Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio

[Avi Kivity <avi@redhat.com>]

On 09/18/2011 10:04 PM, Jan Kiszka wrote:
> >
> >  If you make the core patch add both mr->offset and mrp->offset, then
> >  change isa to drop memory_region_set_offset(), instead adding the delta
> >  to mrp->offset, does that not work out?
>
> Nope. The old API accepted arbitrary portio lists per memory region, the
> new requires one region with a consistent offset per range. I should
> have documented it...

What does "a consistent offset per range" mean?  You aren't actually 
changing the caller's ranges.


>
> >
> >>  >    And I
> >>  >   don't want to remove memory_region_set_offset() until everything (that
> >>  >   can potentially use it, at least) has been converted.
> >>
> >>  IMO it's easier to fix those potential users before converting them. You
> >>  need to review them anyway to decide if an offset might be needed, and
> >>  which one precisely.
> >>
> >>  Are you aware of any candidates? For PIO, there should be none now.
> >
> >  For pio, none, but mmio has some:
> >
> >  hw/sh7750.c:    cpu_register_physical_memory_offset(0x1f000000, 0x1000,
> >  hw/sh7750.c:    cpu_register_physical_memory_offset(0xff000000, 0x1000,
> >  hw/sh7750.c:    cpu_register_physical_memory_offset(0x1f800000, 0x1000,
> >  hw/sh7750.c:    cpu_register_physical_memory_offset(0xff800000, 0x1000,
> >  hw/sh7750.c:    cpu_register_physical_memory_offset(0x1fc00000, 0x1000,
> >  hw/sh7750.c:    cpu_register_physical_memory_offset(0xffc00000, 0x1000,
> >  hw/sh_intc.c:
> >  cpu_register_physical_memory_offset(P4ADDR(address), 4,
> >  hw/sh_intc.c:
> >  cpu_register_physical_memory_offset(A7ADDR(address), 4,
>
> Cool, that's all. Trivial to fix, just push the offset math into those
> few handler. Then we can drop cpu_register_physical_memory_offset as well.

They all use the same handler, so you need to split e.g. 
sh7750_io_memory into six MemoryRegionsOps. Or use tricks with aliases - 
have one giant 4G region with one handler, and map six 4k aliases into 
the system address space.

-- 
error compiling committee.c: too many arguments to function