> -----Original Message----- > From: Daniel P. Berrangé <berra...@redhat.com> > Sent: Monday, June 20, 2022 6:37 PM > To: Zhang, Chen <chen.zh...@intel.com> > Cc: Thomas Huth <th...@redhat.com>; Jason Wang > <jasow...@redhat.com>; qemu-dev <qemu-devel@nongnu.org>; Paolo > Bonzini <pbonz...@redhat.com>; Eduardo Habkost <edua...@habkost.net>; > Eric Blake <ebl...@redhat.com>; Markus Armbruster > <arm...@redhat.com>; Peter Maydell <peter.mayd...@linaro.org>; Laurent > Vivier <lviv...@redhat.com>; Yuri Benditovich > <yuri.benditov...@daynix.com>; Andrew Melnychenko > <and...@daynix.com> > Subject: Re: [RFC PATCH 01/12] configure: Add iovisor/ubpf project as a > submodule for QEMU > > On Mon, Jun 20, 2022 at 10:29:14AM +0000, Zhang, Chen wrote: > > > > > > > -----Original Message----- > > > From: Thomas Huth <th...@redhat.com> > > > Sent: Monday, June 20, 2022 5:44 PM > > > To: Zhang, Chen <chen.zh...@intel.com>; Daniel P. Berrangé > > > <berra...@redhat.com> > > > Cc: Jason Wang <jasow...@redhat.com>; qemu-dev <qemu- > > > de...@nongnu.org>; Paolo Bonzini <pbonz...@redhat.com>; Eduardo > > > Habkost <edua...@habkost.net>; Eric Blake <ebl...@redhat.com>; > > > Markus Armbruster <arm...@redhat.com>; Peter Maydell > > > <peter.mayd...@linaro.org>; Laurent Vivier <lviv...@redhat.com>; > > > Yuri Benditovich <yuri.benditov...@daynix.com>; Andrew Melnychenko > > > <and...@daynix.com> > > > Subject: Re: [RFC PATCH 01/12] configure: Add iovisor/ubpf project > > > as a submodule for QEMU > > > > > > On 20/06/2022 11.29, Zhang, Chen wrote: > > > > > > > > > > > >> -----Original Message----- > > > >> From: Thomas Huth <th...@redhat.com> > > > >> Sent: Monday, June 20, 2022 4:47 PM > > > >> To: Daniel P. Berrangé <berra...@redhat.com>; Zhang, Chen > > > >> <chen.zh...@intel.com> > > > >> Cc: Jason Wang <jasow...@redhat.com>; qemu-dev <qemu- > > > >> de...@nongnu.org>; Paolo Bonzini <pbonz...@redhat.com>; Eduardo > > > >> Habkost <edua...@habkost.net>; Eric Blake <ebl...@redhat.com>; > > > Markus > > > >> Armbruster <arm...@redhat.com>; Peter Maydell > > > >> <peter.mayd...@linaro.org>; Laurent Vivier <lviv...@redhat.com>; > > > >> Yuri Benditovich <yuri.benditov...@daynix.com>; Andrew > > > >> Melnychenko <and...@daynix.com> > > > >> Subject: Re: [RFC PATCH 01/12] configure: Add iovisor/ubpf > > > >> project as a submodule for QEMU > > > >> > > > >> On 20/06/2022 10.11, Daniel P. Berrangé wrote: > > > >>> On Mon, Jun 20, 2022 at 05:59:06AM +0000, Zhang, Chen wrote: > > > >>>> > > > >>>> > > > >>>>> -----Original Message----- > > > >>>>> From: Daniel P. Berrangé <berra...@redhat.com> > > > >>>>> Sent: Friday, June 17, 2022 4:05 PM > > > >>>>> To: Zhang, Chen <chen.zh...@intel.com> > > > >>>>> Cc: Jason Wang <jasow...@redhat.com>; qemu-dev <qemu- > > > >>>>> de...@nongnu.org>; Paolo Bonzini <pbonz...@redhat.com>; > > > >>>>> Eduardo Habkost <edua...@habkost.net>; Eric Blake > > > >>>>> <ebl...@redhat.com>; Markus Armbruster > <arm...@redhat.com>; > > > >>>>> Peter Maydell <peter.mayd...@linaro.org>; Thomas Huth > > > >>>>> <th...@redhat.com>; > > > >> Laurent > > > >>>>> Vivier <lviv...@redhat.com>; Yuri Benditovich > > > >>>>> <yuri.benditov...@daynix.com>; Andrew Melnychenko > > > >>>>> <and...@daynix.com> > > > >>>>> Subject: Re: [RFC PATCH 01/12] configure: Add iovisor/ubpf > > > >>>>> project as a submodule for QEMU > > > >>>>> > > > >>>>> On Fri, Jun 17, 2022 at 03:36:19PM +0800, Zhang Chen wrote: > > > >>>>>> Make iovisor/ubpf project be a git submodule for QEMU. > > > >>>>>> It will auto clone ubpf project when configure QEMU. > > > >>>>> > > > >>>>> I don't think we need todo this. As it is brand new > > > >>>>> functionality we don't have any back compat issues. We should > > > >>>>> just expect the distros to ship ubpf if they want their QEMU > > > >>>>> builds to take advantage > > > of it. > > > >>>>> > > > >>>> > > > >>>> Yes, agree. It's the best way to use the uBPF project. > > > >>>> But current status is distros(ubuntu, RHEL...) does not ship > > > >>>> the iovisor/ubpf like the iovisor/bcc. So I have to do it. > > > >>>> Or do you have any better suggestions? > > > >>> > > > >>> If distros want to support the functionality, they can add > > > >>> packages for it IMHO. > > > >> > > > >> Yes, let's please avoid new submodules. Submodules can sometimes > > > >> be a real PITA (e.g. if you