[PATCH 10/11] perf intel-pt: Split VM-Entry and VM-Exit branches

From: Adrian Hunter
Date: Thu Feb 18 2021 - 06:29:49 EST


Events record a single cpumode so the tools cannot handle a branch from
the host machine to a virtual machine, or vice versa. Split it in two so
that each branch can have a different cpumode.

E.g. host ip -> guest ip

becomes: host ip -> 0
0 -> guest ip

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/util/intel-pt.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index cafb3943d5f6..f6e28ac231b7 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -2171,7 +2171,27 @@ static int intel_pt_sample(struct intel_pt_queue *ptq)
}

if (pt->sample_branches) {
- err = intel_pt_synth_branch_sample(ptq);
+ if (state->from_nr != state->to_nr &&
+ state->from_ip && state->to_ip) {
+ struct intel_pt_state *st = (struct intel_pt_state *)state;
+ u64 to_ip = st->to_ip;
+ u64 from_ip = st->from_ip;
+
+ /*
+ * perf cannot handle having different machines for ip
+ * and addr, so create 2 branches.
+ */
+ st->to_ip = 0;
+ err = intel_pt_synth_branch_sample(ptq);
+ if (err)
+ return err;
+ st->from_ip = 0;
+ st->to_ip = to_ip;
+ err = intel_pt_synth_branch_sample(ptq);
+ st->from_ip = from_ip;
+ } else {
+ err = intel_pt_synth_branch_sample(ptq);
+ }
if (err)
return err;
}
--
2.17.1