hw/arm/virt: Check for attempt to use TrustZone with KVM or HVF

hw/arm/virt: Check for attempt to use TrustZone with KVM or HVF

It's not possible to provide the guest with the Security extensions
(TrustZone) when using KVM or HVF, because the hardware
virtualization extensions don't permit running EL3 guest code.
However, we weren't checking for this combination, with the result
that QEMU would assert if you tried it:

$ qemu-system-aarch64 -enable-kvm -machine virt,secure=on -cpu host -display none
Unexpected error in object_property_find_err() at ../../qom/object.c:1304:
qemu-system-aarch64: Property 'host-arm-cpu.secure-memory' not found
Aborted

Check for this combination of options and report an error, in the
same way we already do for attempts to give a KVM or HVF guest the
Virtualization or MTE extensions. Now we will report:

qemu-system-aarch64: mach-virt: KVM does not support providing Security extensions (TrustZone) to the guest CPU

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/961
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220404155301.566542-1-peter.maydell@linaro.org