xref: /openbmc/qemu/contrib/plugins/traps.c (revision 4889d9666076d8164171d1208ffb8b2be10463f6)
1 /*
2  * SPDX-License-Identifier: GPL-2.0-or-later
3  * Copyright (C) 2025, Julian Ganz <neither@nut.email>
4  *
5  * Traps - count traps
6  *
7  * Count the number of interrupts (asyncronous events), exceptions (synchronous
8  * events) and host calls (e.g. semihosting) per cpu and report those counts on
9  * exit.
10  */
11 
12 #include <stdio.h>
13 
14 #include <qemu-plugin.h>
15 
16 QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
17 
18 typedef struct {
19     uint64_t interrupts;
20     uint64_t exceptions;
21     uint64_t hostcalls;
22 } TrapCounters;
23 
24 static struct qemu_plugin_scoreboard *traps;
25 
26 static void vcpu_discon(qemu_plugin_id_t id, unsigned int vcpu_index,
27                         enum qemu_plugin_discon_type type, uint64_t from_pc,
28                         uint64_t to_pc)
29 {
30     TrapCounters *rec = qemu_plugin_scoreboard_find(traps, vcpu_index);
31     switch (type) {
32     case QEMU_PLUGIN_DISCON_INTERRUPT:
33         rec->interrupts++;
34         break;
35     case QEMU_PLUGIN_DISCON_EXCEPTION:
36         rec->exceptions++;
37         break;
38     case QEMU_PLUGIN_DISCON_HOSTCALL:
39         rec->hostcalls++;
40         break;
41     default:
42         g_assert_not_reached();
43         break;
44     }
45 }
46 
47 static void plugin_exit(qemu_plugin_id_t id, void *p)
48 {
49     g_autoptr(GString) report;
50     report = g_string_new("VCPU, interrupts, exceptions, hostcalls\n");
51     int max_vcpus = qemu_plugin_num_vcpus();
52     int vcpu;
53 
54     for (vcpu = 0; vcpu < max_vcpus; vcpu++) {
55         TrapCounters *rec = qemu_plugin_scoreboard_find(traps, vcpu);
56         g_string_append_printf(report,
57                                "% 4d, % 10"PRId64", % 10"PRId64", % 10"PRId64
58                                "\n", vcpu, rec->interrupts, rec->exceptions,
59                                rec->hostcalls);
60     }
61 
62     qemu_plugin_outs(report->str);
63     qemu_plugin_scoreboard_free(traps);
64 }
65 
66 QEMU_PLUGIN_EXPORT
67 int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
68                         int argc, char **argv)
69 {
70     if (!info->system_emulation) {
71         qemu_plugin_outs("Note: interrupts are only reported in system"
72                          " emulation mode.");
73     }
74 
75     traps = qemu_plugin_scoreboard_new(sizeof(TrapCounters));
76 
77     qemu_plugin_register_vcpu_discon_cb(id, QEMU_PLUGIN_DISCON_ALL,
78                                         vcpu_discon);
79 
80     qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
81 
82     return 0;
83 }
84