/*
* QEMU Plugin Core code
*
* This is the core code that deals with injecting instrumentation into the code
*
* Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
* Copyright (C) 2019, Linaro
*
* License: GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "qemu/osdep.h"
#include "qemu/error-report.h"
#include "qemu/config-file.h"
#include "qapi/error.h"
#include "qemu/lockable.h"
#include "qemu/option.h"
#include "qemu/rcu_queue.h"
#include "qemu/xxhash.h"
#include "qemu/rcu.h"
#include "hw/core/cpu.h"
#include "exec/cpu-common.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
#include "tcg/tcg.h"
#include "tcg/tcg-op.h"
#include "plugin.h"
#include "qemu/compiler.h"
struct qemu_plugin_cb {
struct qemu_plugin_ctx *ctx;
union qemu_plugin_cb_sig f;
void *udata;
QLIST_ENTRY(qemu_plugin_cb) entry;
};
struct qemu_plugin_state plugin;
struct qemu_plugin_ctx *plugin_id_to_ctx_locked(qemu_plugin_id_t id)
{
struct qemu_plugin_ctx *ctx;
qemu_plugin_id_t *id_p;
id_p = g_hash_table_lookup(plugin.id_ht, &id);
ctx = container_of(id_p, struct qemu_plugin_ctx, id);
if (ctx == NULL) {
error_report("plugin: invalid plugin id %" PRIu64, id);
abort();
}
return ctx;
}
static void plugin_cpu_update__async(CPUState *cpu, run_on_cpu_data data)
{
bitmap_copy(cpu->plugin_mask, &data.host_ulong, QEMU_PLUGIN_EV_MAX);
tcg_flush_jmp_cache(cpu);
}
static void plugin_cpu_update__locked(gpointer k, gpointer v, gpointer udata)
{
CPUState *cpu = container_of(k, CPUState, cpu_index);
run_on_cpu_data mask = RUN_ON_CPU_HOST_ULONG(*plugin.mask);
if (cpu->created) {
async_run_on_cpu(cpu, plugin_cpu_update__async, mask);
} else {
plugin_cpu_update__async(cpu, mask);
}
}
void plugin_unregister_cb__locked(struct qemu_plugin_ctx *ctx,
enum qemu_plugin_event ev)
{
struct qemu_plugin_cb *cb = ctx->callbacks[ev];
if (cb == NULL) {
return;
}
QLIST_REMOVE_RCU(cb, entry);
g_free(cb);
ctx->callbacks[ev] = NULL;
if (QLIST_EMPTY_RCU(&plugin.cb_lists[ev])) {
clear_bit(ev, plugin.mask);
g_hash_table_foreach(plugin.cpu_ht, plugin_cpu_update__locked, NULL);
}
}
/*
* Disable CFI checks.
* The callback function has been loaded from an external library so we do not
* have type information
*/
QEMU_DISABLE_CFI
static void plugin_vcpu_cb__simple(CPUState *cpu, enum qemu_plugin_event ev)
{
struct qemu_plugin_cb *cb, *next;
switch (ev) {
case QEMU_PLUGIN_EV_VCPU_INIT:
case QEMU_PLUGIN_EV_VCPU_EXIT:
case QEMU_PLUGIN_EV_VCPU_IDLE:
case QEMU_PLUGIN_EV_VCPU_RESUME:
/* iterate safely; plugins might uninstall themselves at any time */
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_vcpu_simple_cb_t func = cb->f.vcpu_simple;
func(cb->ctx->id, cpu->cpu_index);
}
break;
default:
g_assert_not_reached();
}
}
/*
* Disable CFI checks.
* The callback function has been loaded from an external library so we do not
* have type information
*/
QEMU_DISABLE_CFI
static void plugin_cb__simple(enum qemu_plugin_event ev)
{
struct qemu_plugin_cb *cb, *next;
switch (ev) {
case QEMU_PLUGIN_EV_FLUSH:
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_simple_cb_t func = cb->f.simple;
func(cb->ctx->id);
}
break;
default:
g_assert_not_reached();
}
}
/*
* Disable CFI checks.
