Re: [PATCH v4 2/4] hw/i386: Attach CPUs to machine

AFAIK, we've never defined anything about QOM paths wrt ABI one way or the other ? In the absence of guidelines then it comes down to what are reasonable expectations of the mgmt app. These expectations will be influenced by what it is actually possible to acheive given our API as exposed. I think it is unreasonable to expect /machine/unattached to be stable because by its very nature it is just a dumping ground for anything where the dev hasn't put in any thought to the path placement. IOW, it was/is definitely a bad idea for libvirt to rely on /machine/unattached in any way. That we're liable to be broken is not nice, but its really our own fault - we should have asked for a better solution from day one here. I think it is somewhat reasonable to expect other QOM paths to be stable as there's been some degree of thought put into their placement. If we don't want apps to be considering other paths to be stable, then we need to explain exactly what they can and can't rely on, and most importantly actually provide a way for them to do what they need