Re: [Qemu-devel] [Qemu-ppc] [PATCH 01/10] ppc: Fix rfi/rfid/hrfi/... emulation

[Thomas Huth]

On 20.06.2016 08:17, Cédric Le Goater wrote:
> On 06/20/2016 04:19 AM, David Gibson wrote:
>> On Mon, Jun 20, 2016 at 07:12:38AM +1000, Benjamin Herrenschmidt wrote:
>>> On Sun, 2016-06-19 at 19:23 +0200, Cédric Le Goater wrote:
>>>>> You can run a 32-bit OS or firmware on ppc64, but it needs to know that
>>>>> it's running on a 64-bit chip and do a few things differently.
>>>>
>>>> yes sure but qemu would still allow rfi under 64bit CPUs, that is what 
>>>> I was concerned about. Is that ok ? 
>>>
>>> Why ? A real CPU won't allow it, why should we ?
>>
>> We shouldn't.  However, I'm inclined to in for now, until we have an
>> OpenBIOS fix actually committed.  I'd prefer to keep the existing
>> setup sorta-working when the current situation is unlikely to break
>> working code, even though it's definitely wrong.
>>
>> BenH or Cédric, if you want to resend the hrfi fix patch with the
>> 64-bit rfi support left in for no, that would be good.
> 
> The current patch does not need fixing. I will send the OpenBIOS patch 
> shortly after I have looked at the FPU exception.
> 
> Linux ppc behaves the same on a 970. So we will need to fix the 'rfi's
> there also. 

Really? Wow, that surprises me. That OpenBIOS code likely never ran on a
real 970 hardware, so that's not too much surprising that the "rfi"
sneaked in there, but the Linux kernel certainly ran on a real 970 once,
so I wonder why it's not properly using rfid for the 970 yet?

 Thomas