Re: [Xen-devel] Fail to boot Dom0 on Xen Arm64 after "dma-mapping: bypass indirect calls for dma-direct"

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Thu, Jan 17, 2019 at 11:43:49AM +0000, Julien Grall wrote:
> Looking at the change for arm64, you will always call dma-direct API. In
> previous Linux version, xen-swiotlb will call dev->archdata.dev_dma_ops (a
> copy of dev->dma_ops before setting Xen DMA ops) if not NULL. Does it mean
> we expect dev->dma_ops to always be NULL and hence using dma-direct API?

The way I understood the code from inspecting it and sking the
maintainers a few askings is that for DOM0 we always use xen-swiotlb
as the actual dma_map_ops, but then use the functions in page-coherent.h
only to deal with cache maintainance, so it should be safe.

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