qemu-e2k/include/qemu/plugin.h
Alex Bennée f7e68c9c99 tcg/plugins: implement a qemu_plugin_user_exit helper
In user-mode emulation there is a small race between preexit_cleanup
and exit_group() which means we may end up calling instrumented
instructions before the kernel reaps child threads. To solve this we
implement a new helper which ensures the callbacks are flushed along
with any translations before we let the host do it's a thing.

While we are at it make the documentation of
qemu_plugin_register_atexit_cb clearer as to what the user can expect.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Mahmoud Mandour <ma.mandourr@gmail.com>
Acked-by: Warner Losh <imp@bsdimp.com>
Message-Id: <20210720232703.10650-21-alex.bennee@linaro.org>
2021-07-23 17:22:16 +01:00

268 lines
7.1 KiB
C

/*
* Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
*
* License: GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef QEMU_PLUGIN_H
#define QEMU_PLUGIN_H
#include "qemu/config-file.h"
#include "qemu/qemu-plugin.h"
#include "qemu/error-report.h"
#include "qemu/queue.h"
#include "qemu/option.h"
/*
* Events that plugins can subscribe to.
*/
enum qemu_plugin_event {
QEMU_PLUGIN_EV_VCPU_INIT,
QEMU_PLUGIN_EV_VCPU_EXIT,
QEMU_PLUGIN_EV_VCPU_TB_TRANS,
QEMU_PLUGIN_EV_VCPU_IDLE,
QEMU_PLUGIN_EV_VCPU_RESUME,
QEMU_PLUGIN_EV_VCPU_SYSCALL,
QEMU_PLUGIN_EV_VCPU_SYSCALL_RET,
QEMU_PLUGIN_EV_FLUSH,
QEMU_PLUGIN_EV_ATEXIT,
QEMU_PLUGIN_EV_MAX, /* total number of plugin events we support */
};
/*
* Option parsing/processing.
* Note that we can load an arbitrary number of plugins.
*/
struct qemu_plugin_desc;
typedef QTAILQ_HEAD(, qemu_plugin_desc) QemuPluginList;
#ifdef CONFIG_PLUGIN
extern QemuOptsList qemu_plugin_opts;
static inline void qemu_plugin_add_opts(void)
{
qemu_add_opts(&qemu_plugin_opts);
}
void qemu_plugin_opt_parse(const char *optarg, QemuPluginList *head);
int qemu_plugin_load_list(QemuPluginList *head, Error **errp);
union qemu_plugin_cb_sig {
qemu_plugin_simple_cb_t simple;
qemu_plugin_udata_cb_t udata;
qemu_plugin_vcpu_simple_cb_t vcpu_simple;
qemu_plugin_vcpu_udata_cb_t vcpu_udata;
qemu_plugin_vcpu_tb_trans_cb_t vcpu_tb_trans;
qemu_plugin_vcpu_mem_cb_t vcpu_mem;
qemu_plugin_vcpu_syscall_cb_t vcpu_syscall;
qemu_plugin_vcpu_syscall_ret_cb_t vcpu_syscall_ret;
void *generic;
};
enum plugin_dyn_cb_type {
PLUGIN_CB_INSN,
PLUGIN_CB_MEM,
PLUGIN_N_CB_TYPES,
};
enum plugin_dyn_cb_subtype {
PLUGIN_CB_REGULAR,
PLUGIN_CB_INLINE,
PLUGIN_N_CB_SUBTYPES,
};
/*
* A dynamic callback has an insertion point that is determined at run-time.
* Usually the insertion point is somewhere in the code cache; think for
* instance of a callback to be called upon the execution of a particular TB.
*/
struct qemu_plugin_dyn_cb {
union qemu_plugin_cb_sig f;
void *userp;
enum plugin_dyn_cb_subtype type;
/* @rw applies to mem callbacks only (both regular and inline) */
enum qemu_plugin_mem_rw rw;
/* fields specific to each dyn_cb type go here */
union {
struct {
enum qemu_plugin_op op;
uint64_t imm;
} inline_insn;
};
};
/* Internal context for instrumenting an instruction */
struct qemu_plugin_insn {
GByteArray *data;
uint64_t vaddr;
void *haddr;
GArray *cbs[PLUGIN_N_CB_TYPES][PLUGIN_N_CB_SUBTYPES];
bool calls_helpers;
bool mem_helper;
bool mem_only;
};
/*
* qemu_plugin_insn allocate and cleanup functions. We don't expect to
* cleanup many of these structures. They are reused for each fresh
* translation.
*/
static inline void qemu_plugin_insn_cleanup_fn(gpointer data)
{
struct qemu_plugin_insn *insn = (struct qemu_plugin_insn *) data;
