[libvirt] [PATCH v2 2/2] qemu: network user/direct/hostdev do not support backend.

[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/qemu/qemu_domain.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index cc7596b..0215b2a 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -3608,6 +3608,13 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
                 goto cleanup;
             }
 
+            if (net->backend.tap) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("Custom tap device path is not supported for: %s"),
+                               virDomainNetTypeToString(net->type));
+                goto cleanup;
+            }
+
             for (i = 0; i < net->guestIP.nips; i++) {
                 const virNetDevIPAddr *ip = net->guestIP.ips[i];
 
@@ -3649,6 +3656,14 @@ qemuDomainDeviceDefValidate(const virDomainDeviceDef *dev,
                     }
                 }
             }
+        } else if (net->type == VIR_DOMAIN_NET_TYPE_DIRECT ||
+                   net->type == VIR_DOMAIN_NET_TYPE_HOSTDEV) {
+            if (net->backend.tap) {
+                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                               _("Custom tap device path is not supported for: %s"),
+                               virDomainNetTypeToString(net->type));
+                goto cleanup;
+            }
         } else if (net->guestIP.nroutes || net->guestIP.nips) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                            _("Invalid attempt to set network interface "
-- 
2.7.4