We are in same page now :-)
Gregory Haskins wrote: > 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
