On 19/01/15 15:04, Peter Maydell wrote: > On 19 January 2015 at 12:57, Artyom Tarasenko <atar4q...@gmail.com> wrote: >> But out of curiosity, would it be possible to have a sysbus device >> somewhere in a middle of PCI space? Do sysbus devices have higher >> priority if the address spaces overlap? Or do you mean that the PCI >> controller needs to be modified to have a hole for a sysbus device? > > You can specify the priority when you map devices into a MemoryRegion, > so you can handle this by either making the sysbus device a positive > priority or by making the PCI window have a negative priority. > > (We don't actually get this right on x86 currently, > which has resulted in some awkwardness for the PPC desire to > make PCI address 0 valid.)
I'm not sure this would work for SPARC64 since potentially OpenBIOS can program the I/O BAR for the ebus anywhere (and the NVRAM is located on the ebus). At the moment we cheat by creating an alias to I/O space at the top of memory so that OpenBIOS can always access it at a fixed address. ATB, Mark.
