perf kvm: Add kvm-stat for loongarch64

Add support for 'perf kvm stat' on loongarch64 platform, now only kvm
exit event is supported.

Here is example output about "perf kvm --host stat report" command

   Event name   Samples   Sample%     Time (ns)   Time%   Mean Time (ns)
    Mem Store     83969    51.00%     625697070   8.00%             7451
     Mem Read     37641    22.00%     112485730   1.00%             2988
    Interrupt     15542     9.00%      20620190   0.00%             1326
        IOCSR     15207     9.00%      94296190   1.00%             6200
    Hypercall      4873     2.00%      12265280   0.00%             2516
         Idle      3713     2.00%    6322055860  87.00%          1702681
          FPU      1819     1.00%       2750300   0.00%             1511
   Inst Fetch       502     0.00%       1341740   0.00%             2672
   Mem Modify       324     0.00%        602240   0.00%             1858
       CPUCFG        55     0.00%         77610   0.00%             1411
          CSR        12     0.00%         19690   0.00%             1640
         LASX         3     0.00%          4870   0.00%             1623
          LSX         2     0.00%          2100   0.00%             1050
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

tools/perf/arch/loongarch/Makefile

@@ -4,6 +4,7 @@ PERF_HAVE_DWARF_REGS := 1
 endif
 PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET := 1
 PERF_HAVE_JITDUMP := 1
+HAVE_KVM_STAT_SUPPORT := 1
 
 #
 # Syscall table generation for perf

tools/perf/arch/loongarch/util/Build

+perf-y += header.o
 perf-y += perf_regs.o
 
 perf-$(CONFIG_DWARF)     += dwarf-regs.o
 perf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
 perf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
+perf-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o

tools/perf/arch/loongarch/util/header.c

+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Implementation of get_cpuid().
+ *
+ * Author: Nikita Shubin <n.shubin@yadro.com>
+ *         Bibo Mao <maobibo@loongson.cn>
+ *         Huacai Chen <chenhuacai@loongson.cn>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <api/fs/fs.h>
+#include <errno.h>
+#include "util/debug.h"
+#include "util/header.h"
+
+/*
+ * Output example from /proc/cpuinfo
+ *   CPU Family              : Loongson-64bit
+ *   Model Name              : Loongson-3C5000
+ *   CPU Revision            : 0x10
+ *   FPU Revision            : 0x01
+ */
+#define CPUINFO_MODEL	"Model Name"
+#define CPUINFO		"/proc/cpuinfo"
+
+static char *_get_field(const char *line)
+{
+	char *line2, *nl;
+
+	line2 = strrchr(line, ' ');
+	if (!line2)
+		return NULL;
+
+	line2++;
+	nl = strrchr(line, '\n');
+	if (!nl)
+		return NULL;
+
+	return strndup(line2, nl - line2);
+}
+
+static char *_get_cpuid(void)
+{
+	unsigned long line_sz;
+	char *line, *model, *cpuid;
+	FILE *file;
+
+	file = fopen(CPUINFO, "r");
+	if (file == NULL)
+		return NULL;
+
+	line = model = cpuid = NULL;
+	while (getline(&line, &line_sz, file) != -1) {
+		if (strncmp(line, CPUINFO_MODEL, strlen(CPUINFO_MODEL)))
+			continue;
+
+		model = _get_field(line);
+		if (!model)
+			goto out_free;
+		break;
+	}
+
+	if (model && (asprintf(&cpuid, "%s", model) < 0))
+		cpuid = NULL;
+
+out_free:
+	fclose(file);
+	free(model);
+	return cpuid;
+}
+
+int get_cpuid(char *buffer, size_t sz)
+{
+	int ret = 0;
+	char *cpuid = _get_cpuid();
+
+	if (!cpuid)
+		return EINVAL;
+
+	if (sz < strlen(cpuid)) {
+		ret = ENOBUFS;
+		goto out_free;
+	}
+
+	scnprintf(buffer, sz, "%s", cpuid);
+
+out_free:
+	free(cpuid);
+	return ret;
+}
+
+char *get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
+{
+	return _get_cpuid();
+}

