| 1 | /* |
| 2 | * SPDX-License-Identifier: GPL-2.0-or-later |
| 3 | * Copyright (C) 2025, Julian Ganz <neither@nut.email> |
| 4 | * |
| 5 | * This plugin exercises the discontinuity plugin API and asserts some |
| 6 | * of its behaviour regarding reported program counters. |
| 7 | */ |
| 8 | #include <stdio.h> |
| 9 | |
| 10 | #include <qemu-plugin.h> |
| 11 | |
| 12 | QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION; |
| 13 | |
| 14 | struct cpu_state { |
| 15 | uint64_t last_pc; |
| 16 | uint64_t from_pc; |
| 17 | uint64_t next_pc; |
| 18 | uint64_t has_from; |
| 19 | bool has_next; |
| 20 | enum qemu_plugin_discon_type next_type; |
| 21 | }; |
| 22 | |
| 23 | struct insn_data { |
| 24 | uint64_t addr; |
| 25 | uint64_t next_pc; |
| 26 | bool next_valid; |
| 27 | }; |
| 28 | |
| 29 | static struct qemu_plugin_scoreboard *states; |
| 30 | |
| 31 | static qemu_plugin_u64 last_pc; |
| 32 | static qemu_plugin_u64 from_pc; |
| 33 | static qemu_plugin_u64 has_from; |
| 34 | |
| 35 | static bool abort_on_mismatch; |
| 36 | static bool trace_all_insns; |
| 37 | |
| 38 | static bool addr_eq(uint64_t a, uint64_t b) |
| 39 | { |
| 40 | if (a == b) { |
| 41 | return true; |
| 42 | } |
| 43 | |
| 44 | uint64_t a_hw; |
| 45 | uint64_t b_hw; |
| 46 | if (!qemu_plugin_translate_vaddr(a, &a_hw) || |
| 47 | !qemu_plugin_translate_vaddr(b, &b_hw)) |
| 48 | { |
| 49 | return false; |
| 50 | } |
| 51 | |
| 52 | return a_hw == b_hw; |
| 53 | } |
| 54 | |
| 55 | static void report_mismatch(const char *pc_name, unsigned int vcpu_index, |
| 56 | enum qemu_plugin_discon_type type, uint64_t last, |
| 57 | uint64_t expected, uint64_t encountered) |
| 58 | { |
| 59 | gchar *report; |
| 60 | const char *discon_type_name = "unknown"; |
| 61 | |
| 62 | if (addr_eq(expected, encountered)) { |
| 63 | return; |
| 64 | } |
| 65 | |
| 66 | switch (type) { |
| 67 | case QEMU_PLUGIN_DISCON_INTERRUPT: |
| 68 | discon_type_name = "interrupt"; |
| 69 | break; |
| 70 | case QEMU_PLUGIN_DISCON_EXCEPTION: |
| 71 | discon_type_name = "exception"; |
| 72 | break; |
| 73 | case QEMU_PLUGIN_DISCON_HOSTCALL: |
| 74 | discon_type_name = "hostcall"; |
| 75 | break; |
| 76 | default: |
| 77 | break; |
| 78 | } |
| 79 | |
| 80 | report = g_strdup_printf("Discon %s PC mismatch on VCPU %d\n" |
| 81 | "Expected: %"PRIx64"\nEncountered: %" |
| 82 | PRIx64"\nExecuted Last: %"PRIx64 |
| 83 | "\nEvent type: %s\n", |
| 84 | pc_name, vcpu_index, expected, encountered, last, |
| 85 | discon_type_name); |
| 86 | if (abort_on_mismatch) { |
| 87 | /* |
| 88 | * The qemu log infrastructure may lose messages when aborting. Using |
| 89 | * fputs directly ensures the final report is visible to developers. |
| 90 | */ |
| 91 | fputs(report, stderr); |
| 92 | g_abort(); |
| 93 | } else { |
| 94 | qemu_plugin_outs(report); |
| 95 | } |
| 96 | g_free(report); |
| 97 | } |
| 98 | |
| 99 | static void vcpu_discon(unsigned int vcpu_index, |
| 100 | enum qemu_plugin_discon_type type, uint64_t from_pc, |
| 101 | uint64_t to_pc, void *userdata) |
| 102 | { |
| 103 | struct cpu_state *state = qemu_plugin_scoreboard_find(states, vcpu_index); |
| 104 | |
| 105 | if (type == QEMU_PLUGIN_DISCON_EXCEPTION && |
| 106 | addr_eq(state->last_pc, from_pc)) |
| 107 | { |
| 108 | /* |
| 109 | * For some types of exceptions, insn_exec will be called for the |
| 110 | * instruction that caused the exception. This is valid behaviour and |
| 111 | * does not need to be reported. |
| 112 | */ |
| 113 | } else if (state->has_next) { |
| 114 | /* |
| 115 | * We may encounter discontinuity chains without any instructions |
| 116 | * being executed in between. |
| 117 | */ |
| 118 | report_mismatch("source", vcpu_index, type, state->last_pc, |
| 119 | state->next_pc, from_pc); |
| 120 | } else if (state->has_from) { |
