On Wed, Sep 16, 2009 at 04:57:42PM +0200, Arnd Bergmann wrote: > 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 <>< We are talking about doing this in userspace, not in kernel. -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