tools/perf/arch/loongarch/util/kvm-stat.c

+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <memory.h>
+#include "util/kvm-stat.h"
+#include "util/parse-events.h"
+#include "util/debug.h"
+#include "util/evsel.h"
+#include "util/evlist.h"
+#include "util/pmus.h"
+
+#define LOONGARCH_EXCEPTION_INT		0
+#define LOONGARCH_EXCEPTION_PIL		1
+#define LOONGARCH_EXCEPTION_PIS		2
+#define LOONGARCH_EXCEPTION_PIF		3
+#define LOONGARCH_EXCEPTION_PME		4
+#define LOONGARCH_EXCEPTION_FPD		15
+#define LOONGARCH_EXCEPTION_SXD		16
+#define LOONGARCH_EXCEPTION_ASXD	17
+#define LOONGARCH_EXCEPTION_GSPR	22
+#define  LOONGARCH_EXCEPTION_CPUCFG	100
+#define  LOONGARCH_EXCEPTION_CSR	101
+#define  LOONGARCH_EXCEPTION_IOCSR	102
+#define  LOONGARCH_EXCEPTION_IDLE	103
+#define  LOONGARCH_EXCEPTION_OTHERS	104
+#define LOONGARCH_EXCEPTION_HVC		23
+
+#define loongarch_exception_type				\
+	{LOONGARCH_EXCEPTION_INT,  "Interrupt" },		\
+	{LOONGARCH_EXCEPTION_PIL,  "Mem Read" },		\
+	{LOONGARCH_EXCEPTION_PIS,  "Mem Store" },		\
+	{LOONGARCH_EXCEPTION_PIF,  "Inst Fetch" },		\
+	{LOONGARCH_EXCEPTION_PME,  "Mem Modify" },		\
+	{LOONGARCH_EXCEPTION_FPD,  "FPU" },			\
+	{LOONGARCH_EXCEPTION_SXD,  "LSX" },			\
+	{LOONGARCH_EXCEPTION_ASXD, "LASX" },			\
+	{LOONGARCH_EXCEPTION_GSPR, "Privilege Error" },		\
+	{LOONGARCH_EXCEPTION_HVC,  "Hypercall" },		\
+	{LOONGARCH_EXCEPTION_CPUCFG, "CPUCFG" },		\
+	{LOONGARCH_EXCEPTION_CSR,    "CSR" },			\
+	{LOONGARCH_EXCEPTION_IOCSR,  "IOCSR" },			\
+	{LOONGARCH_EXCEPTION_IDLE,   "Idle" },			\
+	{LOONGARCH_EXCEPTION_OTHERS, "Others" }
+
+define_exit_reasons_table(loongarch_exit_reasons, loongarch_exception_type);
+
+const char *vcpu_id_str = "vcpu_id";
+const char *kvm_exit_reason = "reason";
+const char *kvm_entry_trace = "kvm:kvm_enter";
+const char *kvm_reenter_trace = "kvm:kvm_reenter";
+const char *kvm_exit_trace = "kvm:kvm_exit";
+const char *kvm_events_tp[] = {
+	"kvm:kvm_enter",
+	"kvm:kvm_reenter",
+	"kvm:kvm_exit",
+	"kvm:kvm_exit_gspr",
+	NULL,
+};
+
+static bool event_begin(struct evsel *evsel,
+			struct perf_sample *sample, struct event_key *key)
+{
+	return exit_event_begin(evsel, sample, key);
+}
+
+static bool event_end(struct evsel *evsel,
+		      struct perf_sample *sample __maybe_unused,
+		      struct event_key *key __maybe_unused)
+{
+	/*
+	 * LoongArch kvm is different with other architectures
+	 *
+	 * There is kvm:kvm_reenter or kvm:kvm_enter event adjacent with
+	 * kvm:kvm_exit event.
+	 *   kvm:kvm_enter   means returning to vmm and then to guest
+	 *   kvm:kvm_reenter means returning to guest immediately
+	 */
+	return evsel__name_is(evsel, kvm_entry_trace) || evsel__name_is(evsel, kvm_reenter_trace);
+}
+
+static void event_gspr_get_key(struct evsel *evsel,
+			       struct perf_sample *sample, struct event_key *key)
+{
+	unsigned int insn;
+
+	key->key = LOONGARCH_EXCEPTION_OTHERS;
+	insn = evsel__intval(evsel, sample, "inst_word");
+
+	switch (insn >> 24) {
+	case 0:
+		/* CPUCFG inst trap */
+		if ((insn >> 10) == 0x1b)
+			key->key = LOONGARCH_EXCEPTION_CPUCFG;
+		break;
+	case 4:
+		/* CSR inst trap */
+		key->key = LOONGARCH_EXCEPTION_CSR;
+		break;
+	case 6:
+		/* IOCSR inst trap */
+		if ((insn >> 15) == 0xc90)
+			key->key = LOONGARCH_EXCEPTION_IOCSR;
+		else if ((insn >> 15) == 0xc91)
+			/* Idle inst trap */
+			key->key = LOONGARCH_EXCEPTION_IDLE;
+		break;
+	default:
+		key->key = LOONGARCH_EXCEPTION_OTHERS;
+		break;
+	}
+}
+
+static struct child_event_ops child_events[] = {
+	{ .name = "kvm:kvm_exit_gspr", .get_key = event_gspr_get_key },
+	{ NULL, NULL },
+};
+
+static struct kvm_events_ops exit_events = {
+	.is_begin_event = event_begin,
+	.is_end_event = event_end,
+	.child_ops = child_events,
+	.decode_key = exit_event_decode_key,
+	.name = "VM-EXIT"
+};
+
+struct kvm_reg_events_ops kvm_reg_events_ops[] = {
+	{ .name	= "vmexit", .ops = &exit_events, },
+	{ NULL, NULL },
+};
+
+const char * const kvm_skip_events[] = {
+	NULL,
+};
+
+int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid __maybe_unused)
+{
+	kvm->exit_reasons_isa = "loongarch64";
+	kvm->exit_reasons = loongarch_exit_reasons;
+	return 0;
+}