diff -r bbf009817ffb tools/libxl/libxl.c
--- a/tools/libxl/libxl.c	Fri May 07 19:22:28 2010 +0100
+++ b/tools/libxl/libxl.c	Tue May 11 07:45:01 2010 +0200
@@ -169,7 +169,8 @@ retry_transaction:
 
     xs_write(ctx->xsh, t, libxl_sprintf(ctx, "%s/uuid", vm_path), uuid_string, strlen(uuid_string));
     xs_write(ctx->xsh, t, libxl_sprintf(ctx, "%s/name", vm_path), info->name, strlen(info->name));
-    xs_write(ctx->xsh, t, libxl_sprintf(ctx, "%s/pool_name", vm_path), info->poolname, strlen(info->poolname));
+    if (info->poolname)
+        xs_write(ctx->xsh, t, libxl_sprintf(ctx, "%s/pool_name", vm_path), info->poolname, strlen(info->poolname));
 
     libxl_xs_writev(ctx, t, dom_path, info->xsdata);
     libxl_xs_writev(ctx, t, libxl_sprintf(ctx, "%s/platform", dom_path), info->platformdata);
diff -r bbf009817ffb tools/libxl/libxl_utils.c
--- a/tools/libxl/libxl_utils.c	Fri May 07 19:22:28 2010 +0100
+++ b/tools/libxl/libxl_utils.c	Tue May 11 07:45:01 2010 +0200
@@ -84,6 +84,8 @@ char *libxl_poolid_to_name(struct libxl_
     char path[strlen("/local/pool") + 12];
     char *s;
 
+    if (poolid == 0)
+        return "Pool-0";
     snprintf(path, sizeof(path), "/local/pool/%d/name", poolid);
     s = xs_read(ctx->xsh, XBT_NULL, path, &len);
     libxl_ptr_add(ctx, s);
diff -r bbf009817ffb tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c	Fri May 07 19:22:28 2010 +0100
+++ b/tools/libxl/xl_cmdimpl.c	Tue May 11 07:45:01 2010 +0200
@@ -453,9 +453,15 @@ static void parse_config_data(const char
     if (!xlu_cfg_get_long(config, "oos", &l))
         c_info->oos = l;
 
-    if (!xlu_cfg_get_string (config, "pool", &buf))
+    if (!xlu_cfg_get_string (config, "pool", &buf)) {
+        c_info->poolid = -1;
         pool_qualifier_to_poolid(buf, &c_info->poolid, NULL);
+    }
     c_info->poolname = libxl_poolid_to_name(&ctx, c_info->poolid);
+    if (!c_info->poolname) {
+        fprintf(stderr, "Illegal pool specified\n");
+        exit(1);
+    }
 
     init_build_info(b_info, c_info);