From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: virtualization@lists.linux-foundation.org
Cc: netdev@vger.kernel.org, Willem de Bruijn <willemb@google.com>,
mst@redhat.com
Subject: [PATCH rfc 2/3] virtio-net: support receive timestamp
Date: Mon, 28 Dec 2020 11:22:32 -0500 [thread overview]
Message-ID: <20201228162233.2032571-3-willemdebruijn.kernel@gmail.com> (raw)
In-Reply-To: <20201228162233.2032571-1-willemdebruijn.kernel@gmail.com>
From: Willem de Bruijn <willemb@google.com>
Add optional PTP hardware 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 host may
pass receive timestamps for all or some packets. A timestamp is valid
if non-zero.
The timestamp straddles (virtual) hardware domains. Like PTP, use
international atomic time (CLOCK_TAI) as global clock base. It is
guest responsibility to sync with host, e.g., through kvm-clock.
Signed-off-by: Willem de Bruijn <willemb@google.com>
---
drivers/net/virtio_net.c | 20 +++++++++++++++++++-
include/uapi/linux/virtio_net.h | 12 ++++++++++++
2 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b917b7333928..57744bb6a141 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -204,6 +204,9 @@ struct virtnet_info {
/* Guest will pass tx path info to the host */
bool has_tx_hash;
+ /* Host will pass CLOCK_TAI receive time to the guest */
+ bool has_rx_tstamp;
+
/* Has control virtqueue */
bool has_cvq;
@@ -292,6 +295,13 @@ 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_v12 *skb_vnet_hdr_12(struct sk_buff *skb)
+{
+ BUILD_BUG_ON(sizeof(struct virtio_net_hdr_v12) > 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
@@ -1082,6 +1092,9 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
goto frame_err;
}
+ if (vi->has_rx_tstamp)
+ skb_hwtstamps(skb)->hwtstamp = ns_to_ktime(skb_vnet_hdr_12(skb)->tstamp);
+
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",
@@ -3071,6 +3084,11 @@ 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_v12);
+ }
+
if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT) ||
virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
vi->any_header_sg = true;
@@ -3261,7 +3279,7 @@ 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 f6881b5b77ee..0ffe2eeebd4a 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 /* Host sends TAI receive time */
#define VIRTIO_NET_F_TX_HASH 56 /* Guest sends hash report */
#define VIRTIO_NET_F_HASH_REPORT 57 /* Supports hash report */
#define VIRTIO_NET_F_RSS 60 /* Supports RSS RX steering */
@@ -182,6 +183,17 @@ struct virtio_net_hdr_v1_hash {
};
};
+struct virtio_net_hdr_v12 {
+ struct virtio_net_hdr_v1 hdr;
+ struct {
+ __le32 value;
+ __le16 report;
+ __le16 flow_state;
+ } hash;
+ __virtio32 reserved;
+ __virtio64 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
--
2.29.2.729.g45daf8777d-goog
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2020-12-28 16:22 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-28 16:22 [PATCH rfc 0/3] virtio-net: add tx-hash, rx-tstamp and tx-tstamp Willem de Bruijn
2020-12-28 16:22 ` [PATCH rfc 1/3] virtio-net: support transmit hash report Willem de Bruijn
2020-12-28 16:28 ` Michael S. Tsirkin
2020-12-28 16:47 ` Willem de Bruijn
2020-12-28 17:22 ` Michael S. Tsirkin
2020-12-29 1:19 ` Willem de Bruijn
2020-12-28 21:36 ` Michael S. Tsirkin
2020-12-29 1:23 ` Willem de Bruijn
2020-12-28 16:22 ` Willem de Bruijn [this message]
2020-12-28 17:28 ` [PATCH rfc 2/3] virtio-net: support receive timestamp Michael S. Tsirkin
2020-12-28 19:30 ` Willem de Bruijn
2020-12-28 21:32 ` Michael S. Tsirkin
2020-12-29 1:05 ` Willem de Bruijn
2020-12-29 9:17 ` Jason Wang
2020-12-29 14:20 ` Willem de Bruijn
2020-12-30 8:38 ` Jason Wang
[not found] ` <20201228145953.08673c8c@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
2020-12-29 0:57 ` Willem de Bruijn
2020-12-30 8:44 ` Jason Wang
2021-02-02 13:05 ` kernel test robot
2021-02-02 14:08 ` Michael S. Tsirkin
2021-02-02 22:17 ` Willem de Bruijn
2021-02-02 23:02 ` Michael S. Tsirkin
2021-02-02 23:43 ` Willem de Bruijn
2020-12-28 16:22 ` [PATCH rfc 3/3] virtio-net: support transmit timestamp Willem de Bruijn
[not found] ` <20201230123854.GB2034@hoboy.vegasvil.org>
2020-12-30 15:25 ` Willem de Bruijn
2021-02-02 13:47 ` kernel test robot
2020-12-28 17:29 ` [PATCH rfc 0/3] virtio-net: add tx-hash, rx-tstamp and tx-tstamp Michael S. Tsirkin
2020-12-28 19:51 ` Willem de Bruijn
2020-12-28 21:38 ` Michael S. Tsirkin
2020-12-29 1:14 ` Willem de Bruijn
2021-01-06 20:32 ` Willem de Bruijn
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201228162233.2032571-3-willemdebruijn.kernel@gmail.com \
--to=willemdebruijn.kernel@gmail.com \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=virtualization@lists.linux-foundation.org \
--cc=willemb@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).