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From: Anthony Liguori <anthony@codemonkey.ws>
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Date: Wed, 25 Jul 2012 20:08:55 -0500
Message-ID: <87boj3wcpj.fsf@codemonkey.ws>
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Subject: Re: [Qemu-devel] vga-pci and MMIO BAR
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>, Avi Kivity <avi@redhat.com>
Cc: qemu-devel@nongnu.org

Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:

> On Thu, 2012-07-26 at 08:01 +1000, Benjamin Herrenschmidt wrote:
>> On Wed, 2012-07-25 at 16:59 +0300, Avi Kivity wrote:
>> > > Why ? Who cares ? Especially with vga -std which nobody uses in
>> > practice
>> > > on x86...
>> > 
>> > We'll find out who cares when we break it.
>> 
>> Chances are pretty much close to 0, especially adding a BAR ... do we
>> even use vga "std" on anything ?
>>
>> > We have a system in place to prevent intentional breakage, let's use
>> > it.
>> 
>> And that system is never improve a device ? :-) Or am I missing
>> something ?
>
> Allright, had a chat with Anthony who explained the bit I was missing
> about what you meant by -M old... I'll make sure I don't break that.

For the benefit of the list, Ben didn't know that we could just add a
qdev property to control whether the MMIO BAR was visible making it just
a tiny bit of global magic in the old PC machine models.

PPC still doesn't do versioning of machine models.  Ya'll probably
should spend some time looking at what's done for the PC machine types
and start doing the same for spapr.

Regards,

Anthony Liguori

>
> Cheers,
> Ben