diff --git a/Makefile b/Makefile
index 3df202c26..071baa3db 100644
--- a/Makefile
+++ b/Makefile
@@ -129,11 +129,11 @@ version-obj-$(CONFIG_WIN32) += version.o
 qemu-img.o: qemu-img-cmds.h
 qemu-img.o qemu-tool.o qemu-nbd.o qemu-io.o: $(GENERATED_HEADERS)
 
-qemu-img$(EXESUF): qemu-img.o qemu-tool.o qemu-error.o $(trace-obj-y) $(block-obj-y) $(qobject-obj-y) $(version-obj-y) qemu-timer-common.o
+qemu-img$(EXESUF): qemu-img.o qemu-tool.o qemu-error.o $(oslib-obj-y) $(trace-obj-y) $(block-obj-y) $(qobject-obj-y) $(version-obj-y) qemu-timer-common.o
 
-qemu-nbd$(EXESUF): qemu-nbd.o qemu-tool.o qemu-error.o $(trace-obj-y) $(block-obj-y) $(qobject-obj-y) $(version-obj-y) qemu-timer-common.o
+qemu-nbd$(EXESUF): qemu-nbd.o qemu-tool.o qemu-error.o $(oslib-obj-y) $(trace-obj-y) $(block-obj-y) $(qobject-obj-y) $(version-obj-y) qemu-timer-common.o
 
-qemu-io$(EXESUF): qemu-io.o cmd.o qemu-tool.o qemu-error.o $(trace-obj-y) $(block-obj-y) $(qobject-obj-y) $(version-obj-y) qemu-timer-common.o
+qemu-io$(EXESUF): qemu-io.o cmd.o qemu-tool.o qemu-error.o $(oslib-obj-y) $(trace-obj-y) $(block-obj-y) $(qobject-obj-y) $(version-obj-y) qemu-timer-common.o
 
 qemu-img-cmds.h: $(SRC_PATH)/qemu-img-cmds.hx
 	$(call quiet-command,sh $(SRC_PATH)/hxtool -h < $< > $@,"  GEN   $@")
diff --git a/Makefile.objs b/Makefile.objs
index f07fb01bc..c88e82d0c 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -4,11 +4,17 @@ qobject-obj-y = qint.o qstring.o qdict.o qlist.o qfloat.o qbool.o
 qobject-obj-y += qjson.o json-lexer.o json-streamer.o json-parser.o
 qobject-obj-y += qerror.o
 
+#######################################################################
+# oslib-obj-y is code depending on the OS (win32 vs posix)
+oslib-obj-y = osdep.o
+oslib-obj-$(CONFIG_WIN32) += oslib-win32.o
+oslib-obj-$(CONFIG_POSIX) += oslib-posix.o
+
 #######################################################################
 # block-obj-y is code used by both qemu system emulation and qemu-img
 
 block-obj-y = cutils.o cache-utils.o qemu-malloc.o qemu-option.o module.o
-block-obj-y += nbd.o block.o aio.o aes.o osdep.o qemu-config.o
+block-obj-y += nbd.o block.o aio.o aes.o qemu-config.o
 block-obj-$(CONFIG_POSIX) += posix-aio-compat.o
 block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 
@@ -50,6 +56,7 @@ common-obj-y += $(net-obj-y)
 common-obj-y += $(qobject-obj-y)
 common-obj-$(CONFIG_LINUX) += $(fsdev-obj-$(CONFIG_LINUX))
 common-obj-y += readline.o console.o cursor.o async.o qemu-error.o
+common-obj-y += $(oslib-obj-y)
 common-obj-$(CONFIG_WIN32) += os-win32.o
 common-obj-$(CONFIG_POSIX) += os-posix.o
 
diff --git a/osdep.c b/osdep.c
index 2e05b21ad..581768a90 100644
--- a/osdep.c
+++ b/osdep.c
@@ -61,91 +61,6 @@ extern int madvise(caddr_t, size_t, int);
 #include "sysemu.h"
 #include "qemu_socket.h"
 