forget to update before rsync'ing > > > >> your code to a machine that has limited internet access), and if > > > >> users install QEMU from sources, they can also install ubpf from > sources, too. > > > >> And if distros want to support this feature, they can package > > > >> ubpf on their own, as Daniel said. > > > > > > > > Hi Daniel and Thomas, > > > > > > > > I don't know much the background history of QEMU submodules, but > > > meson > > > > build is a submodule for QEMU too. It means user can't install > > > > QEMU from sources with limited internet access. > > > > > > There is no written policy, but I think the general consensus is > > > that we only ship code in submodules if: > > > > > > 1) It's not available in a required version in distros yet > > > > > > and > > > > > > 2) it is essentially required to build QEMU (like meson) or if the > > > feature has been part of the QEMU sources before and then moved to a > > > separate repository (like slirp). > > > > > > We ship meson as a submodule since we require some meson features > > > that are not available with the meson versions in the distros yet. > > > Once the distros catch up, we'll likely remove the meson submodule from > QEMU. > > > > > > > And back to Daniel's comments, Yes, the best way is distros add > > > > the ubpf packages, But maybe it's too late to implement new > > > > features for us. We can introduce the submodule now and auto > > > > change to the distros's > > > lib when distros add it. For example QEMU's submodule SLIRP do it > > > in the same way. > > > > > > slirp used to be part of the QEMU repository, but then has been > > > moved to a separate project a while ago. However, at that point in > > > time there weren't any packages ins distros yet, so we had to include it > > > as > a submodule. > > > > > > Now that the distros ship it, too, we're planning to remove the > > > slirp submodule from QEMU soon, see: > > > > > > > > > https://lists.gnu.org/archive/html/qemu-devel/2022-04/msg00974.html > > > > > > > It make user experience the latest technology with no other > > > > dependencies. > > > > > > Well, that's only true if we update the submodule in QEMU regularly. > > > If we forget to update, we could easily miss some important (maybe > > > even security > > > related) fixes from the upstream projects. This can be a nightmare > > > for distros, when they then have to go around and look into each and > > > every projects whether they embed a certain code module that needs a > > > CVE fix. It's better if it can be fixed in one central spot instead. > > > > > > > uBPF infrastructure have the ability to extend the capabilities > > > > without requiring changing source code. If we not allow it, we > > > > have to re-implement all the eBPF assembler, disassembler, > > > > interpreter, and JIT > > > compiler like DPDK userspace eBPF support (DPDK can't use ubpf > > > project by license issue). > > > > > > Not sure whether I understood that statement right ... nobody said > > > that QEMU should not allow it - we just suggested to rely on a > > > system installation of ubpf instead of embedding the code. Or is > > > that not possible?? (I don't know that project yet - isn't it > > > possible to compile it as a shared library?) > > > > Thanks for your details explanation. > > It looks better to introduce the uBPF shared library for QEMU. > > For example: > > ./configure --ubpf-lib=path > > I've not looked, so maybe it already does this, but ideally 'uBPF' > would ship a 'pkg-config' file, so that apps can automatically find it and > set > the right cflags/libs etc for the compiler. For configure integration, > normally > we'd expect it to be --enable-ubpf/--disable-ubpf, with it automatically > enabling itself if the pkg-config file is found. > Take a look at handling of some existing libraries we depend on for examples. >
OK, thanks your comments. I reviewed uBPF code, but no pkg-config file. The make install just copy the libubpf.so/.a to /usr/lib. Fortunately, writing this file looks easy. I will try to do it and make QEMU use the libubpf.so like "pixman". Thanks Chen > With regards, > Daniel > -- > |: https://berrange.com -o- > https://www.flickr.com/photos/dberrange :| > |: https://libvirt.org -o- https://fstop138.berrange.com :| > |: https://entangle-photo.org -o- > https://www.instagram.com/dberrange :|
