Re: [RFC PATCH v4 01/15] target/arm: Move 64-bit TCG CPUs into tcg/

[Fabiano Rosas]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 1/19/23 03:54, Fabiano Rosas wrote:
>> Move the 64-bit CPUs that are TCG-only:
>> - cortex-a35
>> - cortex-a55
>> - cortex-a72
>> - cortex-a76
>> - a64fx
>> - neoverse-n1
>> 
>> Keep the CPUs that can be used with KVM:
>> - cortex-a57
>> - cortex-a53
>> - max
>> - host
>
> All of those cpus can be used with kvm, if and only if you have matching 
> hardware.  There 
> is no rationale for considering any of them differently.

But is that allowed by QEMU today? If so I must be missing something. I
see that kvm_arch_init_vcpu looks at cpu->kvm_target, which is only set
at kvm_arm_set_cpu_features_from_host, called from aarch64_host_initfn.

    if (cpu->kvm_target == QEMU_KVM_ARM_TARGET_NONE ||
        !object_dynamic_cast(OBJECT(cpu), TYPE_AARCH64_CPU)) {
        error_report("KVM is not supported for this guest CPU type");
        return -EINVAL;
    }