On 2013-08-05 12:51, Peter Maydell wrote: > On 5 August 2013 11:44, Jan Kiszka <jan.kis...@web.de> wrote: >> On 2013-08-05 12:36, Peter Maydell wrote: >>> On 5 August 2013 11:30, Jan Kiszka <jan.kis...@web.de> wrote: >>>> On 2013-08-05 11:59, Peter Maydell wrote: >>>>> Or do you mean that if we had: >>>>> >>>>> [ system memory region, with its own default read/write ops ] >>>> >>>> I cannot imagine how this could work. The system memory region has no >>>> clue about what the regions below it can handle and what not. So it has >>>> to pass through the io window. >>> >>> The system memory region's just a container, you can add a >>> background region to it at lowest-possible-priority, which >>> then takes accesses which are either (a) not in any subregion >>> or (b) in a subregion but that container doesn't specify >>> its own io ops and nothing in that container handles the >>> access. (Or you could create the system memory region with >>> its own IO ops, which would have the same effect.) >> >> First, we do not render MMIO and IO within the same address space so >> far. > > Is this a statement made because you've checked all the boards > and know that nobody's mapping the system-io memory region into > the system-memory region? (It is technically trivial, you > just need to call memory_region_add_subregion() directly > or indirectly...)
I know this because I just recently wrote the patch that enables this trivial step, i.e. converted PIO dispatching to the memory subsystem. Jan
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