Re: [PATCH RESEND v2 0/6] target/arm: Add nested virtualization support

[Peter Maydell]

On Tue, 27 Apr 2021 at 15:58, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Tue, 27 Apr 2021 at 15:48, Andrew Jones <drjones@redhat.com> wrote:
>
> > Since these types of features seem to blur the line between being a CPU
> > and board property, then I think I'd prefer we call them CPU properties,
> > as they come from the CPU manual.
>
> Conversely, I prefer to call them board properties, because that's
> the way it works in hardware: the hardware board has the necessary
> support for the system-level feature, and part of that is that it
> has an SoC or CPU which has been configured to have the properties
> that are needed for the board to support the feature. Having a CPU
> that nominally supports a feature is useless if the system as a whole
> doesn't handle it.

...this also means that we're consistent between boards: some board
models unconditionally have support for a feature (and always set it
on the CPU, GIC, etc), some don't ever support the feature (and always
disable it), and a few offer the user the choice. Having the user
use CPU properties suggests that they can, for instance, plug a
has-el3 CPU into any board model, which in general won't work.

-- PMM