On Tue, Aug 14, 2012 at 04:05:54PM +0200, Jan Kiszka wrote: > 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? > It can. -- Gleb. -- 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
