Add io memory to test device

index ac5b9cd..ad34e43 100644
@@ -34,14 +34,62 @@ static void test_device_irq_line(void *opaque, uint32_t addr, uint32_t data)
     qemu_set_irq(ioapic_irq_hack[addr - 0x2000], !!data);
 }
 
+static char *iomem_buf;
+
+static uint32_t test_iomem_readb(void *opaque, target_phys_addr_t addr)
+{
+    return iomem_buf[addr];
+}
+
+static uint32_t test_iomem_readw(void *opaque, target_phys_addr_t addr)
+{
+    return *(uint16_t*)(iomem_buf + addr);
+}
+
+static uint32_t test_iomem_readl(void *opaque, target_phys_addr_t addr)
+{
+    return *(uint32_t*)(iomem_buf + addr);
+}
+
+static void test_iomem_writeb(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+    iomem_buf[addr] = val;
+}
+
+static void test_iomem_writew(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+    *(uint16_t*)(iomem_buf + addr) = val;
+}
+
+static void test_iomem_writel(void *opaque, target_phys_addr_t addr, uint32_t val)
+{
+    *(uint32_t*)(iomem_buf + addr) = val;
+}
+
+static CPUReadMemoryFunc * const test_iomem_read[3] = {
+    test_iomem_readb,
+    test_iomem_readw,
+    test_iomem_readl,
+};
+
+static CPUWriteMemoryFunc * const test_iomem_write[3] = {
+    test_iomem_writeb,
+    test_iomem_writew,
+    test_iomem_writel,
+};
+
 static int init_test_device(ISADevice *isa)
 {
     struct testdev *dev = DO_UPCAST(struct testdev, dev, isa);
+    int iomem;
 
     register_ioport_write(0xf1, 1, 1, test_device_serial_write, dev);
     register_ioport_write(0xf4, 1, 4, test_device_exit, dev);
     register_ioport_read(0xd1, 1, 4, test_device_memsize_read, dev);
     register_ioport_write(0x2000, 24, 1, test_device_irq_line, NULL);
+    iomem_buf = qemu_mallocz(0x10000);
+    iomem = cpu_register_io_memory(test_iomem_read, test_iomem_write, NULL);
+    cpu_register_physical_memory(0xff000000, 0x10000, iomem);
     return 0;
 }