Re: [Qemu-devel] [PATCH 4/9] target-i386: convert 'hv_relaxed' to static property

[Eduardo Habkost]

On Wed, Feb 20, 2013 at 10:03:37AM +0100, Igor Mammedov wrote:
> On Tue, 19 Feb 2013 15:45:16 -0300
> Eduardo Habkost <address@hidden> wrote:
> 
> > On Mon, Feb 11, 2013 at 05:35:06PM +0100, Igor Mammedov wrote:
> > > Signed-off-by: Igor Mammedov <address@hidden>
> > > ---
> > >  target-i386/cpu.c |   35 ++++++++++++++++++++++++++++++++++-
> > >  1 files changed, 34 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > > index 1f14b65..b804031 100644
> > > --- a/target-i386/cpu.c
> > > +++ b/target-i386/cpu.c
> > > @@ -528,6 +528,38 @@ PropertyInfo qdev_prop_spinlocks = {
> > >      .defval =
> > > _defval                                                          \ }
> > >  
> > > +static void x86_get_hv_relaxed(Object *obj, Visitor *v, void *opaque,
> > > +                                 const char *name, Error **errp)
> > > +{
> > > +    bool value = hyperv_relaxed_timing_enabled();
> > > +
> > > +    visit_type_bool(v, &value, name, errp);
> > > +}
> > > +
> > > +static void x86_set_hv_relaxed(Object *obj, Visitor *v, void *opaque,
> > > +                                 const char *name, Error **errp)
> > > +{
> > > +    bool value;
> > > +
> > > +    visit_type_bool(v, &value, name, errp);
> > > +    if (error_is_set(errp)) {
> > > +        return;
> > > +    }
> > > +    hyperv_enable_relaxed_timing(value);
> > > +}
> > > +
> > > +PropertyInfo qdev_prop_hv_relaxed = {
> > > +    .name  = "boolean",
> > > +    .get   = x86_get_hv_relaxed,
> > > +    .set   = x86_set_hv_relaxed,
> > > +};
> > > +#define DEFINE_PROP_HV_RELAXED(_n, _defval)
> > > {                                  \
> > > +    .name  =
> > > _n,                                                               \
> > > +    .info  =
> > > &qdev_prop_hv_relaxed,                                            \
> > > +    .qtype =
> > > QTYPE_QBOOL,                                                      \
> > > +    .defval =
> > > _defval                                                          \ +}
> > > +
> > >  static Property cpu_x86_properties[] = {
> > >      DEFINE_PROP_FAMILY("family"),
> > >      DEFINE_PROP_MODEL("model"),
> > > @@ -538,6 +570,7 @@ static Property cpu_x86_properties[] = {
> > >      DEFINE_PROP_MODEL_ID("model-id"),
> > >      DEFINE_PROP_TSC_FREQ("tsc-frequency"),
> > >      DEFINE_PROP_HV_SPINLOCKS("hv-spinlocks",
> > > HYPERV_SPINLOCK_NEVER_RETRY),
> > > +    DEFINE_PROP_HV_RELAXED("hv-relaxed", false),
> > 
> > Why not simply make it a X86CPU struct field, so we don't need a special
> > PropertyInfo?
> > 
> > The whole contents of target-i386/hyperv.c are getters/setters for three
> > static variables that should have been X86CPU fields in the first place.
> I went via less intrusive approach to avoid breaking anything during
> conversion. Can we proceed with conversion first and than decide whether to
> move hv_* into CPU or not?

Personally, I find the complex getter+setter+PropertyInfo+DEFINE_PROP_*
code above more complex and harder to review (thus harder to make me
confident it won't break anything) than simply moving a static variable
to a X86CPU field.

Also, it doesn't even make sense to have a X86CPU property available for
a static variable that is not per-CPU. What do we gain by making it look
like a per-X86CPU property if it is not?


> 
> > 
> > 
> > >      DEFINE_PROP_END_OF_LIST(),
> > >   };
> > >  
> > > @@ -1468,7 +1501,7 @@ static void cpu_x86_parse_featurestr(X86CPU *cpu,
> > > char *features, Error **errp) } else if (!strcmp(featurestr, "enforce")) {
> > >              check_cpuid = enforce_cpuid = 1;
> > >          } else if (!strcmp(featurestr, "hv_relaxed")) {
> > > -            hyperv_enable_relaxed_timing(true);
> > > +            object_property_parse(OBJECT(cpu), "on", "hv-relaxed", errp);
> > >          } else if (!strcmp(featurestr, "hv_vapic")) {
> > >              hyperv_enable_vapic_recommended(true);
> > >          } else {
> > > -- 
> > > 1.7.1
> > > 
> > > 
> > 
> 

-- 
Eduardo