[PATCH v7 09/15] libxl: convert libxl_device_nic_add to an async operation

[Roger Pau Monne <roger.pau@citrix.com>]

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.

Changes since v5:

 * Updated to use the new ao_devices struct.

 * Renamed ao_device in nic_add to aodev.

Changes since v4:

 * Used the macro defined in previous patch to define the generic
   callback to wait for nics to be connected.

Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
---
 tools/libxl/libxl.c          |   39 +++++++++++++++++++++++++------
 tools/libxl/libxl.h          |    3 +-
 tools/libxl/libxl_create.c   |   51 +++++++++++++++++++++++++++++++++++------
 tools/libxl/libxl_device.c   |    1 +
 tools/libxl/libxl_dm.c       |   37 ++++++++++++++++++++++++++++--
 tools/libxl/libxl_internal.h |   18 ++++++++++++++
 tools/libxl/xl_cmdimpl.c     |    2 +-
 7 files changed, 130 insertions(+), 21 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index b20b8dd..84010e5 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2424,12 +2424,27 @@ static int libxl__device_from_nic(libxl__gc *gc, uint32_t domid,
     return 0;
 }
 
-int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic)
+int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic,
+                         const libxl_asyncop_how *ao_how)
 {
-    GC_INIT(ctx);
+    AO_CREATE(ctx, domid, ao_how);
+    libxl__ao_device *aodev;
+
+    GCNEW(aodev);
+    libxl__prepare_ao_device(ao, aodev);
+    aodev->callback = device_addrm_aocomplete;
+    libxl__device_nic_add(egc, domid, nic, aodev);
+
+    return AO_INPROGRESS;
+}
+
+void libxl__device_nic_add(libxl__egc *egc, uint32_t domid,
+                           libxl_device_nic *nic, libxl__ao_device *aodev)
+{
+    STATE_AO_GC(aodev->ao);
     flexarray_t *front;
     flexarray_t *back;
-    libxl__device device;
+    libxl__device *device;
     char *dompath, **l;
     unsigned int nb, rc;
 
@@ -2460,7 +2475,8 @@ int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic)
         }
     }
 
-    rc = libxl__device_from_nic(gc, domid, nic, &device);
+    GCNEW(device);
+    rc = libxl__device_from_nic(gc, domid, nic, device);
     if ( rc != 0 ) goto out_free;
 
     flexarray_append(back, "frontend-id");
@@ -2501,6 +2517,9 @@ int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic)
     flexarray_append(back, libxl__strdup(gc, nic->bridge));
     flexarray_append(back, "handle");
     flexarray_append(back, libxl__sprintf(gc, "%d", nic->devid));
+    flexarray_append(back, "type");
+    flexarray_append(back, libxl__strdup(gc,
+                                     libxl_nic_type_to_string(nic->nictype)));
 
     flexarray_append(front, "backend-id");
     flexarray_append(front, libxl__sprintf(gc, "%d", nic->backend_domid));
@@ -2511,18 +2530,22 @@ int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic)
     flexarray_append(front, "mac");
     flexarray_append(front, libxl__sprintf(gc,
                                     LIBXL_MAC_FMT, LIBXL_MAC_BYTES(nic->mac)));
-    libxl__device_generic_add(gc, XBT_NULL, &device,
+    libxl__device_generic_add(gc, XBT_NULL, device,
                              libxl__xs_kvs_of_flexarray(gc, back, back->count),
                              libxl__xs_kvs_of_flexarray(gc, front, front->count));
 
-    /* FIXME: wait for plug */
+    aodev->dev = device;
+    aodev->action = DEVICE_CONNECT;
+    libxl__wait_device_connection(egc, aodev);
+
     rc = 0;
 out_free:
     flexarray_free(back);
     flexarray_free(front);
 out:
-    GC_FREE;
-    return rc;
+    aodev->rc = rc;
+    if (rc) aodev->callback(egc, aodev);
+    return;
 }
 
 static void libxl__device_nic_from_xs_be(libxl__gc *gc,
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 7516e99..d7ae6e4 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -688,7 +688,8 @@ int libxl_device_disk_getinfo(libxl_ctx *ctx, uint32_t domid,
 int libxl_cdrom_insert(libxl_ctx *ctx, uint32_t domid, libxl_device_disk *disk);
 
 /* Network Interfaces */
-int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic);
+int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic,
+                         const libxl_asyncop_how *ao_how);
 int libxl_device_nic_remove(libxl_ctx *ctx, uint32_t domid,
                             libxl_device_nic *nic,
                             const libxl_asyncop_how *ao_how);
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index c6d1a10..6f4c865 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -562,6 +562,9 @@ static void domcreate_bootloader_done(libxl__egc *egc,
 static void domcreate_launch_dm(libxl__egc *egc, libxl__ao_devices *aodevs,
                                 int rc);
 
+static void domcreate_attach_pci(libxl__egc *egc, libxl__ao_devices *aodevs,
+                                 int rc);
+
 static void domcreate_console_available(libxl__egc *egc,
                                         libxl__domain_create_state *dcs);
 
