Re: [Qemu-devel] KVM call minutes for Feb 8

Peter Maydell
2011-02-10T09:04:28Z

On 10 February 2011 08:36, Anthony Liguori <anthony@codemonkey.ws> wrote:
> On 02/10/2011 09:16 AM, Peter Maydell wrote:
>> On 10 February 2011 07:47, Anthony Liguori<anthony@codemonkey.ws>  wrote:
>>> 2) get rid of the entire concept of machines.  Creating a i440fx is
>>> essentially equivalent to creating a bare machine.
>>
>> Does that make any sense for anything other than target-i386?
>> The concept of a machine model seems a pretty obvious one
>> for ARM boards, for instance, and I'm not sure we'd gain much
>> by having i386 be different to the other architectures...
>
> Yes, it makes a lot of sense, I just don't know the component names as well
> so bear with me :-)
>
> There are two types of Versatile machines today, Versatile/AB and
> Versatile/PB.  They are both made with the same core, ARM926EJ-S, with
> different expansions.
>
> So you would model arm926ej-s as the chipset and then build up the machines
> by modifying parameters of the chipset (like the board id) and/or adding
> different components on top of it.

Er, ARM926 is the CPU, it's not a chipset. The board ID is definitely
not a property of an ARM926, it's a property of the board (clue is in
the name :-)). I don't think versatile boards have a "chipset" really...

In my understanding the "machine" is the thing that says "I need a
926, and an MMC controller at this address, and some UARTS,
and..." ie it is the thing that does the "modifying parameters"
and "adding different components". So if we'd still be doing that
I don't see how we've "got rid of the concept". I guess I'm missing
the point somehow.

> A good way to think about what I'm proposing is that machine->init really
> should be a constructor for a device object.

If you mean that you want machines to be implemented under the
hood as a single huge "device" you can only have one of that spans
the entire memory map, well I guess that's an implementation
detail. But conceptually machines really do exist, and we definitely
still want users to be able to say "I want a beagle machine; I want
a versatile; I want an n900".

-- PMM