examples/tracing/kvm_hypercall.py

#!/usr/bin/env python
#
# kvm_hypercall.py
#
# Demonstrates stateful kvm_entry and kvm_exit recording along with the
# associated hypercall when exit_reason is VMCALL. See kvm_hypercall.txt
# for usage
#
# REQUIRES: Linux 4.7+ (BPF_PROG_TYPE_TRACEPOINT support)
#
# Copyright (c) 2017 ShiftLeft Inc.
#
# Author(s):
#   Suchakrapani Sharma <suchakra@shiftleft.io>


from __future__ import print_function
from bcc import BPF

# load BPF program
b = BPF(text="""
#define EXIT_REASON 18
BPF_HASH(start, u8, u8);

TRACEPOINT_PROBE(kvm, kvm_exit) {
    u8 e = EXIT_REASON;
    u8 one = 1;
    if (args->exit_reason == EXIT_REASON) {
        bpf_trace_printk("KVM_EXIT exit_reason : %d\\n", args->exit_reason);
        start.update(&e, &one);
    }
    return 0;
}

TRACEPOINT_PROBE(kvm, kvm_entry) {
    u8 e = EXIT_REASON;
    u8 zero = 0;
    u8 *s = start.lookup(&e);
    if (s != NULL && *s == 1) {
        bpf_trace_printk("KVM_ENTRY vcpu_id : %u\\n", args->vcpu_id);
        start.update(&e, &zero);
    }
    return 0;
}

TRACEPOINT_PROBE(kvm, kvm_hypercall) {
    u8 e = EXIT_REASON;
    u8 zero = 0;
    u8 *s = start.lookup(&e);
    if (s != NULL && *s == 1) {
        bpf_trace_printk("HYPERCALL nr : %d\\n", args->nr);
    }
    return 0;
};
""")

# header
print("%-18s %-16s %-6s %s" % ("TIME(s)", "COMM", "PID", "EVENT"))

# format output
while 1:
    try:
        (task, pid, cpu, flags, ts, msg) = b.trace_fields()
    except ValueError:
        continue
    print("%-18.9f %-16s %-6d %s" % (ts, task, pid, msg))