[libvirt] [PATCH 2/2] conf: network user/direct/hostdev do not support backend tag.

[Julio Faracco]

The tag backend is not supported for user/direct/hostdev network when you
try to define them inside the domain XML. So, other ways to include devices
cannot be permitted too. But the attach-device command is wrongly adding
unsupported features. This commit fixes this bug.

After the patch:

virsh # attach-device rhel7.4 backend.xml
error: Failed to attach device from backend.xml
error: unsupported configuration: Custom tap device path is not supported for: user

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1480251

Signed-off-by: Julio Faracco <jcfaracco at gmail.com>
---
 src/conf/domain_conf.c   | 10 ++++++++++
 tests/qemuxml2argvtest.c |  6 +++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 0f306b7..2842533 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -10518,6 +10518,16 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
             } else if (virXMLNodeNameEqual(cur, "backend")) {
                 char *tmp = NULL;
 
+                /* user/direct/hostdev do not support backend */
+                if (def->type == VIR_DOMAIN_NET_TYPE_USER ||
+                    def->type == VIR_DOMAIN_NET_TYPE_DIRECT ||
+                    def->type == VIR_DOMAIN_NET_TYPE_HOSTDEV) {
+                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                   _("Custom tap device path is not supported for: %s"),
+                                   virDomainNetTypeToString(def->type));
+                    goto error;
+                }
+
                 if ((tmp = virXMLPropString(cur, "tap")))
                     def->backend.tap = virFileSanitizePath(tmp);
                 VIR_FREE(tmp);
diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index 01e7d6f..fad8aba 100644
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -1219,9 +1219,9 @@ mymain(void)
             QEMU_CAPS_DEVICE_VFIO_PCI, QEMU_CAPS_HOST_PCI_MULTIDOMAIN);
     DO_TEST_FAILURE("net-hostdev-vfio-multidomain",
                     QEMU_CAPS_NODEFCONFIG, QEMU_CAPS_DEVICE_VFIO_PCI);
-    DO_TEST_FAILURE("net-hostdev-fail",
-                    QEMU_CAPS_NODEFCONFIG,
-                    QEMU_CAPS_DEVICE_VFIO_PCI);
+    DO_TEST_PARSE_ERROR("net-hostdev-fail",
+                        QEMU_CAPS_NODEFCONFIG,
+                        QEMU_CAPS_DEVICE_VFIO_PCI);
 
 
     DO_TEST("serial-file-log",
-- 
2.7.4