cpu: Add callback to check architectural watchpoint match

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.fdrv@gmail.com>
Message-id: 1454256948-10485-2-git-send-email-serge.fdrv@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/qom/cpu.c b/qom/cpu.c
index 38dc713..aeb32f1 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -189,6 +189,14 @@
     return 0;
 }
 
+static bool cpu_common_debug_check_watchpoint(CPUState *cpu, CPUWatchpoint *wp)
+{
+    /* 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)
 {
@@ -353,6 +361,7 @@
     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;