On Thu, Aug 06, 2020 at 10:53:32PM -0400, Patrick Magauran wrote:
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 <patmagauran.j@gmail.com> --- src/conf/domain_conf.c | 8 +++++++- src/conf/domain_conf.h | 1 + src/libvirt_private.syms | 1 + src/qemu/qemu_interface.c | 8 ++++---- 4 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 69e0439e7e..cb184110f7 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -30981,7 +30981,13 @@ virDomainNetIsVirtioModel(const virDomainNetDef *net) net->model == VIR_DOMAIN_NET_MODEL_VIRTIO_TRANSITIONAL || net->model == VIR_DOMAIN_NET_MODEL_VIRTIO_NON_TRANSITIONAL); } - +bool +virDomainNetIsVnetCompatModel(const virDomainNetDef *net) +{ + return (virDomainNetIsVirtioModel(net) || + net->model == VIR_DOMAIN_NET_MODEL_E1000E || + net->model == VIR_DOMAIN_NET_MODEL_VMXNET3); +}
Should really live in the qemu_inteface.c file, with a qemuOnterfaceIsVnetCompatModel name, since the decision is inherantly tied to QEMU, and inappropriate for other virt drivers. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|