Add support for configuring feature flags when starting guests.

Guest configuration files may now contain a features= declaration
listing the features which should be enabled in a | separated
list.

Signed-off-by: Ian Campbell <ian.campbell@xensource.com>

tools/python/xen/lowlevel/xc/xc.c

@@ -326,27 +326,29 @@ static PyObject *pyxc_linux_build(XcObject *self,
                                   PyObject *kwds)
 {
     uint32_t dom;
-    char *image, *ramdisk = NULL, *cmdline = "";
+    char *image, *ramdisk = NULL, *cmdline = "", *features = NULL;
     int flags = 0;
     int store_evtchn, console_evtchn;
     unsigned long store_mfn = 0;
     unsigned long console_mfn = 0;
 
-    static char *kwd_list[] = { "dom", "store_evtchn", 
-                                "console_evtchn", "image", 
+    static char *kwd_list[] = { "dom", "store_evtchn",
+                                "console_evtchn", "image",
 				/* optional */
-				"ramdisk", "cmdline", "flags", NULL };
+				"ramdisk", "cmdline", "flags",
+				"features", NULL };
 
-    if ( !PyArg_ParseTupleAndKeywords(args, kwds, "iiis|ssi", kwd_list,
+    if ( !PyArg_ParseTupleAndKeywords(args, kwds, "iiis|ssis", kwd_list,
                                       &dom, &store_evtchn,
-				      &console_evtchn, &image, 
+				      &console_evtchn, &image,
 				      /* optional */
-				      &ramdisk, &cmdline, &flags) )
+				      &ramdisk, &cmdline, &flags,
+				      &features) )
         return NULL;
 
     if ( xc_linux_build(self->xc_handle, dom, image,
-                        ramdisk, cmdline, flags,
-                        store_evtchn, &store_mfn, 
+                        ramdisk, cmdline, features, flags,
+                        store_evtchn, &store_mfn,
 			console_evtchn, &console_mfn) != 0 ) {
         if (!errno)
              errno = EINVAL;

tools/python/xen/xend/image.py

@@ -68,6 +68,7 @@ class ImageHandler:
         self.kernel = None
         self.ramdisk = None
         self.cmdline = None
+        self.features = None
 
         self.configure(imageConfig, deviceConfig)
 
@@ -89,6 +90,7 @@ class ImageHandler:
         if args:
             self.cmdline += " " + args
         self.ramdisk = get_cfg("ramdisk", '')
+        self.features = get_cfg("features", '')
         
         self.vm.storeVm(("image/ostype", self.ostype),
                         ("image/kernel", self.kernel),
@@ -175,13 +177,15 @@ class LinuxImageHandler(ImageHandler):
         log.debug("cmdline        = %s", self.cmdline)
         log.debug("ramdisk        = %s", self.ramdisk)
         log.debug("vcpus          = %d", self.vm.getVCpuCount())
+        log.debug("features       = %s", self.features)
 
         return xc.linux_build(dom            = self.vm.getDomid(),
                               image          = self.kernel,
                               store_evtchn   = store_evtchn,
                               console_evtchn = console_evtchn,
                               cmdline        = self.cmdline,
-                              ramdisk        = self.ramdisk)
+                              ramdisk        = self.ramdisk,
+                              features       = self.features)
 
 class HVMImageHandler(ImageHandler):
 

tools/python/xen/xm/create.py

@@ -137,6 +137,10 @@ gopts.var('ramdisk', val='FILE',
           fn=set_value, default='',
           use="Path to ramdisk.")
 
+gopts.var('features', val='FEATURES',
+          fn=set_value, default='',
+          use="Features to enable in guest kernel")
+
 gopts.var('builder', val='FUNCTION',
           fn=set_value, default='linux',
           use="Function to use to build the domain.")
@@ -445,6 +449,8 @@ def configure_image(vals):
         config_image.append(['root', cmdline_root])
     if vals.extra:
         config_image.append(['args', vals.extra])
+    if vals.features:
+        config_image.append(['features', vals.features])
 
     if vals.builder == 'hvm':
         configure_hvm(config_image, vals)