jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
1/*
2 * QEMU Plugin Core code
3 *
4 * This is the core code that deals with injecting instrumentation into the code
5 *
6 * Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
7 * Copyright (C) 2019, Linaro
8 *
9 * License: GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 *
12 * SPDX-License-Identifier: GPL-2.0-or-later
13 */
14#include "qemu/osdep.h"
15#include "qemu/error-report.h"
16#include "qemu/config-file.h"
17#include "qapi/error.h"
18#include "qemu/lockable.h"
19#include "qemu/option.h"
20#include "qemu/rcu_queue.h"
21#include "qemu/xxhash.h"
22#include "qemu/rcu.h"
23#include "hw/core/cpu.h"
24#include "exec/cpu-common.h"
25
26#include "cpu.h"
27#include "exec/exec-all.h"
28#include "exec/helper-proto.h"
29#include "sysemu/sysemu.h"
30#include "tcg/tcg.h"
31#include "tcg/tcg-op.h"
32#include "trace/mem-internal.h" /* mem_info macros */
33#include "plugin.h"
34
35struct qemu_plugin_cb {
36 struct qemu_plugin_ctx *ctx;
37 union qemu_plugin_cb_sig f;
38 void *udata;
39 QLIST_ENTRY(qemu_plugin_cb) entry;
40};
41
42struct qemu_plugin_state plugin;
43
44struct qemu_plugin_ctx *plugin_id_to_ctx_locked(qemu_plugin_id_t id)
45{
46 struct qemu_plugin_ctx *ctx;
47 qemu_plugin_id_t *id_p;
48
49 id_p = g_hash_table_lookup(plugin.id_ht, &id);
50 ctx = container_of(id_p, struct qemu_plugin_ctx, id);
51 if (ctx == NULL) {
52 error_report("plugin: invalid plugin id %" PRIu64, id);
53 abort();
54 }
55 return ctx;
56}
57
58static void plugin_cpu_update__async(CPUState *cpu, run_on_cpu_data data)
59{
60 bitmap_copy(cpu->plugin_mask, &data.host_ulong, QEMU_PLUGIN_EV_MAX);
61 cpu_tb_jmp_cache_clear(cpu);
62}
63
64static void plugin_cpu_update__locked(gpointer k, gpointer v, gpointer udata)
65{
66 CPUState *cpu = container_of(k, CPUState, cpu_index);
67 run_on_cpu_data mask = RUN_ON_CPU_HOST_ULONG(*plugin.mask);
68
69 if (cpu->created) {
70 async_run_on_cpu(cpu, plugin_cpu_update__async, mask);
71 } else {
72 plugin_cpu_update__async(cpu, mask);
73 }
74}
75
76void plugin_unregister_cb__locked(struct qemu_plugin_ctx *ctx,
77 enum qemu_plugin_event ev)
78{
79 struct qemu_plugin_cb *cb = ctx->callbacks[ev];
80
81 if (cb == NULL) {
82 return;
83 }
84 QLIST_REMOVE_RCU(cb, entry);
85 g_free(cb);
86 ctx->callbacks[ev] = NULL;
87 if (QLIST_EMPTY_RCU(&plugin.cb_lists[ev])) {
88 clear_bit(ev, plugin.mask);
89 g_hash_table_foreach(plugin.cpu_ht, plugin_cpu_update__locked, NULL);
90 }
91}
92
93static void plugin_vcpu_cb__simple(CPUState *cpu, enum qemu_plugin_event ev)
94{
95 struct qemu_plugin_cb *cb, *next;
96
97 switch (ev) {
98 case QEMU_PLUGIN_EV_VCPU_INIT:
99 case QEMU_PLUGIN_EV_VCPU_EXIT:
100 case QEMU_PLUGIN_EV_VCPU_IDLE:
101 case QEMU_PLUGIN_EV_VCPU_RESUME:
102 /* iterate safely; plugins might uninstall themselves at any time */
103 QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
104 qemu_plugin_vcpu_simple_cb_t func = cb->f.vcpu_simple;
105
106 func(cb->ctx->id, cpu->cpu_index);
107 }
108 break;
109 default:
110 g_assert_not_reached();
111 }
112}
113
114static void plugin_cb__simple(enum qemu_plugin_event ev)
115{
116 struct qemu_plugin_cb *cb, *next;
117
118 switch (ev) {
119 case QEMU_PLUGIN_EV_FLUSH:
120 QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
