On 2011-02-03 17:20, Avi Kivity wrote: > On 02/03/2011 06:14 PM, Jan Kiszka wrote: >> On 2011-02-03 16:58, Avi Kivity wrote: >>> On 02/03/2011 05:55 PM, Jan Kiszka wrote: >>>>> >>>>> What's an interrupt window without IRET interception? >>>> >>>> I don't the details, but I thought you could get something like an >>>> interrupt-window-open interception by (fake-)injecting an IRQ and >>>> intercepting on VIRQ acceptance. That will not work if returning to and >>>> staying in irq-disabled guest code, therefore the timeout, but it should >>>> be most efficient (specifically if the guest uses NMIs for things like >>>> perf). >>>> >>> >>> Since NMIs are used to break out of irq-disabled regions (watchdog, NMI >>> IPIs during reboots) I'm wary of such a solution. >> >> Right, but we already use it for Intel. The timeout ensures that you >> can't get stuck forever. I think Xen works this way as well (minus the >> timeout - last time I checked). > > Only without vnmi support, yes? In that case, we can't do any better. > In this case, we can, and we should, even at the expense of performance > or ridiculous complexity. OK, then I guess we should explore the single-step approach and make it waterproof. It's likely still much simpler than iret emulation. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- 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
