starred/qemu-qemu-1
1
0
Fork 0
mirror of https://github.com/qemu/qemu.git synced 2026-04-05 21:46:25 +00:00
Code Issues Packages Projects Releases Wiki Activity

plugins: add flag to specify whether PC is rw

Browse Source 
In addition to the flags specifying whether general-purpose registers
are read-write (rw) during a plugin callback, we add an additional flag
explicitly stating whether the PC is writable. This is in preparation of
a patch that allows to explicitly set the PC to divert control flow from
within a plugin callback, which is currently not possible.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Florian Hofhammer <florian.hofhammer@epfl.ch>
Link: https://lore.kernel.org/qemu-devel/20260305-setpc-v5-v7-2-4c3adba52403@epfl.ch
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
This commit is contained in:
Florian Hofhammer
2026-03-05 11:06:00 +01:00
committed by Pierrick Bouvier
parent 2cc35f14ba
commit d16ffa4244
3 changed files with 22 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
include/plugins/qemu-plugin.h
View File

@@ -325,11 +325,14 @@ 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
* @QEMU_PLUGIN_CB_RW_REGS_PC: callback reads and writes the CPU's
* regs and updates the PC
*/
enum qemu_plugin_cb_flags {
QEMU_PLUGIN_CB_NO_REGS,
QEMU_PLUGIN_CB_R_REGS,
QEMU_PLUGIN_CB_RW_REGS,
QEMU_PLUGIN_CB_RW_REGS_PC,
};
enum qemu_plugin_mem_rw {

4
plugins/api.c
View File

@@ -458,7 +458,9 @@ bool 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) {
if (buf->len == 0 ||
(qemu_plugin_get_cb_flags() != QEMU_PLUGIN_CB_RW_REGS &&
qemu_plugin_get_cb_flags() != QEMU_PLUGIN_CB_RW_REGS_PC)) {
return false;
}

29
plugins/core.c
View File

@@ -119,7 +119,7 @@ static void plugin_vcpu_cb__discon(CPUState *cpu,
struct qemu_plugin_cb *cb, *next;
uint64_t to = cpu->cc->get_pc(cpu);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS_PC);
if (cpu->cpu_index < plugin.num_vcpus) {
/* iterate safely; plugins might uninstall themselves at any time */
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
@@ -395,15 +395,16 @@ 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,
[QEMU_PLUGIN_CB_RW_REGS_PC].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))
};
@@ -425,15 +426,16 @@ 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,
[QEMU_PLUGIN_CB_RW_REGS_PC].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))
};
@@ -464,15 +466,16 @@ 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,
[QEMU_PLUGIN_CB_RW_REGS_PC].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)
@@ -553,7 +556,7 @@ qemu_plugin_vcpu_syscall(CPUState *cpu, int64_t num, uint64_t a1, uint64_t a2,
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_vcpu_syscall_cb_t func = cb->f.vcpu_syscall;
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS_PC);
func(cb->ctx->id, cpu->cpu_index, num, a1, a2, a3, a4, a5, a6, a7, a8);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_NO_REGS);
}
@@ -577,7 +580,7 @@ void qemu_plugin_vcpu_syscall_ret(CPUState *cpu, int64_t num, int64_t ret)
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_vcpu_syscall_ret_cb_t func = cb->f.vcpu_syscall_ret;
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS_PC);
func(cb->ctx->id, cpu->cpu_index, num, ret);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_NO_REGS);
}
@@ -605,7 +608,7 @@ qemu_plugin_vcpu_syscall_filter(CPUState *cpu, int64_t num, uint64_t a1,
clamp_syscall_arguments(&a1, &a2, &a3, &a4, &a5, &a6, &a7, &a8);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS_PC);
QLIST_FOREACH_SAFE_RCU(cb, &plugin.cb_lists[ev], entry, next) {
qemu_plugin_vcpu_syscall_filter_cb_t func = cb->f.vcpu_syscall_filter;
@@ -626,7 +629,7 @@ void qemu_plugin_vcpu_idle_cb(CPUState *cpu)
{
/* idle and resume cb may be called before init, ignore in this case */
if (cpu->cpu_index < plugin.num_vcpus) {
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS_PC);
plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_IDLE);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_NO_REGS);
}
@@ -635,7 +638,7 @@ void qemu_plugin_vcpu_idle_cb(CPUState *cpu)
void qemu_plugin_vcpu_resume_cb(CPUState *cpu)
{
if (cpu->cpu_index < plugin.num_vcpus) {
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_RW_REGS_PC);
plugin_vcpu_cb__simple(cpu, QEMU_PLUGIN_EV_VCPU_RESUME);
qemu_plugin_set_cb_flags(cpu, QEMU_PLUGIN_CB_NO_REGS);
}
@@ -906,6 +909,6 @@ enum qemu_plugin_cb_flags tcg_call_to_qemu_plugin_cb_flags(int flags)
} else if (flags & TCG_CALL_NO_WG) {
return QEMU_PLUGIN_CB_R_REGS;
} else {
return QEMU_PLUGIN_CB_RW_REGS;
return QEMU_PLUGIN_CB_RW_REGS_PC;
}
}