Re: [Qemu-devel] [PATCH 2/2] vga: Fix portio list conversion fallouts

[Jan Kiszka <jan.kiszka@web.de>]

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On 2011-09-18 17:51, Avi Kivity wrote:
> On 09/18/2011 03:44 PM, Jan Kiszka wrote:
>> From: Jan Kiszka<jan.kiszka@siemens.com>
>>
>> Fix copy&paste errors and reduce duplications of the BOCHS VBE ranges.
>>
>> Signed-off-by: Jan Kiszka<jan.kiszka@siemens.com>
>> ---
>>
>>   #ifdef CONFIG_BOCHS_VBE
>>   static const MemoryRegionPortio vbe_portio_list[] = {
>> -# ifdef TARGET_I386
>>       { 0, 1, 2, .read = vbe_ioport_read_index, .write =
>> vbe_ioport_write_index },
>> +# ifdef TARGET_I386
> 
> Strange how the card knows what target it's plugged into.  Fixing this
> is going to involve major pain - need to update the bios and need to
> provide backwards compatibility.  All this assuming guests don't
> hardcode the address.
> 
> Anyway I find the deduplication makes the code harder to read.

That line is rather tricky to deduplicate in mind. So it's not nice for
our readers keeping it duplicated around.

> 
>>       { 1, 1, 2, .read = vbe_ioport_read_data, .write =
>> vbe_ioport_write_data },
>>   # else
>> -    { 0, 2, 2, .read = vbe_ioport_read_index, .write =
>> vbe_ioport_write_index },
>> -    { 2, 2, 2, .read = vbe_ioport_read_data, .write =
>> vbe_ioport_write_data },
>> +    { 2, 1, 2, .read = vbe_ioport_read_data, .write =
>> vbe_ioport_write_data },
> 
> Is this correct?  length 1 region with size 2?

Yes, it prevents accesses on base+1.

Jan


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