diff --git a/sys/dev/virtio/pci/virtio_pci.c b/sys/dev/virtio/pci/virtio_pci.c
index 497abc88363..97fbc0b9382 100644
--- a/sys/dev/virtio/pci/virtio_pci.c
+++ b/sys/dev/virtio/pci/virtio_pci.c
@@ -170,6 +170,9 @@ static void	vtpci_config_intr(void *);
 
 #define vtpci_setup_msi_interrupt vtpci_setup_legacy_interrupt
 
+#define VIRTIO_PCI_CONFIG(_sc) \
+    VIRTIO_PCI_CONFIG_OFF((((_sc)->vtpci_flags & VTPCI_FLAG_MSIX)) != 0)
+
 /*
  * I/O port read/write wrappers.
  */
diff --git a/sys/dev/virtio/pci/virtio_pci.h b/sys/dev/virtio/pci/virtio_pci.h
index 485cf4ff5b1..f071ad638d4 100644
--- a/sys/dev/virtio/pci/virtio_pci.h
+++ b/sys/dev/virtio/pci/virtio_pci.h
@@ -72,8 +72,7 @@
  * The remaining space is defined by each driver as the per-driver
  * configuration space.
  */
-#define VIRTIO_PCI_CONFIG(sc) \
-    (((sc)->vtpci_flags & VTPCI_FLAG_MSIX) ? 24 : 20)
+#define VIRTIO_PCI_CONFIG_OFF(msix_enabled)     ((msix_enabled) ? 24 : 20)
 
 /*
  * How many bits to shift physical queue address written to QUEUE_PFN.