121 qemu_plugin_simple_cb_t func = cb->f.simple;
122
123 func(cb->ctx->id);
124 }
125 break;
126 default:
127 g_assert_not_reached();
128 }
129}
130
131static void plugin_cb__udata(enum qemu_plugin_event ev)
132{
133 struct qemu_plugin_cb *cb, *next;
134
135 switch (ev) {
136 case QEMU_PLUGIN_EV_ATEXIT:
137 QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
138 qemu_plugin_udata_cb_t func = cb->f.udata;
139
140 func(cb->ctx->id, cb->udata);
141 }
142 break;
143 default:
144 g_assert_not_reached();
145 }
146}
147
148static void
149do_plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev,
150 void *func, void *udata)
151{
152 struct qemu_plugin_ctx *ctx;
153
154 QEMU_LOCK_GUARD(&plugin.lock);
155 ctx = plugin_id_to_ctx_locked(id);
156 /* if the plugin is on its way out, ignore this request */
157 if (unlikely(ctx->uninstalling)) {
158 return;
159 }
160 if (func) {
161 struct qemu_plugin_cb *cb = ctx->callbacks[ev];
162
163 if (cb) {
164 cb->f.generic = func;
165 cb->udata = udata;
166 } else {
167 cb = g_new(struct qemu_plugin_cb, 1);
168 cb->ctx = ctx;
169 cb->f.generic = func;
170 cb->udata = udata;
171 ctx->callbacks[ev] = cb;
172 QLIST_INSERT_HEAD_RCU(&plugin.cb_lists[ev], cb, entry);
173 if (!test_bit(ev, plugin.mask)) {
174 set_bit(ev, plugin.mask);
175 g_hash_table_foreach(plugin.cpu_ht, plugin_cpu_update__locked,
176 NULL);
177 }
178 }
179 } else {
180 plugin_unregister_cb__locked(ctx, ev);
181 }
182}
183
184void plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev,
185 void *func)
186{
187 do_plugin_register_cb(id, ev, func, NULL);
188}
189
190void
191plugin_register_cb_udata(qemu_plugin_id_t id, enum qemu_plugin_event ev,
192 void *func, void *udata)
193{
194 do_plugin_register_cb(id, ev, func, udata);
195}
196
197void qemu_plugin_vcpu_init_hook(CPUState *cpu)
198{
199 bool success;
200
201 qemu_rec_mutex_lock(&plugin.lock);
202 plugin_cpu_update__locked(&cpu->cpu_index, NULL, NULL);
203 success = g_hash_table_insert(plugin.cpu_ht, &cpu->cpu_index,
204 &cpu->cpu_index);
205 g_assert(success);
206 qemu_rec_mutex_unlock(&plugin.lock);
207
208 plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_INIT);
209}
210
211void qemu_plugin_vcpu_exit_hook(CPUState *cpu)
212{
213 bool success;
214
215 plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_EXIT);
216
217 qemu_rec_mutex_lock(&plugin.lock);
218 success = g_hash_table_remove(plugin.cpu_ht, &cpu->cpu_index);
219 g_assert(success);
220 qemu_rec_mutex_unlock(&plugin.lock);
221}
222
223struct plugin_for_each_args {
224 struct qemu_plugin_ctx *ctx;
225 qemu_plugin_vcpu_simple_cb_t cb;
226};
227
228static void plugin_vcpu_for_each(gpointer k, gpointer v, gpointer udata)
229{
230 struct plugin_for_each_args *args = udata;
231 int cpu_index = *(int *)k;
232
233 args->cb(args->ctx->id, cpu_index);
234}
235
236void qemu_plugin_vcpu_for_each(qemu_plugin_id_t id,
237 qemu_plugin_vcpu_simple_cb_t cb)
238{
239 struct plugin_for_each_args args;
240
241 if (cb == NULL) {
242 return;
243 }
244 qemu_rec_mutex_lock(&plugin.lock);
245 args.ctx = plugin_id_to_ctx_locked(id);
246 args.cb = cb;
247 g_hash_table_foreach(plugin.cpu_ht, plugin_vcpu_for_each, &args);
248 qemu_rec_mutex_unlock(&plugin.lock);
249}
250
251/* Allocate and return a callback record */
