From 7ba8f40134bf1f4dcb179a102cde1eea63f92aae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Gon=C3=A9ri=20Le=20Bouder?= <goneri@lebouder.net>
Date: Tue, 30 Jun 2020 16:49:57 -0400
Subject: [PATCH] QEMU/KVM: accept vmxnet3 NIC

Add the ability to use vmxnet3 NIC on a host using the QEMU/KVM driver.
Qemu supports the driver since version 1.5, and Libvirt can expose it
properly.

This allow the migration of an ESXi VM to QEMU/KVM, this without any driver changes.
vmxnet3 comes with better performance, and lower latency comparing to an emulated
driver like e1000.

Change-Id: I95203af4ded9a4dbecfb7981b400f0fb988f2d47
---
 nova/tests/unit/virt/libvirt/test_vif.py        | 6 ++++--
 nova/virt/libvirt/vif.py                        | 6 ++++--
 releasenotes/notes/qemu-accept-vmxnet3-nic.yaml | 7 +++++++
 3 files changed, 15 insertions(+), 4 deletions(-)
 create mode 100644 releasenotes/notes/qemu-accept-vmxnet3-nic.yaml

diff --git a/nova/tests/unit/virt/libvirt/test_vif.py b/nova/tests/unit/virt/libvirt/test_vif.py
index 25aca122cc79..5c37c650b672 100644
--- a/nova/tests/unit/virt/libvirt/test_vif.py
+++ b/nova/tests/unit/virt/libvirt/test_vif.py
@@ -840,14 +840,16 @@ class LibvirtVifTestCase(test.NoDBTestCase):
                              network_model.VIF_MODEL_RTL8139,
                              network_model.VIF_MODEL_E1000,
                              network_model.VIF_MODEL_E1000E,
-                             network_model.VIF_MODEL_SPAPR_VLAN)
+                             network_model.VIF_MODEL_SPAPR_VLAN,
+                             network_model.VIF_MODEL_VMXNET3)
             else:
                 supported = (network_model.VIF_MODEL_NE2K_PCI,
                              network_model.VIF_MODEL_PCNET,
                              network_model.VIF_MODEL_RTL8139,
                              network_model.VIF_MODEL_E1000,
                              network_model.VIF_MODEL_E1000E,
-                             network_model.VIF_MODEL_SPAPR_VLAN)
+                             network_model.VIF_MODEL_SPAPR_VLAN,
+                             network_model.VIF_MODEL_VMXNET3)
             for model in supported:
                 image_meta = objects.ImageMeta.from_dict(
                     {'properties': {'hw_vif_model': model}})
diff --git a/nova/virt/libvirt/vif.py b/nova/virt/libvirt/vif.py
index 15e7fabdb1b1..e2b86a8b88c9 100644
--- a/nova/virt/libvirt/vif.py
+++ b/nova/virt/libvirt/vif.py
@@ -67,7 +67,8 @@ SUPPORTED_VIF_MODELS = {
         network_model.VIF_MODEL_E1000,
         network_model.VIF_MODEL_E1000E,
         network_model.VIF_MODEL_LAN9118,
-        network_model.VIF_MODEL_SPAPR_VLAN],
+        network_model.VIF_MODEL_SPAPR_VLAN,
+        network_model.VIF_MODEL_VMXNET3],
     'kvm': [
         network_model.VIF_MODEL_VIRTIO,
         network_model.VIF_MODEL_NE2K_PCI,
@@ -75,7 +76,8 @@ SUPPORTED_VIF_MODELS = {
         network_model.VIF_MODEL_RTL8139,
         network_model.VIF_MODEL_E1000,
         network_model.VIF_MODEL_E1000E,
-        network_model.VIF_MODEL_SPAPR_VLAN],
+        network_model.VIF_MODEL_SPAPR_VLAN,
+        network_model.VIF_MODEL_VMXNET3],
     'xen': [
         network_model.VIF_MODEL_NETFRONT,
         network_model.VIF_MODEL_NE2K_PCI,
diff --git a/releasenotes/notes/qemu-accept-vmxnet3-nic.yaml b/releasenotes/notes/qemu-accept-vmxnet3-nic.yaml
new file mode 100644
index 000000000000..a5aef594ecaa
--- /dev/null
+++ b/releasenotes/notes/qemu-accept-vmxnet3-nic.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Add the ability to use ``vmxnet3`` NIC on a host using the QEMU/KVM driver. This allows
+    the migration of an ESXi VM to QEMU/KVM, without any driver changes. ``vmxnet3``
+    comes with better performance and lower latency comparing to an emulated driver like
+    ``e1000``.