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

[Andrew Jones]

On Mon, Aug 23, 2021 at 10:53:48AM -0700, Richard Henderson wrote:
> 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.

Good idea. I'll do that for v3.

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

Thanks,
drew