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Message-ID: <20221201173252-mutt-send-email-mst@kernel.org>
Date: Thu, 1 Dec 2022 17:33:11 -0500
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Andrew Melnychenko <andrew@...nix.com>
Cc: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
pabeni@...hat.com, jasowang@...hat.com, yoshfuji@...ux-ipv6.org,
dsahern@...nel.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
virtualization@...ts.linux-foundation.org, devel@...nix.com
Subject: Re: [PATCH v4 0/6] TUN/VirtioNet USO features support.
On Thu, Dec 01, 2022 at 11:56:38PM +0200, Andrew Melnychenko 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 the transmission of large UDP packets.
>
> UDP Segmentation Offload (USO/GSO_UDP_L4) - ability to split UDP packets
> into several segments. It's similar to UFO, except it doesn't use IP
> fragmentation. The drivers may push big packets and the NIC will split
> them(or assemble them in case of receive), but in the case of VirtioNet
> we just pass big UDP to the host. So we are freeing the driver from doing
> the unnecessary job of splitting. The same thing for several guests
> on one host, we can pass big packets between guests.
>
> 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.
>
> New types for virtio-net already in virtio-net specification:
> https://github.com/oasis-tcs/virtio-spec/issues/120
>
> Test it WIP Qemu https://github.com/daynix/qemu/tree/USOv3
>
> 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.
>
> Andrew Melnychenko (1):
> udp: allow header check for dodgy GSO_UDP_L4 packets.
I don't see patches except 0 on list.
> drivers/net/tap.c | 10 ++++++++--
> drivers/net/tun.c | 8 +++++++-
> drivers/net/virtio_net.c | 24 +++++++++++++++++++++---
> include/linux/virtio_net.h | 9 +++++++++
> include/uapi/linux/if_tun.h | 2 ++
> include/uapi/linux/virtio_net.h | 5 +++++
> net/ipv4/udp_offload.c | 3 ++-
> net/ipv6/udp_offload.c | 3 ++-
> 8 files changed, 56 insertions(+), 8 deletions(-)
>
> --
> 2.38.1
>
> _______________________________________________
> Virtualization mailing list
> Virtualization@...ts.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization
>
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