| 121 | report_mismatch("source", vcpu_index, type, state->last_pc, |
| 122 | state->from_pc, from_pc); |
| 123 | } |
| 124 | |
| 125 | state->has_from = false; |
| 126 | |
| 127 | state->next_pc = to_pc; |
| 128 | state->next_type = type; |
| 129 | state->has_next = true; |
| 130 | } |
| 131 | |
| 132 | static void insn_exec(unsigned int vcpu_index, void *userdata) |
| 133 | { |
| 134 | struct cpu_state *state = qemu_plugin_scoreboard_find(states, vcpu_index); |
| 135 | |
| 136 | if (state->has_next) { |
| 137 | report_mismatch("target", vcpu_index, state->next_type, state->last_pc, |
| 138 | state->next_pc, state->last_pc); |
| 139 | state->has_next = false; |
| 140 | } |
| 141 | |
| 142 | if (trace_all_insns) { |
| 143 | g_autoptr(GString) report = g_string_new(NULL); |
| 144 | g_string_append_printf(report, "Exec insn at %"PRIx64" on VCPU %d\n", |
| 145 | state->last_pc, vcpu_index); |
| 146 | qemu_plugin_outs(report->str); |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | static void vcpu_tb_trans(struct qemu_plugin_tb *tb, void *userdata) |
| 151 | { |
| 152 | size_t n_insns = qemu_plugin_tb_n_insns(tb); |
| 153 | for (size_t i = 0; i < n_insns; i++) { |
| 154 | struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i); |
| 155 | uint64_t pc = qemu_plugin_insn_vaddr(insn); |
| 156 | uint64_t next_pc = pc + qemu_plugin_insn_size(insn); |
| 157 | uint64_t has_next = (i + 1) < n_insns; |
| 158 | |
| 159 | qemu_plugin_register_vcpu_insn_exec_inline_per_vcpu(insn, |
| 160 | QEMU_PLUGIN_INLINE_STORE_U64, |
| 161 | last_pc, pc); |
| 162 | qemu_plugin_register_vcpu_insn_exec_inline_per_vcpu(insn, |
| 163 | QEMU_PLUGIN_INLINE_STORE_U64, |
| 164 | from_pc, next_pc); |
| 165 | qemu_plugin_register_vcpu_insn_exec_inline_per_vcpu(insn, |
| 166 | QEMU_PLUGIN_INLINE_STORE_U64, |
| 167 | has_from, has_next); |
| 168 | qemu_plugin_register_vcpu_insn_exec_cb(insn, insn_exec, |
| 169 | QEMU_PLUGIN_CB_NO_REGS, NULL); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id, |
| 174 | const qemu_info_t *info, |
| 175 | int argc, char **argv) |
| 176 | { |
| 177 | if (!info->system_emulation) { |
| 178 | qemu_plugin_outs("Testing of the disontinuity plugin API is only" |
| 179 | " possible in system emulation mode."); |
| 180 | return 0; |
| 181 | } |
| 182 | |
| 183 | /* Set defaults */ |
| 184 | abort_on_mismatch = true; |
| 185 | trace_all_insns = false; |
| 186 | |
| 187 | for (int i = 0; i < argc; i++) { |
| 188 | char *opt = argv[i]; |
| 189 | g_auto(GStrv) tokens = g_strsplit(opt, "=", 2); |
| 190 | if (g_strcmp0(tokens[0], "abort") == 0) { |
| 191 | if (!qemu_plugin_bool_parse(tokens[0], tokens[1], |
| 192 | &abort_on_mismatch)) { |
| 193 | fprintf(stderr, "boolean argument parsing failed: %s\n", opt); |
| 194 | return -1; |
| 195 | } |
| 196 | } else if (g_strcmp0(tokens[0], "trace-all") == 0) { |
| 197 | if (!qemu_plugin_bool_parse(tokens[0], tokens[1], |
| 198 | &trace_all_insns)) { |
| 199 | fprintf(stderr, "boolean argument parsing failed: %s\n", opt); |
| 200 | return -1; |
| 201 | } |
| 202 | } else { |
| 203 | fprintf(stderr, "option parsing failed: %s\n", opt); |
| 204 | return -1; |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | states = qemu_plugin_scoreboard_new(sizeof(struct cpu_state)); |
| 209 | last_pc = qemu_plugin_scoreboard_u64_in_struct(states, struct cpu_state, |
| 210 | last_pc); |
| 211 | from_pc = qemu_plugin_scoreboard_u64_in_struct(states, struct cpu_state, |
| 212 | from_pc); |
| 213 | has_from = qemu_plugin_scoreboard_u64_in_struct(states, struct cpu_state, |
| 214 | has_from); |
| 215 | |
| 216 | qemu_plugin_register_vcpu_discon_cb(id, QEMU_PLUGIN_DISCON_ALL, |
| 217 | vcpu_discon, NULL); |
| 218 | qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans, NULL); |
| 219 | |
| 220 | return 0; |
| 221 | } |