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Message-Id: <1453442292-7790-3-git-send-email-ravi.bangoria@linux.vnet.ibm.com>
Date:	Fri, 22 Jan 2016 11:28:11 +0530
From:	Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
To:	acme@...nel.org
Cc:	mingo@...nel.org, peterz@...radead.org,
	linux-kernel@...r.kernel.org, hemant@...ux.vnet.ibm.com,
	naveen.n.rao@...ux.vnet.ibm.com,
	Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
Subject: [PATCH v2 2/3] perf kvm: enable record|report feature on powerpc

This patch contains core logic for enabling perf kvm {record|report} on
powerpc.

For perf kvm record,
This patch will replace default event(cycle) with kvm_hv:kvm_guest_exit
while recording guest data from host.

For perf kvm report,
This patch makes use of the 'kvm_guest_exit' tracepoint and checks the
exit reason for any kvm exit. If it is HV_DECREMENTER, then the
instruction pointer dumped along with this tracepoint is retrieved and
mapped with the guest kallsyms.

Signed-off-by: Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
Signed-off-by: Hemant Kumar <hemant@...ux.vnet.ibm.com>
---
changes in v2:
    - Breakdown of v1 patch into two sub patches
    - Merged parse-tp.c and evlist.c from tools/perf/arch/powerpc/util/ into
      single file with name kvm.c

 tools/perf/arch/powerpc/util/Build |   1 +
 tools/perf/arch/powerpc/util/kvm.c | 104 +++++++++++++++++++++++++++++++++++++
 tools/perf/util/event.c            |  12 ++++-
 tools/perf/util/evlist.c           |   9 ++++
 tools/perf/util/evlist.h           |   1 +
 tools/perf/util/evsel.c            |   7 +++
 tools/perf/util/evsel.h            |   4 ++
 tools/perf/util/session.c          |   9 ++--
 tools/perf/util/util.c             |   5 ++
 tools/perf/util/util.h             |   1 +
 10 files changed, 147 insertions(+), 6 deletions(-)
 create mode 100644 tools/perf/arch/powerpc/util/kvm.c

diff --git a/tools/perf/arch/powerpc/util/Build b/tools/perf/arch/powerpc/util/Build
index 7b8b0d1..eb819e0 100644
--- a/tools/perf/arch/powerpc/util/Build
+++ b/tools/perf/arch/powerpc/util/Build
@@ -1,5 +1,6 @@
 libperf-y += header.o
 libperf-y += sym-handling.o
+libperf-y += kvm.o
 
