diff --git a/hw/i386/Makefile.objs b/hw/i386/Makefile.objs
index 56aaa9d..1ac5fc5 100644
--- a/hw/i386/Makefile.objs
+++ b/hw/i386/Makefile.objs
@@ -12,5 +12,6 @@ obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen-host-pci-device.o
 obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pt.o xen_pt_config_init.o xen_pt_msi.o
 obj-y += kvm/
 obj-$(CONFIG_SPICE) += qxl.o qxl-logger.o qxl-render.o
+obj-y += pc-testdev.o
 
 obj-y := $(addprefix ../,$(obj-y))
diff --git a/hw/pc-testdev.c b/hw/pc-testdev.c
index b652956..75889e7 100644
--- a/hw/pc-testdev.c
+++ b/hw/pc-testdev.c
@@ -41,10 +41,13 @@
 #include "isa.h"
 #include "exec-memory.h"
 
+#define IOMEM_LEN    0x10000
+
 typedef struct PCTestdev {
     ISADevice dev;
     MemoryRegion iomem;
     uint32_t ioport_data;
+    char iomem_buf[IOMEM_LEN];
 } PCTestdev;
 
 #define TYPE_TESTDEV "pc-testdev"
@@ -74,48 +77,35 @@ static void test_device_flush_page(void *opaque, uint32_t addr, uint32_t data)
     hwaddr len = 4096;
     void *a = cpu_physical_memory_map(data & ~0xffful, &len, 0);
 
-    mprotect(a, 4096, PROT_NONE);
-    mprotect(a, 4096, PROT_READ|PROT_WRITE);
+    /* We might not be able to get the full page, only mprotect what we actually
+       have mapped */
+    mprotect(a, len, PROT_NONE);
+    mprotect(a, len, PROT_READ|PROT_WRITE);
     cpu_physical_memory_unmap(a, len, 0, 0);
 }
 
-static char *iomem_buf;
-
-static uint32_t test_iomem_readb(void *opaque, hwaddr addr)
-{
-    return iomem_buf[addr];
-}
-
-static uint32_t test_iomem_readw(void *opaque, hwaddr addr)
-{
-    return *(uint16_t*)(iomem_buf + addr);
-}
-
-static uint32_t test_iomem_readl(void *opaque, hwaddr addr)
+static uint64_t test_iomem_read(void *opaque, hwaddr addr, unsigned len)
 {
-    return *(uint32_t*)(iomem_buf + addr);
-}
-
-static void test_iomem_writeb(void *opaque, hwaddr addr, uint32_t val)
-{
-    iomem_buf[addr] = val;
-}
+    struct PCTestdev *dev = opaque;
+    uint64_t ret = 0;
+    memcpy(&ret, &dev->iomem_buf[addr], len);
+    ret = le64_to_cpu(ret);
 
-static void test_iomem_writew(void *opaque, hwaddr addr, uint32_t val)
-{
-    *(uint16_t*)(iomem_buf + addr) = val;
+    return ret;
 }
 
-static void test_iomem_writel(void *opaque, hwaddr addr, uint32_t val)
+static void test_iomem_write(void *opaque, hwaddr addr, uint64_t val,
+                             unsigned len)
 {
-    *(uint32_t*)(iomem_buf + addr) = val;
+    struct PCTestdev *dev = opaque;
+    val = cpu_to_le64(val);
+    memcpy(&dev->iomem_buf[addr], &val, len);
+    dev->iomem_buf[addr] = val;
 }
 
 static const MemoryRegionOps test_iomem_ops = {
-    .old_mmio = {
-        .read = { test_iomem_readb, test_iomem_readw, test_iomem_readl, },
-        .write = { test_iomem_writeb, test_iomem_writew, test_iomem_writel, },
-    },
+    .read = test_iomem_read,
+    .write = test_iomem_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
@@ -137,9 +127,8 @@ static int init_test_device(ISADevice *isa)
                      NULL, "pc-testdev");
     portio_list_add(test_dev_port_list, get_system_io(), 0x0);
 
-    iomem_buf = g_malloc0(0x10000);
     memory_region_init_io(&dev->iomem, &test_iomem_ops, dev,
-                          "pc-testdev", 0x10000);
+                          "pc-testdev", IOMEM_LEN);
     memory_region_add_subregion(isa_address_space(&dev->dev), 0xff000000,
                                                   &dev->iomem);
     return 0;