Hi Ashok, On Thu, Dec 22, 2016 at 03:45:08PM -0800, Raj, Ashok wrote: > Hi Bjorn > > None in the platform group say they know about this. So i'm fairly sure > we don't do that on Intel hardware (x86). I'm pretty sure there was once an x86 prototype for which PCI bus addresses were not identical to CPU physical addresses, but I have no idea whether it shipped that way. Even if such a system never shipped, the x86 arch code supports _TRA, and there's no reason to make the unnecessary assumption in this code that _TRA is always zero. If we didn't want to use pcibios_resource_to_bus() here for some reason, we should at least add a comment about why we think it's OK to use a CPU physical address as an IOVA. Bjorn -- 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