 libperf-$(CONFIG_DWARF) += dwarf-regs.o
 libperf-$(CONFIG_DWARF) += skip-callchain-idx.o
diff --git a/tools/perf/arch/powerpc/util/kvm.c b/tools/perf/arch/powerpc/util/kvm.c
new file mode 100644
index 0000000..317f29a
--- /dev/null
+++ b/tools/perf/arch/powerpc/util/kvm.c
@@ -0,0 +1,104 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * Copyright (C) 2016 Hemant Kumar Shaw, IBM Corporation
+ * Copyright (C) 2016 Ravikumar B. Bangoria, IBM Corporation
+ */
+
+#include <linux/err.h>
+#include "../../../util/evsel.h"
+#include "../../../util/evlist.h"
+#include "../../../util/trace-event.h"
+#include "../../../util/session.h"
+#include "../../../util/util.h"
+
+#define KVMPPC_EXIT "kvm_hv:kvm_guest_exit"
+#define HV_DECREMENTER 2432
+#define HV_BIT 3
+#define PR_BIT 49
+#define PPC_MAX 63
+
+/*
+ * To sample for only guest, record kvm_hv:kvm_guest_exit.
+ * Otherwise go via normal way(cycles).
+ */
+int perf_evlist__arch_add_default(struct perf_evlist *evlist)
+{
+	struct perf_evsel *evsel;
+
+	if (!perf_guest_only())
+		return -1;
+
+	evsel = perf_evsel__newtp_idx("kvm_hv", "kvm_guest_exit", 0);
+	if (IS_ERR(evsel))
+		return PTR_ERR(evsel);
+
+	perf_evlist__add(evlist, evsel);
+	return 0;
+}
+
+static bool is_kvmppc_exit_event(struct perf_evsel *evsel)
+{
+	static unsigned int kvmppc_exit;
+
+	if (evsel->attr.type != PERF_TYPE_TRACEPOINT)
+		return false;
+
+	if (unlikely(kvmppc_exit == 0)) {
+		if (strcmp(KVMPPC_EXIT, evsel->name))
+			return false;
+		kvmppc_exit = evsel->attr.config;
+	} else if (kvmppc_exit != evsel->attr.config) {
+		return false;
+	}
+
+	return true;
+}
+
+static bool is_hv_dec_trap(struct perf_evsel *evsel, struct perf_sample *sample)
+{
+	int trap = perf_evsel__intval(evsel, sample, "trap");
+	return trap == HV_DECREMENTER;
+}
+
+/*
+ * Get the instruction pointer from the tracepoint data
+ */
+u64 arch__get_ip(struct perf_evsel *evsel, struct perf_sample *sample)
+{
+	if (perf_guest_only() &&
+	    is_kvmppc_exit_event(evsel) &&
+	    is_hv_dec_trap(evsel, sample))
+		return perf_evsel__intval(evsel, sample, "pc");
+
+	return sample->ip;
+}
+
+/*
+ * Get the HV and PR bits and accordingly, determine the cpumode
+ */
+u8 arch__get_cpumode(const union perf_event *event, struct perf_evsel *evsel,
+		     struct perf_sample *sample)
+{
+	unsigned long hv, pr, msr;
+	u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+
+	if (!perf_guest_only() || !is_kvmppc_exit_event(evsel))
+		goto ret;
+
+	if (sample->raw_data && is_hv_dec_trap(evsel, sample)) {
+		msr = perf_evsel__intval(evsel, sample, "msr");
+		hv = msr & ((unsigned long)1 << (PPC_MAX - HV_BIT));
+		pr = msr & ((unsigned long)1 << (PPC_MAX - PR_BIT));
+
+		if (!hv && pr)
+			cpumode = PERF_RECORD_MISC_GUEST_USER;
+		else
+			cpumode = PERF_RECORD_MISC_GUEST_KERNEL;
+	}
+
+ret:
+	return cpumode;
+}
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index f86e172..b8105a6 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -1291,6 +1291,13 @@ void thread__find_addr_location(struct thread *thread,
 		al->sym = NULL;
 }
 
+u8 __weak arch__get_cpumode(const union perf_event *event,
+			    struct perf_evsel *evsel __maybe_unused,
+			    struct perf_sample *sample __maybe_unused)
+{
+	return event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+}
+
 /*
  * Callers need to drop the reference to al->thread, obtained in
  * machine__findnew_thread()
@@ -1301,13 +1308,14 @@ int perf_event__preprocess_sample(const union perf_event *event,
 				  struct perf_sample *sample,
 				  struct perf_evsel *evsel)
 {
-	u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+	u8 cpumode;
 	struct thread *thread = machine__findnew_thread(machine, sample->pid,
 							sample->tid);
-
 	if (thread == NULL)
 		return -1;
 
+	al->cpumode = cpumode = arch__get_cpumode(event, evsel, sample);
+
 	dump_printf(" ... thread: %s:%d\n", thread__comm_str(thread), thread->tid);
 	/*
 	 * Have we already created the kernel maps for this machine?
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index d81f13d..d0dca72 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -231,6 +231,12 @@ void perf_event_attr__set_max_precise_ip(struct perf_event_attr *attr)
 	}
 }
 
+int __weak
+perf_evlist__arch_add_default(struct perf_evlist *evlist __maybe_unused)
+{
+	return -1;
+}
+
 int perf_evlist__add_default(struct perf_evlist *evlist)
 {
 	struct perf_event_attr attr = {
@@ -239,6 +245,9 @@ int perf_evlist__add_default(struct perf_evlist *evlist)
 	};
 	struct perf_evsel *evsel;
 
