1 files changed, 26 insertions, 5 deletions

diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index 942be7bd11..404a445138 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -2498,7 +2498,7 @@ static const VMStateDescription vmstate_VecInfo = {
     .name = "armv7m_nvic_info",
     .version_id = 1,
     .minimum_version_id = 1,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_INT16(prio, VecInfo),
         VMSTATE_UINT8(enabled, VecInfo),
         VMSTATE_UINT8(pending, VecInfo),
@@ -2543,7 +2543,7 @@ static const VMStateDescription vmstate_nvic_security = {
     .minimum_version_id = 1,
     .needed = nvic_security_needed,
     .post_load = &nvic_security_post_load,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_STRUCT_ARRAY(sec_vectors, NVICState, NVIC_INTERNAL_VECTORS, 1,
                              vmstate_VecInfo, VecInfo),
         VMSTATE_UINT32(prigroup[M_REG_S], NVICState),
@@ -2557,13 +2557,13 @@ static const VMStateDescription vmstate_nvic = {
     .version_id = 4,
     .minimum_version_id = 4,
     .post_load = &nvic_post_load,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_STRUCT_ARRAY(vectors, NVICState, NVIC_MAX_VECTORS, 1,
                              vmstate_VecInfo, VecInfo),
         VMSTATE_UINT32(prigroup[M_REG_NS], NVICState),
         VMSTATE_END_OF_LIST()
     },
-    .subsections = (const VMStateDescription*[]) {
+    .subsections = (const VMStateDescription * const []) {
         &vmstate_nvic_security,
         NULL
     }
@@ -2572,6 +2572,11 @@ static const VMStateDescription vmstate_nvic = {
 static Property props_nvic[] = {
     /* Number of external IRQ lines (so excluding the 16 internal exceptions) */
     DEFINE_PROP_UINT32("num-irq", NVICState, num_irq, 64),
+    /*
+     * Number of the maximum priority bits that can be used. 0 means
+     * to use a reasonable default.
+     */
+    DEFINE_PROP_UINT8("num-prio-bits", NVICState, num_prio_bits, 0),
     DEFINE_PROP_END_OF_LIST()
 };
 
@@ -2685,7 +2690,23 @@ static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
     /* include space for internal exception vectors */
     s->num_irq += NVIC_FIRST_IRQ;
 
-    s->num_prio_bits = arm_feature(&s->cpu->env, ARM_FEATURE_V7) ? 8 : 2;
+    if (s->num_prio_bits == 0) {
+        /*
+         * If left unspecified, use 2 bits by default on Cortex-M0/M0+/M1
+         * and 8 bits otherwise.
+         */
+        s->num_prio_bits = arm_feature(&s->cpu->env, ARM_FEATURE_V7) ? 8 : 2;
+    } else {
+        uint8_t min_prio_bits =
+            arm_feature(&s->cpu->env, ARM_FEATURE_V7) ? 3 : 2;
+        if (s->num_prio_bits < min_prio_bits || s->num_prio_bits > 8) {
+            error_setg(errp,
+                       "num-prio-bits %d is outside "
+                       "NVIC acceptable range [%d-8]",
+                       s->num_prio_bits, min_prio_bits);
+            return;
+        }
+    }
 
     /*
      * This device provides a single memory region which covers the