diff -r 4f39505426cb tools/Rules.mk
--- a/tools/Rules.mk	Wed Jul 28 11:53:38 2010 +0200
+++ b/tools/Rules.mk	Wed Jul 28 13:25:50 2010 +0200
@@ -26,6 +26,8 @@ LDFLAGS_libxenguest = -L$(XEN_LIBXC) -lx
 CFLAGS_libxenstore = -I$(XEN_XENSTORE) $(CFLAGS_include)
 LDFLAGS_libxenstore = -L$(XEN_XENSTORE) -lxenstore
 
+LIBXL_BLKTAP = y
+
 CFLAGS_libblktapctl = -I$(XEN_BLKTAP2)/control -I$(XEN_BLKTAP2)/include $(CFLAGS_include)
 LDFLAGS_libblktapctl = -L$(XEN_BLKTAP2)/control -lblktapctl
 
diff -r 4f39505426cb tools/libxl/Makefile
--- a/tools/libxl/Makefile	Wed Jul 28 11:53:38 2010 +0200
+++ b/tools/libxl/Makefile	Wed Jul 28 13:25:50 2010 +0200
@@ -18,6 +18,10 @@ CFLAGS += $(CFLAGS_libxenctrl) $(CFLAGS_
 LIBS = $(LDFLAGS_libxenctrl) $(LDFLAGS_libxenguest) $(LDFLAGS_libxenstore) $(LDFLAGS_libblktapctl) $(UTIL_LIBS)
 
 LIBXL_OBJS-y = osdeps.o libxl_paths.o libxl_bootloader.o
+ifeq ($(LIBXL_BLKTAP),y)
+LIBXL_OBJS-y += libxl_blktap2.c
+endif
+
 LIBXL_OBJS = flexarray.o libxl.o libxl_pci.o libxl_dom.o libxl_exec.o libxl_xshelp.o libxl_device.o libxl_internal.o xenguest.o libxl_utils.o $(LIBXL_OBJS-y)
 
 AUTOINCS= libxlu_cfg_y.h libxlu_cfg_l.h
diff -r 4f39505426cb tools/libxl/libxl.c
--- a/tools/libxl/libxl.c	Wed Jul 28 11:53:38 2010 +0200
+++ b/tools/libxl/libxl.c	Wed Jul 28 13:25:50 2010 +0200
@@ -34,7 +34,6 @@
 #include "libxl_utils.h"
 #include "libxl_internal.h"
 #include "flexarray.h"
-#include "tap-ctl.h"
 
 #define PAGE_TO_MEMKB(pages) ((pages) * 4)
 
@@ -1430,27 +1429,6 @@ int libxl_confirm_device_model_startup(s
 
 /******************************************************************************/
 
-static char *get_blktap2_device(struct libxl_ctx *ctx,
-				const char *name, const char *type)
-{
-    int minor = tap_ctl_find_minor(type, name);
-    if (minor < 0)
-        return NULL;
-    return libxl_sprintf(ctx, "/dev/xen/blktap-2/tapdev%d", minor);
-}
-
-static char *make_blktap2_device(struct libxl_ctx *ctx,
-				 const char *name, const char *type)
-{
-    char *params, *devname = NULL;
-    int err;
-    params = libxl_sprintf(ctx, "%s:%s", type, name);
-    err = tap_ctl_create(params, &devname);
-    if (!err)
-        libxl_ptr_add(ctx, devname);
-    return err ? NULL : devname;
-}
-
 int libxl_device_disk_add(struct libxl_ctx *ctx, uint32_t domid, libxl_device_disk *disk)
 {
     flexarray_t *front;
@@ -1499,14 +1477,13 @@ int libxl_device_disk_add(struct libxl_c
         case PHYSTYPE_FILE:
             /* let's pretend is tap:aio for the moment */
             disk->phystype = PHYSTYPE_AIO;
-        case PHYSTYPE_AIO: case PHYSTYPE_QCOW: case PHYSTYPE_QCOW2: case PHYSTYPE_VHD: {
-            const char *msg;
-            if (!tap_ctl_check(&msg)) {
-                const char *type = device_disk_string_of_phystype(disk->phystype);
-                char *dev;
-                dev = get_blktap2_device(ctx, disk->physpath, type);
-                if (!dev)
-                    dev = make_blktap2_device(ctx, disk->physpath, type);
+        case PHYSTYPE_AIO:
+        case PHYSTYPE_QCOW:
+        case PHYSTYPE_QCOW2:
+        case PHYSTYPE_VHD:
+            if (libxl_blktap_enabled(ctx)) {
+                const char *dev = libxl_blktap_devpath(ctx,
+                                               disk->physpath, disk->phystype);
                 if (!dev)
                     return ERROR_FAIL;
                 flexarray_set(back, boffset++, "tapdisk-params");
@@ -1527,7 +1504,7 @@ int libxl_device_disk_add(struct libxl_c
 
