Andi Kleen <ak@xxxxxxx> writes: >> >> I think we should be intercepting this startup call at a higher level, >> where we can just say: Start secondary cpu with this stack >> and with this esp. Or something like that. > > The reason VMI tends to thing lower level is that most of its > interfaces are like real hardware and of the code > would be just copied then if it did high level interfaces. > > I suspect this specific hook could only be made better if > smpboot.c was refactored into more pieces and callable, but I doubt > that would be a big overall improvement. We have to functions do_boot_cpu that does all of the basic setup. And wakeup_secondary_cpu that does the arch specific stuff to setup a cpu. (That is the current pre paravirt factoring). Guess what. Instead of making the hook wakeup_secondary_cpu. The hook is lost in the guts of one of the implementations of wakeup_secondary_cpu. Where the variable it wants t pass are not even available except as globals. It's ridiculous. We should have init_wakeup_secondary_cpu, nmi_wakeup_secondary_cpu, and vmi_wakeup_secondary_cpu. Having init_wakeup_secondary_cpu and vmi_wakeup_secondary_cpu share code looks like a strong false code sharing, and a major code pain. Further it skips the early setup in head.S, which is wrong. Either we need to do it or it needs to be removed from the smp startup path in head.S Further because it doesn't expose the difference at the same place we setup parameters and do something subtle and sneaky it is very easy to overlook and I suspect it is going to break just as often as voyager, because it is hard to see that the dependencies are there. So yes this is a real problem, and maybe we need to do a little refactoring to make it better because it doesn't need the initial boot code page. But there is no way it is a good long term solution the way it is. I doubt it does the correct thing to begin with. Eric _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
