perf intel-pt: Add a tree for VMCS information

Even when VMX TSC Offset is not changing (during perf record), different
virtual machines can have different TSC Offsets. There is a Virtual Machine
Control Structure (VMCS) for each virtual CPU, the address of which is
reported to Intel PT in the VMCS packet. We do not know which VMCS belongs
to which virtual machine, so use a tree to keep track of VMCS information.
Then the decoder will be able to use the current VMCS value to look up the
current TSC Offset.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20210430070309.17624-9-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 66 insertions, 0 deletions

diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index a494d47aa1ad..8f6df8eec9b8 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -133,6 +133,9 @@ struct intel_pt {
 
 	struct ip_callchain *chain;
 	struct branch_stack *br_stack;
+
+	u64 dflt_tsc_offset;
+	struct rb_root vmcs_info;
 };
 
 enum switch_state {
@@ -271,6 +274,65 @@ static bool intel_pt_log_events(struct intel_pt *pt, u64 tm)
 	return !n || !perf_time__ranges_skip_sample(range, n, tm);
 }
 
+static struct intel_pt_vmcs_info *intel_pt_findnew_vmcs(struct rb_root *rb_root,
+							u64 vmcs,
+							u64 dflt_tsc_offset)
+{
+	struct rb_node **p = &rb_root->rb_node;
+	struct rb_node *parent = NULL;
+	struct intel_pt_vmcs_info *v;
+
+	while (*p) {
+		parent = *p;
+		v = rb_entry(parent, struct intel_pt_vmcs_info, rb_node);
+
+		if (v->vmcs == vmcs)
+			return v;
+
+		if (vmcs < v->vmcs)
+			p = &(*p)->rb_left;
+		else
+			p = &(*p)->rb_right;
+	}
+
+	v = zalloc(sizeof(*v));
+	if (v) {
+		v->vmcs = vmcs;
+		v->tsc_offset = dflt_tsc_offset;
+		v->reliable = dflt_tsc_offset;
+
+		rb_link_node(&v->rb_node, parent, p);
+		rb_insert_color(&v->rb_node, rb_root);
+	}
+
+	return v;
+}
+
+static struct intel_pt_vmcs_info *intel_pt_findnew_vmcs_info(void *data, uint64_t vmcs)
+{
+	struct intel_pt_queue *ptq = data;
+	struct intel_pt *pt = ptq->pt;
+
+	if (!vmcs && !pt->dflt_tsc_offset)
+		return NULL;
+
+	return intel_pt_findnew_vmcs(&pt->vmcs_info, vmcs, pt->dflt_tsc_offset);
+}
+
+static void intel_pt_free_vmcs_info(struct intel_pt *pt)
+{
+	struct intel_pt_vmcs_info *v;
+	struct rb_node *n;
+
+	n = rb_first(&pt->vmcs_info);
+	while (n) {
+		v = rb_entry(n, struct intel_pt_vmcs_info, rb_node);
+		n = rb_next(n);
+		rb_erase(&v->rb_node, &pt->vmcs_info);
+		free(v);
+	}
+}
+
 static int intel_pt_do_fix_overlap(struct intel_pt *pt, struct auxtrace_buffer *a,
 				   struct auxtrace_buffer *b)
 {
@@ -1109,6 +1171,7 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt,
 	params.get_trace = intel_pt_get_trace;
 	params.walk_insn = intel_pt_walk_next_insn;
 	params.lookahead = intel_pt_lookahead;
+	params.findnew_vmcs_info = intel_pt_findnew_vmcs_info;
 	params.data = ptq;
 	params.return_compression = intel_pt_return_compression(pt);
 	params.branch_enable = intel_pt_branch_enable(pt);
@@ -2970,6 +3033,7 @@ static void intel_pt_free(struct perf_session *session)
 	auxtrace_heap__free(&pt->heap);
 	intel_pt_free_events(session);
 	session->auxtrace = NULL;
+	intel_pt_free_vmcs_info(pt);
 	thread__put(pt->unknown_thread);
 	addr_filters__exit(&pt->filts);
 	zfree(&pt->chain);
@@ -3475,6 +3539,8 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
 	if (!pt)
 		return -ENOMEM;
 
+	pt->vmcs_info = RB_ROOT;
+
 	addr_filters__init(&pt->filts);
 
 	err = perf_config(intel_pt_perf_config, pt);