Re: [Qemu-devel] [Qemu-ppc] [PATCH] target-ppc: Change default machine for 64-bit

[Anthony Liguori <aliguori@us.ibm.com>]

Scott Wood <scottwood@freescale.com> writes:

> On 06/13/2013 01:31:48 PM, Anthony Liguori wrote:
>> Alexander Graf <agraf@suse.de> writes:
>> 
>> > On 17.05.2013, at 09:42, Andreas Färber wrote:
>> >
>> >> Am 17.05.2013 06:25, schrieb David Gibson:
>> >>> Currently, for qemu-system-ppc64, the default machine type is  
>> 'mac99'.
>> >>> Since the mac99 machine is not being actively maintained, and  
>> shows quite
>> >>> a few signs of bitrot,
>> >>
>> >> Please be more specific than making such general claims in a commit
>> >> message! As the default machine it certainly compiles, so where  
>> are you
>> >> seeing bitrot? The DEC bridge cleanup that I once started kind of
>> >> depends on the PCI cleanup you recently looked into.
>> >
>> > The mac99 machine for 64bit is actually worse than anything bitrot
>> > could give you. It emulates a machine that in its form never  
>> possibly
>> > could have existed in real hardware, which makes it very fragile and
>> > dependent on the guest's mercy to handle this gracefully.
>> 
>> I'll note that we have a CONFIG_PSERIES today.  I'd suggest getting  
>> rid
>> of it first before making pseries the default.
>
> Why?

I believe it's there only because libfdt used to be optional.  libfdt is
no longer optional.

> As long as it's present in the default ppc64 build, you'll have a  
> default machine.  If a user makes a custom config without it,  
> presumably they know they want to run some other machine, so why do you  
> need a default?

That's fair.

Regards,

Anthony Liguori

>
> QEMU has too much mandatory stuff as is.
>
> -Scott