This patch adds functionality to enforce the requested QEMU_PLUGIN_CB_
flags level passed when registering a callback function using the
plugins API. Each time a callback is about to be invoked, a thread-local
variable will be updated with the level that callback requested. Then,
called API functions (in particular, the register read and write API)
will call qemu_plugin_get_cb_flags() to check the level is at least the
level they require.
Signed-off-by: Rowan Hart <rowanbh...@gmail.com>
---
accel/tcg/plugin-gen.c | 27 +++++++++++++++++
include/qemu/plugin.h | 12 ++++++++
include/qemu/qemu-plugin.h | 3 --
plugins/api.c | 8 +++++
plugins/core.c | 60 ++++++++++++++++++++++++++++++++++----
5 files changed, 101 insertions(+), 9 deletions(-)
diff --git a/accel/tcg/plugin-gen.c b/accel/tcg/plugin-gen.c
index c1da753894..ceb2314bc1 100644
--- a/accel/tcg/plugin-gen.c
+++ b/accel/tcg/plugin-gen.c
@@ -117,10 +117,19 @@ static TCGv_i32 gen_cpu_index(void)
static void gen_udata_cb(struct qemu_plugin_regular_cb *cb)
{
TCGv_i32 cpu_index = gen_cpu_index();
+ enum qemu_plugin_cb_flags cb_flags =
+ tcg_call_to_qemu_plugin_cb_flags(cb->info->flags);
+ TCGv_i32 flags = tcg_constant_i32(cb_flags);
+ tcg_gen_call1(qemu_plugin_set_cb_flags,
+ qemu_plugin_get_set_cb_flags_helper_info(), NULL,
+ tcgv_i32_temp(flags));
tcg_gen_call2(cb->f.vcpu_udata, cb->info, NULL,
tcgv_i32_temp(cpu_index),
tcgv_ptr_temp(tcg_constant_ptr(cb->userp)));
+ tcg_gen_call0(qemu_plugin_clear_cb_flags,
+ qemu_plugin_get_clear_cb_flags_helper_info(), NULL);
tcg_temp_free_i32(cpu_index);
+ tcg_temp_free_i32(flags);
}
static TCGv_ptr gen_plugin_u64_ptr(qemu_plugin_u64 entry)
@@ -173,10 +182,19 @@ static void gen_udata_cond_cb(struct
qemu_plugin_conditional_cb *cb)
tcg_gen_ld_i64(val, ptr, 0);
tcg_gen_brcondi_i64(cond, val, cb->imm, after_cb);
TCGv_i32 cpu_index = gen_cpu_index();
+ enum qemu_plugin_cb_flags cb_flags =
+ tcg_call_to_qemu_plugin_cb_flags(cb->info->flags);
+ TCGv_i32 flags = tcg_constant_i32(cb_flags);
+ tcg_gen_call1(qemu_plugin_set_cb_flags,
+ qemu_plugin_get_set_cb_flags_helper_info(), NULL,
+ tcgv_i32_temp(flags));
tcg_gen_call2(cb->f.vcpu_udata, cb->info, NULL,
tcgv_i32_temp(cpu_index),
tcgv_ptr_temp(tcg_constant_ptr(cb->userp)));
+ tcg_gen_call0(qemu_plugin_clear_cb_flags,
+ qemu_plugin_get_clear_cb_flags_helper_info(), NULL);
tcg_temp_free_i32(cpu_index);
+ tcg_temp_free_i32(flags);
gen_set_label(after_cb);
tcg_temp_free_i64(val);
@@ -210,12 +228,21 @@ static void gen_mem_cb(struct qemu_plugin_regular_cb *cb,
qemu_plugin_meminfo_t meminfo, TCGv_i64 addr)
{
TCGv_i32 cpu_index = gen_cpu_index();
+ enum qemu_plugin_cb_flags cb_flags =
+ tcg_call_to_qemu_plugin_cb_flags(cb->info->flags);
+ TCGv_i32 flags = tcg_constant_i32(cb_flags);
+ tcg_gen_call1(qemu_plugin_set_cb_flags,
+ qemu_plugin_get_set_cb_flags_helper_info(), NULL,
+ tcgv_i32_temp(flags));
tcg_gen_call4(cb->f.vcpu_mem, cb->info, NULL,
