Re: [Qemu-devel] [RFC 20/20] target-i386: move default init of cpuid_kvm_features bitmap into CPU initializer from cpudef

[Eduardo Habkost]

On Wed, Aug 15, 2012 at 02:23:46PM +0200, Igor Mammedov wrote:
> On Fri, 10 Aug 2012 12:24:48 -0300
> Eduardo Habkost <address@hidden> wrote:
> 
> > On Fri, Aug 10, 2012 at 01:22:36PM +0200, Igor Mammedov wrote:
> > > Moving it inside CPU initializer from cpudef will help to split
> > > cpu_x86_find_by_name() into default init and user settable properties.
> > > 
> > > PS:
> > >   Is kvm_features field necessary in cpudef, what the point
> > >   if it's almost imediately overwritten to ~0? Could it be removed
> > >   from cpudef?
> > 
> > We could probably drop it, but: maybe better than dropping it is to
> > initialize it properly with all the currently-supported KVM feature
> > flags, instead of initializing it to ~0 and then filter the bits later.
> > Otherwise "-cpu enforce" would not be able to check the KVM feature bits
> > properly.
> Looking at current core, It should be doable, lets postpone it to a separate
> series.
> For now lets keep it initialized to ~0 and plan to improve it later.

Agreed. Let's move one step at a time. The good thing is that the
cleanup is making those weird exceptions in the code easier to spot.

> 
> > 
> > > 
> > > Signed-off-by: Igor Mammedov <address@hidden>
> > > ---
> > >  target-i386/cpu.c | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > > index 43601a3..e266792 100644
> > > --- a/target-i386/cpu.c
> > > +++ b/target-i386/cpu.c
> > > @@ -1093,6 +1093,9 @@ static void cpudef_2_x86_cpu(X86CPU *cpu, x86_def_t 
> > > *def, Error **errp)
> > >      env->cpuid_7_0_ebx = def->cpuid_7_0_ebx_features;
> > >      env->cpuid_xlevel2 = def->xlevel2;
> > >  
> > > +    /* not supported bits will be filtered out later */
> > > +    env->cpuid_kvm_features = ~0;
> > > +
> > >      object_property_set_bool(OBJECT(cpu), true, "hypervisor", errp);
> > >  }
> > >  
> > > @@ -1175,9 +1178,6 @@ static int cpu_x86_find_by_name(X86CPU *cpu, 
> > > x86_def_t *x86_cpu_def,
> > >  
> > >      cpudef_2_x86_cpu(cpu, def, errp);
> > >  
> > > -    /* not supported bits will be filtered out later */
> > > -    env->cpuid_kvm_features = ~0;
> > > -
> > >      for (ent = qdict_first(features); ent; ent = qdict_next(features, 
> > > ent)) {
> > >          const QString *qval = qobject_to_qstring(qdict_entry_value(ent));
> > >          object_property_parse(OBJECT(cpu), qstring_get_str(qval),
> > > -- 
> > > 1.7.11.2
> > > 
> > 
> > -- 
> > Eduardo
> > 
> 
> 
> -- 
> Regards,
>   Igor

-- 
Eduardo