perf, kvm/arm64: Add stat support on arm64

virt inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4IZPY
CVE: NA

-------------------------------------------------

'perf kvm stat report/record' generates a statistical analysis of KVM
events and can be used to analyze guest exit reasons. This patch tries
to add stat support on arm64.

We have a mapping between guest's "exit_code" and "exit_reason" which
already exists under arch/arm64/include/asm/ (kvm_arm_exception_type),
and we've used it to report guest's exit type through trace_kvm_exit().
Copy kvm_arm_exception_type into aarch64_guest_exits.h, thus export it
to userspace.

It records on two available KVM tracepoints for arm64: "kvm:kvm_entry"
and "kvm:kvm_exit", and reports statistical data which includes events
handles time, samples, and so on.

A simple test go below:

 # pgrep qemu
6039
9937

 # ./tools/perf/perf kvm stat record -p 6039
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 15.629 MB perf.data.guest (199063 samples) ]

 # ./tools/perf/perf kvm stat report --event=vmexit

Analyze events for all VMs, all VCPUs:

             VM-EXIT    Samples  Samples%     Time%    Min Time    Max Time         Avg time

                TRAP      49040    97.15%   100.00%      2.60us   4072.98us   3431.60us ( +-   0.17% )
                 IRQ       1437     2.85%     0.00%      0.90us     24.56us      2.06us ( +-   1.37% )

Total Samples:50477, Total events handled time:168288630.04us.
Signed-off-by: NZenghui Yu <yuzenghui@huawei.com>
Reviewed-by: NHailiang Zhang <zhang.zhanghailiang@huawei.com>
Signed-off-by: NZenghui Yu <yuzenghui@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/1560330526-15468-5-git-send-email-yuzenghui@huawei.com
Link: https://gitee.com/openeuler/kernel/commit/15db05576381Reviewed-by: NYanan Wang <wangyanan55@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

tools/perf/arch/arm64/Makefile

@@ -2,6 +2,8 @@
 ifndef NO_DWARF
 PERF_HAVE_DWARF_REGS := 1
 endif
+
+HAVE_KVM_STAT_SUPPORT := 1
 PERF_HAVE_JITDUMP := 1
 PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET := 1
 

tools/perf/arch/arm64/util/Build

@@ -2,6 +2,7 @@ perf-y += header.o
 perf-y += machine.o
 perf-y += perf_regs.o
 perf-y += tsc.o
+perf-y += kvm-stat.o
 perf-$(CONFIG_DWARF)     += dwarf-regs.o
 perf-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind.o
 perf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o

tools/perf/arch/arm64/util/aarch64_guest_exits.h

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ */
+
+#ifndef ARCH_PERF_AARCH64_GUEST_EXITS_H
+#define ARCH_PERF_AARCH64_GUEST_EXITS_H
+
+/* virt.h */
+/* Error returned when an invalid stub number is passed into x0 */
+#define HVC_STUB_ERR	0xbadca11
+
+/* kvm_asm.h */
+#define ARM_EXCEPTION_IRQ         0
+#define ARM_EXCEPTION_EL1_SERROR  1
+#define ARM_EXCEPTION_TRAP        2
+#define ARM_EXCEPTION_IL          3
+/* The hyp-stub will return this for any kvm_call_hyp() call */
+#define ARM_EXCEPTION_HYP_GONE    HVC_STUB_ERR
+
+#define kvm_arm_exception_type					\
+	{ARM_EXCEPTION_IRQ,		"IRQ"		},	\
+	{ARM_EXCEPTION_EL1_SERROR,	"SERROR"	},	\
+	{ARM_EXCEPTION_TRAP,		"TRAP"		},	\
+	{ARM_EXCEPTION_HYP_GONE,	"HYP_GONE"	}
+
+#endif /* ARCH_PERF_AARCH64_GUEST_EXITS_H */

tools/perf/arch/arm64/util/kvm-stat.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Arch specific functions for perf kvm stat.
+ * Copyright(c) 2019 Huawei Technologies Co., Ltd
+ */
+
+#include "../../../util/kvm-stat.h"
+#include "aarch64_guest_exits.h"
+
+define_exit_reasons_table(arm64_exit_reasons, kvm_arm_exception_type);
+
+static struct kvm_events_ops exit_events = {
+	.is_begin_event = exit_event_begin,
+	.is_end_event = exit_event_end,
+	.decode_key = exit_event_decode_key,
+	.name = "VM-EXIT"
+};
+
+const char *vcpu_id_str = "vcpu_id";
+const int decode_str_len = 20;
+const char *kvm_exit_reason = "ret";
+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,
+};
+
+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 = arm64_exit_reasons;
+	kvm->exit_reasons_isa = "aarch64";
+
+	return 0;
+}