Re: [libvirt PATCH v2] Adds e1000e/vmxnet3 Vnet_hdr suuport

[Daniel Henrique Barboza]

Be mindful of the typo in the commit title: suuport -> support

Just a nit below:

On 8/8/20 10:59 AM, Patrick Magauran wrote:

Changes from Original:
Moved Comparison to qemuInterfaceIsVnetCompatModel in qemu_interface.c per the 
recommendation of Daniel Berrangé

-----
Libvirt bases its decision about whether to apply the vnet_hdr flag to the tap 
interface on whether or not the selected model is VirtIO. Originally, VirtIO was 
the only model to support the vnet_hdr in QEMU; however, the e1000e & vmxnet3 
adapters also support it(seemingly from introduction based on commits). This passes 
the whole packet to the host, reducing emulation overhead and improving performance.

Signed-off-by: Patrick Magauran <patmagaura...@gmail.com>
---
  src/qemu/qemu_interface.c | 15 +++++++++++----
  src/qemu/qemu_interface.h |  1 +
  2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/qemu/qemu_interface.c b/src/qemu/qemu_interface.c
index ffec992596..229bb299aa 100644
--- a/src/qemu/qemu_interface.c
+++ b/src/qemu/qemu_interface.c
@@ -230,6 +230,13 @@ qemuInterfaceStopDevices(virDomainDefPtr def)
      return 0;
  }

+bool qemuInterfaceIsVnetCompatModel(const virDomainNetDef *net)

+{
+    return (virDomainNetIsVirtioModel(net) ||
+           net->model == VIR_DOMAIN_NET_MODEL_E1000E ||
+           net->model == VIR_DOMAIN_NET_MODEL_VMXNET3);
+}

^ indentation here is misaligned by a few spaces:

    return (virDomainNetIsVirtioModel(net) ||
            net->model == VIR_DOMAIN_NET_MODEL_E1000E ||
            net->model == VIR_DOMAIN_NET_MODEL_VMXNET3);


Rest of the code LGTM. I'm CC'ing Laine because I don't have authority to
decide if what you're doing here is enough or more changes are required,
and network is Laine's turf. As far as I understand:


Reviewed-by: Daniel Henrique Barboza <danielhb...@gmail.com>

+

/**

   * qemuInterfaceDirectConnect:
@@ -255,7 +262,7 @@ 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 +424,7 @@ 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 +443,7 @@ 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 +566,7 @@ qemuInterfaceBridgeConnect(virDomainDefPtr def,
          template_ifname = true;
      }

- if (virDomainNetIsVirtioModel(net))

+    if (qemuInterfaceIsVnetCompatModel(net))
          tap_create_flags |= VIR_NETDEV_TAP_CREATE_VNET_HDR;

if (driver->privileged) {

diff --git a/src/qemu/qemu_interface.h b/src/qemu/qemu_interface.h
index 0464b903d7..9e3f61e8e0 100644
--- a/src/qemu/qemu_interface.h
+++ b/src/qemu/qemu_interface.h
@@ -58,3 +58,4 @@ int qemuInterfaceOpenVhostNet(virDomainDefPtr def,

qemuSlirpPtr qemuInterfacePrepareSlirp(virQEMUDriverPtr driver,

                                         virDomainNetDefPtr net);
+bool qemuInterfaceIsVnetCompatModel(const virDomainNetDef *net);