Re: [PATCH 1/3] iommu/io-pgtable-arm: Add nents_per_pgtable in struct io_pgtable_cfg

Nicolin Chen
2024-01-25T05:09:36Z

On Wed, Jan 24, 2024 at 02:20:14PM +0800, zhangzekun (A) wrote:
> Also, it seems to me that SVA use cases and, say, DMA API cases are
> somewhat different where we may be willing to wait longer for DMA API.

> Hmm, the lockup that my patch fixed was for an SVA case that
> doesn't seem to involve DMA API:
> https://lore.kernel.org/linux-iommu/20230901203904.4073-1-nicolinc@nvidia.com/
>
> And the other lockup fix for a non-SVA case from Zhang doesn't
> seem to involve DMA API either:
> https://lore.kernel.org/linux-iommu/e74ea905-d107-4202-97ca-c2c509e7aa1e@huawei.com/
>
>
> Hi, Nicolin
>
> These patches do involve DMA APIs, because it modifies arm_smmu_tlb_inv_walk() which will be called when unmapping dma address space.
>
> iommu_dma_unmap_page
> __iommu_dma_unmap
> __iommu_unmap
> arm_smmu_unmap_pages
> arm_lpae_unmap_pages
> io_pgtable_tlb_flush_walk
> arm_smmu_tlb_inv_walk
>

Oh, thanks for clarifying. I was just looking at your trace log
there, but overlooked other places.