Re: [PATCH 14/24] i386: Register feature bit properties as class properties

[Eduardo Habkost]

On Mon, Sep 21, 2020 at 06:10:35PM -0400, Eduardo Habkost wrote:
> Class properties make QOM introspection simpler and easier, as
> they don't require an object to be instantiated.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Eduardo Habkost <ehabkost@redhat.com>
> Cc: qemu-devel@nongnu.org
> ---
>  target/i386/cpu.c | 33 ++++++++++++++++-----------------
>  1 file changed, 16 insertions(+), 17 deletions(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 66792f28ba7..1aba87e0a5b 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -6819,16 +6819,17 @@ static void x86_cpu_release_bit_prop(Object *obj, 
> const char *name,
>   * multiple bits in the same FeatureWord. In that case, the getter will 
> return
>   * true only if all bits are set.
>   */
> -static void x86_cpu_register_bit_prop(X86CPU *cpu,
> +static void x86_cpu_register_bit_prop(X86CPUClass *xcc,
>                                        const char *prop_name,
>                                        FeatureWord w,
>                                        int bitnr)
>  {
> +    ObjectClass *oc = OBJECT_CLASS(xcc);
>      BitProperty *fp;
>      ObjectProperty *op;
>      uint64_t mask = (1ULL << bitnr);
>  
> -    op = object_property_find(OBJECT(cpu), prop_name, NULL);
> +    op = object_class_property_find(oc, prop_name, NULL);
>      if (op) {
>          fp = op->opaque;
>          assert(fp->w == w);
> @@ -6837,14 +6838,14 @@ static void x86_cpu_register_bit_prop(X86CPU *cpu,
>          fp = g_new0(BitProperty, 1);
>          fp->w = w;
>          fp->mask = mask;
> -        object_property_add(OBJECT(cpu), prop_name, "bool",
> -                            x86_cpu_get_bit_prop,
> -                            x86_cpu_set_bit_prop,
> -                            x86_cpu_release_bit_prop, fp);
> +        object_class_property_add(oc, prop_name, "bool",
> +                                  x86_cpu_get_bit_prop,
> +                                  x86_cpu_set_bit_prop,
> +                                  x86_cpu_release_bit_prop, fp);

This one is broken.  x86_cpu_release_bit_prop() frees fp, and
now fp should never be freed.  The release function shouldn't be
set.

I will send a new version of this patch later.

> [...]

-- 
Eduardo