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Message-ID: <c089cb3e-96cb-b42a-5ce1-d54d298987c4@redhat.com>
Date: Tue, 9 Feb 2021 12:13:15 +0800
From: Jason Wang <jasowang@...hat.com>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>,
virtualization@...ts.linux-foundation.org
Cc: netdev@...r.kernel.org, mst@...hat.com, richardcochran@...il.com,
Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH RFC v2 2/4] virtio-net: support receive timestamp
On 2021/2/9 上午2:55, Willem de Bruijn wrote:
> From: Willem de Bruijn <willemb@...gle.com>
>
> Add optional PTP hardware rx timestamp offload for virtio-net.
>
> Accurate RTT measurement requires timestamps close to the wire.
> Introduce virtio feature VIRTIO_NET_F_RX_TSTAMP. If negotiated, the
> virtio-net header is expanded with room for a timestamp.
>
> A device may pass receive timestamps for all or some packets. Flag
> VIRTIO_NET_HDR_F_TSTAMP signals whether a timestamp is recorded.
>
> A driver that supports hardware timestamping must also support
> ioctl SIOCSHWTSTAMP. Implement that, as well as information getters
> ioctl SIOCGHWTSTAMP and ethtool get_ts_info (`ethtool -T $DEV`).
>
> The timestamp straddles (virtual) hardware domains. Like PTP, use
> international atomic time (CLOCK_TAI) as global clock base. The driver
> must sync with the device, e.g., through kvm-clock.
>
> Tested:
> guest: ./timestamping eth0 \
> SOF_TIMESTAMPING_RAW_HARDWARE \
> SOF_TIMESTAMPING_RX_HARDWARE
> host: nc -4 -u 192.168.1.1 319
>
> Changes RFC -> RFCv2
> - rename virtio_net_hdr_v12 to virtio_net_hdr_hash_ts
> - add ethtool .get_ts_info to query capabilities
> - add ioctl SIOC[GS]HWTSTAMP to configure feature
> - add vi->enable_rx_tstamp to store configuration
> - convert virtioXX_to_cpu to leXX_to_cpu
> - convert reserved to __u32
>
> Signed-off-by: Willem de Bruijn <willemb@...gle.com>
> ---
> drivers/net/virtio_net.c | 113 +++++++++++++++++++++++++++++++-
> include/uapi/linux/virtio_net.h | 13 ++++
> 2 files changed, 124 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 7f822b2a5205..ac44c5efa0bc 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -204,6 +204,12 @@ struct virtnet_info {
> /* Driver will pass tx path info to the device */
> bool has_tx_hash;
>
> + /* Device can pass CLOCK_TAI receive time to the driver */
> + bool has_rx_tstamp;
> +
> + /* Device will pass rx timestamp. Requires has_rx_tstamp */
> + bool enable_rx_tstamp;
> +
> /* Has control virtqueue */
> bool has_cvq;
>
> @@ -292,6 +298,13 @@ static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb)
> return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb;
> }
>
> +static inline struct virtio_net_hdr_hash_ts *skb_vnet_hdr_ht(struct sk_buff *skb)
> +{
> + BUILD_BUG_ON(sizeof(struct virtio_net_hdr_hash_ts) > sizeof(skb->cb));
> +
> + return (void *)skb->cb;
> +}
> +
> /*
> * private is used to chain pages for big packets, put the whole
> * most recent used list in the beginning for reuse
> @@ -1030,6 +1043,19 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
> return NULL;
> }
>
> +static inline void virtnet_record_rx_tstamp(const struct virtnet_info *vi,
> + struct sk_buff *skb)
> +{
> + const struct virtio_net_hdr_hash_ts *h = skb_vnet_hdr_ht(skb);
