Re: [Qemu-devel] [PATCH QEMU-XEN v4 7/9] xen: Use stable library interfaces when they are available.

[Ian Campbell]

On Fri, 2015-10-23 at 12:31 +0100, Stefano Stabellini wrote:
> > diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
> > index 2a5f27a..38293b4 100644
> > --- a/include/hw/xen/xen_common.h
> > +++ b/include/hw/xen/xen_common.h
> > @@ -6,6 +6,17 @@
> >  #include <stddef.h>
> >  #include <inttypes.h>
> >  
> > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 470
> > +/*
> > + * If we have new enough libxenctrl then we do not want/need these compat
> > + * interfaces, despite what the user supplied cflags might say. They
> > + * must be undefined before including xenctrl.h
> > + */
> > +#undef XC_WANT_COMPAT_EVTCHN_API
> > +#undef XC_WANT_COMPAT_GNTTAB_API
> > +#undef XC_WANT_COMPAT_MAP_FOREIGN_API
> > +#endif
> 
> Can we always do the #under given that earlier libxenctrl versions will
> simple ignore them? I am asking because I would prefer to avoid
> introducing another ifdef here outside the sequence if ifdefs already
> present below.

Ah yes, we can indeed.

Ian.