Per Anup Patel in [*]:
> Currently, we only support running rv64 guest on rv64 host
> and rv32 guest on rv32 host.
>
> In the future, we might support running rv32 guest on rv64
> host but as of now we don't see a strong push for it.
Therefore, when only using the KVM accelerator it is pointless
to build qemu-system-riscv32 on a rv64 host (or qemu-system-riscv64
on a rv32 host). Restrict meson to only build the correct binary,
avoiding to waste ressources building unusable code.
[*]
CAAhSdy2JeRHeeoEc1XKQhPO3aDz4YKeyQsPT4S8yKJcYTA+AiQ@mail.gmail.com/">https://lore.kernel.org/qemu-devel/CAAhSdy2JeRHeeoEc1XKQhPO3aDz4YKeyQsPT4S8yKJcYTA+AiQ@mail.gmail.com/
Based-on: <20230626232007.8933-1-philmd@linaro.org>
"target/riscv: Allow building without TCG (KVM-only so far)"
20230626232007.8933-1-philmd@linaro.org/">https://lore.kernel.org/qemu-devel/20230626232007.8933-1-philmd@linaro.org/