Re: [PATCH v2 3/4] target/arm/cpu64: Replace kvm_supported with sve_vq_supported

[Richard Henderson]

On 8/23/21 9:06 AM, Andrew Jones wrote:
> Now that we have an ARMCPU member sve_vq_supported we no longer
> need the local kvm_supported bitmap for KVM's supported vector
> lengths.
>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   target/arm/cpu64.c | 19 +++++++++++--------
>   1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
> index eb9318c83b74..557fd4757740 100644
> --- a/target/arm/cpu64.c
> +++ b/target/arm/cpu64.c
> @@ -265,14 +265,17 @@ void arm_cpu_sve_finalize(ARMCPU *cpu, Error **errp)
>        * any of the above.  Finally, if SVE is not disabled, then at least one
>        * vector length must be enabled.
>        */
> -    DECLARE_BITMAP(kvm_supported, ARM_MAX_VQ);
>       DECLARE_BITMAP(tmp, ARM_MAX_VQ);
>       uint32_t vq, max_vq = 0;
>   
> -    /* Collect the set of vector lengths supported by KVM. */
> -    bitmap_zero(kvm_supported, ARM_MAX_VQ);
> +    /*
> +     * CPU models specify a set of supported vector lengths which are
> +     * enabled by default.  Attempting to enable any vector length not set
> +     * in the supported bitmap results in an error.  When KVM is enabled we
> +     * fetch the supported bitmap from the host.
> +     */
>       if (kvm_enabled() && kvm_arm_sve_supported()) {
> -        kvm_arm_sve_get_vls(CPU(cpu), kvm_supported);
> +        kvm_arm_sve_get_vls(CPU(cpu), cpu->sve_vq_supported);
>       } else if (kvm_enabled()) {
>           assert(!cpu_isar_feature(aa64_sve, cpu));
>       }

I think this whole stanza should now be moved into kvm_arm_get_host_cpu_features, where we 
detect sve and fetch ID_AA64ZFR0_EL1.

As a separate patch, since this one is simply the variable rename.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~