252static struct qemu_plugin_dyn_cb *plugin_get_dyn_cb(GArray **arr)
253{
254 GArray *cbs = *arr;
255
256 if (!cbs) {
257 cbs = g_array_sized_new(false, false,
258 sizeof(struct qemu_plugin_dyn_cb), 1);
259 *arr = cbs;
260 }
261
262 g_array_set_size(cbs, cbs->len + 1);
263 return &g_array_index(cbs, struct qemu_plugin_dyn_cb, cbs->len - 1);
264}
265
266void plugin_register_inline_op(GArray **arr,
267 enum qemu_plugin_mem_rw rw,
268 enum qemu_plugin_op op, void *ptr,
269 uint64_t imm)
270{
271 struct qemu_plugin_dyn_cb *dyn_cb;
272
273 dyn_cb = plugin_get_dyn_cb(arr);
274 dyn_cb->userp = ptr;
275 dyn_cb->type = PLUGIN_CB_INLINE;
276 dyn_cb->rw = rw;
277 dyn_cb->inline_insn.op = op;
278 dyn_cb->inline_insn.imm = imm;
279}
280
281static inline uint32_t cb_to_tcg_flags(enum qemu_plugin_cb_flags flags)
282{
283 uint32_t ret;
284
285 switch (flags) {
286 case QEMU_PLUGIN_CB_RW_REGS:
287 ret = 0;
288 break;
289 case QEMU_PLUGIN_CB_R_REGS:
290 ret = TCG_CALL_NO_WG;
291 break;
292 case QEMU_PLUGIN_CB_NO_REGS:
293 default:
294 ret = TCG_CALL_NO_RWG;
295 }
296 return ret;
297}
298
299inline void
300plugin_register_dyn_cb__udata(GArray **arr,
301 qemu_plugin_vcpu_udata_cb_t cb,
302 enum qemu_plugin_cb_flags flags, void *udata)
303{
304 struct qemu_plugin_dyn_cb *dyn_cb = plugin_get_dyn_cb(arr);
305
306 dyn_cb->userp = udata;
307 dyn_cb->tcg_flags = cb_to_tcg_flags(flags);
308 dyn_cb->f.vcpu_udata = cb;
309 dyn_cb->type = PLUGIN_CB_REGULAR;
310}
311
312void plugin_register_vcpu_mem_cb(GArray **arr,
313 void *cb,
314 enum qemu_plugin_cb_flags flags,
315 enum qemu_plugin_mem_rw rw,
316 void *udata)
317{
318 struct qemu_plugin_dyn_cb *dyn_cb;
319
320 dyn_cb = plugin_get_dyn_cb(arr);
321 dyn_cb->userp = udata;
322 dyn_cb->tcg_flags = cb_to_tcg_flags(flags);
323 dyn_cb->type = PLUGIN_CB_REGULAR;
324 dyn_cb->rw = rw;
325 dyn_cb->f.generic = cb;
326}
327
328void qemu_plugin_tb_trans_cb(CPUState *cpu, struct qemu_plugin_tb *tb)
329{
330 struct qemu_plugin_cb *cb, *next;
331 enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_TB_TRANS;
332
333 /* no plugin_mask check here; caller should have checked */
334
335 QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
336 qemu_plugin_vcpu_tb_trans_cb_t func = cb->f.vcpu_tb_trans;
337
338 func(cb->ctx->id, tb);
339 }
340}
341
342void
343qemu_plugin_vcpu_syscall(CPUState *cpu, int64_t num, uint64_t a1, uint64_t a2,
344 uint64_t a3, uint64_t a4, uint64_t a5,
345 uint64_t a6, uint64_t a7, uint64_t a8)
346{
347 struct qemu_plugin_cb *cb, *next;
348 enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_SYSCALL;
349
350 if (!test_bit(ev, cpu->plugin_mask)) {
351 return;
352 }
353
354 QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
355 qemu_plugin_vcpu_syscall_cb_t func = cb->f.vcpu_syscall;
356
357 func(cb->ctx->id, cpu->cpu_index, num, a1, a2, a3, a4, a5, a6, a7, a8);
358 }
359}
360
361void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret)
362{
363 struct qemu_plugin_cb *cb, *next;
364 enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_SYSCALL_RET;
365
366 if (!test_bit(ev, cpu->plugin_mask)) {
367 return;
368 }
369
370 QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
371 qemu_plugin_vcpu_syscall_ret_cb_t func = cb->f.vcpu_syscall_ret;
372
373 func(cb->ctx->id, cpu->cpu_index, num, ret);
374 }
375}
376
