Re: [Qemu-devel] 'blank' address space for unknown arm peripherals?

[Peter Maydell]

On 7 May 2017 at 01:23, Marty Plummer <address@hidden> wrote:
> Its my understanding that for creating machine definitions for qemu one
> uses what amount to 'drivers' or 'hardware simulations'. I was wondering
> if there was what amounted to a blank or raw memory area one could use
> as a placeholder for a peripheral which is currently undocumented and
> lacking source code for the linux kernel drivers the vendor ships.

We added the 'unimplemented-device' recently for this purpose:
code in hw/misc/unimp.c, example of use in hw/arm/stellaris.c
(calls to create_unimplemented_device()). NB that since by default
accesses to bits of the address space which don't have a device
will read-as-zero/writes-ignored, using this won't change the
behaviour at all, but unimplemented-device has tracing so that
if you use '-d unimp' on the QEMU command line it will print out
all the accesses the guest makes to these areas.

thanks
-- PMM