diff --git a/cutils.c b/cutils.c
index 2d65357ee4..9617e083c6 100644
--- a/cutils.c
+++ b/cutils.c
@@ -97,7 +97,7 @@ time_t mktimegm(struct tm *tm)
     return t;
 }
 
-int fls(int i)
+int qemu_fls(int i)
 {
     return 32 - clz32(i);
 }
diff --git a/hw/virtio.c b/hw/virtio.c
index 24a4b26718..dba80f81c0 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -858,7 +858,7 @@ VirtIODevice *virtio_init_pci(PCIBus *bus, const char *name,
 
     size = 20 + config_size;
     if (size & (size-1))
-        size = 1 << fls(size);
+        size = 1 << qemu_fls(size);
 
     pci_register_io_region(pci_dev, 0, size, PCI_ADDRESS_SPACE_IO,
                            virtio_map);
diff --git a/qemu-common.h b/qemu-common.h
index cb5d46541e..d3df63ea01 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -104,7 +104,7 @@ char *pstrcat(char *buf, int buf_size, const char *s);
 int strstart(const char *str, const char *val, const char **ptr);
 int stristart(const char *str, const char *val, const char **ptr);
 time_t mktimegm(struct tm *tm);
-int fls(int i);
+int qemu_fls(int i);
 
 #define qemu_isalnum(c)		isalnum((unsigned char)(c))
 #define qemu_isalpha(c)		isalpha((unsigned char)(c))