> +
> + if (h->hdr.flags & VIRTIO_NET_HDR_F_TSTAMP &&
> + vi->enable_rx_tstamp) {
> + u64 ts = le64_to_cpu(h->tstamp);
> +
> + skb_hwtstamps(skb)->hwtstamp = ns_to_ktime(ts);
> + }
> +}
> +
> static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
> void *buf, unsigned int len, void **ctx,
> unsigned int *xdp_xmit,
> @@ -1076,6 +1102,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
> goto frame_err;
> }
>
> + virtnet_record_rx_tstamp(vi, skb);
> skb_record_rx_queue(skb, vq2rxq(rq->vq));
> skb->protocol = eth_type_trans(skb, dev);
> pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
> @@ -2263,6 +2290,28 @@ static int virtnet_get_coalesce(struct net_device *dev,
> return 0;
> }
>
> +static int virtnet_get_ts_info(struct net_device *dev,
> + struct ethtool_ts_info *info)
> +{
> + struct virtnet_info *vi = netdev_priv(dev);
> +
> + /* setup default software timestamp */
> + ethtool_op_get_ts_info(dev, info);
> +
> + /* return rx capabilities (which may differ from current enable) */
> + if (vi->has_rx_tstamp) {
> + info->so_timestamping |= SOF_TIMESTAMPING_RX_HARDWARE |
> + SOF_TIMESTAMPING_RAW_HARDWARE;
> + info->rx_filters = HWTSTAMP_FILTER_ALL;
> + } else {
> + info->rx_filters = HWTSTAMP_FILTER_NONE;
> + }
> +
> + info->tx_types = HWTSTAMP_TX_OFF;
> +
> + return 0;
> +}
> +
> static void virtnet_init_settings(struct net_device *dev)
> {
> struct virtnet_info *vi = netdev_priv(dev);
> @@ -2300,7 +2349,7 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
> .get_ethtool_stats = virtnet_get_ethtool_stats,
> .set_channels = virtnet_set_channels,
> .get_channels = virtnet_get_channels,
> - .get_ts_info = ethtool_op_get_ts_info,
> + .get_ts_info = virtnet_get_ts_info,
> .get_link_ksettings = virtnet_get_link_ksettings,
> .set_link_ksettings = virtnet_set_link_ksettings,
> .set_coalesce = virtnet_set_coalesce,
> @@ -2558,6 +2607,60 @@ static int virtnet_set_features(struct net_device *dev,
> return 0;
> }
>
> +static int virtnet_ioctl_set_hwtstamp(struct net_device *dev, struct ifreq *ifr)
> +{
> + struct virtnet_info *vi = netdev_priv(dev);
> + struct hwtstamp_config tsconf;
> +
> + if (copy_from_user(&tsconf, ifr->ifr_data, sizeof(tsconf)))
> + return -EFAULT;
> + if (tsconf.flags)
> + return -EINVAL;
> + if (tsconf.tx_type != HWTSTAMP_TX_OFF)
> + return -ERANGE;
> + if (tsconf.rx_filter != HWTSTAMP_FILTER_NONE &&
> + tsconf.rx_filter != HWTSTAMP_FILTER_ALL)
> + tsconf.rx_filter = HWTSTAMP_FILTER_ALL;
> +
> + if (!vi->has_rx_tstamp)
> + tsconf.rx_filter = HWTSTAMP_FILTER_NONE;
> + else
> + vi->enable_rx_tstamp = tsconf.rx_filter == HWTSTAMP_FILTER_ALL;
> +
> + if (copy_to_user(ifr->ifr_data, &tsconf, sizeof(tsconf)))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> +static int virtnet_ioctl_get_hwtstamp(struct net_device *dev, struct ifreq *ifr)
> +{
> + struct virtnet_info *vi = netdev_priv(dev);
> + struct hwtstamp_config tsconf;
> +
> + tsconf.flags = 0;
> + tsconf.rx_filter = vi->enable_rx_tstamp ? HWTSTAMP_FILTER_ALL :
> + HWTSTAMP_FILTER_NONE;
> + tsconf.tx_type = HWTSTAMP_TX_OFF;
> +
> + if (copy_to_user(ifr->ifr_data, &tsconf, sizeof(tsconf)))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
