On Mon, Jul 30, 2012 at 07:12:15PM -0600, Alex Williamson wrote: > > > > > > > kvm_eoifd.fd specifies the eventfd used for > > > > > > > +notification. KVM_EOIFD_FLAG_DEASSIGN is used to de-assign an eoifd > > > > > > > +once assigned. KVM_EOIFD also requires additional bits set in > > > > > > > +kvm_eoifd.flags to bind to the proper interrupt line. The > > > > > > > +KVM_EOIFD_FLAG_LEVEL_IRQFD indicates that kvm_eoifd.key is provided > > > > > > > +and is a key from a level triggered interrupt (configured from > > > > > > > +KVM_IRQFD using KVM_IRQFD_FLAG_LEVEL). The EOI notification is bound > > > > > > > +to the same GSI and irqchip input as the irqfd. Both kvm_eoifd.key > > > > > > > +and KVM_EOIFD_FLAG_LEVEL_IRQFD must be specified on assignment and > > > > > > > +de-assignment of KVM_EOIFD. A level irqfd may only be bound to a > > > > > > > +single eoifd. KVM_CAP_EOIFD_LEVEL_IRQFD indicates support of > > > > > > > +KVM_EOIFD_FLAG_LEVEL_IRQFD. > > > > > > > > > > > > > > > > > > > Hmm returning the key means we'll need to keep refcounting for source > > > > > > IDs around forever. I liked passing the fd better: make implementation > > > > > > match interface and not the other way around. > > > > > > > > > > False, a source ID has a finite lifecycle. The fd approach was broken. > > > > > Holding the irqfd context imposed too many dependencies between eoifd > > > > > and irqfd necessitating things like one interface disabling another. I > > > > > thoroughly disagree with that approach. > > > > > > > > You keep saying this but it is still true: once irqfd > > > > is closed eoifd does not get any more interrupts. > > > > > > How does that matter? > > > > Well if it does not get events it is disabled. > > so you have one ifc disabling another, anyway. > > And a level irqfd without an eoifd can never be de-asserted. Either we > make modular components, assemble them to do useful work, and > disassemble them independently so they can be used by future interfaces > or we bundle eoifd as just an option of irqfd. Which is it gonna be? I'm fine just making it an option. I think Gleb wanted a separate EOIFD to handle timedrift but it later seemed that eventfd is not suitable for that? -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
