Re: [Qemu-devel] QEMU build breakage on ARM against Xen 4.9 caused by libxendevicemodel

[Paul Durrant <Paul.Durrant@citrix.com>]

> -----Original Message-----
> From: Anthony PERARD [mailto:anthony.perard@citrix.com]
> Sent: 03 May 2017 17:49
> To: Stefano Stabellini <sstabellini@kernel.org>
> Cc: Paul Durrant <Paul.Durrant@citrix.com>; qemu-devel@nongnu.org; Wei
> Liu <wei.liu2@citrix.com>; xen-devel@lists.xenproject.org
> Subject: Re: QEMU build breakage on ARM against Xen 4.9 caused by
> libxendevicemodel
> 
> On Thu, Apr 20, 2017 at 11:05:33AM -0700, Stefano Stabellini wrote:
> > On Thu, 20 Apr 2017, Paul Durrant wrote:
> > > I think xencall should be part of the base xen_stable_libs anyway.
> >
> > Yes, you are right. However I noticed that -lxencall needs to come after
> > -lxendevicemodel. So, I'll have to move -lxendevicemodel before
> > $xen_stable_libs, see below. I'll merge this patch into "configure:
> > detect presence of libxendevicemodel", if that's OK.
> >
> > diff --git a/configure b/configure
> > index 99d6cbc..3133ef8 100755
> > --- a/configure
> > +++ b/configure
> > @@ -1992,7 +1992,7 @@ if test "$xen" != "no" ; then
> >    else
> >
> >      xen_libs="-lxenstore -lxenctrl -lxenguest"
> > -    xen_stable_libs="-lxenforeignmemory -lxengnttab -lxenevtchn"
> > +    xen_stable_libs="-lxencall -lxenforeignmemory -lxengnttab -
> lxenevtchn"
> >
> >      # First we test whether Xen headers and libraries are available.
> >      # If no, we are done and there is no Xen support.
> > @@ -2027,9 +2027,9 @@ int main(void) {
> >    return 0;
> >  }
> >  EOF
> > -        compile_prog "" "$xen_libs $xen_stable_libs -lxendevicemodel"
> > +        compile_prog "" "$xen_libs -lxendevicemodel $xen_stable_libs"
> >        then
> > -      xen_stable_libs="$xen_stable_libs -lxendevicemodel"
> > +      xen_stable_libs="-lxendevicemodel $xen_stable_libs"
> >        xen_ctrl_version=40900
> >        xen=yes
> >      elif
> 
> Hey, now that this patch is merged, xen.git fail to build QEMU. (osstest
> qemu-mainline branch fail.)
> 
> That's because -lxencall is not found because -L$path_to_libxencall is
> missing in xen.git.
> 
> But I've notice something else, libxendevicemodel.so is not linked
> against libxencall, that might be the root of the issues on arm.
> (libxenctrl.so is linked against libxencall.)
> 
> Thought?
> 

That's definitely an oversight. It should be linked against libxencall.

  Paul

> 
> We probably need this patch in xen:
> 
> diff --git a/tools/libs/devicemodel/Makefile
> b/tools/libs/devicemodel/Makefile
> index 55626a5049..81fa5a4ac4 100644
> --- a/tools/libs/devicemodel/Makefile
> +++ b/tools/libs/devicemodel/Makefile
> @@ -63,7 +63,7 @@ libxendevicemodel.so.$(MAJOR):
> libxendevicemodel.so.$(MAJOR).$(MINOR)
>         $(SYMLINK_SHLIB) $< $@
> 
>  libxendevicemodel.so.$(MAJOR).$(MINOR): $(PIC_OBJS)
> libxendevicemodel.map
> -       $(CC) $(LDFLAGS) $(PTHREAD_LDFLAGS) -Wl,$(SONAME_LDFLAG) -
> Wl,libxendevicemodel.so.$(MAJOR) $(SHLIB_LDFLAGS) -o $@ $(PIC_OBJS)
> $(LDLIBS_libxentoollog) $(APPEND_LDFLAGS)
> +       $(CC) $(LDFLAGS) $(PTHREAD_LDFLAGS) -Wl,$(SONAME_LDFLAG) -
> Wl,libxendevicemodel.so.$(MAJOR) $(SHLIB_LDFLAGS) -o $@ $(PIC_OBJS)
> $(LDLIBS_libxentoollog) $(LDLIBS_libxencall) $(APPEND_LDFLAGS)
> 
>  .PHONY: install
>  install: build
> 
> --
> Anthony PERARD