Re: [Qemu-devel] [PATCH 2/3] ppc64-softmmu: Remove unsupported FDC from config

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 03/10/2015 04:38 PM, Alexander Graf wrote:
>
>
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>> Am 09.03.2015 um 23:44 schrieb Alexey Kardashevskiy <aik@ozlabs.ru>:
>>
>>> On 03/10/2015 02:58 PM, David Gibson wrote:
>>>> On Tue, Mar 10, 2015 at 02:52:48PM +1100, Alexey Kardashevskiy wrote:
>>>>> On 03/10/2015 01:39 AM, Alexey Kardashevskiy wrote:
>>>>>> On 03/09/2015 11:31 PM, Alexander Graf wrote:
>>>>>>
>>>>>>
>>>>>>> On 02.03.15 00:46, Alexey Kardashevskiy wrote:
>>>>>>> This removes floppy disks support as it is not supported by any PPC64
>>>>>>> system anyway as the only way to have floppy disk on such systems would
>>>>>>> be an ISA bus and Linux kernels seems have never had such support.
>>>>>>>
>>>>>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>>>>>>
>>>>>> I removed this patch from my queue again. The ppc64-softmmu target can
>>>>>> execute -M PReP which in turn uses the fdc.
>>>>>
>>>>>
>>>>> Out of curiosity - do you have actual 64bit guests being able to run on
>>>>> PReP? :) Current Linux ditched its support...
>>>>
>>>>
>>>> Paul suggested that there has never ever been a 64bit PReP CPU so there is
>>>> no point in emulating it in QEMU. Or there is some reason for that?
>>>
>>> IIUC, qemu-system-ppc64 (roughly speaking) emulates a superset of what
>>> qemu-system-ppc does, not a different set of hardware.
>>
>> Well, default-configs/ppc-softmmu.mak does not include default-configs/ppc64-softmmu.mak or vice versa so I would say these are pretty independent and I would simply remove CONFIG_PREP* from default-configs/ppc64-softmmu.mak.
>
> Convention so far has been that ppc64 includes ppc includes ppcemb. I don't see why we should break that assumption.



[aik@vpl2 ~]$ ./qemu-system-ppc64 -device help 2>&1 | grep fdc
name "isa-fdc", bus ISA
name "sysbus-fdc", bus System


afaik there is no way to get "fdc" working with qemu-system-ppc64 but 
"-device help" suggests there is a way and libvirt thinks (the original 
request came from there) it can add floppy disk. If later we use "-fda" 
with QEMU, it will warn about "Orphaned drive" as there is no fdc device. 
Ok, I can be sneakier and add "-device i82378" but I wonder if there is a 
PPC64 guest with FDC driver enabled. When I try to enable it in the current 
upstream (or anything since 2010), it needs ISA which depends on CHRP 
(about to be ditched, and PReP is ditched already) which depends on 6xx 
which is not defined at all (PPC_6xx is but not 6xx).

So if you know how to get working floppy disk with qemu-system-ppc64, that 
would help me a lot in rejecting requests from libvirt folks :) Thanks :)



> However I do agree that we should probably reflect it with includes in the mak files.
>
>
> Alex
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>>
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>> --
>> Alexey


-- 
Alexey