kernel/linux.git/include/uapi/linux/virtio_net.h, branch v6.18.21

virtio_net: fix alignment for virtio_net_hdr_v1_hash

2025-11-05T01:14:07+00:00

Changing alignment of header would mean it's no longer safe to cast a 2 byte aligned pointer between formats. Use two 16 bit fields to make it 2 byte aligned as previously. This fixes the performance regression since commit ("virtio_net: enable gso over UDP tunnel support.") as it uses virtio_net_hdr_v1_hash_tunnel which embeds virtio_net_hdr_v1_hash. Pktgen in guest + XDP_DROP on TAP + vhost_net shows the TX PPS is recovered from 2.4Mpps to 4.45Mpps. Fixes: 56a06bd40fab ("virtio_net: enable gso over UDP tunnel support.") Cc: stable@vger.kernel.org Signed-off-by: Michael S. Tsirkin Signed-off-by: Jason Wang Tested-by: Lei Yang Link: https://patch.msgid.link/20251031060551.126-1-jasowang@redhat.com Signed-off-by: Jakub Kicinski

net: implement virtio helpers to handle UDP GSO tunneling.

2025-07-08T16:05:47+00:00

The virtio specification are introducing support for GSO over UDP tunnel. This patch brings in the needed defines and the additional virtio hdr parsing/building helpers. The UDP tunnel support uses additional fields in the virtio hdr, and such fields location can change depending on other negotiated features - specifically VIRTIO_NET_F_HASH_REPORT. Try to be as conservative as possible with the new field validation. Existing implementation for plain GSO offloads allow for invalid/ self-contradictory values of such fields. With GSO over UDP tunnel we can be more strict, with no need to deal with legacy implementation. Since the checksum-related field validation is asymmetric in the driver and in the device, introduce a separate helper to implement the new checks (to be used only on the driver side). Note that while the feature space exceeds the 64-bit boundaries, the guest offload space is fixed by the specification of the VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET command to a 64-bit size. Prior to the UDP tunnel GSO support, each guest offload bit corresponded to the feature bit with the same value and vice versa. Due to the limited 'guest offload' space, relevant features in the high 64 bits are 'mapped' to free bits in the lower range. That is simpler than defining a new command (and associated features) to exchange an extended guest offloads set. As a consequence, the uAPIs also specify the mapped guest offload value corresponding to the UDP tunnel GSO features. Acked-by: Jason Wang Signed-off-by: Paolo Abeni -- v4 -> v5: - avoid lines above 80 chars v3 -> v4: - fixed offset for UDP GSO tunnel, update accordingly the helpers - tried to clarified vlan_hlen semantic - virtio_net_chk_data_valid() -> virtio_net_handle_csum_offload() v2 -> v3: - add definitions for possible vnet hdr layouts with tunnel support v1 -> v2: - 'relay' -> 'rely' typo - less unclear comment WRT enforced inner GSO checks - inner header fields are allowed only with 'modern' virtio, thus are always le - clarified in the commit message the need for 'mapped features' defines - assume little_endian is true when UDP GSO is enabled. - fix inner proto type value

virtio_net: Split struct virtio_net_rss_config

2025-03-25T16:30:21+00:00

struct virtio_net_rss_config was less useful in actual code because of a flexible array placed in the middle. Add new structures that split it into two to avoid having a flexible array in the middle. Suggested-by: Jason Wang Signed-off-by: Akihiko Odaki Acked-by: Jason Wang Reviewed-by: Xuan Zhuo Acked-by: Michael S. Tsirkin Tested-by: Lei Yang Link: https://patch.msgid.link/20250321-virtio-v2-1-33afb8f4640b@daynix.com Signed-off-by: Jakub Kicinski

virtio_net: introduce device stats feature and structures

2024-04-30T08:51:32+00:00

The virtio-net device stats spec: https://github.com/oasis-tcs/virtio-spec/commit/42f389989823039724f95bbbd243291ab0064f82 We introduce the relative feature and structures. Signed-off-by: Xuan Zhuo Acked-by: Jason Wang Signed-off-by: Paolo Abeni

virtio_net: support per queue interrupt coalesce command

2023-08-02T04:02:00+00:00

Add interrupt_coalesce config in send_queue and receive_queue to cache user config. Send per virtqueue interrupt moderation config to underlying device in order to have more efficient interrupt moderation and cpu utilization of guest VM. Additionally, address all the VQs when updating the global configuration, as now the individual VQs configuration can diverge from the global configuration. Signed-off-by: Gavin Li Reviewed-by: Dragos Tatulea Reviewed-by: Jiri Pirko Acked-by: Michael S. Tsirkin Reviewed-by: Heng Qi Acked-by: Jason Wang Link: https://lore.kernel.org/r/20230731070656.96411-3-gavinl@nvidia.com Signed-off-by: Jakub Kicinski