> +static int virtnet_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
> +{
> + switch (cmd) {
> + case SIOCSHWTSTAMP:
> + return virtnet_ioctl_set_hwtstamp(dev, ifr);
> +
> + case SIOCGHWTSTAMP:
> + return virtnet_ioctl_get_hwtstamp(dev, ifr);
> + }
> + return -EOPNOTSUPP;
> +}
> +
> static const struct net_device_ops virtnet_netdev = {
> .ndo_open = virtnet_open,
> .ndo_stop = virtnet_close,
> @@ -2573,6 +2676,7 @@ static const struct net_device_ops virtnet_netdev = {
> .ndo_features_check = passthru_features_check,
> .ndo_get_phys_port_name = virtnet_get_phys_port_name,
> .ndo_set_features = virtnet_set_features,
> + .ndo_do_ioctl = virtnet_ioctl,
> };
>
> static void virtnet_config_changed_work(struct work_struct *work)
> @@ -3069,6 +3173,11 @@ static int virtnet_probe(struct virtio_device *vdev)
> vi->hdr_len = sizeof(struct virtio_net_hdr_v1_hash);
> }
>
> + if (virtio_has_feature(vdev, VIRTIO_NET_F_RX_TSTAMP)) {
> + vi->has_rx_tstamp = true;
> + vi->hdr_len = sizeof(struct virtio_net_hdr_hash_ts);
Does this mean even if the device doesn't pass timestamp, the header
still contains the timestamp fields.
> + }
> +
> if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
> virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
> vi->any_header_sg = true;
> @@ -3260,7 +3369,7 @@ static struct virtio_device_id id_table[] = {
> VIRTIO_NET_F_CTRL_MAC_ADDR, \
> VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \
> VIRTIO_NET_F_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY, \
> - VIRTIO_NET_F_TX_HASH
> + VIRTIO_NET_F_TX_HASH, VIRTIO_NET_F_RX_TSTAMP
>
> static unsigned int features[] = {
> VIRTNET_FEATURES,
> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
> index 273d43c35f59..a5c84410cf92 100644
> --- a/include/uapi/linux/virtio_net.h
> +++ b/include/uapi/linux/virtio_net.h
> @@ -57,6 +57,7 @@
> * Steering */
> #define VIRTIO_NET_F_CTRL_MAC_ADDR 23 /* Set MAC address */
>
> +#define VIRTIO_NET_F_RX_TSTAMP 55 /* Device sends TAI receive time */
> #define VIRTIO_NET_F_TX_HASH 56 /* Driver sends hash report */
> #define VIRTIO_NET_F_HASH_REPORT 57 /* Supports hash report */
> #define VIRTIO_NET_F_RSS 60 /* Supports RSS RX steering */
> @@ -126,6 +127,7 @@ struct virtio_net_hdr_v1 {
> #define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 /* Use csum_start, csum_offset */
> #define VIRTIO_NET_HDR_F_DATA_VALID 2 /* Csum is valid */
> #define VIRTIO_NET_HDR_F_RSC_INFO 4 /* rsc info in csum_ fields */
> +#define VIRTIO_NET_HDR_F_TSTAMP 8 /* timestamp is recorded */
> __u8 flags;
> #define VIRTIO_NET_HDR_GSO_NONE 0 /* Not a GSO frame */
> #define VIRTIO_NET_HDR_GSO_TCPV4 1 /* GSO frame, IPv4 TCP (TSO) */
> @@ -181,6 +183,17 @@ struct virtio_net_hdr_v1_hash {
> };
> };
>
> +struct virtio_net_hdr_hash_ts {
> + struct virtio_net_hdr_v1 hdr;
> + struct {
> + __le32 value;
> + __le16 report;
> + __le16 flow_state;
> + } hash;
Any reason for not embedding structure virtio_net_hdr_v1_hash?
Thanks
> + __u32 reserved;
> + __le64 tstamp;
> +};
> +
> #ifndef VIRTIO_NET_NO_LEGACY
> /* This header comes first in the scatter-gather list.
> * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, it must
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