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

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 18/11/25 10:49, Bernhard Beschow wrote:
> 
> 
> Am 17. November 2025 17:38:03 UTC schrieb Peter Maydell <peter.maydell@linaro.org>:
>> 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) ?
>>
>> 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.
> 
> Do we need this treatment for further machines, e.g. isapc, e500, mips? Or shall the CPU type handling in the SoC consider kvm_enabled()?

Good point. My understanding is only virt x86/arm/ppc64/s390x are
"security covered", but there is no explicit mention of that in
our doc. (btw why not include isapc? as it is a subset of other
covered x86 machines?)