tcgv_i32_temp(cpu_index),
tcgv_i32_temp(tcg_constant_i32(meminfo)),
tcgv_i64_temp(addr),
tcgv_ptr_temp(tcg_constant_ptr(cb->userp)));
+ tcg_gen_call0(qemu_plugin_clear_cb_flags,
+ qemu_plugin_get_clear_cb_flags_helper_info(), NULL);
tcg_temp_free_i32(cpu_index);
+ tcg_temp_free_i32(flags);
}
static void inject_cb(struct qemu_plugin_dyn_cb *cb)
diff --git a/include/qemu/plugin.h b/include/qemu/plugin.h
index 9726a9ebf3..f312cc1a72 100644
--- a/include/qemu/plugin.h
+++ b/include/qemu/plugin.h
@@ -209,6 +209,18 @@ void qemu_plugin_user_prefork_lock(void);
*/
void qemu_plugin_user_postfork(bool is_child);
+enum qemu_plugin_cb_flags tcg_call_to_qemu_plugin_cb_flags(int flags);
+
+void qemu_plugin_set_cb_flags(enum qemu_plugin_cb_flags flags);
+
+enum qemu_plugin_cb_flags qemu_plugin_get_cb_flags(void);
+
+void qemu_plugin_clear_cb_flags(void);
+
+TCGHelperInfo *qemu_plugin_get_set_cb_flags_helper_info(void);
+
+TCGHelperInfo *qemu_plugin_get_clear_cb_flags_helper_info(void);
+
#else /* !CONFIG_PLUGIN */
static inline void qemu_plugin_add_opts(void)
diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index cfe1692ecb..120fb626a6 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -254,9 +254,6 @@ typedef struct {
* @QEMU_PLUGIN_CB_NO_REGS: callback does not access the CPU's regs
* @QEMU_PLUGIN_CB_R_REGS: callback reads the CPU's regs
* @QEMU_PLUGIN_CB_RW_REGS: callback reads and writes the CPU's regs
- *
- * Note: currently QEMU_PLUGIN_CB_RW_REGS is unused, plugins cannot change
- * system register state.
*/
enum qemu_plugin_cb_flags {
QEMU_PLUGIN_CB_NO_REGS,
diff --git a/plugins/api.c b/plugins/api.c
index 3a7add50d2..16141f5c25 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -437,6 +437,10 @@ int qemu_plugin_read_register(struct qemu_plugin_register
*reg, GByteArray *buf)
{
g_assert(current_cpu);
+ if (qemu_plugin_get_cb_flags() == QEMU_PLUGIN_CB_NO_REGS) {
+ return -1;
+ }
+
return gdb_read_register(current_cpu, buf, GPOINTER_TO_INT(reg) - 1);
}
@@ -445,6 +449,10 @@ int qemu_plugin_write_register(struct qemu_plugin_register *reg,
{
g_assert(current_cpu);
+ if (buf->len == 0 || qemu_plugin_get_cb_flags() != QEMU_PLUGIN_CB_RW_REGS) {
+ return 0;
+ }
+
return gdb_write_register(current_cpu, buf->data, GPOINTER_TO_INT(reg) -
1);
}
diff --git a/plugins/core.c b/plugins/core.c
index eb9281fe54..0ebde1fb87 100644
--- a/plugins/core.c
+++ b/plugins/core.c
@@ -30,6 +30,9 @@ struct qemu_plugin_cb {
};
struct qemu_plugin_state plugin;
+static __thread enum qemu_plugin_cb_flags call_cb_flags;
+static TCGHelperInfo qemu_plugin_set_cb_flags_helper;
+static TCGHelperInfo qemu_plugin_clear_cb_flags_helper;
struct qemu_plugin_ctx *plugin_id_to_ctx_locked(qemu_plugin_id_t id)
{
@@ -364,14 +367,15 @@ void plugin_register_dyn_cb__udata(GArray **arr,
enum qemu_plugin_cb_flags flags,
void *udata)
{
- static TCGHelperInfo info[3] = {
+ static TCGHelperInfo info[4] = {
