[libvirt] [PATCH] conf: don't ignore <target dev='blah'/> for macvtap interfaces

[Laine Stump]

The parser had been clearing out *all* suggested device names for
type='direct' (aka macvtap) interfaces. All of the code implementing
macvtap allows for a user-specified device name, so we should allow
it. In the case that an interface name starts with "macvtap" or
"macvlan" though, we do still clear it out, just as we do with "vnet"
(which is the prefix used for automatically generated tap device
names), since those are the prefixes for the names we autogenerate for
macvtap and macvlan devices.

Resolves: https://bugzilla.redhat.com/1335798
---
 docs/formatdomain.html.in | 6 +++---
 src/conf/domain_conf.c    | 6 +++++-
 src/conf/domain_conf.h    | 4 ++++
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 4a3123e..8a2294f 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -5125,9 +5125,9 @@ qemu-kvm -net nic,model=? /dev/null
       If no target is specified, certain hypervisors will
       automatically generate a name for the created tun device. This
       name can be manually specified, however the name <i>should not
-      start with either 'vnet' or 'vif'</i>, which are prefixes
-      reserved by libvirt and certain hypervisors. Manually specified
-      targets using these prefixes may be ignored.
+      start with either 'vnet', 'vif', 'macvtap', or 'macvlan'</i>,
+      which are prefixes reserved by libvirt and certain hypervisors.
+      Manually specified targets using these prefixes may be ignored.
     </p>
 
     <p>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 2139ab0..4b80018 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -9826,8 +9826,12 @@ virDomainNetDefParseXML(virDomainXMLOptionPtr xmlopt,
         def->data.direct.linkdev = dev;
         dev = NULL;
 
-        if (flags & VIR_DOMAIN_DEF_PARSE_INACTIVE)
+        if (ifname &&
+            flags & VIR_DOMAIN_DEF_PARSE_INACTIVE &&
+            (STRPREFIX(ifname, VIR_NET_GENERATED_MACVTAP_PREFIX) ||
+             STRPREFIX(ifname, VIR_NET_GENERATED_MACVTAP_PREFIX))) {
             VIR_FREE(ifname);
+        }
 
         break;
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 8e6d874..38a15f1 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1033,6 +1033,10 @@ struct _virDomainNetDef {
  * by libvirt, and cannot be used for a persistent network name.  */
 # define VIR_NET_GENERATED_PREFIX "vnet"
 
+/* except to macvtap/macvlan interfaces, which start with "macv(tap|lan) */
+# define VIR_NET_GENERATED_MACVTAP_PREFIX "macvtap"
+# define VIR_NET_GENERATED_MACVLAN_PREFIX "macvlan"
+
 typedef enum {
     VIR_DOMAIN_CHR_DEVICE_STATE_DEFAULT = 0,
     VIR_DOMAIN_CHR_DEVICE_STATE_CONNECTED,
-- 
2.9.3