Paolo Bonzini <pbonz...@redhat.com> writes: > Il 21/02/2013 08:44, Paolo Bonzini ha scritto: >> Il 20/02/2013 22:03, Anthony Liguori ha scritto: >>> Paolo Bonzini <pbonz...@redhat.com> writes: >>> >>>> Il 20/02/2013 21:26, Anthony Liguori ha scritto: >>>>> Cole Robinson <crobi...@redhat.com> writes: >>>>> >>>>>> This switch will turn on all the migration compat bits needed to >>>>>> perform migration from qemu-kvm to qemu. It's just a stub for now. >>>>>> >>>>>> This compat will break incoming migration from qemu < 1.3, but for >>>>>> distros where qemu-kvm was the only shipped package for years it's >>>>>> not a big loss (and I don't know any way to avoid it). >>>>>> >>>>>> Signed-off-by: Cole Robinson <crobi...@redhat.com> >>>>> >>>>> This can't be a build time option. It's ugly and just reintroduces a >>>>> fork. >>>> >>>> It is not a fork; it does not change the migration format of QEMU >>>> itself, only the parsing of old VMState versions. The importance of the >>>> fork will dwindle over time, as the distros EOL the releases that used >>>> qemu-kvm. >>> >>> Once a distro enables CONFIG_QEMU_KVM, it must keep it enabled forever. >>> So the distros will contineut o do CONFIG_QEMU_KVM whereas upstream does >>> not set it. It's a fork all within the same tree. >> >> They will set it for a while. For example, F18 is the last Fedora >> release that had qemu-kvm < 1.3.0. As soon as F18 goes end-of-life >> (which is with F21), Fedora will not need to set the configure option >> anymore. >> >> Of course other distros will keep it for years rather than months, but >> the idea is the same. >> >>> What about having something processed by readconfig that wasn't disabled >>> by -nodefaults? Then we could make it a runtime option, but that's >>> configurable globally. Then the distros can choose the default value in >>> the config file. >>> >>> At least then, we can write unit tests with the option at run time, >>> don't need to sprinkle #ifdefs everywhere, etc. >> >> That would make sense, but it shouldn't block this patch. What would >> happen otherwise is that distros (who care about migration >> compatibility) will just patch their code without even the #ifdefs. >> It's already happening, these patches are in F18. > > Ping, where do we stand here? Shall we discuss it next Tuesday?
My only requirement for this patch series is that it *also* be made to be dynamically configurable. This should be toggable with a command line option and the default can be set by configure. At least that makes it testable with make check. Regards, Anthony Liguori > > Paolo
