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Well not quite. The approach PCI_P2PDMA_MAP_BUS_ADDR takes is fundamentally tied to only map a physical CPU address into a PCI address and doesn't take into account that in a lot of configurations the CPU can't access all resources. So when VFIO uses PCI_P2PDMA_MAP_BUS_ADDR it only works for a small subset of the use cases DMA-buf supports, but yeah as always in DMA-buf pretty much everything is optional. Regards, Christian. > > Thanks