The irq number is unsigned; we reject negative values.  But -1
is used for the isairq array, which is declared unsigned!  And
since we have a definition for the number of ISA IRQs, use it.

Based on a patch by Philippe Mathieu-Daudé.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/isa/isa-bus.c     | 11 +++++++----
 include/hw/isa/isa.h |  8 ++++----
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 3888006..798dd91 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -82,24 +82,27 @@ void isa_bus_irqs(ISABus *bus, qemu_irq *irqs)
  * This function is only for special cases such as the 'ferr', and
  * temporary use for normal devices until they are converted to qdev.
  */
-qemu_irq isa_get_irq(ISADevice *dev, int isairq)
+qemu_irq isa_get_irq(ISADevice *dev, unsigned isairq)
 {
     assert(!dev || ISA_BUS(qdev_get_parent_bus(DEVICE(dev))) == isabus);
-    if (isairq < 0 || isairq > 15) {
+    if (isairq >= ISA_NUM_IRQS) {
         hw_error("isa irq %d invalid", isairq);
     }
     return isabus->irqs[isairq];
 }
 
-void isa_init_irq(ISADevice *dev, qemu_irq *p, int isairq)
+void isa_init_irq(ISADevice *dev, qemu_irq *p, unsigned isairq)
 {
     assert(dev->nirqs < ARRAY_SIZE(dev->isairq));
+    if (isairq >= ISA_NUM_IRQS) {
+        hw_error("isa irq %d invalid", isairq);
+    }
     dev->isairq[dev->nirqs] = isairq;
     *p = isa_get_irq(dev, isairq);
     dev->nirqs++;
 }
 
-void isa_connect_gpio_out(ISADevice *isadev, int gpioirq, int isairq)
+void isa_connect_gpio_out(ISADevice *isadev, int gpioirq, unsigned isairq)
 {
     qemu_irq irq;
     isa_init_irq(isadev, &irq, isairq);
diff --git a/include/hw/isa/isa.h b/include/hw/isa/isa.h
index 79f703f..e9ac1f1 100644
--- a/include/hw/isa/isa.h
+++ b/include/hw/isa/isa.h
@@ -88,7 +88,7 @@ struct ISADevice {
     DeviceState parent_obj;
     /*< public >*/
 
-    uint32_t isairq[2];
+    int8_t isairq[2];      /* -1 = unassigned */
     int nirqs;
     int ioport_id;
 };
@@ -96,9 +96,9 @@ struct ISADevice {
 ISABus *isa_bus_new(DeviceState *dev, MemoryRegion *address_space,
                     MemoryRegion *address_space_io, Error **errp);
 void isa_bus_irqs(ISABus *bus, qemu_irq *irqs);
-qemu_irq isa_get_irq(ISADevice *dev, int isairq);
-void isa_init_irq(ISADevice *dev, qemu_irq *p, int isairq);
-void isa_connect_gpio_out(ISADevice *isadev, int gpioirq, int isairq);
+qemu_irq isa_get_irq(ISADevice *dev, unsigned isairq);
+void isa_init_irq(ISADevice *dev, qemu_irq *p, unsigned isairq);
+void isa_connect_gpio_out(ISADevice *isadev, int gpioirq, unsigned isairq);
 void isa_bus_dma(ISABus *bus, IsaDma *dma8, IsaDma *dma16);
 IsaDma *isa_get_dma(ISABus *bus, int nchan);
 MemoryRegion *isa_address_space(ISADevice *dev);
-- 
1.8.3.1