Messages in this thread | | | Date | Mon, 2 Dec 2019 20:07:31 -0800 | From | Ram Pai <> | Subject | RE: [PATCH v4 2/2] powerpc/pseries/iommu: Use dma_iommu_ops for Secure VMs aswell. |
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On Tue, Dec 03, 2019 at 11:58:18AM +1100, Alexey Kardashevskiy wrote: > > > On 02/12/2019 17:45, Ram Pai wrote: > > Commit edea902c1c1e ("powerpc/pseries/iommu: Don't use dma_iommu_ops on > > secure guests") > > disabled dma_iommu_ops path, for secure VMs. The rationale for disabling > > the dma_iommu_ops path, was to use the dma_direct path, since it had > > inbuilt support for bounce-buffering through SWIOTLB. > > > > However dma_iommu_ops is functionally much richer. Depending on the > > capabilities of the platform, it can handle direct DMA; with or without > > bounce buffering, and it can handle indirect DMA. Hence its better to > > leverage the richer functionality supported by dma_iommu_ops. > > What exactly do we leverage after applying this patch? afaict things are > going to work in exact same old way with this applied, no? Thanks,
Yes. You got it right. Another way of saying this is, it reverts the changes.
RP
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