377void qemu_plugin_vcpu_idle_cb(CPUState *cpu)
378{
379 plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_IDLE);
380}
381
382void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
383{
384 plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_RESUME);
385}
386
387void qemu_plugin_register_vcpu_idle_cb(qemu_plugin_id_t id,
388 qemu_plugin_vcpu_simple_cb_t cb)
389{
390 plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_IDLE, cb);
391}
392
393void qemu_plugin_register_vcpu_resume_cb(qemu_plugin_id_t id,
394 qemu_plugin_vcpu_simple_cb_t cb)
395{
396 plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_RESUME, cb);
397}
398
399void qemu_plugin_register_flush_cb(qemu_plugin_id_t id,
400 qemu_plugin_simple_cb_t cb)
401{
402 plugin_register_cb(id, QEMU_PLUGIN_EV_FLUSH, cb);
403}
404
405static bool free_dyn_cb_arr(void *p, uint32_t h, void *userp)
406{
407 g_array_free((GArray *) p, true);
408 return true;
409}
410
411void qemu_plugin_flush_cb(void)
412{
413 qht_iter_remove(&plugin.dyn_cb_arr_ht, free_dyn_cb_arr, NULL);
414 qht_reset(&plugin.dyn_cb_arr_ht);
415
416 plugin_cb__simple(QEMU_PLUGIN_EV_FLUSH);
417}
418
419void exec_inline_op(struct qemu_plugin_dyn_cb *cb)
420{
421 uint64_t *val = cb->userp;
422
423 switch (cb->inline_insn.op) {
424 case QEMU_PLUGIN_INLINE_ADD_U64:
425 *val += cb->inline_insn.imm;
426 break;
427 default:
428 g_assert_not_reached();
429 }
430}
431
432void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr, uint32_t info)
433{
434 GArray *arr = cpu->plugin_mem_cbs;
435 size_t i;
436
437 if (arr == NULL) {
438 return;
439 }
440 for (i = 0; i < arr->len; i++) {
441 struct qemu_plugin_dyn_cb *cb =
442 &g_array_index(arr, struct qemu_plugin_dyn_cb, i);
443 int w = !!(info & TRACE_MEM_ST) + 1;
444
445 if (!(w & cb->rw)) {
446 break;
447 }
448 switch (cb->type) {
449 case PLUGIN_CB_REGULAR:
450 cb->f.vcpu_mem(cpu->cpu_index, info, vaddr, cb->userp);
451 break;
452 case PLUGIN_CB_INLINE:
453 exec_inline_op(cb);
454 break;
455 default:
456 g_assert_not_reached();
457 }
458 }
459}
460
461void qemu_plugin_atexit_cb(void)
462{
463 plugin_cb__udata(QEMU_PLUGIN_EV_ATEXIT);
464}
465
466void qemu_plugin_register_atexit_cb(qemu_plugin_id_t id,
467 qemu_plugin_udata_cb_t cb,
468 void *udata)
469{
470 plugin_register_cb_udata(id, QEMU_PLUGIN_EV_ATEXIT, cb, udata);
471}
472
473/*
474 * Call this function after longjmp'ing to the main loop. It's possible that the
475 * last instruction of a TB might have used helpers, and therefore the
476 * "disable" instruction will never execute because it ended up as dead code.
477 */
478void qemu_plugin_disable_mem_helpers(CPUState *cpu)
479{
480 cpu->plugin_mem_cbs = NULL;
481}
482
483static bool plugin_dyn_cb_arr_cmp(const void *ap, const void *bp)
484{
485 return ap == bp;
486}
487
488static void __attribute__((__constructor__)) plugin_init(void)
489{
490 int i;
491
492 for (i = 0; i < QEMU_PLUGIN_EV_MAX; i++) {
493 QLIST_INIT(&plugin.cb_lists[i]);
494 }
495 qemu_rec_mutex_init(&plugin.lock);
496 plugin.id_ht = g_hash_table_new(g_int64_hash, g_int64_equal);
497 plugin.cpu_ht = g_hash_table_new(g_int_hash, g_int_equal);
498 QTAILQ_INIT(&plugin.ctxs);
499 qht_init(&plugin.dyn_cb_arr_ht, plugin_dyn_cb_arr_cmp, 16,
500 QHT_MODE_AUTO_RESIZE);
501 atexit(qemu_plugin_atexit_cb);
502}