> - You discuss interrupt delivery without stating that you have MSIs in > mind. Some aspects may be helpful for legacy interrupts as well, but > you obviously can't achieve exit-less operation there. Not an issue, > should just be made clear. Can you eleborate on why exit-less operation cannot be achieved without MSI? Doesn't the VMCS flag to avoid exiting on external interrupts apply to any interrupts? Or something else won't work? In any case, you're right that our implementation and tests all used MSI. > > need paravirtualize the guest: no if you have x2APIC. > > ...and the guest makes use of it. This excludes older OSes. When did > Windows start to use it? Iff you can't use x2APIC, and don't want to paravirtualize the guest, you still get exit-less interrupt *delivery*, which as we showed in the benchmarks, gets you more than half of the performance improvement (although with newer KVM's improvement in EOI emulation performance, the over-half improvement should be somewhat less pronounced). Nadav. -- 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
