On 26 October 2012 13:36, 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.
If it's really in the memory space of the device itself then our device model should be handling it. -- PMM
