Commit 699b045a authored by Alvaro Karsz's avatar Alvaro Karsz Committed by Michael S. Tsirkin
Browse files

net: virtio_net: notifications coalescing support 

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: default avatarAlvaro Karsz <alvaro.karsz@solid-run.com>
Message-Id: <20220718091102.498774-1-alvaro.karsz@solid-run.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarJakub Kicinski <kuba@kernel.org>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
parent 95bf9798

drivers/net/virtio_net.c

+96 −15
Original line number Diff line number Diff line
@@ -270,6 +270,12 @@ struct virtnet_info { 
	u8 duplex;

	u32 speed;



	/* Interrupt coalescing settings */

	u32 tx_usecs;

	u32 rx_usecs;

	u32 tx_max_packets;

	u32 rx_max_packets;



	unsigned long guest_offloads;

	unsigned long guest_offloads_capable;
@@ -2737,27 +2743,89 @@ static int virtnet_get_link_ksettings(struct net_device *dev, 
	return 0;

}



static int virtnet_send_notf_coal_cmds(struct virtnet_info *vi,

				       struct ethtool_coalesce *ec)

{

	struct scatterlist sgs_tx, sgs_rx;

	struct virtio_net_ctrl_coal_tx coal_tx;

	struct virtio_net_ctrl_coal_rx coal_rx;



	coal_tx.tx_usecs = cpu_to_le32(ec->tx_coalesce_usecs);

	coal_tx.tx_max_packets = cpu_to_le32(ec->tx_max_coalesced_frames);

	sg_init_one(&sgs_tx, &coal_tx, sizeof(coal_tx));



	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,

				  VIRTIO_NET_CTRL_NOTF_COAL_TX_SET,

				  &sgs_tx))

		return -EINVAL;



	/* Save parameters */

	vi->tx_usecs = ec->tx_coalesce_usecs;

	vi->tx_max_packets = ec->tx_max_coalesced_frames;



	coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);

	coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames);

	sg_init_one(&sgs_rx, &coal_rx, sizeof(coal_rx));



	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,

				  VIRTIO_NET_CTRL_NOTF_COAL_RX_SET,

				  &sgs_rx))

		return -EINVAL;



	/* Save parameters */

	vi->rx_usecs = ec->rx_coalesce_usecs;

	vi->rx_max_packets = ec->rx_max_coalesced_frames;



	return 0;

}



static int virtnet_coal_params_supported(struct ethtool_coalesce *ec)

{

	/* usecs coalescing is supported only if VIRTIO_NET_F_NOTF_COAL

	 * feature is negotiated.

	 */

	if (ec->rx_coalesce_usecs || ec->tx_coalesce_usecs)

		return -EOPNOTSUPP;



	if (ec->tx_max_coalesced_frames > 1 ||

	    ec->rx_max_coalesced_frames != 1)

		return -EINVAL;



	return 0;

}



static int virtnet_set_coalesce(struct net_device *dev,

				struct ethtool_coalesce *ec,

				struct kernel_ethtool_coalesce *kernel_coal,

				struct netlink_ext_ack *extack)

{

	struct virtnet_info *vi = netdev_priv(dev);

	int i, napi_weight;



	if (ec->tx_max_coalesced_frames > 1 ||

	    ec->rx_max_coalesced_frames != 1)

		return -EINVAL;

	int ret, i, napi_weight;

	bool update_napi = false;



	/* Can't change NAPI weight if the link is up */

	napi_weight = ec->tx_max_coalesced_frames ? NAPI_POLL_WEIGHT : 0;

	if (napi_weight ^ vi->sq[0].napi.weight) {

		if (dev->flags & IFF_UP)

			return -EBUSY;

		else

			update_napi = true;

	}



	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL))

		ret = virtnet_send_notf_coal_cmds(vi, ec);

	else

		ret = virtnet_coal_params_supported(ec);



	if (ret)

		return ret;



	if (update_napi) {

		for (i = 0; i < vi->max_queue_pairs; i++)

			vi->sq[i].napi.weight = napi_weight;

	}



	return 0;

	return ret;

}



static int virtnet_get_coalesce(struct net_device *dev,
@@ -2765,16 +2833,19 @@ static int virtnet_get_coalesce(struct net_device *dev, 
				struct kernel_ethtool_coalesce *kernel_coal,

				struct netlink_ext_ack *extack)

{

	struct ethtool_coalesce ec_default = {

		.cmd = ETHTOOL_GCOALESCE,

		.rx_max_coalesced_frames = 1,

	};

	struct virtnet_info *vi = netdev_priv(dev);



	memcpy(ec, &ec_default, sizeof(ec_default));

	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) {

		ec->rx_coalesce_usecs = vi->rx_usecs;

		ec->tx_coalesce_usecs = vi->tx_usecs;

		ec->tx_max_coalesced_frames = vi->tx_max_packets;

		ec->rx_max_coalesced_frames = vi->rx_max_packets;

	} else {

		ec->rx_max_coalesced_frames = 1;



		if (vi->sq[0].napi.weight)

			ec->tx_max_coalesced_frames = 1;

	}



	return 0;

}
@@ -2893,7 +2964,8 @@ static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info) 
}



static const struct ethtool_ops virtnet_ethtool_ops = {

	.supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES,

	.supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES |

		ETHTOOL_COALESCE_USECS,

	.get_drvinfo = virtnet_get_drvinfo,

	.get_link = ethtool_op_get_link,

	.get_ringparam = virtnet_get_ringparam,
@@ -3606,6 +3678,8 @@ static bool virtnet_validate_features(struct virtio_device *vdev) 
	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_RSS,

			     "VIRTIO_NET_F_CTRL_VQ") ||

	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_HASH_REPORT,

			     "VIRTIO_NET_F_CTRL_VQ") ||

	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_NOTF_COAL,

			     "VIRTIO_NET_F_CTRL_VQ"))) {

		return false;

	}
@@ -3742,6 +3816,13 @@ static int virtnet_probe(struct virtio_device *vdev) 
	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))

		vi->mergeable_rx_bufs = true;



	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) {

		vi->rx_usecs = 0;

		vi->tx_usecs = 0;

		vi->tx_max_packets = 0;

		vi->rx_max_packets = 0;

	}



	if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))

		vi->has_rss_hash_report = true;
@@ -3977,7 +4058,7 @@ 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_RSS, VIRTIO_NET_F_HASH_REPORT

	VIRTIO_NET_F_RSS, VIRTIO_NET_F_HASH_REPORT, VIRTIO_NET_F_NOTF_COAL



static unsigned int features[] = {

	VIRTNET_FEATURES,

include/uapi/linux/virtio_net.h

+33 −1
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ 
#define VIRTIO_NET_F_MQ	22	/* