[PULL 03/12] plugins: Ensure register handles are not NULL

["Alex Bennée" <alex.bennee@linaro.org>]

From: Akihiko Odaki <akihiko.odaki@daynix.com>

Ensure register handles are not NULL so that a plugin can assume NULL is
invalid as a register handle.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-Id: <20240229-null-v1-1-e716501d981e@daynix.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240620152220.2192768-4-alex.bennee@linaro.org>

diff --git a/plugins/api.c b/plugins/api.c
index 5a0a7f8c71..6bdb26bbe3 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -507,7 +507,7 @@ static GArray *create_register_handles(GArray *gdbstub_regs)
         }
 
         /* Create a record for the plugin */
-        desc.handle = GINT_TO_POINTER(grd->gdb_reg);
+        desc.handle = GINT_TO_POINTER(grd->gdb_reg + 1);
         desc.name = g_intern_string(grd->name);
         desc.feature = g_intern_string(grd->feature_name);
         g_array_append_val(find_data, desc);
@@ -528,7 +528,7 @@ int qemu_plugin_read_register(struct qemu_plugin_register *reg, GByteArray *buf)
 {
     g_assert(current_cpu);
 
-    return gdb_read_register(current_cpu, buf, GPOINTER_TO_INT(reg));
+    return gdb_read_register(current_cpu, buf, GPOINTER_TO_INT(reg) - 1);
 }
 
 struct qemu_plugin_scoreboard *qemu_plugin_scoreboard_new(size_t element_size)
-- 
2.39.2