qemu: Add e1000e/vmxnet3 IFF_VNET_HDR support

Setting IFF_VNET_HDR for a tap device passes the whole packet to the
host, reducing emulation overhead and improving performance.

Libvirt bases its decision about applying IFF_VNET_HDR to the tap
interface on whether or not the model of the emulated network device
is virtio.  Originally, virtio was the only model to support
IFF_VNET_HDR in QEMU; however, the e1000e & vmxnet3 adapters have also
supported it since their introductions - QEMU commit
786fd2b0f87 for vmxnet3, and QEMU commit 6f3fbe4ed0 for e1000e, so it
should be set for those models too.

Signed-off-by: Patrick Magauran <patmagauran.j@gmail.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Laine Stump <laine@redhat.com>

diff --git a/src/qemu/qemu_interface.c b/src/qemu/qemu_interface.c
index ffec992596c09aa77ce580dac3a99ce2edc16d4c..10a87a2528e95963e655c1acbe5e3e7910a2cad1 100644 (file)
--- a/src/qemu/qemu_interface.c
+++ b/src/qemu/qemu_interface.c
@@ -231,6 +231,15 @@ qemuInterfaceStopDevices(virDomainDefPtr def)
 }
 
 
+static bool
+qemuInterfaceIsVnetCompatModel(const virDomainNetDef *net)
+{
+    return (virDomainNetIsVirtioModel(net) ||
+            net->model == VIR_DOMAIN_NET_MODEL_E1000E ||
+            net->model == VIR_DOMAIN_NET_MODEL_VMXNET3);
+}
+
+
 /**
  * qemuInterfaceDirectConnect:
  * @def: the definition of the VM (needed by 802.1Qbh and audit)
@@ -255,7 +264,7 @@ qemuInterfaceDirectConnect(virDomainDefPtr def,
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     unsigned int macvlan_create_flags = VIR_NETDEV_MACVLAN_CREATE_WITH_TAP;
 
-    if (virDomainNetIsVirtioModel(net))
+    if (qemuInterfaceIsVnetCompatModel(net))
         macvlan_create_flags |= VIR_NETDEV_MACVLAN_VNET_HDR;
 
     if (virNetDevMacVLanCreateWithVPortProfile(net->ifname,
@@ -417,7 +426,7 @@ qemuInterfaceEthernetConnect(virDomainDefPtr def,
         }
     }
 
-    if (virDomainNetIsVirtioModel(net))
+    if (qemuInterfaceIsVnetCompatModel(net))
         tap_create_flags |= VIR_NETDEV_TAP_CREATE_VNET_HDR;
 
     if (net->managed_tap == VIR_TRISTATE_BOOL_NO) {
@@ -436,7 +445,7 @@ qemuInterfaceEthernetConnect(virDomainDefPtr def,
             if (virNetDevMacVLanTapOpen(net->ifname, tapfd, tapfdSize) < 0)
                 goto cleanup;
             if (virNetDevMacVLanTapSetup(tapfd, tapfdSize,
-                                         virDomainNetIsVirtioModel(net)) < 0) {
+                                         qemuInterfaceIsVnetCompatModel(net)) < 0) {
                 goto cleanup;
             }
         } else {
@@ -559,7 +568,7 @@ qemuInterfaceBridgeConnect(virDomainDefPtr def,
         template_ifname = true;
     }
 
-    if (virDomainNetIsVirtioModel(net))
+    if (qemuInterfaceIsVnetCompatModel(net))
         tap_create_flags |= VIR_NETDEV_TAP_CREATE_VNET_HDR;
 
     if (driver->privileged) {