#! /usr/bin/python3
#
# kvmexit.py
#
# Display the exit_reason and its statistics of each vm exit
# for all vcpus of all virtual machines. For example:
# $./kvmexit.py
# PID TID KVM_EXIT_REASON COUNT
# 1273551 1273568 EXIT_REASON_MSR_WRITE 6
# 1274253 1274261 EXIT_REASON_EXTERNAL_INTERRUPT 1
# 1274253 1274261 EXIT_REASON_HLT 12
# ...
#
# Besides, we also allow users to specify one pid, tid(s), or one
# pid and its vcpu. See kvmexit_example.txt for more examples.
#
# @PID: each vitual machine's pid in the user space.
# @TID: the user space's thread of each vcpu of that virtual machine.
# @KVM_EXIT_REASON: the reason why the vm exits.
# @COUNT: the counts of the @KVM_EXIT_REASONS.
#
# REQUIRES: Linux 4.7+ (BPF_PROG_TYPE_TRACEPOINT support)
#
# Copyright (c) 2021 ByteDance Inc. All rights reserved.
#
# Author(s):
# Fei Li <lifei.shirley@bytedance.com>
from __future__ import print_function
from time import sleep
from bcc import BPF
import argparse
import multiprocessing
import os
import subprocess
#
# Process Arguments
#
def valid_args_list(args):
args_list = args.split(",")
for arg in args_list:
try:
int(arg)
except:
raise argparse.ArgumentTypeError("must be valid integer")
return args_list
# arguments
examples = """examples:
./kvmexit # Display kvm_exit_reason and its statistics in real-time until Ctrl-C
./kvmexit 5 # Display in real-time after sleeping 5s
./kvmexit -p 3195281 # Collpase all tids for pid 3195281 with exit reasons sorted in descending order
./kvmexit -p 3195281 20 # Collpase all tids for pid 3195281 with exit reasons sorted in descending order, and display after sleeping 20s
./kvmexit -p 3195281 -v 0 # Display only vcpu0 for pid 3195281, descending sort by default
./kvmexit -p 3195281 -a # Display all tids for pid 3195281
./kvmexit -t 395490 # Display only for tid 395490 with exit reasons sorted in descending order
./kvmexit -t 395490 20 # Display only for tid 395490 with exit reasons sorted in descending order after sleeping 20s
./kvmexit -T '395490,395491' # Display for a union like {395490, 395491}
"""
parser = argparse.ArgumentParser(
description="Display kvm_exit_reason and its statistics at a timed interval",
formatter_class=argparse.RawDescriptionHelpFormatter,
epilog=examples)
parser.add_argument("duration", nargs="?", default=99999999, type=int, help="show delta for next several seconds")
parser.add_argument("-p", "--pid", type=int, help="trace this PID only")
exgroup = parser.add_mutually_exclusive_group()
exgroup.add_argument("-t", "--tid", type=int, help="trace this TID only")
exgroup.add_argument("-T", "--tids", type=valid_args_list, help="trace a comma separated series of tids with no space in between")
exgroup.add_argument("-v", "--vcpu", type=int, help="trace this vcpu only")
exgroup.add_argument("-a", "--alltids", action="store_true", help="trace all tids for this pid")
args = parser.parse_args()
duration = int(args.duration)
#
# Setup BPF
#
# load BPF program
bpf_text = """
#include <linux/delay.h>
#define REASON_NUM 69
#define TGID_NUM 1024
struct exit_count {
u64 exit_ct[REASON_NUM];
};
BPF_PERCPU_ARRAY(init_value, struct exit_count, 1);
BPF_TABLE("percpu_hash", u64, struct exit_count, pcpu_kvm_stat, TGID_NUM);
struct cache_info {
u64 cache_pid_tgid;
struct exit_count cache_exit_ct;
};
BPF_PERCPU_ARRAY(pcpu_cache, struct cache_info, 1);
TRACEPOINT_PROBE(kvm, kvm_exit) {
int cache_miss = 0;
int zero = 0;
u32 er = args->exit_reason;
if (er >= REASON_NUM) {
return 0;
}
u64 cur_pid_tgid = bpf_get_current_pid_tgid();
u32 tgid = cur_pid_tgid >> 32;
u32 pid = cur_pid_tgid;
if (THREAD_FILTER)
return 0;
struct exit_count *tmp_info = NULL, *initial = NULL;
struct cache_info *cache_p;
cache_p = pcpu_cache.lookup(&zero);
if (cache_p == NULL) {
return 0;
}
if (cache_p->cache_pid_tgid == cur_pid_tgid) {
//a. If the cur_pid_tgid hit this physical cpu consecutively, save it to pcpu_cache
tmp_info = &cache_p->cache_exit_ct;
} else {
//b. If another pid_tgid matches this pcpu for the last hit, OR it is the first time to hit this physical cpu.
