Hi Christian, On Tue, Oct 27, 2015 at 11:48:48PM +0100, Christian Borntraeger wrote: > +static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page, > + unsigned long offset, size_t size, > + enum dma_data_direction dir, > + struct dma_attrs *attrs) > +{ > + return page_to_phys(page) + offset; > +} X86 also has its own version of these noop dma_ops, see arch/x86/kernel/pci-nommu.c. This one also checks the dma_mask and prints a warning if the physical address doesn't fit into the mask. I think this would make sense here too, and that we can also make x86 use the same generic noop-dma-ops your are introducing. 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