Re: [Qemu-devel] [PATCH 07/13] target/arm/kvm: max cpu: Allow sve max vector length setting

[Richard Henderson]

On 5/12/19 1:36 AM, Andrew Jones wrote:
> @@ -292,7 +292,7 @@ static void aarch64_max_initfn(Object *obj)
>  
>      if (kvm_enabled()) {
>          kvm_arm_set_cpu_features_from_host(cpu);
> -        cpu->sve_max_vq = ARM_MAX_VQ;
> +        cpu->sve_max_vq = -1; /* set in kvm_arch_init_vcpu() */

Perhaps a better comment is "unspecified, to be finalized in ..."

> +    object_property_add(obj, "sve-max-vq", "uint32", cpu_max_get_sve_vq,
> +                        cpu_max_set_sve_vq, NULL, NULL, &error_fatal);

as one can set it here, via the command-line.

> @@ -644,6 +702,24 @@ int kvm_arch_init_vcpu(CPUState *cs)
>      }
>  
>      if (cpu->sve_max_vq) {
> +        uint64_t sve_vls[KVM_ARM64_SVE_VLS_WORDS];
> +        ret = kvm_arm_get_sve_vls(cs, sve_vls);
> +        if (ret < 0) {
> +            return ret;
> +        }
> +        if (cpu->sve_max_vq == -1) {
> +            cpu->sve_max_vq = ret;

You still cannot set a value larger than ARM_MAX_VQ, as that is the fixed
amount of space allocated within the cpu structure.


r~