table *iommu_pseries_alloc_table(int node)
>   {
> @@ -118,7 +120,9 @@ static struct iommu_table *iommu_pseries_alloc_table(int node)
>   	return tbl;
>   }
>   
> +#ifdef CONFIG_IOMMU_API
>   static struct iommu_table_group_ops spapr_tce_table_group_ops;
> +#endif
>   
>   static struct iommu_table_group *iommu_pseries_alloc_group(int node)
>   {
> @@ -1702,6 +1706,7 @@ static bool iommu_bypass_supported_pSeriesLP(struct pci_dev *pdev, u64 dma_mask)
>   	return false;
>   }
>   
> +#ifdef CONFIG_IOMMU_API
>   /*
>    * A simple iommu_table_group_ops which only allows reusing the existing
>    * iommu_table. This handles VFIO for POWER7 or the nested KVM.
> @@ -1792,6 +1797,7 @@ static struct iommu_table_group_ops spapr_tce_table_group_ops = {
>   	.take_ownership = spapr_tce_take_ownership,
>   	.release_ownership = spapr_tce_release_ownership,
>   };
> +#endif
>   
>   static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
>   		void *data)