Re: [Qemu-devel] [PATCH 0/2] target-arm: "any" CPUs for system-mode

[Peter Crosthwaite]

On Mon, Jul 6, 2015 at 3:49 PM, Peter Maydell <address@hidden> wrote:
> On 6 July 2015 at 23:42, Peter Crosthwaite <address@hidden> wrote:
>> On Mon, Jul 6, 2015 at 3:29 PM, Peter Maydell <address@hidden> wrote:
>>> On 6 July 2015 at 19:53,  <address@hidden> wrote:
>>>> From: Meador Inge <address@hidden>
>>>>
>>>> This patch series opens up the "any" CPU for system-mode and
>>>> adds a new "any" variant named "anyvfp" that initializes the
>>>> FP coprocessors as well.
>>>
>>> We deliberately removed cpu "any" for system mode in
>>> commit f5f6d38b7458b8a back in 2013; I think the rationale
>>> for its removal still holds. If you're emulating a system
>>> you're emulating a specific system and you get a real
>>> CPU. A CPU with no impdef sysregs or initialized feature
>>> and ID registers is broken...
>>
>> You can still have a CPU+RAM only machine model, load elfs and get
>> meaningful result on a debugger.
>
> Yeah, but what does "any" get you over just going ahead
> and specifying your CPU type? What interrupt controller
> should the "any" CPU type have? Generic timers? Etc.
>

None and none. You are only interested in CPU internal state with no IO at all.

> There isn't zero utility there, but I don't really think
> there's enough to justify cluttering up QEMU with when
> "-cpu cortex-a15" is not very much more to type, and
> has the advantage of being something that actually
> exists in reality.

There is a clean definition of an ARM CPU without any IO however which
has utility in compiler testing.

Regards,
Peter

>
> -- PMM
>