Re: [PATCH v3 1/2] hw/arm/imx8mp-evk: Add KVM support

[Cornelia Huck <cohuck@redhat.com>]

On Mon, Nov 17 2025, Peter Maydell <peter.maydell@linaro.org> wrote:

> On Mon, 17 Nov 2025 at 17:13, Cornelia Huck <cohuck@redhat.com> wrote:
>> Running current master (resp. with this patch applied), I'm getting make
>> check failures on an aarch64 (Mt. Snow) host ("qemu-system-aarch64:
>> unknown type 'arm-gicv3'" while using this machine); going back right
>> before this patch, everything works fine. Haven't tried to debug this
>> yet (maybe I'm the one with the weird config again...)
>
> Is this a KVM-only config (no TCG) ?

Yes, it is. (Forgot about that...)

However, I noticed that a build I did after enabling tcg still failed,
and only after starting over with a fresh build directory, it worked  --
I'm wondering if I managed to trigger an unrelated problem?

>
> I think this happens because the KConfig now says
> +    depends on TCG || KVM
>
> but because the machine by default doesn't use KVM then
> trying to run the machine with no extra arguments falls
> over if TCG isn't present.
>
> This thing we put in to handle "creation of the SoC object
> via device introspection means it doesn't have an ms->cpu_type
> to look at":
>
> +    const char *cpu_type = ms->cpu_type ?: ARM_CPU_TYPE_NAME("cortex-a53");
>
> also probably won't do anything useful under a KVM-only config.
>
> I think the simplest thing here is to put the KConfig back to:
>
>   depends on TCG && AARCH64
>
> People building a KVM-only config almost certainly do not
> want this machine type and its devices, because the main
> reason to build KVM-only is because you're in the
> "virtualization use case" and want to not build in a
> load of not-security-supported machine types.

I think that's a reasonable assumption.