Am Dienstag 26 Mai 2009 09:57:58 schrieb Avi Kivity: > > I could add that behaviour, but that could make our normal interrupt > > handling much slower. Therefore I don't want to call that function, > > but on the other hand I like the "skip if the request is already set" > > functionality and think about adding that in my loop. > > I don't understand why it would affect your interrupt handling. We need As far as I understand x86, every host interrupt causes a guest exit. On s390 the SIE instruction is interruptible. On a host interrupt (like an IPI) the host interrupt handler runs and finally jumps back into the SIE instruction. The hardware will continue with guest execution. This has the advantage, that we dont have to load/save guest and host registers on host interrupts. (the low level interrupt handler saves the registers of the interrupted context) In our low-level interrupt handler we do check for signal_pending, machine_check_pending and need_resched to leave the sie instruction. For anything else a the host sees a cpu bound guest always in the SIE instruction. Christian -- 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