* The callback function has been loaded from an external library so we do not
* have type information
*/
QEMU_DISABLE_CFI
static void plugin_cb__udata(enum qemu_plugin_event ev)
{
struct qemu_plugin_cb *cb, *next;
switch (ev) {
case QEMU_PLUGIN_EV_ATEXIT:
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_udata_cb_t func = cb->f.udata;
func(cb->ctx->id, cb->udata);
}
break;
default:
g_assert_not_reached();
}
}
static void
do_plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev,
void *func, void *udata)
{
struct qemu_plugin_ctx *ctx;
QEMU_LOCK_GUARD(&plugin.lock);
ctx = plugin_id_to_ctx_locked(id);
/* if the plugin is on its way out, ignore this request */
if (unlikely(ctx->uninstalling)) {
return;
}
if (func) {
struct qemu_plugin_cb *cb = ctx->callbacks[ev];
if (cb) {
cb->f.generic = func;
cb->udata = udata;
} else {
cb = g_new(struct qemu_plugin_cb, 1);
cb->ctx = ctx;
cb->f.generic = func;
cb->udata = udata;
ctx->callbacks[ev] = cb;
QLIST_INSERT_HEAD_RCU(&plugin.cb_lists[ev], cb, entry);
if (!test_bit(ev, plugin.mask)) {
set_bit(ev, plugin.mask);
g_hash_table_foreach(plugin.cpu_ht, plugin_cpu_update__locked,
NULL);
}
}
} else {
plugin_unregister_cb__locked(ctx, ev);
}
}
void plugin_register_cb(qemu_plugin_id_t id, enum qemu_plugin_event ev,
void *func)
{
do_plugin_register_cb(id, ev, func, NULL);
}
void
plugin_register_cb_udata(qemu_plugin_id_t id, enum qemu_plugin_event ev,
void *func, void *udata)
{
do_plugin_register_cb(id, ev, func, udata);
}
void qemu_plugin_vcpu_init_hook(CPUState *cpu)
{
bool success;
qemu_rec_mutex_lock(&plugin.lock);
plugin_cpu_update__locked(&cpu->cpu_index, NULL, NULL);
success = g_hash_table_insert(plugin.cpu_ht, &cpu->cpu_index,
&cpu->cpu_index);
g_assert(success);
qemu_rec_mutex_unlock(&plugin.lock);
plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_INIT);
}
void qemu_plugin_vcpu_exit_hook(CPUState *cpu)
{
bool success;
plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_EXIT);
qemu_rec_mutex_lock(&plugin.lock);
success = g_hash_table_remove(plugin.cpu_ht, &cpu->cpu_index);
g_assert(success);
qemu_rec_mutex_unlock(&plugin.lock);
}
struct plugin_for_each_args {
struct qemu_plugin_ctx *ctx;
qemu_plugin_vcpu_simple_cb_t cb;
};
static void plugin_vcpu_for_each(gpointer k, gpointer v, gpointer udata)
{
struct plugin_for_each_args *args = udata;
int cpu_index = *(int *)k;
args->cb(args->ctx->id, cpu_index);
}
void qemu_plugin_vcpu_for_each(qemu_plugin_id_t id,
qemu_plugin_vcpu_simple_cb_t cb)
{
struct plugin_for_each_args args;
if (cb == NULL) {
return;
}
qemu_rec_mutex_lock(&plugin.lock);
args.ctx = plugin_id_to_ctx_locked(id);
args.cb = cb;
g_hash_table_foreach(plugin.cpu_ht, plugin_vcpu_for_each, &args);
qemu_rec_mutex_unlock(&plugin.lock);
}
/* Allocate and return a callback record */
static struct qemu_plugin_dyn_cb *plugin_get_dyn_cb(GArray **arr)
{
GArray *cbs = *arr;
if (!cbs) {
cbs = g_array_sized_new(false, false,
sizeof(struct qemu_plugin_dyn_cb), 1);
*arr = cbs;
}
g_array_set_size(cbs, cbs->len + 1);
return &g_array_index(cbs, struct qemu_plugin_dyn_cb, cbs->len - 1);
}
void plugin_register_inline_op(GArray **arr,
enum qemu_plugin_mem_rw rw,
enum qemu_plugin_op op, void *ptr,
uint64_t imm)
{
struct qemu_plugin_dyn_cb *dyn_cb;
dyn_cb = plugin_get_dyn_cb(arr);
dyn_cb->userp = ptr;
dyn_cb->type = PLUGIN_CB_INLINE;
dyn_cb->rw = rw;
dyn_cb->inline_insn.op = op;
dyn_cb->inline_insn.imm = imm;
}
void plugin_register_dyn_cb__udata(GArray **arr,
qemu_plugin_vcpu_udata_cb_t cb,
enum qemu_plugin_cb_flags flags,
void *udata)
{
struct qemu_plugin_dyn_cb *dyn_cb = plugin_get_dyn_cb(arr);
dyn_cb->userp = udata;
/* Note flags are discarded as unused. */
dyn_cb->f.vcpu_udata = cb;
dyn_cb->type = PLUGIN_CB_REGULAR;
}
void plugin_register_vcpu_mem_cb(GArray **arr,
void *cb,
enum qemu_plugin_cb_flags flags,
enum qemu_plugin_mem_rw rw,
void *udata)
{
struct qemu_plugin_dyn_cb *dyn_cb;
dyn_cb = plugin_get_dyn_cb(arr);
dyn_cb->userp = udata;
/* Note flags are discarded as unused. */
dyn_cb->type = PLUGIN_CB_REGULAR;
dyn_cb->rw = rw;
dyn_cb->f.generic = cb;
}
/*
* Disable CFI checks.
