Messages in this thread | | | Date | Mon, 8 Jun 2020 22:32:40 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH v2 08/11] swiotlb-xen: introduce phys_to_dma/dma_to_phys translations |
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On Mon, Jun 08, 2020 at 04:06:57PM -0700, Stefano Stabellini wrote: > I understand what you are suggesting about having something like: > > xen_phys_to_dma(...) > { > phys_addr_t phys = xen_phys_to_bus(dev, paddr) > return phys_to_dma(phys); > } > > I thought about it myself. I'll do it.
"something", yes. Except that I think the bus is a little confusing, isn't it? What is the Xen term for these addresses? Also we probably don't need the extra local variable.
> But I don't think I understood the comment about XEN_PFN_PHYS.
There is a comment above xen_phys_to_bus that it avoids using XEN_PFN_PHYS because XEN_PFN_PHYS of the phys_addr_t vs dma_addr_t mismatch. But XEN_PFN_PHYS could just use a u64 instead of the phys_addr_t and then we could use it. Especially as XEN_PFN_PHYS isn't actually used anywhere except in swiotlb-xen.c. Or we could remove XEN_PFN_PHYS enirely, as it isn't all that useful to start with.
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