When QEMU watchpoint matches, that is not definitely an architectural
watchpoint match yet. If it is a stop-before-access watchpoint then that
is hardly possible to ignore it after throwing a TCG exception.
A special callback is introduced to check for architectural watchpoint
match before raising a TCG exception.
Signed-off-by: Sergey Fedorov <serge.f...@gmail.com>
---
Notes:
Changes in v2:
* Check moved before setting cpu->watchpoint_hit
* Pointer to watchpoint being checked passed to debug_check_watchpoint()
callback
* Comment for debug_check_watchpoint() callback improved
exec.c | 5 +++++
include/qom/cpu.h | 3 +++
qom/cpu.c | 9 +++++++++
3 files changed, 17 insertions(+)
diff --git a/exec.c b/exec.c
index 9e076bc..a20f8ea 100644
--- a/exec.c
+++ b/exec.c
@@ -2024,6 +2024,7 @@ static const MemoryRegionOps notdirty_mem_ops = {
static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags)
{
CPUState *cpu = current_cpu;
+ CPUClass *cc = CPU_GET_CLASS(cpu);
CPUArchState *env = cpu->env_ptr;
target_ulong pc, cs_base;
target_ulong vaddr;
@@ -2050,6 +2051,10 @@ static void check_watchpoint(int offset, int len,
MemTxAttrs attrs, int flags)
wp->hitattrs = attrs;
if (!cpu->watchpoint_hit) {
cpu->watchpoint_hit = wp;
+ if (wp->flags & BP_CPU && !cc->debug_check_watchpoint(cpu)) {
+ cpu->watchpoint_hit = NULL;
+ continue;
+ }
tb_check_watchpoint(cpu);
if (wp->flags & BP_STOP_BEFORE_ACCESS) {
cpu->exception_index = EXCP_DEBUG;
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 035179c..095ba08 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -106,6 +106,8 @@ struct TranslationBlock;
* a memory access with the specified memory transaction attributes.
* @gdb_read_register: Callback for letting GDB read a register.
* @gdb_write_register: Callback for letting GDB write a register.
+ * @debug_check_watchpoint: Callback for checking an architectural watchpoint
+ * match.
* @debug_excp_handler: Callback for handling debug exceptions.
* @write_elf64_note: Callback for writing a CPU-specific ELF note to a
* 64-bit VM coredump.
@@ -165,6 +167,7 @@ typedef struct CPUClass {
int (*asidx_from_attrs)(CPUState *cpu, MemTxAttrs attrs);
int (*gdb_read_register)(CPUState *cpu, uint8_t *buf, int reg);
int (*gdb_write_register)(CPUState *cpu, uint8_t *buf, int reg);
+ bool (*debug_check_watchpoint)(CPUState *cpu);
void (*debug_excp_handler)(CPUState *cpu);
int (*write_elf64_note)(WriteCoreDumpFunction f, CPUState *cpu,
diff --git a/qom/cpu.c b/qom/cpu.c
index 8f537a4..5caa0ee 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -188,6 +188,14 @@ static int cpu_common_gdb_write_register(CPUState *cpu,
uint8_t *buf, int reg)
return 0;
}
+static bool cpu_common_debug_check_watchpoint(CPUState *cpu)
+{
+ /* If no extra check is required, QEMU watchpoint match can be considered
+ * as an architectural match.
+ */
+ return true;
+}
+
bool target_words_bigendian(void);
static bool cpu_common_virtio_is_big_endian(CPUState *cpu)
{
@@ -352,6 +360,7 @@ static void cpu_class_init(ObjectClass *klass, void *data)
k->gdb_write_register = cpu_common_gdb_write_register;
k->virtio_is_big_endian = cpu_common_virtio_is_big_endian;
k->debug_excp_handler = cpu_common_noop;
+ k->debug_check_watchpoint = cpu_common_debug_check_watchpoint;
k->cpu_exec_enter = cpu_common_noop;
k->cpu_exec_exit = cpu_common_noop;
k->cpu_exec_interrupt = cpu_common_exec_interrupt;
--
1.9.1
