Re: [PATCH 0/3] hw/arm/virt: Use generic CPU invalidation

[Peter Maydell]

On Fri, 14 Jul 2023 at 12:50, Igor Mammedov <imammedo@redhat.com> wrote:
>
> On Thu, 13 Jul 2023 12:59:55 +0100
> Peter Maydell <peter.maydell@linaro.org> wrote:
>
> > On Thu, 13 Jul 2023 at 12:52, Marcin Juszkiewicz
> > <marcin.juszkiewicz@linaro.org> wrote:
> > >
> > > W dniu 13.07.2023 o 13:44, Peter Maydell pisze:
> > >
> > > > I see this isn't a change in this patch, but given that
> > > > what the user specifies is not "cortex-a8-arm-cpu" but
> > > > "cortex-a8", why do we include the "-arm-cpu" suffix in
> > > > the error messages? It's not valid syntax to say
> > > > "-cpu cortex-a8-arm-cpu", so it's a bit misleading...
> > >
> > > Internally those cpu names are "max-{TYPE_ARM_CPU}" and similar for
> > > other architectures.
> >
> > Yes; my question is "why are we not using the user-facing
> > string rather than the internal type name?".
>
> With other targets full CPU type name can also be valid
> user-facing string. Namely we use it with -device/device_add
> interface. Considering we would like to have CPU hotplug
> on ARM as well, we shouldn't not outlaw full type name.
> (QMP/monitor interface also mostly uses full type names)

You don't seem to be able to use the full type name on
x86-64 either:

$ ./build/all/qemu-system-x86_64 -cpu pentium-x86_64-cpu
qemu-system-x86_64: unable to find CPU model 'pentium-x86_64-cpu'

and '-cpu help' does not list them with the suffix.

> Instead it might be better to consolidate on what has
> been done on making CPU '-device' compatible and
> allow to use full CPU type name with '-cpu' on arm machines.
>
> Then later call suffix-less legacy => deprecate/drop it from
> user-facing side including cleanup of all the infra we've
> invented to keep mapping between cpu_model and typename.

This seems to me like a worsening of the user interface,
and in practice there is not much likelihood of being
able to deprecate-and-drop the nicer user-facing names,
because they are baked into so many command lines and
scripts.

thanks
-- PMM