Re: [Qemu-arm] [PATCH 1/4] hw/arm/virt: Set default machine and CPU types for mach-virt

[Peter Maydell]

On 1 February 2018 at 17:28, Wei Huang <address@hidden> wrote:
> Unlike most other QEMU architectures, the default machine type for
> mach-virt is not set.

This is deliberate. There is no single "right" choice for
a machine type for Arm boards. We had a bunch of problems
back when we did have a default type, because it was the
ancient integratorcp board, and users got confused expecting
QEMU to just work without specifying a machine type.

> This causes problems in situations where the
> default machine types are not provided (e.g. qtest_start() function
> in many QEMU tests). This patch designates the latest mach-virt
> machine type (alias of "virt") as the default machine type. It also
> changes the default CPU depending on the target.

> +#ifdef TARGET_AARCH64
> +    mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-a57");
> +#else
>      mc->default_cpu_type = ARM_CPU_TYPE_NAME("cortex-a15");
> +#endif

This makes the behaviour be different depending whether you're
running qemu-system-arm or qemu-system-aarch64. The two are
supposed to behave the same way if you give them the same
command line options (like x86 QEMU).


thanks
-- PMM