On Thu, 2007-06-21 at 22:57 +0800, Dong, Eddie wrote: > Gregory Haskins wrote: > > > So assuming this newly enlightened position is true, I think this > > means we have a choice: > > > > 1) Drop support for mixed "level-1" mode and move the PIC to the > > kernel now as Eddie is doing > > > > 2) Keep the level-1/2 distinction, and add support for making sure > > that once a vector is acked in the PIC, it truely gets put into > > service immediately. > > > > I can think of a really simple interface for (2). All we > > really need to > > do is > > > > a) go back to synchronous injection (as previously suggested) > > For level-2 support, that means no PIC/APIC in user space, it is the > device want to assert/dessert an irq line request. There is no notion > of injecting IRQ. That is why I added new APIs. > Even with level-1 in consideration, we still need these new APIs to > support level-2. A device such as kerboard could frequently assert > and dessert the irq line. A single ker strobe will see 5-10 dessert > request from device model and 1 assert request. > > So new APIs are a must IMO.
Fully agree, but I already added them as well ;) 1) KVM_ISA_INTERRUPT: In level-1 mode, this API allows the userspace pic to dispatch a vector to the kernel. In level-2 mode, this allows any userspace app to tickle an isa based irq line (which feeds into the inputs of the PIC and IOAPIC. In other words, a level-2 based userspace would substitute KVM_ISA_INTERRUPT for pic_set_irq(). 2) KVM_APIC_MESSAGE allows any entity (presumably an IOAPIC in userspace, though there is no restriction here) to send APIC messages. This will probably only be used in level-1 mode, but its there for both modes nonetheless. -Greg ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
