3 files changed, 33 insertions, 11 deletions

diff --git a/hw/irq.c b/hw/irq.c
index d413a0b235..f4e2a7804a 100644
--- a/hw/irq.c
+++ b/hw/irq.c
@@ -38,24 +38,37 @@ void qemu_set_irq(qemu_irq irq, int level)
     irq->handler(irq->opaque, irq->n, level);
 }
 
-qemu_irq *qemu_allocate_irqs(qemu_irq_handler handler, void *opaque, int n)
+qemu_irq *qemu_extend_irqs(qemu_irq *old, int n_old, qemu_irq_handler handler,
+                           void *opaque, int n)
 {
     qemu_irq *s;
     struct IRQState *p;
     int i;
 
-    s = (qemu_irq *)g_malloc0(sizeof(qemu_irq) * n);
-    p = (struct IRQState *)g_malloc0(sizeof(struct IRQState) * n);
-    for (i = 0; i < n; i++) {
-        p->handler = handler;
-        p->opaque = opaque;
-        p->n = i;
+    if (!old) {
+        n_old = 0;
+    }
+    s = old ? g_renew(qemu_irq, old, n + n_old) : g_new(qemu_irq, n);
+    p = old ? g_renew(struct IRQState, s[0], n + n_old) :
+                g_new(struct IRQState, n);
+    for (i = 0; i < n + n_old; i++) {
+        if (i >= n_old) {
+            p->handler = handler;
+            p->opaque = opaque;
+            p->n = i;
+        }
         s[i] = p;
         p++;
     }
     return s;
 }
 
+qemu_irq *qemu_allocate_irqs(qemu_irq_handler handler, void *opaque, int n)
+{
+    return qemu_extend_irqs(NULL, 0, handler, opaque, n);
+}
+
+
 void qemu_free_irqs(qemu_irq *s)
 {
     g_free(s[0]);
diff --git a/hw/irq.h b/hw/irq.h
index 56c55f0c46..e640c105e7 100644
--- a/hw/irq.h
+++ b/hw/irq.h
@@ -23,8 +23,17 @@ static inline void qemu_irq_pulse(qemu_irq irq)
     qemu_set_irq(irq, 0);
 }
 
-/* Returns an array of N IRQs.  */
+/* Returns an array of N IRQs. Each IRQ is assigned the argument handler and
+ * opaque data.
+ */
 qemu_irq *qemu_allocate_irqs(qemu_irq_handler handler, void *opaque, int n);
+
+/* Extends an Array of IRQs. Old IRQs have their handlers and opaque data
+ * preserved. New IRQs are assigned the argument handler and opaque data.
+ */
+qemu_irq *qemu_extend_irqs(qemu_irq *old, int n_old, qemu_irq_handler handler,
+                                void *opaque, int n);
+
 void qemu_free_irqs(qemu_irq *s);
 
 /* Returns a new IRQ with opposite polarity.  */
diff --git a/hw/qdev.c b/hw/qdev.c
index b6e9207ede..9b9aba376b 100644
--- a/hw/qdev.c
+++ b/hw/qdev.c
@@ -285,9 +285,9 @@ BusState *qdev_get_parent_bus(DeviceState *dev)
 
 void qdev_init_gpio_in(DeviceState *dev, qemu_irq_handler handler, int n)
 {
-    assert(dev->num_gpio_in == 0);
-    dev->num_gpio_in = n;
-    dev->gpio_in = qemu_allocate_irqs(handler, dev, n);
+    dev->gpio_in = qemu_extend_irqs(dev->gpio_in, dev->num_gpio_in, handler,
+                                        dev, n);
+    dev->num_gpio_in += n;
 }
 
 void qdev_init_gpio_out(DeviceState *dev, qemu_irq *pins, int n)