On Mon, 2012-09-10 at 10:40 -0600, David Ahern wrote: > PEBS cannot be used with guest mode. See: > https://lkml.org/lkml/2012/7/9/264
Expanding and not relying on external stuff is so much better. So in particular you want something like: "Intel PEBS in VT-x context uses the DS address as a guest linear address, even though its programmed by the host as a host linear address. This either results in guest memory corruption and or the hardware faulting and 'crashing' the virtual machine Therefore we have to disable PEBS on VT-x enter and re-enable on VT-x exit, enforcing a strict exclude_guest. AMB IBS does work but doesn't currently support exclude_* at all, setting an exclude_* bit will make it fail. ... explain how one can use IBS if we auto-fallback to !precise ..." Hmm ? > If user adds :p modifier set exclude_guest as well. > > Signed-off-by: David Ahern <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Robert Richter <[email protected]> > Cc: Gleb Natapov <[email protected]> > Cc: Avi Kivity <[email protected]> > --- > tools/perf/util/parse-events.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c > index a031ee1..f2c02b2 100644 > --- a/tools/perf/util/parse-events.c > +++ b/tools/perf/util/parse-events.c > @@ -694,6 +694,9 @@ static int get_event_modifier(struct event_modifier *mod, > char *str, > eH = 0; > } else if (*str == 'p') { > precise++; > + /* use of precise requires exclude_guest */ > + if (!exclude_GH) > + eG = 1; > } else > break; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