[QEMU_PLUGIN_CB_NO_REGS].flags = TCG_CALL_NO_RWG,
[QEMU_PLUGIN_CB_R_REGS].flags = TCG_CALL_NO_WG,
+ [QEMU_PLUGIN_CB_RW_REGS].flags = 0,
/*
* Match qemu_plugin_vcpu_udata_cb_t:
* void (*)(uint32_t, void *)
*/
- [0 ... 2].typemask = (dh_typemask(void, 0) |
+ [0 ... 3].typemask = (dh_typemask(void, 0) |
dh_typemask(i32, 1) |
dh_typemask(ptr, 2))
};
@@ -393,14 +397,15 @@ void plugin_register_dyn_cond_cb__udata(GArray **arr,
uint64_t imm,
void *udata)
{
- static TCGHelperInfo info[3] = {
+ static TCGHelperInfo info[4] = {
[QEMU_PLUGIN_CB_NO_REGS].flags = TCG_CALL_NO_RWG,
[QEMU_PLUGIN_CB_R_REGS].flags = TCG_CALL_NO_WG,
+ [QEMU_PLUGIN_CB_RW_REGS].flags = 0,
/*
* Match qemu_plugin_vcpu_udata_cb_t:
* void (*)(uint32_t, void *)
*/
- [0 ... 2].typemask = (dh_typemask(void, 0) |
+ [0 ... 3].typemask = (dh_typemask(void, 0) |
dh_typemask(i32, 1) |
dh_typemask(ptr, 2))
};
@@ -431,14 +436,15 @@ void plugin_register_vcpu_mem_cb(GArray **arr,
!__builtin_types_compatible_p(qemu_plugin_meminfo_t, uint32_t) &&
!__builtin_types_compatible_p(qemu_plugin_meminfo_t, int32_t));
- static TCGHelperInfo info[3] = {
+ static TCGHelperInfo info[4] = {
[QEMU_PLUGIN_CB_NO_REGS].flags = TCG_CALL_NO_RWG,
[QEMU_PLUGIN_CB_R_REGS].flags = TCG_CALL_NO_WG,
+ [QEMU_PLUGIN_CB_RW_REGS].flags = 0,
/*
* Match qemu_plugin_vcpu_mem_cb_t:
* void (*)(uint32_t, qemu_plugin_meminfo_t, uint64_t, void *)
*/
- [0 ... 2].typemask =
+ [0 ... 3].typemask =
(dh_typemask(void, 0) |
dh_typemask(i32, 1) |
(__builtin_types_compatible_p(qemu_plugin_meminfo_t, uint32_t)
@@ -730,6 +736,11 @@ static void __attribute__((__constructor__))
plugin_init(void)
qht_init(&plugin.dyn_cb_arr_ht, plugin_dyn_cb_arr_cmp, 16,
QHT_MODE_AUTO_RESIZE);
atexit(qemu_plugin_atexit_cb);
+ qemu_plugin_set_cb_flags_helper.flags = 0;
+ qemu_plugin_set_cb_flags_helper.typemask = (dh_typemask(void, 0) |
+ dh_typemask(i32, 1));
+ qemu_plugin_clear_cb_flags_helper.flags = 0;
+ qemu_plugin_clear_cb_flags_helper.typemask = dh_typemask(void, 0);
}
int plugin_num_vcpus(void)
@@ -760,3 +771,40 @@ void plugin_scoreboard_free(struct qemu_plugin_scoreboard
*score)
g_array_free(score->data, TRUE);
g_free(score);
}
+
+enum qemu_plugin_cb_flags tcg_call_to_qemu_plugin_cb_flags(int flags)
+{
+ if (flags & TCG_CALL_NO_RWG) {
+ return QEMU_PLUGIN_CB_NO_REGS;
+ } else if (flags & TCG_CALL_NO_WG) {
+ return QEMU_PLUGIN_CB_R_REGS;
+ } else {
+ return QEMU_PLUGIN_CB_RW_REGS;
+ }
+}
+
+void qemu_plugin_set_cb_flags(enum qemu_plugin_cb_flags flags)
+{
+ call_cb_flags = flags;
+}
+
+enum qemu_plugin_cb_flags qemu_plugin_get_cb_flags(void)
+{
+ return call_cb_flags;
+}
+
+void qemu_plugin_clear_cb_flags(void)
+{
+ call_cb_flags = QEMU_PLUGIN_CB_NO_REGS;
+}
+
+
+TCGHelperInfo *qemu_plugin_get_set_cb_flags_helper_info(void)
+{
+ return &qemu_plugin_set_cb_flags_helper;
+}
+
+TCGHelperInfo *qemu_plugin_get_clear_cb_flags_helper_info(void)
+{
+ return &qemu_plugin_clear_cb_flags_helper;
+}
