Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 11 Jun 2019 23:53:14 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH v2 8/8] habanalabs: enable 64-bit DMA mask in POWER9 |
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On Wed, Jun 12, 2019 at 04:35:22PM +1000, Oliver O'Halloran wrote: > Setting a 48 bit DMA mask doesn't work today because we only allocate > IOMMU tables to cover the 0..2GB range of PCI bus addresses.
I don't think that is true upstream, and if it is we need to fix bug in the powerpc code. powerpc should be falling back treating a 48-bit dma mask like a 32-bit one at least, that is use dynamic iommu mappings instead of using the direct mapping. And from my reding of arch/powerpc/kernel/dma-iommu.c that is exactly what it does.
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