g_byte_array_free(insn->data, true);
}
static inline struct qemu_plugin_insn *qemu_plugin_insn_alloc(void)
{
int i, j;
struct qemu_plugin_insn *insn = g_new0(struct qemu_plugin_insn, 1);
insn->data = g_byte_array_sized_new(4);
for (i = 0; i < PLUGIN_N_CB_TYPES; i++) {
for (j = 0; j < PLUGIN_N_CB_SUBTYPES; j++) {
insn->cbs[i][j] = g_array_new(false, false,
sizeof(struct qemu_plugin_dyn_cb));
}
}
return insn;
}
/* Internal context for this TranslationBlock */
struct qemu_plugin_tb {
GPtrArray *insns;
size_t n;
uint64_t vaddr;
uint64_t vaddr2;
void *haddr1;
void *haddr2;
bool mem_only;
GArray *cbs[PLUGIN_N_CB_SUBTYPES];
};
/**
* qemu_plugin_tb_insn_get(): get next plugin record for translation.
*
*/
static inline
struct qemu_plugin_insn *qemu_plugin_tb_insn_get(struct qemu_plugin_tb *tb)
{
struct qemu_plugin_insn *insn;
int i, j;
if (unlikely(tb->n == tb->insns->len)) {
struct qemu_plugin_insn *new_insn = qemu_plugin_insn_alloc();
g_ptr_array_add(tb->insns, new_insn);
}
insn = g_ptr_array_index(tb->insns, tb->n++);
g_byte_array_set_size(insn->data, 0);
insn->calls_helpers = false;
insn->mem_helper = false;
for (i = 0; i < PLUGIN_N_CB_TYPES; i++) {
for (j = 0; j < PLUGIN_N_CB_SUBTYPES; j++) {
g_array_set_size(insn->cbs[i][j], 0);
}
}
return insn;
}
void qemu_plugin_vcpu_init_hook(CPUState *cpu);
void qemu_plugin_vcpu_exit_hook(CPUState *cpu);
void qemu_plugin_tb_trans_cb(CPUState *cpu, struct qemu_plugin_tb *tb);
void qemu_plugin_vcpu_idle_cb(CPUState *cpu);
void qemu_plugin_vcpu_resume_cb(CPUState *cpu);
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);
void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret);
void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr, uint32_t meminfo);
void qemu_plugin_flush_cb(void);
void qemu_plugin_atexit_cb(void);
void qemu_plugin_add_dyn_cb_arr(GArray *arr);
void qemu_plugin_disable_mem_helpers(CPUState *cpu);
/**
* qemu_plugin_user_exit(): clean-up callbacks before calling exit callbacks
*
* This is a user-mode only helper that ensure we have fully cleared
* callbacks from all threads before calling the exit callbacks. This
* is so the plugins themselves don't have to jump through hoops to
* guard against race conditions.
*/
void qemu_plugin_user_exit(void);
#else /* !CONFIG_PLUGIN */
static inline void qemu_plugin_add_opts(void)
{ }
static inline void qemu_plugin_opt_parse(const char *optarg,
QemuPluginList *head)
{
error_report("plugin interface not enabled in this build");
exit(1);
}
static inline int qemu_plugin_load_list(QemuPluginList *head, Error **errp)
{
return 0;
}
static inline void qemu_plugin_vcpu_init_hook(CPUState *cpu)
{ }
static inline void qemu_plugin_vcpu_exit_hook(CPUState *cpu)
{ }
static inline void qemu_plugin_tb_trans_cb(CPUState *cpu,
struct qemu_plugin_tb *tb)
{ }
static inline void qemu_plugin_vcpu_idle_cb(CPUState *cpu)
{ }
static inline void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
{ }
static inline 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)
{ }
static inline
void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret)
{ }
static inline void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t vaddr,
uint32_t meminfo)
{ }
static inline void qemu_plugin_flush_cb(void)
{ }
static inline void qemu_plugin_atexit_cb(void)
{ }
static inline
void qemu_plugin_add_dyn_cb_arr(GArray *arr)
{ }
static inline void qemu_plugin_disable_mem_helpers(CPUState *cpu)
{ }
static inline void qemu_plugin_user_exit(void)
{ }
#endif /* !CONFIG_PLUGIN */
#endif /* QEMU_PLUGIN_H */