On 10/15/2013 08:42 AM, Peter Maydell wrote: > The documentation of how overlapping memory regions behave and how > the priority system works was rather brief, and confusion about > priorities seems to be quite common for developers trying to understand > how the memory region system works, so expand and clarify it. > This includes a worked example with overlaps, documentation of the > behaviour when an overlapped container has "holes", and mention > that it's valid for a region to have both MMIO callbacks and > subregions (and how this interacts with priorities when it does). > > Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> > --- > Changes v1->v2: various minor improvements as per review comments > from MST and subsequent discussion. >
> > +It is valid to add subregions to a region which is not a pure container > +(that is, to an MMIO, RAM or ROM region). This means that the region > +will act like a container, except that any addresses within the container's > +region which are not claimed by any subregion are handled by the > +container itself (ie by its MMIO callbacks or RAM backing). However s/ie/ie./ > +it is generally possible to achieve the same effect with a pure container s/container/container,/ > +one of whose subregions is a low priority "background" region covering > +the whole address range; this is often clearer and is preferred. > +Subregions cannot be added to an alias region. > -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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