On Thu, Mar 12, 2026 at 01:25:04PM +0800, Yanfei Xu wrote: > > On Wed, Mar 11, 2026 at 01:16:58PM +0800, Yanfei Xu wrote: > > > /old-style vmstate doesn't use vmsd and instead rely on SaveStateEntry/ > > > /ops. Check is_active for old-style vmstate to determine whether they/ > > > /should be skipped during migration./ > > > > Would you please dscribe the use case? > > > > We only have two users in upstream tree that provided is_active(), and > > neither of them provided save_state(). IOW, so far it works kind of mutual > > exclusively v.s. save_state(), afaict. > > Sorry for the lack of background information. > > We follow the vfio SaveVMHandlers and add an extra vfio SaveVMHandlers > variant with is_active. In our internal codebase, we set it inactive > during migration but active in a specific scenario. > > You are right that upstream tree works well. I sent this patch because I > assumed the semantics of is_active is similiar to the "needed" field in > vmsd. > > I'd like to get your opinion on this. Perhaps this case we used won't > occur in upstream?
Thanks for explaining. That makes sense on its own, but I think you're also correct since it won't occur in upstream then it means we're adding dead code into upstream code that has zero use. I suggest you stick your patch with your downstream, until you plan to upstream the whole thing. -- Peter Xu