cache_miss = 1;
// b.a Try to load the last cache struct if exists.
tmp_info = pcpu_kvm_stat.lookup(&cur_pid_tgid);
// b.b If it is the first time for the cur_pid_tgid to hit this pcpu, employ a
// per_cpu array to initialize pcpu_kvm_stat's exit_count with each exit reason's count is zero
if (tmp_info == NULL) {
initial = init_value.lookup(&zero);
if (initial == NULL) {
return 0;
}
pcpu_kvm_stat.update(&cur_pid_tgid, initial);
tmp_info = pcpu_kvm_stat.lookup(&cur_pid_tgid);
// To pass the verifier
if (tmp_info == NULL) {
return 0;
}
}
}
if (er < REASON_NUM) {
tmp_info->exit_ct[er]++;
if (cache_miss == 1) {
if (cache_p->cache_pid_tgid != 0) {
// b.*.a Let's save the last hit cache_info into kvm_stat.
pcpu_kvm_stat.update(&cache_p->cache_pid_tgid, &cache_p->cache_exit_ct);
}
// b.* As the cur_pid_tgid meets current pcpu_cache_array for the first time, save it.
cache_p->cache_pid_tgid = cur_pid_tgid;
bpf_probe_read(&cache_p->cache_exit_ct, sizeof(*tmp_info), tmp_info);
}
return 0;
}
return 0;
}
"""
# format output
exit_reasons = (
"EXCEPTION_NMI",
"EXTERNAL_INTERRUPT",
"TRIPLE_FAULT",
"INIT_SIGNAL",
"N/A",
"N/A",
"N/A",
"INTERRUPT_WINDOW",
"NMI_WINDOW",
"TASK_SWITCH",
"CPUID",
"N/A",
"HLT",
"INVD",
"INVLPG",
"RDPMC",
"RDTSC",
"N/A",
"VMCALL",
"VMCLEAR",
"VMLAUNCH",
"VMPTRLD",
"VMPTRST",
"VMREAD",
"VMRESUME",
"VMWRITE",
"VMOFF",
"VMON",
"CR_ACCESS",
"DR_ACCESS",
"IO_INSTRUCTION",
"MSR_READ",
"MSR_WRITE",
"INVALID_STATE",
"MSR_LOAD_FAIL",
"N/A",
"MWAIT_INSTRUCTION",
"MONITOR_TRAP_FLAG",
"N/A",
"MONITOR_INSTRUCTION",
"PAUSE_INSTRUCTION",
"MCE_DURING_VMENTRY",
"N/A",
"TPR_BELOW_THRESHOLD",
"APIC_ACCESS",
"EOI_INDUCED",
"GDTR_IDTR",
"LDTR_TR",
"EPT_VIOLATION",
"EPT_MISCONFIG",
"INVEPT",
"RDTSCP",
"PREEMPTION_TIMER",
"INVVPID",
"WBINVD",
"XSETBV",
"APIC_WRITE",
"RDRAND",
"INVPCID",
"VMFUNC",
"ENCLS",
"RDSEED",
"PML_FULL",
"XSAVES",
"XRSTORS",
"N/A",
"N/A",
"UMWAIT",
"TPAUSE"
)
#
# Do some checks
#
try:
# Currently, only adapte on intel architecture
cmd = "cat /proc/cpuinfo | grep vendor_id | head -n 1"
arch_info = subprocess.check_output(cmd, shell=True).strip()
if b"Intel" in arch_info:
pass
else:
raise Exception("Currently we only support Intel architecture, please do expansion if needs more.")
