On 05/01/2012 04:50 PM, Anthony Liguori wrote: > On 05/01/2012 08:01 AM, Avi Kivity wrote: >> On 05/01/2012 03:49 PM, Peter Maydell wrote: >>> On 1 May 2012 13:48, Avi Kivity<a...@redhat.com> wrote: >>>> On 05/01/2012 03:43 PM, Peter Maydell wrote: >>>>> On 1 May 2012 13:42, Avi Kivity<a...@redhat.com> wrote: >>>>>> sysbus should just die. >>>>> >>>>> Totally agreed. It's not going to go quietly though... >>>> >>>> Not if you keep suggesting workarounds when I tell unsuspecting >>>> developers to qomify their devices. >>> >>> When QOM supports (1) exporting gpio signals and > > This is trivial. It'll come in as soon as 1.2 opens up. If folks > want to start working on a branch with it: > > https://github.com/aliguori/qemu/tree/qom-pin.4 > >>> (2) exporting memory regions, then it will be providing the >>> main things that sysbus provides. > > This is a little tricky. Here's the problems I've encountered so far: > > a) A lot of devices need the equivalent of it_shift. it_shift affects > how addresses are decoded and the size of the memory region. it_shift > usually needs to be a device property. > > Since we need to know the size of the memory region to initialize it, > we need to know the value of it_shift before we can initialize it > which means we have to delay the initialization of the mmemory region > until realize. > > I think a nice fix would be to make it_shift as memory region mutator > and allow it to be set after initialization.
Indeed I wanted to make it_shift as part of the memory core. But a mutator? It doesn't change in real hardware, so this looks artificial. So far all mutators really change at runtime. What is the problem with delaying region initialization until realize? > > b) There's some duplication in MemoryRegions with respect to QOM. > Memory regions want to have a name but with QOM they'll be addressable > via a path. I go back and forth about how aggressively we want to > refactor MemoryRegions. These days region names are purely for debugging. The ABI bit was moved to a separate function. -- error compiling committee.c: too many arguments to function
