Re: IOMMU and domain binding/unbinding logic

[Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>]

Hi Jerome,

On Thu, Mar 26, 2015 at 01:58:58PM -0400, Jerome Glisse wrote:
> Of course if dev.archdata.dma_ops is pointing to nommu_dma_ops then every
> things is fine, but here i am wondering for the case where the ops are
> actualy amd_iommu_dma_ops. In the first place ie at iommu initialization
> or when hotpluging a new device (as in the hotpluging case it always set
> dev.archdata.dma_ops to amd_iommu_dma_ops AFAICT.

Yes, every device that is IOMMUv2 capable (ATS + PRI + PASID capability
present) is put into the passthrough domain at boot time. The dma_ops
point to nommu_dma_ops and after the device is used for IOMMUv2 mappings
the old DMA-API mappings remain valid.

For details you can have a look into the AMD IOMMU driver and how the
return value of pci_iommuv2_capable() is propageted.


	Joerg