net: virtio_net: implement exact header length guest feature

2023-03-13T23:32:16+00:00

Virtio spec introduced a feature VIRTIO_NET_F_GUEST_HDRLEN which when set implicates that device benefits from knowing the exact size of the header. For compatibility, to signal to the device that the header is reliable driver also needs to set this feature. Without this feature set by driver, device has to figure out the header size itself. Quoting the original virtio spec: "hdr_len is a hint to the device as to how much of the header needs to be kept to copy into each packet" "a hint" might not be clear for the reader what does it mean, if it is "maybe like that" of "exactly like that". This feature just makes it crystal clear and let the device count on the hdr_len being filled up by the exact length of header. Also note the spec already has following note about hdr_len: "Due to various bugs in implementations, this field is not useful as a guarantee of the transport header size." Without this feature the device needs to parse the header in core data path handling. Accurate information helps the device to eliminate such header parsing and directly use the hardware accelerators for GSO operation. virtio_net_hdr_from_skb() fills up hdr_len to skb_headlen(skb). The driver already complies to fill the correct value. Introduce the feature and advertise it. Note that virtio spec also includes following note for device implementation: "Caution should be taken by the implementation so as to prevent a malicious driver from attacking the device by setting an incorrect hdr_len." There is a plan to support this feature in our emulated device. A device of SolidRun offers this feature bit. They claim this feature will save the device a few cycles for every GSO packet. Link: https://docs.oasis-open.org/virtio/virtio/v1.2/cs01/virtio-v1.2-cs01.html#x1-230006x3 Signed-off-by: Jiri Pirko Reviewed-by: Parav Pandit Reviewed-by: Alvaro Karsz Acked-by: Michael S. Tsirkin Acked-by: Willem de Bruijn Link: https://lore.kernel.org/r/20230309094559.917857-1-jiri@resnulli.us Signed-off-by: Jakub Kicinski

uapi/linux/virtio_net.h: Added USO types.

2022-12-12T09:29:56+00:00

Added new GSO type for USO: VIRTIO_NET_HDR_GSO_UDP_L4. Feature VIRTIO_NET_F_HOST_USO allows to enable NETIF_F_GSO_UDP_L4. Separated VIRTIO_NET_F_GUEST_USO4 & VIRTIO_NET_F_GUEST_USO6 features required for Windows guests. Signed-off-by: Andrew Melnychenko Signed-off-by: David S. Miller

net: virtio_net: fix notification coalescing comments

2022-08-31T05:44:25+00:00

Fix wording in comments for the notifications coalescing feature. Signed-off-by: Alvaro Karsz Acked-by: Michael S. Tsirkin Link: https://lore.kernel.org/r/20220823073947.14774-1-alvaro.karsz@solid-run.com Signed-off-by: Jakub Kicinski

net: virtio_net: notifications coalescing support

2022-08-11T08:26:07+00:00

New VirtIO network feature: VIRTIO_NET_F_NOTF_COAL. Control a Virtio network device notifications coalescing parameters using the control virtqueue. A device that supports this fetature can receive VIRTIO_NET_CTRL_NOTF_COAL control commands. - VIRTIO_NET_CTRL_NOTF_COAL_TX_SET: Ask the network device to change the following parameters: - tx_usecs: Maximum number of usecs to delay a TX notification. - tx_max_packets: Maximum number of packets to send before a TX notification. - VIRTIO_NET_CTRL_NOTF_COAL_RX_SET: Ask the network device to change the following parameters: - rx_usecs: Maximum number of usecs to delay a RX notification. - rx_max_packets: Maximum number of packets to receive before a RX notification. VirtIO spec. patch: https://lists.oasis-open.org/archives/virtio-comment/202206/msg00100.html Signed-off-by: Alvaro Karsz Message-Id: <20220718091102.498774-1-alvaro.karsz@solid-run.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: Jakub Kicinski Acked-by: Jason Wang

virtio_net: use LE accessors for speed/duplex

2020-08-05T15:08:41+00:00

Speed and duplex config fields depend on VIRTIO_NET_F_SPEED_DUPLEX which being 63>31 depends on VIRTIO_F_VERSION_1. Accordingly, use LE accessors for these fields. Reported-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin