Markus Armbruster <arm...@redhat.com> wrote: > Test compile gripes: > > hw/xen/xen-common.c: In function ‘xen_init’: > hw/xen/xen-common.c:147:5: warning: implicit declaration of function > ‘register_compat_prop’ [-Wimplicit-function-declaration] > register_compat_prop("migration", "store-global-state", "off"); > ^~~~~~~~~~~~~~~~~~~~ > hw/xen/xen-common.c:147:5: warning: nested extern declaration of > ‘register_compat_prop’ [-Wnested-externs] > > You might want to install Xen development packages to catch such issues > earlier. > > Test run: > > $ qemu-system-x86_64 -device migration,help > migration.skip-section-footer=bool > migration.store-global-state=bool > migration.only-migratable=bool > migration.skip-configuration=bool > > What would adding this device do?
Parameters, capabilities, options for migration. This was what we discussed on irc. We want to have a way to control migration features that depend on versions. So we disable new features for old machine types (normal thing that we do). But right now, creating such a new feature requires creating a couple of functions to set/clear the feature, adding includes on the destination side, etc. This was supposed to be a global property (or a qemu_opt, or whatever). Just something that could be enabled/disabled easily on machine types, and if possible independently of machine types. This (for instance) would allow that store-global-state is disabled by defaulte for machine-2.9 (I forgot the exact name for the machine type), but I can enable it by hand. That is very handy for testing. So, I think that the question is, how/where can we set that kind of properties? At least for me, being able to *also* set migration capabilities/parameters with this mechanism on the command line would be very nice, for instance -global migration.xbzrle on or -global migration.max-speed 2G I don't care about what is the exact syntax, or where we hang them, i.e. a new device, a new list, somewhere that already exist. That is what we ask for advice. Thanks for the review and the suggestions. Later, Juan.