             device.backend_kind = DEVICE_TAP;
             break;
-        }
+
         default:
             XL_LOG(ctx, XL_LOG_ERROR, "unrecognized disk physical type: %d\n", disk->phystype);
             return ERROR_INVAL;
@@ -1591,7 +1568,7 @@ int libxl_device_disk_del(struct libxl_c
 
 const char * libxl_device_disk_local_attach(struct libxl_ctx *ctx, libxl_device_disk *disk)
 {
-    char *dev = NULL;
+    const char *dev = NULL;
     int phystype = disk->phystype;
     switch (phystype) {
         case PHYSTYPE_PHY: {
@@ -1602,16 +1579,14 @@ const char * libxl_device_disk_local_att
         case PHYSTYPE_FILE:
             /* let's pretend is tap:aio for the moment */
             phystype = PHYSTYPE_AIO;
-        case PHYSTYPE_AIO: case PHYSTYPE_QCOW: case PHYSTYPE_QCOW2: case PHYSTYPE_VHD: {
-            const char *msg;
-            if (!tap_ctl_check(&msg)) {
-                const char *type = device_disk_string_of_phystype(phystype);
-                dev = get_blktap2_device(ctx, disk->physpath, type);
-                if (!dev)
-                    dev = make_blktap2_device(ctx, disk->physpath, type);
-            }
+        case PHYSTYPE_AIO:
+        case PHYSTYPE_QCOW:
+        case PHYSTYPE_QCOW2:
+        case PHYSTYPE_VHD:
+            if (libxl_blktap_enabled(ctx))
+                dev = libxl_blktap_devpath(ctx, disk->physpath, phystype);
             break;
-        }
+
         default:
             XL_LOG(ctx, XL_LOG_ERROR, "unrecognized disk physical type: %d\n", phystype);
             break;
diff -r 4f39505426cb tools/libxl/libxl_blktap2.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/libxl/libxl_blktap2.c	Wed Jul 28 13:25:50 2010 +0200
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2010      Advanced Micro Devices
+ * Author Christoph Egger <Christoph.Egger@xxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ */
+
+#include "libxl.h"
+#include "libxl_osdeps.h"
+#include "libxl_internal.h"
+
+#include "tap-ctl.h"
+
+int libxl_blktap_enabled(struct libxl_ctx *ctx)
+{
+    const char *msg;
+    return !tap_ctl_check(&msg);
+}
+
+const char *libxl_blktap_devpath(struct libxl_ctx *ctx,
+                                 const char *disk,
+                                 libxl_disk_phystype phystype)
+{
+    const char *type;
+    char *params, *devname;
+    int minor, err;
+
+    type = device_disk_string_of_phystype(phystype);
+    minor = tap_ctl_find_minor(type, disk);
+    if (minor >= 0) {
+        devname = libxl_sprintf(ctx, "/dev/xen/blktap-2/tapdev%d", minor);
+        if (devname)
+            return devname;
+    }
+
+    params = libxl_sprintf(ctx, "%s:%s", type, disk);
+    err = tap_ctl_create(params, &devname);
+    if (!err) {
+        libxl_ptr_add(ctx, devname);
+        return devname;
+    }
+
+    return NULL;
+}
diff -r 4f39505426cb tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h	Wed Jul 28 11:53:38 2010 +0200
+++ b/tools/libxl/libxl_internal.h	Wed Jul 28 13:25:50 2010 +0200
@@ -225,5 +225,24 @@ char *libxl_abs_path(struct libxl_ctx *c
 /* Error handling */
 int libxl_xc_error(int xc_err);
 
+/*
+ * blktap2 support
+ */
+
+/* libxl_blktap_enabled:
+ *    return true if blktap/blktap2 support is available.
+ */
+int libxl_blktap_enabled(struct libxl_ctx *ctx);
+
+/* libxl_blktap_devpath:
+ *    Argument: path and disk image as specified in config file.
+ *      The type specifies whether this is aio, qcow, qcow2, etc.
+ *    returns device path xenstore wants to have. returns NULL
+ *      if no device corresponds to the disk.
+ */
+const char *libxl_blktap_devpath(struct libxl_ctx *ctx,
+                                 const char *disk,
+                                 libxl_disk_phystype phystype);
+
 #endif