libxl: convert libxl_device_nic_add to an async operation

This patch converts libxl_device_nic_add to an ao operation that
waits for device backend to reach state XenbusStateInitWait and then
marks the operation as completed. This is not really useful now, but
will be used by latter patches that will launch hotplug scripts after
we reached the desired xenbus state.

Calls to libxl_device_nic_add have also been moved to occur after the
device model has been launched, so when hotplug scripts are called
from this functions the interfaces already exists.

As usual, libxl_device_nic_add callers have been modified, and the
internal function libxl__device_disk_add has been used if the call was
inside an already running ao.

Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 35 insertions, 3 deletions

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 8a731ae500..1b17ef516f 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -716,6 +716,10 @@ static void spawn_stubdom_pvqemu_cb(libxl__egc *egc,
 static void spawn_stub_launch_dm(libxl__egc *egc,
                                  libxl__ao_devices *aodevs, int ret);
 
+static void stubdom_pvqemu_cb(libxl__egc *egc,
+                              libxl__ao_devices *aodevs,
+                              int rc);
+
 static void spaw_stubdom_pvqemu_destroy_cb(libxl__egc *egc,
                                            libxl__destroy_domid_state *dis,
                                            int rc);
@@ -887,9 +891,11 @@ static void spawn_stub_launch_dm(libxl__egc *egc,
      }
 
     for (i = 0; i < dm_config->num_nics; i++) {
-        ret = libxl_device_nic_add(ctx, dm_domid, &dm_config->nics[i]);
-        if (ret)
-            goto out;
+         /* We have to init the nic here, because we still haven't
+         * called libxl_device_nic_add at this point, but qemu needs
+         * the nic information to be complete.
+         */
+        libxl__device_nic_setdefault(gc, &dm_config->nics[i]);
     }
     ret = libxl_device_vfb_add(ctx, dm_domid, &dm_config->vfbs[0]);
     if (ret)
@@ -966,9 +972,35 @@ static void spawn_stubdom_pvqemu_cb(libxl__egc *egc,
         CONTAINER_OF(stubdom_dmss, *sdss, pvqemu);
     STATE_AO_GC(sdss->dm.spawn.ao);
     uint32_t dm_domid = sdss->pvqemu.guest_domid;
+    libxl_domain_config *d_config = stubdom_dmss->guest_config;
 
     if (rc) goto out;
 
+    if (d_config->num_nics > 0) {
+        sdss->aodevs.size = d_config->num_nics;
+        sdss->aodevs.callback = stubdom_pvqemu_cb;
+        libxl__prepare_ao_devices(ao, &sdss->aodevs);
+        libxl__add_nics(egc, ao, dm_domid, 0, d_config, &sdss->aodevs);
+        return;
+    }
+
+out:
+    stubdom_pvqemu_cb(egc, &sdss->aodevs, rc);
+}
+
+static void stubdom_pvqemu_cb(libxl__egc *egc,
+                              libxl__ao_devices *aodevs,
+                              int rc)
+{
+    libxl__stub_dm_spawn_state *sdss = CONTAINER_OF(aodevs, *sdss, aodevs);
+    STATE_AO_GC(sdss->dm.spawn.ao);
+    uint32_t dm_domid = sdss->pvqemu.guest_domid;
+
+    if (rc) {
+        LOGE(ERROR, "error connecting nics devices");
+        goto out;
+    }
+
     rc = libxl_domain_unpause(CTX, dm_domid);
     if (rc) goto out;