pc: Re-order pc_init1 to initialize the ISA bus before ISA devices

In particular, the i8259 was being initialized before the ISA bus,
leading to a crash.
Signed-off-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAvi Kivity <avi@redhat.com>

hw/pc_piix.c

@@ -130,17 +130,7 @@ static void pc_init1(MemoryRegion *system_memory,
                        pci_enabled ? rom_memory : system_memory, &ram_memory);
     }
 
-    if (!xen_enabled()) {
-        cpu_irq = pc_allocate_cpu_irq();
-        i8259 = i8259_init(cpu_irq[0]);
-    } else {
-        i8259 = xen_interrupt_controller_init();
-    }
     isa_irq_state = g_malloc0(sizeof(*isa_irq_state));
-    isa_irq_state->i8259 = i8259;
-    if (pci_enabled) {
-        ioapic_init(isa_irq_state);
-    }
     isa_irq = qemu_allocate_irqs(isa_irq_handler, isa_irq_state, 24);
 
     if (pci_enabled) {
@@ -161,6 +151,18 @@ static void pc_init1(MemoryRegion *system_memory,
     }
     isa_bus_irqs(isa_irq);
 
+    if (!xen_enabled()) {
+        cpu_irq = pc_allocate_cpu_irq();
+        i8259 = i8259_init(cpu_irq[0]);
+    } else {
+        i8259 = xen_interrupt_controller_init();
+    }
+
+    isa_irq_state->i8259 = i8259;
+    if (pci_enabled) {
+        ioapic_init(isa_irq_state);
+    }
+
     pc_register_ferr_irq(isa_get_irq(13));
 
     pc_vga_init(pci_enabled? pci_bus: NULL);