On Fri, Oct 30, 2015 at 01:55:56PM +0100, Christian Borntraeger wrote: > It not trivial without understanding the dma mask details. Do I read > the x86 implementation right, that it limits the dma to 32 bit? Then > we cannot collapse both implementations. Or maybe we can hide this in > dma_capable. Dont know No, DMA is not limited to 32bit on x86. Each device has its own dma_mask, and the requested address+size is checked against it. The DMA_BIT_MASK(32) check is only to there to print a warning when a 32bit capable device trys to access memory above 4GB. Joerg -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html