Arjan van de Ven wrote: >> Can't it be done by a helper function using a timer and a signal (or >> whatever mechanism we use to wake up vcpus)? >> > > one could do that but it's not optimal; if the process DOES get waken up > earlier, it should take the interrupt then immediately, so that it > doesn't have to wake up again when the timer fires. > > (in fact it would be nice if the guest could somehow poll at the irq > mask at waking from idle, so that it wouldn't need a vmexit/entry for > every such interrupt, but just do the right thing for all pending work) > > In addition, yes it'll be a helper function, but since all drivers will > want the functionality its probably best off in the generic code > >
That's what Xen does (I'm not sure about the timer, but they do avoid unnecessary interrupts). As you can have memory shared between the guest and host, it's quite simple: 0. host puts data in ring 1. host sets interrupt timer 2. guest wakes up for unrelated reasons 3. guest sees data in ring, consumes it, and bumps the consumer pointer 4. timer fires, host sees consumer == producer, no need to issue interrupt They have that code abstracted out and reusable by multiple drivers. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
