libxl: set the device model version earlier in xenstore

So libxl doesn't have to pass the build info around just to get the device
model used by the guest. This allows to simplify
libxl__device_nic_setdefault.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>

tools/libxl/libxl.c

@@ -3299,7 +3299,7 @@ out:
 /******************************************************************************/
 
 int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic,
-                                 uint32_t domid, libxl_domain_build_info *info)
+                                 uint32_t domid)
 {
     int rc;
 
@@ -3337,21 +3337,11 @@ int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic,
     switch (libxl__domain_type(gc, domid)) {
     case LIBXL_DOMAIN_TYPE_HVM:
         if (!nic->nictype) {
-            if (info != NULL) {
-                /* Path taken at creation time. */
-                if (info->device_model_version ==
-                    LIBXL_DEVICE_MODEL_VERSION_NONE)
-                    nic->nictype = LIBXL_NIC_TYPE_VIF;
-                else
-                    nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU;
-            } else {
-                /* Path taken when hot-adding a nic. */
-                if (libxl__device_model_version_running(gc, domid) ==
-                    LIBXL_DEVICE_MODEL_VERSION_NONE)
-                    nic->nictype = LIBXL_NIC_TYPE_VIF;
-                else
-                    nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU;
-            }
+            if (libxl__device_model_version_running(gc, domid) ==
+                LIBXL_DEVICE_MODEL_VERSION_NONE)
+                nic->nictype = LIBXL_NIC_TYPE_VIF;
+            else
+                nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU;
         }
         break;
     case LIBXL_DOMAIN_TYPE_PV:
@@ -3401,7 +3391,7 @@ void libxl__device_nic_add(libxl__egc *egc, uint32_t domid,
     libxl_device_nic_init(&nic_saved);
     libxl_device_nic_copy(CTX, &nic_saved, nic);
 
-    rc = libxl__device_nic_setdefault(gc, nic, domid, NULL);
+    rc = libxl__device_nic_setdefault(gc, nic, domid);
     if (rc) goto out;
 
     front = flexarray_make(gc, 16, 1);

tools/libxl/libxl_create.c

@@ -916,6 +916,12 @@ static void initiate_domain_create(libxl__egc *egc,
         goto error_out;
     }
 
+    /*
+     * Set the dm version quite early so that libxl doesn't have to pass the
+     * build info around just to know if the domain has a device model or not.
+     */
+    store_libxl_entry(gc, domid, &d_config->b_info);
+
     for (i = 0; i < d_config->num_disks; i++) {
         ret = libxl__device_disk_setdefault(gc, &d_config->disks[i]);
         if (ret) {
@@ -940,8 +946,7 @@ static void initiate_domain_create(libxl__egc *egc,
          * called libxl_device_nic_add when domcreate_launch_dm gets called,
          * but qemu needs the nic information to be complete.
          */
-        ret = libxl__device_nic_setdefault(gc, &d_config->nics[i], domid,
-                                           &d_config->b_info);
+        ret = libxl__device_nic_setdefault(gc, &d_config->nics[i], domid);
         if (ret) {
             LOG(ERROR, "Unable to set nic defaults for nic %d", i);
             goto error_out;

tools/libxl/libxl_dm.c

@@ -1811,8 +1811,7 @@ static void spawn_stub_launch_dm(libxl__egc *egc,
          * called libxl_device_nic_add at this point, but qemu needs
          * the nic information to be complete.
          */
-        ret = libxl__device_nic_setdefault(gc, &dm_config->nics[i], dm_domid,
-                                           &dm_config->b_info);
+        ret = libxl__device_nic_setdefault(gc, &dm_config->nics[i], dm_domid);
         if (ret)
             goto out;
     }

tools/libxl/libxl_internal.h

@@ -1216,8 +1216,7 @@ _hidden int libxl__domain_build_info_setdefault(libxl__gc *gc,
 _hidden int libxl__device_disk_setdefault(libxl__gc *gc,
                                           libxl_device_disk *disk);
 _hidden int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic,
-                                         uint32_t domid,
-                                         libxl_domain_build_info *info);
+                                         uint32_t domid);
 _hidden int libxl__device_vtpm_setdefault(libxl__gc *gc, libxl_device_vtpm *vtpm);
 _hidden int libxl__device_vfb_setdefault(libxl__gc *gc, libxl_device_vfb *vfb);
 _hidden int libxl__device_vkb_setdefault(libxl__gc *gc, libxl_device_vkb *vkb);