On 2012-08-14 16:04, Avi Kivity wrote: > On 08/14/2012 05:00 PM, Jan Kiszka wrote: > >>>> The host can prevent this by leaving disabling the guest pmu. But >>>> disabling jump labels for real-time kernels may be acceptable too. We >>>> can probably to it at run time by forcing the slow path at all times. >>> Yes, it is possible to add module option that will force slow path if >>> needed. >> >> Should I write a patch or will you? Having host-side stop_machine due to >> such common guest operations is indeed a no-go for RT. >> > > Note that an additional patch is needed for perf, otherwise the guest > (or a user, but that's less of a concern for realtime) can easily invoke > stop_machine by configuring and unconfiguring its pmu. Hmm, can't the PMU be blocked by taking away some CPU features? Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE 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
