On Fri, Oct 26, 2012 at 10:36 PM, Gerd Hoffmann <kra...@redhat.com> wrote: > On 10/26/12 07:47, Peter Crosthwaite wrote: >> Just put RAM regions in the unimplemented spaces in the MMIO region. These >> regions have undefined behaviour, but this at least stops QEMU from >> segfaulting >> when the guest bangs on these registers (and sucessfully fakes reading and >> writing the registers with no side effects). > > Make that an io region, have the read() handler return 0xff, write > handler do nothing except maybe logging/tracing the access for debugging > purposes. That is more correct for unassigned mmio space than backing > by memory. Adding memory also breaks migration btw. > > I somehow still think this should be handled one layer up (i.e. the > parent region) which could do the approximate arch-specific action. > > Any chance the access you are seeing is at offset 0x68? >
0x1a8. which for the opregbase + 0x068 for zynq so probably what you are thinking about. I think the linux kernel is trying to explicitly put the device in root mode rather than device mode, but those regs are unimplemented in EHCI. Regards, Peter > cheers, > Gerd > >
