Re: [Qemu-devel] [PATCH v5] target-i386: Register QOM properties for feature flags

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 14 Apr 2015 12:28:24 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> This uses the feature name arrays to register QOM properties for feature
> flags. This simply adds properties that can be configured using -global,
> but doesn't change x86_cpu_parse_featurestr() to use them yet.
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v1 -> v2:
> * Use "cpuid-" prefix instead of "feat-"
> * Register release function for property
> * Convert '_' to '-' on feature name before registering property
> * Add dev->realized check to property setter
> 
> Changes v2 -> v3:
> * Register alias properties for feature name aliases
> * Patch is based on x86 tree, at:
>   https://github.com/ehabkost/qemu.git x86
> 
> Changes v3 -> v4:
> * Remove "cpuid-" prefix altogether
> 
> Changes v4 -> v5:
> * Coding style changes (mostly blank lines after variable declarations)
> * Change feature property registration to be a generic "bit property"
>   registration function
> * Check for visitor errors on bit property setter
> * Rename "bit" variables to "bitnr"
> * Get bitnr as argument to bit property registration function, instead
>   of mask
> ---
>  target-i386/cpu.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 121 insertions(+)
> 
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 3305e09..9b11208 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2841,12 +2841,125 @@ out:
>      }
>  }
>  
> +typedef struct BitProperty {
> +    uint32_t *ptr;
> +    uint32_t mask;
> +} BitProperty;
> +
> +static void x86_cpu_get_bit_prop(Object *obj,
> +                                 struct Visitor *v,
> +                                 void *opaque,
> +                                 const char *name,
> +                                 Error **errp)
> +{
> +    BitProperty *fp = opaque;
> +    bool value = (*fp->ptr & fp->mask) == fp->mask;
> +    visit_type_bool(v, &value, name, errp);
> +}
> +
> +static void x86_cpu_set_bit_prop(Object *obj,
> +                                 struct Visitor *v,
> +                                 void *opaque,
> +                                 const char *name,
> +                                 Error **errp)
> +{
> +    DeviceState *dev = DEVICE(obj);
> +    BitProperty *fp = opaque;
> +    Error *local_err = NULL;
> +    bool value;
> +
> +    if (dev->realized) {
> +        qdev_prop_set_after_realize(dev, name, errp);
> +        return;
> +    }
> +
> +    visit_type_bool(v, &value, name, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
> +
> +    if (value) {
> +        *fp->ptr |= fp->mask;
> +    } else {
> +        *fp->ptr &= ~fp->mask;
> +    }
> +}
> +
> +static void x86_cpu_release_bit_prop(Object *obj, const char *name,
> +                                         void *opaque)
indent went astray ^^^

> +{
> +    BitProperty *prop = opaque;
> +    g_free(prop);
> +}
> +
> +/* Register a boolean property to get/set a single bit in a uint32_t field.
> + *
> + * The same property name can be registered multiple times to make it affect
> + * 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,
> +                                      const char *prop_name,
> +                                      uint32_t *field,
> +                                      int bitnr)
> +{
> +    BitProperty *fp;
> +    ObjectProperty *op;
> +    uint32_t mask = (1UL << bitnr);
> +
> +    op = object_property_find(OBJECT(cpu), prop_name, NULL);
> +    if (op) {
> +        fp = op->opaque;
> +        assert(fp->ptr == field);
> +        fp->mask |= mask;
> +    } else {
> +        fp = g_new0(BitProperty, 1);
> +        fp->ptr = field;
> +        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, &error_abort);
> +    }
> +}
> +
> +static void x86_cpu_register_feature_bit_props(X86CPU *cpu,
> +                                               FeatureWord w,
> +                                               int bitnr)
> +{
> +    Object *obj = OBJECT(cpu);
> +    int i;
> +    char **names;
> +    FeatureWordInfo *fi = &feature_word_info[w];
> +
> +    if (!fi->feat_names) {
> +        return;
> +    }
> +    if (!fi->feat_names[bitnr]) {
> +        return;
> +    }
> +
> +    names = g_strsplit(fi->feat_names[bitnr], "|", 0);
> +
> +    feat2prop(names[0]);
> +    x86_cpu_register_bit_prop(cpu, names[0], &cpu->env.features[w], bitnr);
> +
> +    for (i = 1; names[i]; i++) {
> +        feat2prop(names[i]);
> +        object_property_add_alias(obj, names[i], obj, names[0], &error_abort);
> +    }
> +
> +    g_strfreev(names);
> +}
> +
>  static void x86_cpu_initfn(Object *obj)
>  {
>      CPUState *cs = CPU(obj);
>      X86CPU *cpu = X86_CPU(obj);
>      X86CPUClass *xcc = X86_CPU_GET_CLASS(obj);
>      CPUX86State *env = &cpu->env;
> +    FeatureWord w;
>      static int inited;
>  
>      cs->env_ptr = env;
> @@ -2887,6 +3000,14 @@ static void x86_cpu_initfn(Object *obj)
>      cpu->apic_id = -1;
>  #endif
>  
> +    for (w = 0; w < FEATURE_WORDS; w++) {
> +        int bitnr;
> +
> +        for (bitnr = 0; bitnr < 32; bitnr++) {
> +            x86_cpu_register_feature_bit_props(cpu, w, bitnr);
> +        }
> +    }
> +
>      x86_cpu_load_def(cpu, xcc->cpu_def, &error_abort);
>  
>      /* init various static tables used in TCG mode */

With comment above fixed,
Reviewed-by: Igor Mammedov <imammedo@redhat.com>