* The callback function has been loaded from an external library so we do not
* have type information
*/
QEMU_DISABLE_CFI
void qemu_plugin_tb_trans_cb(CPUState *cpu, struct qemu_plugin_tb *tb)
{
struct qemu_plugin_cb *cb, *next;
enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_TB_TRANS;
/* no plugin_mask check here; caller should have checked */
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_vcpu_tb_trans_cb_t func = cb->f.vcpu_tb_trans;
func(cb->ctx->id, tb);
}
}
/*
* Disable CFI checks.
* The callback function has been loaded from an external library so we do not
* have type information
*/
QEMU_DISABLE_CFI
void
qemu_plugin_vcpu_syscall(CPUState *cpu, int64_t num, uint64_t a1, uint64_t a2,
uint64_t a3, uint64_t a4, uint64_t a5,
uint64_t a6, uint64_t a7, uint64_t a8)
{
struct qemu_plugin_cb *cb, *next;
enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_SYSCALL;
if (!test_bit(ev, cpu->plugin_mask)) {
return;
}
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_vcpu_syscall_cb_t func = cb->f.vcpu_syscall;
func(cb->ctx->id, cpu->cpu_index, num, a1, a2, a3, a4, a5, a6, a7, a8);
}
}
/*
* Disable CFI checks.
* The callback function has been loaded from an external library so we do not
* have type information
*/
QEMU_DISABLE_CFI
void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret)
{
struct qemu_plugin_cb *cb, *next;
enum qemu_plugin_event ev = QEMU_PLUGIN_EV_VCPU_SYSCALL_RET;
if (!test_bit(ev, cpu->plugin_mask)) {
return;
}
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_vcpu_syscall_ret_cb_t func = cb->f.vcpu_syscall_ret;
func(cb->ctx->id, cpu->cpu_index, num, ret);
}
}
void qemu_plugin_vcpu_idle_cb(CPUState *cpu)
{
plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_IDLE);
}
void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
{
plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_RESUME);
}
void qemu_plugin_register_vcpu_idle_cb(qemu_plugin_id_t id,
qemu_plugin_vcpu_simple_cb_t cb)
{
plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_IDLE, cb);
}
void qemu_plugin_register_vcpu_resume_cb(qemu_plugin_id_t id,
qemu_plugin_vcpu_simple_cb_t cb)
{
plugin_register_cb(id, QEMU_PLUGIN_EV_VCPU_RESUME, cb);
}
void qemu_plugin_register_flush_cb(qemu_plugin_id_t id,
qemu_plugin_simple_cb_t cb)
{
plugin_register_cb(id, QEMU_PLUGIN_EV_FLUSH, cb);
}
static bool free_dyn_cb_arr(void *p, uint32_t h, void *userp)
{
g_array_free((GArray *) p, true);
return true;
}
void qemu_plugin_flush_cb(void)
{
qht_iter_remove(&plugin.dyn_cb_arr_ht, free_dyn_cb_arr, NULL);
qht_reset(&plugin.dyn_cb_arr_ht);
plugin_cb__simple(QEMU_PLUGIN_EV_FLUSH);
}
void exec_inline_op(struct qemu_plugin_dyn_cb *cb)
{
uint64_t *val = cb->userp;
switch (cb->inline_insn.op) {
case QEMU_PLUGIN_INLINE_ADD_U64:
*val += cb->inline_insn.imm;
break;
default:
g_assert_not_reached();
}
}
