On Sun, Oct 27, 2019 at 07:11:17PM -0400, Luwei Kang wrote: > For PEBS output to Intel PT, a Intel PT event should be the group > leader of an PEBS counter event in host. For Intel PT > virtualization enabling in KVM guest, the PT facilities will be > passthrough to guest and do not allocate PT event from host perf > event framework. This is different with PMU virtualization. > > Intel new hardware feature that can make PEBS enabled in KVM guest > by output PEBS records to Intel PT buffer. KVM need to allocate > a event counter for this PEBS event without Intel PT event leader. > > This patch add event owner check for PEBS output to PT event that > only non-kernel event need group leader(PT). > > Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx> > --- > arch/x86/events/core.c | 3 ++- > include/linux/perf_event.h | 1 + > kernel/events/core.c | 2 +- > 3 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c > index 7b21455..214041a 100644 > --- a/arch/x86/events/core.c > +++ b/arch/x86/events/core.c > @@ -1014,7 +1014,8 @@ static int collect_events(struct cpu_hw_events *cpuc, struct perf_event *leader, > * away, the group was broken down and this singleton event > * can't schedule any more. > */ > - if (is_pebs_pt(leader) && !leader->aux_event) > + if (is_pebs_pt(leader) && !leader->aux_event && > + !is_kernel_event(leader)) indent fail, but also, I'm not sure I buy this. Surely pt-on-kvm has a perf event to claim PT for the vCPU context? Even if not, this is not strictly correct. Not even now is KVM the sole user of perf_event_create_kernel_counter(), so saying any kernel event is excempt from this scheduling constraint is jsut wrong. > return -EINVAL; > > /*
