Re: [Xen-devel] [PATCH raisin 4/4] Update to 4.7, update qemu and qemu_traditional recipes

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Tue, Jun 14, 2016 at 03:00:12PM +0100, George Dunlap wrote:
> On 14/06/16 14:53, Anthony PERARD wrote:
> > On Tue, Jun 14, 2016 at 11:34:43AM +0100, George Dunlap wrote:
> >> That code might be in qemu-upstream, but it's not in the qemu-xen trees;
> >> if you revert this bit of the patch and try to build with raisin it will
> >> fail.  That's why I even bothered to add these in in the first place;
> >> and why IanC added these runes to tools/Makefile.
> >>
> >> Anthony, can you comment more authoritatively here on what's going on?
> > 
> > Yes, easy, xen-4.7 introduce a new API but qemu-xen-4.7 does not know
> > about it, so qemu-xen will fail to compile. But there are some magic
> > flags that are use to provide an compatible API and can qemu-xen
> > compile.
> > 
> > QEMU have been taught about the new API and will use it, without the
> > magic flags. QEMU will actually ignore the magic flags with a bunch of
> > #undef.
> 
> So wait, I'm confused.  Isn't qemu-xen supposed to be upstream qemu plus
> a handful of patches on top?  Or has there not been a QEMU release since
> the time the new API?

The first release to include the new stuff appear to be 2.6, which have
been released a month ago. So the answer is no.

> Why on earth are we shipping in 4.7 a qemu that
> can't use the new API we define in 4.7?

Who knows...

> >> Would it be possible for 4.7.1 to backport the configure auto-detection
> >> stuff?
> > 
> > I think that would be possible. But backporting the use of the new api
> > will probably be harder. I guess we could just have qemu-xen define the
> > magic flags itself instead of relying on them been given via a configure
> > option.
> 
> Well at this point it's a bit late to import support for the new API
> into qemu-xen-4.7; but it would be good for 4.7.1 to have qemu-xen's
> configure set the necessary flags rather than bodging them in via
> "--extra-cflags" in the Xen makefile.

Yes.

-- 
Anthony PERARD

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