# Check if kvm module is loaded
if os.access("/dev/kvm", os.R_OK | os.W_OK):
pass
else:
raise Exception("Please insmod kvm module to use kvmexit tool.")
except Exception as e:
raise Exception("Failed to do precondition check, due to: %s." % e)
def find_tid(tgt_dir, tgt_vcpu):
for tid in os.listdir(tgt_dir):
path = tgt_dir + "/" + tid + "/comm"
fp = open(path, "r")
comm = fp.read()
if (comm.find(tgt_vcpu) != -1):
return tid
return -1
# set process/thread filter
thread_context = ""
header_format = ""
need_collapse = not args.alltids
if args.tid is not None:
thread_context = "TID %s" % args.tid
thread_filter = 'pid != %s' % args.tid
elif args.tids is not None:
thread_context = "TIDS %s" % args.tids
thread_filter = "pid != " + " && pid != ".join(args.tids)
header_format = "TIDS "
elif args.pid is not None:
thread_context = "PID %s" % args.pid
thread_filter = 'tgid != %s' % args.pid
if args.vcpu is not None:
thread_context = "PID %s VCPU %s" % (args.pid, args.vcpu)
# transfer vcpu to tid
tgt_dir = '/proc/' + str(args.pid) + '/task'
tgt_vcpu = "CPU " + str(args.vcpu)
args.tid = find_tid(tgt_dir, tgt_vcpu)
if args.tid == -1:
raise Exception("There's no v%s for PID %d." % (tgt_vcpu, args.pid))
thread_filter = 'pid != %s' % args.tid
elif args.alltids:
thread_context = "PID %s and its all threads" % args.pid
header_format = "TID "
else:
thread_context = "all threads"
thread_filter = '0'
header_format = "PID TID "
bpf_text = bpf_text.replace('THREAD_FILTER', thread_filter)
b = BPF(text=bpf_text)
# header
print("Display kvm exit reasons and statistics for %s" % thread_context, end="")
if duration < 99999999:
print(" after sleeping %d secs." % duration)
else:
print("... Hit Ctrl-C to end.")
try:
sleep(duration)
except KeyboardInterrupt:
print()
# Currently, sort multiple tids in descending order is not supported.
if (args.pid or args.tid):
ct_reason = []
if args.pid:
tgid_exit = [0 for i in range(len(exit_reasons))]
# output
print("%s%-35s %s" % (header_format, "KVM_EXIT_REASON", "COUNT"))
pcpu_kvm_stat = b["pcpu_kvm_stat"]
pcpu_cache = b["pcpu_cache"]
for k, v in pcpu_kvm_stat.items():
tgid = k.value >> 32
pid = k.value & 0xffffffff
for i in range(0, len(exit_reasons)):
sum1 = 0
for inner_cpu in range(0, multiprocessing.cpu_count()):
cachePIDTGID = pcpu_cache[0][inner_cpu].cache_pid_tgid
# Take priority to check if it is in cache
if cachePIDTGID == k.value:
sum1 += pcpu_cache[0][inner_cpu].cache_exit_ct.exit_ct[i]
# If not in cache, find from kvm_stat
else:
sum1 += v[inner_cpu].exit_ct[i]
if sum1 == 0:
continue
if (args.pid and args.pid == tgid and need_collapse):
tgid_exit[i] += sum1
elif (args.tid and args.tid == pid):
ct_reason.append((sum1, i))
elif not need_collapse or args.tids:
print("%-8u %-35s %-8u" % (pid, exit_reasons[i], sum1))
else:
print("%-8u %-8u %-35s %-8u" % (tgid, pid, exit_reasons[i], sum1))
# Display only for the target tid in descending sort
if (args.tid and args.tid == pid):
ct_reason.sort(reverse=True)
for i in range(0, len(ct_reason)):
if ct_reason[i][0] == 0:
continue
print("%-35s %-8u" % (exit_reasons[ct_reason[i][1]], ct_reason[i][0]))
break
# Aggregate all tids' counts for this args.pid in descending sort
if args.pid and need_collapse:
for i in range(0, len(exit_reasons)):
ct_reason.append((tgid_exit[i], i))
ct_reason.sort(reverse=True)
for i in range(0, len(ct_reason)):
if ct_reason[i][0] == 0:
continue
print("%-35s %-8u" % (exit_reasons[ct_reason[i][1]], ct_reason[i][0]))
Mini Shell