* Vadim Galitsyn (vadim.galit...@profitbricks.com) wrote: > Hi Guys, > > This thread is a continuation of discussion started in > http://lists.nongnu.org/archive/html/qemu-devel/2017-02/msg03182.html. > > This series introduces ‘writeconfig’ command support for QMP and HMP > monitors. This functionality might be useful for live migration for cases > when guest configuration was modified in runtime (for example as a result of > hot- plug/unplug operations) and actual Qemu command line no longer reflects > setup exposed to guest. > > Original series has ‘qemu_opts’ patch as well > (http://lists.nongnu.org/archive/html/qemu-devel/2017-02/msg03183.html) > because HMP’s ‘object_add’ result was not reflected in ‘writeconfig’ output. > Later I found that QMP’s ‘object-add’ has the same issue. Anyway, I don’t > include ‘qemu_opts’ patches here because Markus mentioned (here > http://lists.nongnu.org/archive/html/qemu-devel/2017-02/msg03476.html) that > this functionality is going to be reworked in some future and such patches > might collide with the rework process. > > Markus, could you please post if you have an update on this topic? Current > ‘master’ branch (9993c82dc2f5ce58b41d708b765e1a717ad4281d) still has the > issue. > > Also, Markus mentioned that once configuration was changed during live > migration -- it might be an issue because ‘writeconfig’ data became outdated > (and might be make sense to think about to embed this data into migration > stream itself). In the same time David said that this is another problem > which is unrelated to this patch series. What is your current opinion on this > topic? Can we consider these patches to be included into ‘master’ taking into > account that not all configuration is dumped by ‘writeconfig’ (‘object_add’ > problem), but this can be fixed later?
I don't see anything wrong with having a 'writeconfig' command - we already have the command line equivalent - that is assuming hotplug etc all cause the values written to be correct. The data becoming outdated doesn't sound like a big issue to me; it's the management layer that's doing any hotplugs, it can reissue another 'writeconfig' command. Dave > > Best regards, > Vadim > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
