hw/xen: Create initial XenStore nodes

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>

hw/i386/kvm/xen_xenstore.c

@@ -76,9 +76,39 @@ struct XenXenstoreState *xen_xenstore_singleton;
 static void xen_xenstore_event(void *opaque);
 static void fire_watch_cb(void *opaque, const char *path, const char *token);
 
+static void G_GNUC_PRINTF (4, 5) relpath_printf(XenXenstoreState *s,
+                                                GList *perms,
+                                                const char *relpath,
+                                                const char *fmt, ...)
+{
+    gchar *abspath;
+    gchar *value;
+    va_list args;
+    GByteArray *data;
+    int err;
+
+    abspath = g_strdup_printf("/local/domain/%u/%s", xen_domid, relpath);
+    va_start(args, fmt);
+    value = g_strdup_vprintf(fmt, args);
+    va_end(args);
+
+    data = g_byte_array_new_take((void *)value, strlen(value));
+
+    err = xs_impl_write(s->impl, DOMID_QEMU, XBT_NULL, abspath, data);
+    assert(!err);
+
+    g_byte_array_unref(data);
+
+    err = xs_impl_set_perms(s->impl, DOMID_QEMU, XBT_NULL, abspath, perms);
+    assert(!err);
+
+    g_free(abspath);
+}
+
 static void xen_xenstore_realize(DeviceState *dev, Error **errp)
 {
     XenXenstoreState *s = XEN_XENSTORE(dev);
+    GList *perms;
 
     if (xen_mode != XEN_EMULATE) {
         error_setg(errp, "Xen xenstore support is for Xen emulation");
@@ -102,6 +132,46 @@ static void xen_xenstore_realize(DeviceState *dev, Error **errp)
                        xen_xenstore_event, NULL, NULL, NULL, s);
 
     s->impl = xs_impl_create(xen_domid);
+
+    /* Populate the default nodes */
+
+    /* Nodes owned by 'dom0' but readable by the guest */
+    perms = g_list_append(NULL, xs_perm_as_string(XS_PERM_NONE, DOMID_QEMU));
+    perms = g_list_append(perms, xs_perm_as_string(XS_PERM_READ, xen_domid));
+
+    relpath_printf(s, perms, "", "%s", "");
+
+    relpath_printf(s, perms, "domid", "%u", xen_domid);
+
+    relpath_printf(s, perms, "control/platform-feature-xs_reset_watches", "%u", 1);
+    relpath_printf(s, perms, "control/platform-feature-multiprocessor-suspend", "%u", 1);
+
+    relpath_printf(s, perms, "platform/acpi", "%u", 1);
+    relpath_printf(s, perms, "platform/acpi_s3", "%u", 1);
+    relpath_printf(s, perms, "platform/acpi_s4", "%u", 1);
+    relpath_printf(s, perms, "platform/acpi_laptop_slate", "%u", 0);
+
+    g_list_free_full(perms, g_free);
+
+    /* Nodes owned by the guest */
+    perms = g_list_append(NULL, xs_perm_as_string(XS_PERM_NONE, xen_domid));
+
+    relpath_printf(s, perms, "attr", "%s", "");
+
+    relpath_printf(s, perms, "control/shutdown", "%s", "");
+    relpath_printf(s, perms, "control/feature-poweroff", "%u", 1);
+    relpath_printf(s, perms, "control/feature-reboot", "%u", 1);
+    relpath_printf(s, perms, "control/feature-suspend", "%u", 1);
+    relpath_printf(s, perms, "control/feature-s3", "%u", 1);
+    relpath_printf(s, perms, "control/feature-s4", "%u", 1);
+
+    relpath_printf(s, perms, "data", "%s", "");
+    relpath_printf(s, perms, "device", "%s", "");
+    relpath_printf(s, perms, "drivers", "%s", "");
+    relpath_printf(s, perms, "error", "%s", "");
+    relpath_printf(s, perms, "feature", "%s", "");
+
+    g_list_free_full(perms, g_free);
 }
 
 static bool xen_xenstore_is_needed(void *opaque)