libxl: set correct nic type depending on the guest

Fix the use of nic type, which results in the following for each type
of domain:

 * HVM: let the user choose, if none specified use VIF_IOEMU.
 * PV: use VIF is none provided, return error if VIF_IOEMU requested.

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>

4 files changed, 30 insertions, 7 deletions

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 0a5e4e9ee2..da9ddff4aa 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2457,7 +2457,8 @@ out:
 
 /******************************************************************************/
 
-int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic)
+int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic,
+                                 uint32_t domid)
 {
     if (!nic->mtu)
         nic->mtu = 1492;
@@ -2487,8 +2488,25 @@ int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic)
     if ( !nic->script && asprintf(&nic->script, "%s/vif-bridge",
                                   libxl__xen_script_dir_path()) < 0 )
         return ERROR_FAIL;
-    if (!nic->nictype)
-        nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU;
+
+    switch (libxl__domain_type(gc, domid)) {
+    case LIBXL_DOMAIN_TYPE_HVM:
+        if (!nic->nictype)
+            nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU;
+        break;
+    case LIBXL_DOMAIN_TYPE_PV:
+        if (nic->nictype == LIBXL_NIC_TYPE_VIF_IOEMU) {
+            LOG(ERROR, "trying to create PV guest with an emulated interface");
+            return ERROR_INVAL;
+        }
+        nic->nictype = LIBXL_NIC_TYPE_VIF;
+        break;
+    case LIBXL_DOMAIN_TYPE_INVALID:
+        return ERROR_FAIL;
+    default:
+        abort();
+    }
+
     return 0;
 }
 
@@ -2516,7 +2534,7 @@ void libxl__device_nic_add(libxl__egc *egc, uint32_t domid,
     char *dompath, **l;
     unsigned int nb, rc;
 
-    rc = libxl__device_nic_setdefault(gc, nic);
+    rc = libxl__device_nic_setdefault(gc, nic, domid);
     if (rc) goto out;
 
     front = flexarray_make(16, 1);
diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index b9dd547c6a..3fd33e7065 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -943,7 +943,9 @@ static void domcreate_launch_dm(libxl__egc *egc, libxl__ao_devices *aodevs,
          * 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]);
+        ret = libxl__device_nic_setdefault(gc, &d_config->nics[i], domid);
+        if (ret)
+            goto error_out;
     }
     switch (d_config->c_info.type) {
     case LIBXL_DOMAIN_TYPE_HVM:
diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index dec7c19661..606cc29cdd 100644
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -898,7 +898,9 @@ 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.
          */
-        libxl__device_nic_setdefault(gc, &dm_config->nics[i]);
+        ret = libxl__device_nic_setdefault(gc, &dm_config->nics[i], dm_domid);
+        if (ret)
+            goto out;
     }
     ret = libxl_device_vfb_add(ctx, dm_domid, &dm_config->vfbs[0]);
     if (ret)
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 1ac681db55..382ec79dd7 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -938,7 +938,8 @@ _hidden int libxl__domain_build_info_setdefault(libxl__gc *gc,
                                         libxl_domain_build_info *b_info);
 _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);
+_hidden int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic,
+                                         uint32_t domid);
 _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);
 _hidden int libxl__device_pci_setdefault(libxl__gc *gc, libxl_device_pci *pci);