-#if !defined(_POSIX_C_SOURCE) || defined(_WIN32) || defined(__sun__)
-static void *oom_check(void *ptr)
-{
-    if (ptr == NULL) {
-#if defined(_WIN32)
-        fprintf(stderr, "Failed to allocate memory: %lu\n", GetLastError());
-#else
-        fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
-#endif
-        abort();
-    }
-    return ptr;
-}
-#endif
-
-#if defined(_WIN32)
-void *qemu_memalign(size_t alignment, size_t size)
-{
-    void *ptr;
-
-    if (!size) {
-        abort();
-    }
-    ptr = oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
-    trace_qemu_memalign(alignment, size, ptr);
-    return ptr;
-}
-
-void *qemu_vmalloc(size_t size)
-{
-    void *ptr;
-
-    /* FIXME: this is not exactly optimal solution since VirtualAlloc
-       has 64Kb granularity, but at least it guarantees us that the
-       memory is page aligned. */
-    if (!size) {
-        abort();
-    }
-    ptr = oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
-    trace_qemu_vmalloc(size, ptr);
-    return ptr;
-}
-
-void qemu_vfree(void *ptr)
-{
-    trace_qemu_vfree(ptr);
-    VirtualFree(ptr, 0, MEM_RELEASE);
-}
-
-#else
-
-void *qemu_memalign(size_t alignment, size_t size)
-{
-    void *ptr;
-#if defined(_POSIX_C_SOURCE) && !defined(__sun__)
-    int ret;
-    ret = posix_memalign(&ptr, alignment, size);
-    if (ret != 0) {
-        fprintf(stderr, "Failed to allocate %zu B: %s\n",
-                size, strerror(ret));
-        abort();
-    }
-#elif defined(CONFIG_BSD)
-    ptr = oom_check(valloc(size));
-#else
-    ptr = oom_check(memalign(alignment, size));
-#endif
-    trace_qemu_memalign(alignment, size, ptr);
-    return ptr;
-}
-
-/* alloc shared memory pages */
-void *qemu_vmalloc(size_t size)
-{
-    return qemu_memalign(getpagesize(), size);
-}
-
-void qemu_vfree(void *ptr)
-{
-    trace_qemu_vfree(ptr);
-    free(ptr);
-}
-
-#endif
-
 int qemu_madvise(void *addr, size_t len, int advice)
 {
     if (advice == QEMU_MADV_INVALID) {
diff --git a/oslib-posix.c b/oslib-posix.c
new file mode 100644
index 000000000..df973042f
--- /dev/null
+++ b/oslib-posix.c
@@ -0,0 +1,74 @@
+/*
+ * os-posix-lib.c
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2010 Red Hat, Inc.
+ *
+ * QEMU library functions on POSIX which are shared between QEMU and
+ * the QEMU tools.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "config-host.h"
+#include "sysemu.h"
+#include "trace.h"
+
+#if !defined(_POSIX_C_SOURCE) || defined(__sun__)
+static void *oom_check(void *ptr)
+{
+    if (ptr == NULL) {
+        fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
+        abort();
+    }
+    return ptr;
+}
+#endif
+
+void *qemu_memalign(size_t alignment, size_t size)
+{
+    void *ptr;
+#if defined(_POSIX_C_SOURCE) && !defined(__sun__)
+    int ret;
+    ret = posix_memalign(&ptr, alignment, size);
+    if (ret != 0) {
+        fprintf(stderr, "Failed to allocate %zu B: %s\n",
+                size, strerror(ret));
+        abort();
+    }
+#elif defined(CONFIG_BSD)
+    ptr = oom_check(valloc(size));
+#else
+    ptr = oom_check(memalign(alignment, size));
+#endif
+    trace_qemu_memalign(alignment, size, ptr);
+    return ptr;
+}
+
+/* alloc shared memory pages */
+void *qemu_vmalloc(size_t size)
+{
+    return qemu_memalign(getpagesize(), size);
+}
+
+void qemu_vfree(void *ptr)
+{
+    trace_qemu_vfree(ptr);
+    free(ptr);
+}
diff --git a/oslib-win32.c b/oslib-win32.c
new file mode 100644
index 000000000..3b5245d12
--- /dev/null
+++ b/oslib-win32.c
@@ -0,0 +1,73 @@
+/*
+ * os-win32.c
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2010 Red Hat, Inc.
+ *
+ * QEMU library functions for win32 which are shared between QEMU and
+ * the QEMU tools.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include <windows.h>
+#include "config-host.h"
+#include "sysemu.h"
+#include "trace.h"
+
+static void *oom_check(void *ptr)
+{
+    if (ptr == NULL) {
+        fprintf(stderr, "Failed to allocate memory: %lu\n", GetLastError());
+        abort();
+    }
+    return ptr;
+}
+
+void *qemu_memalign(size_t alignment, size_t size)
+{
+    void *ptr;
+
+    if (!size) {
+        abort();
+    }
+    ptr = oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
+    trace_qemu_memalign(alignment, size, ptr);
+    return ptr;
+}
+
+void *qemu_vmalloc(size_t size)
+{
+    void *ptr;
+
+    /* FIXME: this is not exactly optimal solution since VirtualAlloc
+       has 64Kb granularity, but at least it guarantees us that the
+       memory is page aligned. */
+    if (!size) {
+        abort();
+    }
+    ptr = oom_check(VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE));
+    trace_qemu_vmalloc(size, ptr);
+    return ptr;
+}
+
+void qemu_vfree(void *ptr)
+{
+    trace_qemu_vfree(ptr);
+    VirtualFree(ptr, 0, MEM_RELEASE);
+}