Messages in this thread | | | Subject | Re: [PATCH 5/5] dma-direct: always allow dma mask <= physiscal memory size | From | Benjamin Herrenschmidt <> | Date | Tue, 09 Oct 2018 16:01:18 +1100 |
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On Wed, 2018-10-03 at 16:10 -0700, Alexander Duyck wrote: > > - * Because 32-bit DMA masks are so common we expect every architecture > > - * to be able to satisfy them - either by not supporting more physical > > - * memory, or by providing a ZONE_DMA32. If neither is the case, the > > - * architecture needs to use an IOMMU instead of the direct mapping. > > - */ > > - if (mask < phys_to_dma(dev, DMA_BIT_MASK(32))) > > + u64 min_mask; > > + > > + if (IS_ENABLED(CONFIG_ZONE_DMA)) > > + min_mask = DMA_BIT_MASK(ARCH_ZONE_DMA_BITS); > > + else > > + min_mask = DMA_BIT_MASK(32); > > + > > + min_mask = min_t(u64, min_mask, (max_pfn - 1) << PAGE_SHIFT); > > + > > + if (mask >= phys_to_dma(dev, min_mask)) > > return 0; > > -#endif > > return 1; > > } > > So I believe I have run into the same issue that Guenter reported. On > an x86_64 system w/ Intel IOMMU. I wasn't able to complete boot and > all probe attempts for various devices were failing with -EIO errors. > > I believe the last mask check should be "if (mask < phys_to_dma(dev, > min_mask))" not a ">=" check.
Right, that test is backwards. I needed to change it here too (powermac with the rest of the powerpc series).
Cheers, Ben.
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