+	if (!perf_evlist__arch_add_default(evlist))
+		return 0;
+
 	event_attr_init(&attr);
 
 	perf_event_attr__set_max_precise_ip(&attr);
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index 7c4d9a2..98e24cd 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -75,6 +75,7 @@ void perf_evlist__delete(struct perf_evlist *evlist);
 
 void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry);
 void perf_evlist__remove(struct perf_evlist *evlist, struct perf_evsel *evsel);
+int perf_evlist__arch_add_default(struct perf_evlist *evlist);
 int perf_evlist__add_default(struct perf_evlist *evlist);
 int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
 				     struct perf_event_attr *attrs, size_t nr_attrs);
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 4678086..afe1091 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1607,6 +1607,12 @@ static inline bool overflow(const void *endp, u16 max_size, const void *offset,
 #define OVERFLOW_CHECK_u64(offset) \
 	OVERFLOW_CHECK(offset, sizeof(u64), sizeof(u64))
 
+u64 __weak arch__get_ip(struct perf_evsel *evsel __maybe_unused,
+			struct perf_sample *sample)
+{
+	return sample->ip;
+}
+
 int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
 			     struct perf_sample *data)
 {
@@ -1780,6 +1786,7 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
 		OVERFLOW_CHECK(array, data->raw_size, max_size);
 		data->raw_data = (void *)array;
 		array = (void *)array + data->raw_size;
+		data->ip = arch__get_ip(evsel, data);
 	}
 
 	if (type & PERF_SAMPLE_BRANCH_STACK) {
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 8e75434..eb6f52e 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -400,4 +400,8 @@ typedef int (*attr__fprintf_f)(FILE *, const char *, const char *, void *);
 int perf_event_attr__fprintf(FILE *fp, struct perf_event_attr *attr,
 			     attr__fprintf_f attr__fprintf, void *priv);
 
+u64 arch__get_ip(struct perf_evsel *evsel, struct perf_sample *sample);
+u8 arch__get_cpumode(const union perf_event *event, struct perf_evsel *evsel,
+		     struct perf_sample *sample);
+
 #endif /* __PERF_EVSEL_H */
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 40b7a0d..1081ee0 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1130,10 +1130,11 @@ static void dump_sample(struct perf_evsel *evsel, union perf_event *event,
 }
 
 static struct machine *machines__find_for_cpumode(struct machines *machines,
-					       union perf_event *event,
-					       struct perf_sample *sample)
+						  union perf_event *event,
+						  struct perf_sample *sample,
+						  struct perf_evsel *evsel)
 {
-	const u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+	u8 cpumode = arch__get_cpumode(event, evsel, sample);
 	struct machine *machine;
 
 	if (perf_guest &&
@@ -1237,7 +1238,7 @@ static int machines__deliver_event(struct machines *machines,
 
 	evsel = perf_evlist__id2evsel(evlist, sample->id);
 
-	machine = machines__find_for_cpumode(machines, event, sample);
+	machine = machines__find_for_cpumode(machines, event, sample, evsel);
 
 	switch (event->header.type) {
 	case PERF_RECORD_SAMPLE:
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 7a2da7e..5e48ef1 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -37,6 +37,11 @@ bool test_attr__enabled;
 bool perf_host  = true;
 bool perf_guest = false;
 
+bool perf_guest_only(void)
+{
+	return !perf_host && perf_guest;
+}
+
 void event_attr_init(struct perf_event_attr *attr)
 {
 	if (!perf_host)
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 61650f0..eff1d8f 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -344,5 +344,6 @@ int fetch_kernel_version(unsigned int *puint,
 
 const char *perf_tip(const char *dirpath);
 bool is_regular_file(const char *file);
+bool perf_guest_only(void);
 
 #endif /* GIT_COMPAT_UTIL_H */
-- 
2.1.4

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