Re: [PATCH 3/3] system/physmem: Assign global system I/O Memory to machine

[Philippe Mathieu-Daudé]

(+Markus I forgot to Cc)

On 9/2/24 17:06, Peter Maydell wrote:
> On Fri, 9 Feb 2024 at 15:01, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
> > So far there is only one system I/O and one system
> > memory per machine.
> >
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> > ---
> >   system/physmem.c | 7 ++++---
> >   1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/system/physmem.c b/system/physmem.c
> > index 5e66d9ae36..50947a374e 100644
> > --- a/system/physmem.c
> > +++ b/system/physmem.c
> > @@ -2554,12 +2554,13 @@ static void memory_map_init(void)
> >   {
> >       system_memory = g_malloc(sizeof(*system_memory));
> >
> > -    memory_region_init(system_memory, NULL, "system", UINT64_MAX);
> > +    memory_region_init(system_memory, OBJECT(current_machine),
> > +                       "system", UINT64_MAX);
> >       address_space_init(&address_space_memory, system_memory, "memory");
> >
> >       system_io = g_malloc(sizeof(*system_io));
> > -    memory_region_init_io(system_io, NULL, &unassigned_io_ops, NULL, "io",
> > -                          65536);
> > +    memory_region_init_io(system_io, OBJECT(current_machine),
> > +                          &unassigned_io_ops, NULL, "io", 65535);
> >       address_space_init(&address_space_io, system_io, "I/O");
> >   }
>
> What's the intention in doing this? What does it change?

We want to remove access to pre-QOM and possibly hotplug QOM paths
from external API (CLI & QMP so far).

When the parent object is obvious and missing we simply have to
explicit it.

> It seems to be OK to pass a non-Device owner in for
> memory_region_init() (whereas it is *not* OK to do that
> for memory_region_init_ram()), but this seems to be
> getting a bit tricky.

Yes, memory_region_init_ram() is problematic; I'm hardly trying
to ignore it at this point.