On Tuesday 15 September 2009, Michael S. Tsirkin wrote: > Userspace in x86 maps a PCI region, uses it for communication with ppc? This might have portability issues. On x86 it should work, but if the host is powerpc or similar, you cannot reliably access PCI I/O memory through copy_tofrom_user but have to use memcpy_toio/fromio or readl/writel calls, which don't work on user pointers. Specifically on powerpc, copy_from_user cannot access unaligned buffers if they are on an I/O mapping. Arnd <>< -- 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