On Thu, May 12, 2022 at 7:33 PM Andrew Melnychenko <andrew at daynix.com> wrote:> > Added new offloads for TUN devices TUN_F_USO4 and TUN_F_USO6. > Technically they enable NETIF_F_GSO_UDP_L4 > (and only if USO4 & USO6 are set simultaneously). > It allows to transmission of large UDP packets. > > Different features USO4 and USO6 are required for qemu where Windows guests can > enable disable USO receives for IPv4 and IPv6 separately. > On the other side, Linux can't really differentiate USO4 and USO6, for now. > For now, to enable USO for TUN it requires enabling USO4 and USO6 together. > In the future, there would be a mechanism to control UDP_L4 GSO separately. > > Test it WIP Qemu https://github.com/daynix/qemu/tree/Dev_USOv2 > > New types for VirtioNet already on mailing: > https://lists.oasis-open.org/archives/virtio-comment/202110/msg00010.html > > Also, there is a known issue with transmitting packages between two guests.Could you explain this more? It looks like a bug. (Or any pointer to the discussion) Thanks> Without hacks with skb's GSO - packages are still segmented on the host's postrouting. > > Andrew (5): > uapi/linux/if_tun.h: Added new offload types for USO4/6. > driver/net/tun: Added features for USO. > uapi/linux/virtio_net.h: Added USO types. > linux/virtio_net.h: Support USO offload in vnet header. > drivers/net/virtio_net.c: Added USO support. > > drivers/net/tap.c | 10 ++++++++-- > drivers/net/tun.c | 8 +++++++- > drivers/net/virtio_net.c | 19 +++++++++++++++---- > include/linux/virtio_net.h | 9 +++++++++ > include/uapi/linux/if_tun.h | 2 ++ > include/uapi/linux/virtio_net.h | 4 ++++ > 6 files changed, 45 insertions(+), 7 deletions(-) > > -- > 2.35.1 >
Andrew Melnichenko
2022-May-24 11:06 UTC
[RFC PATCH v2 0/5] TUN/VirtioNet USO features support.
Hi all, The issue is that host segments packets between guests on the same host. Tests show that it happens because SKB_GSO_DODGY skb offload in virtio_net_hdr_from_skb(). To do segmentation you need to remove SKB_GSO_DODGY or add SKB_GSO_PARTIAL The solution with DODGY/PARTIAL offload looks like a dirty hack, so for now, I've lived it as it is for further investigation. On Tue, May 17, 2022 at 9:32 AM Jason Wang <jasowang at redhat.com> wrote:> > On Thu, May 12, 2022 at 7:33 PM Andrew Melnychenko <andrew at daynix.com> wrote: > > > > Added new offloads for TUN devices TUN_F_USO4 and TUN_F_USO6. > > Technically they enable NETIF_F_GSO_UDP_L4 > > (and only if USO4 & USO6 are set simultaneously). > > It allows to transmission of large UDP packets. > > > > Different features USO4 and USO6 are required for qemu where Windows guests can > > enable disable USO receives for IPv4 and IPv6 separately. > > On the other side, Linux can't really differentiate USO4 and USO6, for now. > > For now, to enable USO for TUN it requires enabling USO4 and USO6 together. > > In the future, there would be a mechanism to control UDP_L4 GSO separately. > > > > Test it WIP Qemu https://github.com/daynix/qemu/tree/Dev_USOv2 > > > > New types for VirtioNet already on mailing: > > https://lists.oasis-open.org/archives/virtio-comment/202110/msg00010.html > > > > Also, there is a known issue with transmitting packages between two guests. > > Could you explain this more? It looks like a bug. (Or any pointer to > the discussion) > > Thanks > > > Without hacks with skb's GSO - packages are still segmented on the host's postrouting. > > > > Andrew (5): > > uapi/linux/if_tun.h: Added new offload types for USO4/6. > > driver/net/tun: Added features for USO. > > uapi/linux/virtio_net.h: Added USO types. > > linux/virtio_net.h: Support USO offload in vnet header. > > drivers/net/virtio_net.c: Added USO support. > > > > drivers/net/tap.c | 10 ++++++++-- > > drivers/net/tun.c | 8 +++++++- > > drivers/net/virtio_net.c | 19 +++++++++++++++---- > > include/linux/virtio_net.h | 9 +++++++++ > > include/uapi/linux/if_tun.h | 2 ++ > > include/uapi/linux/virtio_net.h | 4 ++++ > > 6 files changed, 45 insertions(+), 7 deletions(-) > > > > -- > > 2.35.1 > > >