[PATCH 9/9] hw/arm/armv7m: Pass CPU/NVIC using object_property_add_const_link()

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Avoid having QOM objects poke at each other internals.
Instead, pass references using QOM link properties.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 hw/arm/armv7m.c       | 4 ++--
 hw/intc/armv7m_nvic.c | 3 ++-
 target/arm/cpu.c      | 3 ++-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/hw/arm/armv7m.c b/hw/arm/armv7m.c
index 50a9507c0b..edde774da2 100644
--- a/hw/arm/armv7m.c
+++ b/hw/arm/armv7m.c
@@ -338,8 +338,8 @@ static void armv7m_realize(DeviceState *dev, Error **errp)
      * Tell the CPU where the NVIC is; it will fail realize if it doesn't
      * have one. Similarly, tell the NVIC where its CPU is.
      */
-    s->cpu->env.nvic = &s->nvic;
-    s->nvic.cpu = s->cpu;
+    object_property_add_const_link(OBJECT(s->cpu), "nvic", OBJECT(&s->nvic));
+    object_property_add_const_link(OBJECT(&s->nvic), "cpu", OBJECT(s->cpu));
 
     if (!qdev_realize(DEVICE(s->cpu), NULL, errp)) {
         return;
diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index d9c7e414bc..e43898a9e0 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -2668,7 +2668,8 @@ static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
     NVICState *s = NVIC(dev);
 
     /* The armv7m container object will have set our CPU pointer */
-    if (!s->cpu || !arm_feature(&s->cpu->env, ARM_FEATURE_M)) {
+    s->cpu = ARM_CPU(object_property_get_link(OBJECT(dev), "cpu", &error_abort));
+    if (!arm_feature(&s->cpu->env, ARM_FEATURE_M)) {
         error_setg(errp, "The NVIC can only be used with a Cortex-M CPU");
         return;
     }
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 876ab8f3bf..f081861947 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1573,12 +1573,13 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
      * error and will result in segfaults if not caught here.
      */
     if (arm_feature(env, ARM_FEATURE_M)) {
+        env->nvic = NVIC(object_property_get_link(OBJECT(dev), "nvic", NULL));
         if (!env->nvic) {
             error_setg(errp, "This board cannot be used with Cortex-M CPUs");
             return;
         }
     } else {
-        if (env->nvic) {
+        if (object_property_find(OBJECT(dev), "nvic")) {
             error_setg(errp, "This board can only be used with Cortex-M CPUs");
             return;
         }
-- 
2.38.1