diff --git a/hw/msi.c b/hw/msi.c
index f214fcf..5d6ceb6 100644
--- a/hw/msi.c
+++ b/hw/msi.c
@@ -36,6 +36,9 @@
 
 #define PCI_MSI_VECTORS_MAX     32
 
+/* Flag for interrupt controller to declare MSI/MSI-X support */
+bool msi_supported;
+
 /* If we get rid of cap allocator, we won't need this. */
 static inline uint8_t msi_cap_sizeof(uint16_t flags)
 {
@@ -116,6 +119,11 @@
     uint16_t flags;
     uint8_t cap_size;
     int config_offset;
+
+    if (!msi_supported) {
+        return -ENOTSUP;
+    }
+
     MSI_DEV_PRINTF(dev,
                    "init offset: 0x%"PRIx8" vector: %"PRId8
                    " 64bit %d mask %d\n",
diff --git a/hw/msi.h b/hw/msi.h
index 5766018..3040bb0 100644
--- a/hw/msi.h
+++ b/hw/msi.h
@@ -24,6 +24,8 @@
 #include "qemu-common.h"
 #include "pci.h"
 
+extern bool msi_supported;
+
 bool msi_enabled(const PCIDevice *dev);
 int msi_init(struct PCIDevice *dev, uint8_t offset,
              unsigned int nr_vectors, bool msi64bit, bool msi_per_vector_mask);
diff --git a/hw/msix.c b/hw/msix.c
index f47d26b..3835eaa 100644
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -15,6 +15,7 @@
  */
 
 #include "hw.h"
+#include "msi.h"
 #include "msix.h"
 #include "pci.h"
 #include "range.h"
@@ -35,9 +36,6 @@
 #define MSIX_MAX_ENTRIES 32
 
 
-/* Flag for interrupt controller to declare MSI-X support */
-int msix_supported;
-
 /* Add MSI-X capability to the config space for the device. */
 /* Given a bar and its size, add MSI-X table on top of it
  * and fill MSI-X capability in the config space.
@@ -238,10 +236,11 @@
               unsigned bar_nr, unsigned bar_size)
 {
     int ret;
-    /* Nothing to do if MSI is not supported by interrupt controller */
-    if (!msix_supported)
-        return -ENOTSUP;
 
+    /* Nothing to do if MSI is not supported by interrupt controller */
+    if (!msi_supported) {
+        return -ENOTSUP;
+    }
     if (nentries > MSIX_MAX_ENTRIES)
         return -EINVAL;
 
diff --git a/hw/msix.h b/hw/msix.h
index 7e04336..5aba22b 100644
--- a/hw/msix.h
+++ b/hw/msix.h
@@ -29,6 +29,4 @@
 
 void msix_reset(PCIDevice *dev);
 
-extern int msix_supported;
-
 #endif
diff --git a/hw/pc.c b/hw/pc.c
index 85304cf..04304e0 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -36,7 +36,7 @@
 #include "elf.h"
 #include "multiboot.h"
 #include "mc146818rtc.h"
-#include "msix.h"
+#include "msi.h"
 #include "sysbus.h"
 #include "sysemu.h"
 #include "blockdev.h"
@@ -896,7 +896,7 @@
         apic_mapped = 1;
     }
 
-    msix_supported = 1;
+    msi_supported = true;
 
     return dev;
 }