@@ -891,14 +894,13 @@ static void domcreate_launch_dm(libxl__egc *egc, libxl__ao_devices *aodevs,
         LOG(ERROR, "unable to add disk devices");
         goto error_out;
     }
+
     for (i = 0; i < d_config->num_nics; i++) {
-        ret = libxl_device_nic_add(ctx, domid, &d_config->nics[i]);
-        if (ret) {
-            LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
-                       "cannot add nic %d to domain: %d", i, ret);
-            ret = ERROR_FAIL;
-            goto error_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, &d_config->nics[i]);
     }
     switch (d_config->c_info.type) {
     case LIBXL_DOMAIN_TYPE_HVM:
@@ -971,7 +973,6 @@ static void domcreate_devmodel_started(libxl__egc *egc,
 {
     libxl__domain_create_state *dcs = CONTAINER_OF(dmss, *dcs, dmss.dm);
     STATE_AO_GC(dmss->spawn.ao);
-    int i;
     libxl_ctx *ctx = CTX;
     int domid = dcs->guest_domid;
 
@@ -991,6 +992,40 @@ static void domcreate_devmodel_started(libxl__egc *egc,
         }
     }
 
+    /* Plug nic interfaces */
+    if (d_config->num_nics > 0) {
+        /* Attach nics */
+        dcs->aodevs.size = d_config->num_nics;
+        libxl__add_nics(egc, ao, domid, d_config, &dcs->aodevs,
+                        domcreate_attach_pci);
+        return;
+    }
+
+    domcreate_attach_pci(egc, &dcs->aodevs, 0);
+    return;
+
+error_out:
+    assert(ret);
+    domcreate_complete(egc, dcs, ret);
+}
+
+static void domcreate_attach_pci(libxl__egc *egc, libxl__ao_devices *aodevs,
+                                 int rc)
+{
+    libxl__domain_create_state *dcs = CONTAINER_OF(aodevs, *dcs, aodevs);
+    STATE_AO_GC(dcs->ao);
+    int i, ret = 0;
+    libxl_ctx *ctx = CTX;
+    int domid = dcs->guest_domid;
+
+    /* convenience aliases */
+    libxl_domain_config *const d_config = dcs->guest_config;
+
+    if (rc) {
+        LOG(ERROR, "unable to add nic devices");
+        goto error_out;
+    }
+
     for (i = 0; i < d_config->num_pcidevs; i++)
         libxl__device_pci_add(gc, domid, &d_config->pcidevs[i], 1);
 
diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 9438a82..13f9ecb 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -471,6 +471,7 @@ void libxl__ao_devices_callback(libxl__egc *egc, libxl__ao_device *aodev)
     }
 
 DEFINE_DEVICES_ADD(disk)
+DEFINE_DEVICES_ADD(nic)
 
 #undef DEFINE_DEVICES_ADD
 
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index 30b7556..b4a5f1f 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -697,6 +697,10 @@ static void spawn_stubdom_pvqemu_cb(libxl__egc *egc,
 static void spawn_stub_launch_dm(libxl__egc *egc,
                                  libxl__ao_devices *aodevs, int rc);
 
+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);
@@ -863,9 +867,11 @@ 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)
@@ -942,9 +948,34 @@ 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;
+        libxl__add_nics(egc, ao, dm_domid, d_config, &sdss->aodevs,
+                        stubdom_pvqemu_cb);
+        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;
 
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 90fa19a..df2db10 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1810,6 +1810,11 @@ _hidden void libxl__device_disk_add(libxl__egc *egc, uint32_t domid,
                                     libxl_device_disk *disk,
                                     libxl__ao_device *aodev);
 
+/* AO operation to connect a nic device */
+_hidden void libxl__device_nic_add(libxl__egc *egc, uint32_t domid,
+                                   libxl_device_nic *nic,
+                                   libxl__ao_device *aodev);
+
 /* Waits for the passed device to reach state XenbusStateInitWait.
  * This is not really useful by itself, but is important when executing
  * hotplug scripts, since we need to be sure the device is in the correct
@@ -2198,6 +2203,19 @@ void libxl__add_disks(libxl__egc *egc, libxl__ao *ao, uint32_t domid,
                       libxl__ao_devices *aodevs,
                       libxl__devices_callback *callback);
 
+/* Helper function to add a bunch of nics. This should be used when
+ * the caller is inside an async op. "devices" will be prepared by this
+ * function, so there's no need to call _prepare before calling this
+ * function.
+ *
+ * The "callback" will be called for each device, and the user is responsible
+ * for calling libxl__ao_device_check_last on the callback.
+ */
+void libxl__add_nics(libxl__egc *egc, libxl__ao *ao, uint32_t domid,
+                     libxl_domain_config *d_config,
+                     libxl__ao_devices *aodevs,
+                     libxl__devices_callback *callback);
+
 /*----- device model creation -----*/
 
 /* First layer; wraps libxl__spawn_spawn. */
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 11ad0e8..4c3cabd 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -5209,7 +5209,7 @@ int main_networkattach(int argc, char **argv)
         return 0;
     }
 
-    if (libxl_device_nic_add(ctx, domid, &nic)) {
+    if (libxl_device_nic_add(ctx, domid, &nic, 0)) {
         fprintf(stderr, "libxl_device_nic_add failed.\n");
         return 1;
     }
-- 
1.7.7.5 (Apple Git-26)