Re: [Qemu-devel] [PATCH 06/10] target-i386: print obsolete warnings if +-features are used

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 7 Jun 2016 14:36:51 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 07/06/2016 14:32, Igor Mammedov wrote:
> >> > Could you detect using +foo together with foo=off, and -foo together
> >> > with foo=on?  Those are the really problematic cases, without them +foo
> >> > and -foo can become synonyms for =on and =off.  
> > That's (legacy)current semantic of -cpu +-foo where it overrides any foo=x,
> > potentially it's possible to track foo=x locally in parser
> > and then compare with +-foo both ways.
> > But all we can do currently is to print warning about such use case.
> > 
> > I think Eduardo's suggestion to just warn that +-foo is obsolete for now
> > and drop support for it in several releases is sufficient(good) enough.  
> 
> kvm-unit-tests and libvirt both use it, especially because =on and =off
> are relatively new I think?  It seems like it's really widespread.
Yep, that's why it's not removed now.
Looks like libvirt would be able to switch to foo=x syntax,
I can take a look at kvm-unit-tests and make it use foo=x too.