[Qemu-devel] Re: [Qemu-commits] [COMMIT 883ecbf] Remove noisy printf when KVMmasks CPU features

[Anthony Liguori]

Avi Kivity wrote:
> Anthony Liguori wrote:
> > From: Anthony Liguori <address@hidden>
> >
> > Signed-off-by: Anthony Liguori <address@hidden>
> >
> > diff --git a/target-i386/helper.c b/target-i386/helper.c
> > index bdf242b..5c03e3a 100644
> > --- a/target-i386/helper.c
> > +++ b/target-i386/helper.c
> > @@ -102,7 +102,6 @@ static void kvm_trim_features(uint32_t *features, 
> > uint32_t supported,
> >      for (i = 0; i < 32; ++i) {
> >          mask = 1U << i;
> >          if ((*features & mask) && !(supported & mask)) {
> > -            printf("Processor feature %s not supported by kvm\n", 
> > names[i]);
> >              *features &= ~mask;
> >          }
> >      }
> >   
>
> That was intentional, I didn't want to silently drop features the user 
> requested as those may impact live migration or load/save (or 
> application performance).

Why not provide a monitor option to view the list of CPUID features that 
are enabled?

printing to stdio is a bad idea.  We print the names of pty devices to 
stdio and tools have to parse that today.   I hope they're sufficiently 
robust but this isn't something we want to introduce if we don't have to.

> Maybe it's better to only do that if -cpu was specified on the command 
> line; and exit() as well.  The user can easily pick up the missing 
> bits and remove them from the requested cpu features.

Yes, that's also a good idea.

Regards,

Anthony Liguori


--
Regards,

Anthony Liguori