Re: [Qemu-devel] [PATCH v3 11/14] ioport: Switch dispatching to memory core layer

[Alexander Graf]

On 24.06.2013, at 08:07, Jan Kiszka wrote:

> On 2013-06-23 22:50, Hervé Poussineau wrote:
>> Jan Kiszka a écrit :
>>> From: Jan Kiszka <address@hidden>
>>> 
>>> The current ioport dispatcher is a complex beast, mostly due to the
>>> need to deal with old portio interface users. But we can overcome it
>>> without converting all portio users by embedding the required base
>>> address of a MemoryRegionPortio access into that data structure. That
>>> removes the need to have the additional MemoryRegionIORange structure
>>> in the loop on every access.
>>> 
>>> To handle old portio memory ops, we simply install dispatching handlers
>>> for portio memory regions when registering them with the memory core.
>>> This removes the need for the old_portio field.
>>> 
>>> We can drop the additional aliasing of ioport regions and also the
>>> special address space listener. cpu_in and cpu_out now simply call
>>> address_space_read/write. And we can concentrate portio handling in a
>>> single source file.
>>> 
>>> Signed-off-by: Jan Kiszka <address@hidden>
>>> ---
>> 
>> ...
>> 
>>> +
>>> +static void portio_write(void *opaque, hwaddr addr, uint64_t data,
>>> +                         unsigned size)
>>> +{
>>> +    MemoryRegionPortioList *mrpio = opaque;
>>> +    const MemoryRegionPortio *mrp = find_portio(mrpio, addr, size,
>>> true);
>>> +
>>> +    if (mrp) {
>>> +        mrp->write(mrpio->portio_opaque, mrp->base + addr, data);
>>> +    } else if (size == 2) {
>>> +        mrp = find_portio(mrpio, addr, 1, true);
>>> +        assert(mrp);
>>> +        mrp->write(mrpio->portio_opaque, mrp->base + addr, data & 0xff);
>>> +        mrp->write(mrpio->portio_opaque, mrp->base + addr + 1, data
>>>>> 8);
>>> +    }
>>> +}
>>> +
>>> +static const MemoryRegionOps portio_ops = {
>>> +    .read = portio_read,
>>> +    .write = portio_write,
>>> +    .valid.unaligned = true,
>>> +    .impl.unaligned = true,
>>> +};
>>> +
>> 
>> You need to mark these operations as DEVICE_LITTLE_ENDIAN.
>> In portio_write above, you clearly assume that data is in LE format.
> 
> Anything behind PIO is little endian, of course. Will add this.

This patch breaks VGA on PPC as it is in master today.


Alex

> 
>> 
>> This fixes PPC PReP emulation, which would otherwise be broken with this
>> patchset.
> 
> Thanks,
> Jan
> 
>