On Mon, Jul 24, 2023 at 10:32 AM Yui Washizu <yui.wash...@gmail.com> wrote: > > > On 2023/07/20 11:20, Jason Wang wrote: > > On Wed, Jul 19, 2023 at 9:59 AM Yui Washizu <yui.wash...@gmail.com> wrote: > >> This patch series is the first step towards enabling > >> hardware offloading of the L2 packet switching feature on virtio-net > >> device to host machine. > >> We are considering that this hardware offloading enables > >> the use of high-performance networks in virtual infrastructures, > >> such as container infrastructures on VMs. > >> > >> To enable L2 packet switching by SR-IOV VFs, we are considering the > >> following: > >> - making the guest recognize virtio-net devices as SR-IOV PF devices > >> (archived with this patch series) > >> - allowing virtio-net devices to connect SR-IOV VFs to the backend > >> networks, > >> leaving the L2 packet switching feature to the management layer like > >> libvirt > > Could you please show the qemu command line you want to propose here? > > > I am considering how to specify the properties of VFs to connect SR-IOV > VFs to the backend networks. > > > For example: > > > qemu-system-x86_64 -device > pcie-root-port,port=8,chassis=8,id=pci.8,bus=pcie.0,multifunction=on > -netdev tap,id=hostnet0,vhost=on > -netdev tap,id=vfnet1,vhost=on # backend network for > SR-IOV VF 1 > -netdev tap,id=vfnet2,vhost=on # backend network for > SR-IOV VF 2 > -device > virtio-net-pci,netdev=hostnet0,sriov_max_vfs=2,sriov_netdev=vfnet1:vfnet2,... > > > In this example, we can specify multiple backend networks to the VFs > by adding "sriov_netdev" and separating them with ":".
This seems what is in my mind as well, more below > Additionally, when passing properties like "rx_queue_size" to VFs, we > can utilize new properties, > such as "sriov_rx_queue_size_per_vfs," to ensure that the same value is > passed to all VFs. Or we can introduce new device like: -netdev tap,id=hn0 \ -device virtio-net-pci,netdev=hn0,id=vnet_pf \ -netdev tap,netdev=hn1 \ -device virtio-net-pci-vf,netdev=hn1,id=vf0,pf=vnet_pf,rx_queue_size=XYZ ... \ This allows us to reuse the codes for configuring vf parameters. But note that rx_queue_size doesn't make too much sense to vhost-vDPA, as qemu can perform nothing more than a simple sanity test. Thanks > > I'm still considering about how to specify it, so please give me any > comments if you have any. > > > >> - This makes hardware offloading of L2 packet switching possible. > >> For example, when using vDPA devices, it allows the guest > >> to utilize SR-IOV NIC embedded switch of hosts. > > This would be interesting. > > > > Thanks > > > >> This patch series aims to enable SR-IOV emulation on virtio-net devices. > >> With this series, the guest can identify the virtio-net device as an > >> SR-IOV PF device. > >> The newly added property 'sriov_max_vfs' allows us to enable the SR-IOV > >> feature > >> on the virtio-net device. > >> Currently, we are unable to specify the properties of a VF created from > >> the guest. > >> The properties are set to their default values. > >> In the future, we plan to allow users to set the properties. > >> > >> qemu-system-x86_64 --device virtio-net,sriov_max_vfs=<num> > >> # when 'sriov_max_vfs' is present, the SR-IOV feature will be > >> automatically enabled > >> # <num> means the max number of VF on guest > >> > >> Example commands to create VFs in virtio-net device from the guest: > >> > >> guest% readlink -f /sys/class/net/eth1/device > >> /sys/devices/pci0000:00/0000:00:02.0/0000:01:00.0/virtio1 > >> guest% echo "2" > > >> /sys/devices/pci0000:00/0000:00:02.0/0000:01:00.0/sriov_numvfs > >> guest% ip link show > >> eth0: .... > >> eth1: .... > >> eth2: .... #virtual VF created > >> eth3: .... #virtual VF created > >> > >> Please note that communication between VF and PF/VF is not possible by > >> this patch series itself. > >> > >> Yui Washizu (1): > >> virtio-pci: add SR-IOV capability > >> > >> hw/pci/msix.c | 8 +++-- > >> hw/pci/pci.c | 4 +++ > >> hw/virtio/virtio-pci.c | 62 ++++++++++++++++++++++++++++++---- > >> include/hw/virtio/virtio-pci.h | 1 + > >> 4 files changed, 66 insertions(+), 9 deletions(-) > >> > >> -- > >> 2.39.3 > >> >
