On Thu, 23 Mar 2017 15:19:28 +0100 Paolo Bonzini <pbonz...@redhat.com> wrote:
> On 23/03/2017 14:55, Juergen Gross wrote: > > On 23/03/17 14:00, Greg Kurz wrote: > >> On Mon, 20 Mar 2017 11:19:05 -0700 > >> Stefano Stabellini <sstabell...@kernel.org> wrote: > >> > >>> Do not use the ring.h header installed on the system. Instead, import > >>> the header into the QEMU codebase. This avoids problems when QEMU is > >>> built against a Xen version too old to provide all the ring macros. > >>> > >>> Signed-off-by: Stefano Stabellini <stef...@aporeto.com> > >>> Reviewed-by: Greg Kurz <gr...@kaod.org> > >>> CC: anthony.per...@citrix.com > >>> CC: jgr...@suse.com > >>> --- > >>> NB: The new macros have not been committed to Xen yet. Do not apply this > >>> patch until they do. > >>> --- > >> > >> Looking at your other series for the kernel part of this feature: > >> > >> https://lkml.org/lkml/2017/3/22/761 > >> > >> I realize that the ring.h header from Xen also exists in the kernel > >> tree... > >> > >> Shouldn't all the code that can be used in both kernel and userspace go to > >> a > >> header file under include/uapi in the kernel tree ? And then we would > >> import > >> it under include/standard-headers/linux in the QEMU tree and we could keep > >> it > >> in sync using scripts/update-linux-headers.sh. > >> > >> Cc'ing Paolo for insights. > > > > As Xen isn't part of the kernel we don't want that. You can use and/or > > build qemu with xen-9pfs backend support on an old Linux kernel without > > the related frontend. > > As long as the header changes rarely, I guess it's fine not to go > through update-linux-headers.sh. > > Paolo > If the header (or at least the parts that are relevant to QEMU) are stable then my questioning can be ignored :) Thanks. -- Greg > > OTOH I don't see the advantage of not using the headers from Xen. This > > is working for qdisk and pvusb backends and for all the Xen libraries. > > Do you expect the 9pfs backend to be used for a qemu version built > > against a Xen version not supporting that backend? > > > > > > Juergen > >
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