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Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_off
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio |
Date: |
Mon, 19 Sep 2011 14:29:40 +0200 |
User-agent: |
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On 2011-09-19 14:14, Avi Kivity wrote:
> 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.
I'm changing the way isa_register_portio_1 registers portios with the
core: only one per offset. The new commit log says:
"This implies that MemoryRegionPortio::offset is no longer used as
offset within the memory region but just as a correction value for the
offset passed to legacy handlers that expect absolute port addresses."
>
>
>>
>> >
>> >> > 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.
Looks more like 3 regions with one alias each. But we likely need to
disentangle all that logic first. I would be surprised if there wasn't a
more readable way to express it via the memory API.
Jan
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- [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Jan Kiszka, 2011/09/18
- [Qemu-devel] [PATCH] memory: Eliminate region offset, Jan Kiszka, 2011/09/18
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Avi Kivity, 2011/09/18
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Jan Kiszka, 2011/09/18
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Avi Kivity, 2011/09/18
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Jan Kiszka, 2011/09/18
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Avi Kivity, 2011/09/19
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio,
Jan Kiszka <=
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Avi Kivity, 2011/09/19
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Jan Kiszka, 2011/09/19
- Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Avi Kivity, 2011/09/19
Re: [Qemu-devel] [PATCH] isa: Avoid using obsolete memory_region_set_offset for old portio, Richard Henderson, 2011/09/18