Re: [Qemu-devel] [PATCH v4 02/18] target-i386: Simplify reporting of unavailable features

[Eduardo Habkost]

On Thu, May 15, 2014 at 02:21:12PM +0200, Andreas Färber wrote:
> Am 30.04.2014 18:48, schrieb Eduardo Habkost:
> > Instead of checking and calling unavailable_host_feature() once for each
> > bit, simply call the function (now renamed to
> > report_unavailable_features()) once for each feature word.
> > 
> > Signed-off-by: Eduardo Habkost <address@hidden>
> > ---
> > Changes v1 -> v2:
> >  * Rebase to latest qom-cpu (commit 90c5d39c)
> > Changes v2 -> v3:
> >  * Trivial rebase after QEMU 2.0 (onto commit 2d03b49)
> > ---
> >  target-i386/cpu.c | 16 +++++++---------
> >  1 file changed, 7 insertions(+), 9 deletions(-)
> > 
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index 7ec706f..9cd0039 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -1236,11 +1236,11 @@ static const TypeInfo host_x86_cpu_type_info = {
> >  
> >  #endif
> >  
> > -static int unavailable_host_feature(FeatureWordInfo *f, uint32_t mask)
> > +static int report_unavailable_features(FeatureWordInfo *f, uint32_t mask)
> >  {
> >      int i;
> >  
> > -    for (i = 0; i < 32; ++i)
> > +    for (i = 0; i < 32; ++i) {
> >          if (1 << i & mask) {
> >              const char *reg = get_register_name_32(f->cpuid_reg);
> >              assert(reg);
> > @@ -1249,8 +1249,8 @@ static int unavailable_host_feature(FeatureWordInfo 
> > *f, uint32_t mask)
> >                  f->cpuid_eax, reg,
> >                  f->feat_names[i] ? "." : "",
> >                  f->feat_names[i] ? f->feat_names[i] : "", i);
> > -            break;
> >          }
> > +    }
> >      return 0;
> >  }
> >  
> > @@ -1274,12 +1274,10 @@ static int kvm_check_features_against_host(KVMState 
> > *s, X86CPU *cpu)
> >          uint32_t host_feat = kvm_arch_get_supported_cpuid(s, wi->cpuid_eax,
> >                                                               wi->cpuid_ecx,
> >                                                               
> > wi->cpuid_reg);
> > -        uint32_t mask;
> > -        for (mask = 1; mask; mask <<= 1) {
> > -            if (guest_feat & mask && !(host_feat & mask)) {
> > -                unavailable_host_feature(wi, mask);
> > -                rv = 1;
> > -            }
> > +        uint32_t unavailable_features = guest_feat & ~host_feat;
> > +        if (unavailable_features) {
> > +            report_unavailable_features(wi, unavailable_features);
> > +            rv = 1;
> >          }
> >      }
> >      return rv;
> 
> Both before and after your patch the return value is never checked.
> Shall we/I change it to void?

I will change this on my tree, but feel free to change my patch before
applying, if you prefer.

Thanks,

-- 
Eduardo