Re: [Qemu-devel] ppc vga output breakage since commit c3c1bb99

[Paolo Bonzini]

On 28/03/2015 20:19, Mark Cave-Ayland wrote:
> On 28/03/15 19:04, BALATON Zoltan wrote:
> 
>> Hello,
>>
>> Commit c3c1bb99d1c11978d9ce94d1bdcf0705378c1459 (exec: Respect
>> as_tranlsate_internal length clamp) seems to break vga output with
>> qemu-system-ppc on x86_64 host. Since this commit, the output window
>> does not get to the OpenBIOS console but stays black. (Easy to reproduce
>> by just starting qemu-system-ppc.)
>>
>> The reason may be that this change has exposed another bug somewhere
>> else but this is all quite obscure to me. Does anyone have any idea what
>> could be wrong or where to look further. Any help is appreciated.
> 
> Hi Zoltan,
> 
> Yes indeed, this has been picked up in the last few days and is on the
> list of issues to be dealt with for -rc2. So watch this space...

This is an OpenBIOS bug; the port at 0x1ce is 1 byte wide, but OpenBIOS
is accessing it as 2 bytes.

Of course, there's a QEMU regression too and I'm thinking of how to fix it.

Paolo