Re: [Qemu-devel] [PATCH v2] configure: use pkg-config for obtaining xen version

[Stefano Stabellini]

On Mon, 27 Mar 2017, Paul Durrant wrote:
> > -----Original Message-----
> > From: Juergen Gross [mailto:address@hidden
> > Sent: 27 March 2017 10:15
> > To: Paul Durrant <address@hidden>; address@hidden; xen-
> > address@hidden
> > Cc: Anthony Perard <address@hidden>; address@hidden;
> > address@hidden
> > Subject: Re: [PATCH v2] configure: use pkg-config for obtaining xen version
> > 
> > On 27/03/17 11:07, Paul Durrant wrote:
> > >> -----Original Message-----
> > >> From: Juergen Gross [mailto:address@hidden
> > >> Sent: 27 March 2017 08:43
> > >> To: address@hidden; address@hidden
> > >> Cc: Anthony Perard <address@hidden>; address@hidden;
> > >> address@hidden; Paul Durrant <address@hidden>; Juergen
> > >> Gross <address@hidden>
> > >> Subject: [PATCH v2] configure: use pkg-config for obtaining xen version
> > >>
> > >> Instead of trying to guess the Xen version to use by compiling various
> > >> test programs first just ask the system via pkg-config. Only if it
> > >> can't return the version fall back to the test program scheme.
> > >>
> > >> If configure is being called with dedicated flags for the Xen libraries
> > >> use those instead of the pkg-config output. This will avoid breaking
> > >> an in-tree Xen build of an old Xen version while a new Xen version is
> > >> installed on the build machine: pkg-config would pick up the installed
> > >> Xen config files as the Xen tree wouldn't contain any of them.
> > >>
> > >> Signed-off-by: Juergen Gross <address@hidden>
> > >> ---
> > >> V2: - use pkg-config only if no Xen library paths have been specified via
> > >>       --extra-ldflags
> > >>     - keep test program for detecting Xen 4.9
> > >
> > > This all looks plausible but it doesn't seem to be working for me when
> > trying to build 4.8. I'm still getting a xen ctrl version of 40900... still 
> > trying to
> > figure out why.
> > 
> > I suppose you reverted my previous patch?
> > 
> 
> Yes, I reverted that then applied this one.
> 
> > Do you happen to have some stale 4.9 libraries in your Xen tree?
> >
> 
> Yes, it was picking up a libxendevicemodel when it should not have been. It 
> would be handy if the probe compilations used --nostdlib, but that's not 
> regression introduced by your patch. Now that pkg-config is used for 
> out-of-tree builds I guess it may be possible to add that though.
>  
> > What happens without this patch?
> > 
> > > Also, the whitespace changes later on in the patch should probably be 
> > > split
> > out.
> > 
> > Hmm, those are just due to the nesting level of the if's changed.
> > I don't think they can easily be split out without having a
> > malformed indentation.
> > 
> 
> Ok, I see that now I look at the code rather than just the patch. So, having 
> fixed my linkage issue...
> 
> Tested-by: Paul Durrant <address@hidden>

Yes, that works.

Reviewed-by: Stefano Stabellini <address@hidden>