On 8/4/2016 2:56 PM, hch@xxxxxxxxxxxxx wrote: >> Anyway, I understand exposing the CMB directly might be a little too >> low level. What do you think would work better? Something like >> direct_access that returns bus addresses instead of pfns? > > This would be my primary choicse. We'll really need to built an > in-kernel framework for a) PCI P2P access involving drivers for the PCI > switches etc, I was thinking perhaps the dma_map_resource patches by Will Davis [1] could be used (adding him to the thread). > and then on top of that build something speicifly for > block drivers. Which will be a bit complicated because both have the > case of directly memory mapped device as well as indirect devices like > the CMB. I'm pretty sure we won't get it right at the first attempt, > so exposing it to userspace is an absolute no-go as that will lock us > into the first ABI forever. I understand. I'll try to think of something for kernel usage only for the next attempt. Thanks, Haggai [1] https://lists.linuxfoundation.org/pipermail/iommu/2015-August/014106.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
