perf kvm/riscv: Port perf kvm stat to RISC-V

'perf kvm stat report/record' generates a statistical analysis of KVM
events and can be used to analyze guest exit reasons.

"report" reports statistical analysis of guest exit events.

To record kvm events on the host:
 # perf kvm stat record -a

To report kvm VM EXIT events:
 # perf kvm stat report --event=vmexit

Signed-off-by: Shenlin Liang <liangshenlin@eswincomputing.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20240422080833.8745-3-liangshenlin@eswincomputing.com
Signed-off-by: Anup Patel <anup@brainfault.org>

tools/perf/arch/riscv/Makefile

@@ -3,3 +3,4 @@ PERF_HAVE_DWARF_REGS := 1
 endif
 PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET := 1
 PERF_HAVE_JITDUMP := 1
+HAVE_KVM_STAT_SUPPORT := 1

tools/perf/arch/riscv/util/Build

@@ -1,5 +1,6 @@
 perf-y += perf_regs.o
 perf-y += header.o
 
+perf-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
 perf-$(CONFIG_DWARF) += dwarf-regs.o
 perf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o

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

@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Arch specific functions for perf kvm stat.
+ *
+ * Copyright 2024 Beijing ESWIN Computing Technology Co., Ltd.
+ *
+ */
+#include <errno.h>
+#include <memory.h>
+#include "../../../util/evsel.h"
+#include "../../../util/kvm-stat.h"
+#include "riscv_exception_types.h"
+#include "debug.h"
+
+define_exit_reasons_table(riscv_exit_reasons, kvm_riscv_exception_class);
+
+const char *vcpu_id_str = "id";
+const char *kvm_exit_reason = "scause";
+const char *kvm_entry_trace = "kvm:kvm_entry";
+const char *kvm_exit_trace = "kvm:kvm_exit";
+
+const char *kvm_events_tp[] = {
+	"kvm:kvm_entry",
+	"kvm:kvm_exit",
+	NULL,
+};
+
+static void event_get_key(struct evsel *evsel,
+			  struct perf_sample *sample,
+			  struct event_key *key)
+{
+	key->info = 0;
+	key->key = evsel__intval(evsel, sample, kvm_exit_reason);
+	key->exit_reasons = riscv_exit_reasons;
+}
+
+static bool event_begin(struct evsel *evsel,
+			struct perf_sample *sample __maybe_unused,
+			struct event_key *key __maybe_unused)
+{
+	return evsel__name_is(evsel, kvm_entry_trace);
+}
+
+static bool event_end(struct evsel *evsel,
+		      struct perf_sample *sample,
+		      struct event_key *key)
+{
+	if (evsel__name_is(evsel, kvm_exit_trace)) {
+		event_get_key(evsel, sample, key);
+		return true;
+	}
+	return false;
+}
+
+static struct kvm_events_ops exit_events = {
+	.is_begin_event = event_begin,
+	.is_end_event	= event_end,
+	.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 = "riscv64";
+	return 0;
+}

tools/perf/arch/riscv/util/riscv_exception_types.h

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef ARCH_PERF_RISCV_EXCEPTION_TYPES_H
+#define ARCH_PERF_RISCV_EXCEPTION_TYPES_H
+
+#define EXC_INST_MISALIGNED 0
+#define EXC_INST_ACCESS 1
+#define EXC_INST_ILLEGAL 2
+#define EXC_BREAKPOINT 3
+#define EXC_LOAD_MISALIGNED 4
+#define EXC_LOAD_ACCESS 5
+#define EXC_STORE_MISALIGNED 6
+#define EXC_STORE_ACCESS 7
+#define EXC_SYSCALL 8
+#define EXC_HYPERVISOR_SYSCALL 9
+#define EXC_SUPERVISOR_SYSCALL 10
+#define EXC_INST_PAGE_FAULT 12
+#define EXC_LOAD_PAGE_FAULT 13
+#define EXC_STORE_PAGE_FAULT 15
+#define EXC_INST_GUEST_PAGE_FAULT 20
+#define EXC_LOAD_GUEST_PAGE_FAULT 21
+#define EXC_VIRTUAL_INST_FAULT 22
+#define EXC_STORE_GUEST_PAGE_FAULT 23
+
+#define EXC(x) {EXC_##x, #x }
+
+#define kvm_riscv_exception_class                                         \
+	EXC(INST_MISALIGNED), EXC(INST_ACCESS), EXC(INST_ILLEGAL),         \
+	EXC(BREAKPOINT), EXC(LOAD_MISALIGNED), EXC(LOAD_ACCESS),           \
+	EXC(STORE_MISALIGNED), EXC(STORE_ACCESS), EXC(SYSCALL),            \
+	EXC(HYPERVISOR_SYSCALL), EXC(SUPERVISOR_SYSCALL),                  \
+	EXC(INST_PAGE_FAULT), EXC(LOAD_PAGE_FAULT), EXC(STORE_PAGE_FAULT), \
+	EXC(INST_GUEST_PAGE_FAULT), EXC(LOAD_GUEST_PAGE_FAULT),            \
+	EXC(VIRTUAL_INST_FAULT), EXC(STORE_GUEST_PAGE_FAULT)
+
+#endif /* ARCH_PERF_RISCV_EXCEPTION_TYPES_H */