void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr,
MemOpIdx oi, enum qemu_plugin_mem_rw rw)
{
GArray *arr = cpu->plugin_mem_cbs;
size_t i;
if (arr == NULL) {
return;
}
for (i = 0; i < arr->len; i++) {
struct qemu_plugin_dyn_cb *cb =
&g_array_index(arr, struct qemu_plugin_dyn_cb, i);
if (!(rw & cb->rw)) {
break;
}
switch (cb->type) {
case PLUGIN_CB_REGULAR:
cb->f.vcpu_mem(cpu->cpu_index, make_plugin_meminfo(oi, rw),
vaddr, cb->userp);
break;
case PLUGIN_CB_INLINE:
exec_inline_op(cb);
break;
default:
g_assert_not_reached();
}
}
}
void qemu_plugin_atexit_cb(void)
{
plugin_cb__udata(QEMU_PLUGIN_EV_ATEXIT);
}
void qemu_plugin_register_atexit_cb(qemu_plugin_id_t id,
qemu_plugin_udata_cb_t cb,
void *udata)
{
plugin_register_cb_udata(id, QEMU_PLUGIN_EV_ATEXIT, cb, udata);
}
/*
* Handle exit from linux-user. Unlike the normal atexit() mechanism
* we need to handle the clean-up manually as it's possible threads
* are still running. We need to remove all callbacks from code
* generation, flush the current translations and then we can safely
* trigger the exit callbacks.
*/
void qemu_plugin_user_exit(void)
{
enum qemu_plugin_event ev;
CPUState *cpu;
QEMU_LOCK_GUARD(&plugin.lock);
start_exclusive();
/* un-register all callbacks except the final AT_EXIT one */
for (ev = 0; ev < QEMU_PLUGIN_EV_MAX; ev++) {
if (ev != QEMU_PLUGIN_EV_ATEXIT) {
struct qemu_plugin_ctx *ctx;
QTAILQ_FOREACH(ctx, &plugin.ctxs, entry) {
plugin_unregister_cb__locked(ctx, ev);
}
}
}
tb_flush(current_cpu);
CPU_FOREACH(cpu) {
qemu_plugin_disable_mem_helpers(cpu);
}
end_exclusive();
/* now it's safe to handle the exit case */
qemu_plugin_atexit_cb();
}
/*
* Helpers for *-user to ensure locks are sane across fork() events.
*/
void qemu_plugin_user_prefork_lock(void)
{
qemu_rec_mutex_lock(&plugin.lock);
}
void qemu_plugin_user_postfork(bool is_child)
{
if (is_child) {
/* should we just reset via plugin_init? */
qemu_rec_mutex_init(&plugin.lock);
} else {
qemu_rec_mutex_unlock(&plugin.lock);
}
}
/*
* Call this function after longjmp'ing to the main loop. It's possible that the
* last instruction of a TB might have used helpers, and therefore the
* "disable" instruction will never execute because it ended up as dead code.
*/
void qemu_plugin_disable_mem_helpers(CPUState *cpu)
{
cpu->plugin_mem_cbs = NULL;
}
static bool plugin_dyn_cb_arr_cmp(const void *ap, const void *bp)
{
return ap == bp;
}
static void __attribute__((__constructor__)) plugin_init(void)
{
int i;
for (i = 0; i < QEMU_PLUGIN_EV_MAX; i++) {
QLIST_INIT(&plugin.cb_lists[i]);
}
qemu_rec_mutex_init(&plugin.lock);
plugin.id_ht = g_hash_table_new(g_int64_hash, g_int64_equal);
plugin.cpu_ht = g_hash_table_new(g_int_hash, g_int_equal);
QTAILQ_INIT(&plugin.ctxs);
qht_init(&plugin.dyn_cb_arr_ht, plugin_dyn_cb_arr_cmp, 16,
QHT_MODE_AUTO_RESIZE);
atexit(qemu_plugin_atexit_cb);
}
