Re: [Qemu-devel] [PATCH v3 1/4] target-arm: Add CPU property to disable AArch64

[Christoffer Dall]

On Tue, Feb 3, 2015 at 10:15 PM, Peter Maydell <address@hidden> wrote:
> On 3 February 2015 at 19:14, Peter Maydell <address@hidden> wrote:
>> On 27 January 2015 at 23:58, Greg Bellows <address@hidden> wrote:
>>>  static void aarch64_cpu_initfn(Object *obj)
>>>  {
>>> +    object_property_add_bool(obj, "aarch64", aarch64_cpu_get_aarch64,
>>> +                             aarch64_cpu_set_aarch64, NULL);
>>> +    object_property_set_description(obj, "aarch64",
>>> +                                    "Set on/off to enable/disable aarch64 "
>>> +                                    "execution state ",
>>> +                                    NULL);
>>>  }
>>
>> This all looks OK code-wise. Still need to think about whether we
>> can manage to end up with a nicer interface to the user than
>> cpuname,-aarch64, though.
>
> [I meant "-cpu cpuname,aarch64=off", hadn't processed that we've
> updated to the new style syntax.]
>
> I had a think about this as I was cycling home, and I (re)convinced
> myself that modelling this as "remove the AArch64 feature flag" is
> the right way to do it, which then just leaves us with "what's the
> best user-facing UI we can manage to expose that?".
>
> Suppose that we had two properties/feature flag switches that do
> the same thing but have inverse sense:
>
>   aarch64=off
>   aarch32-only=on
>
> Would that help, or just be more confusing?
>
that would help, imho.

-Christoffer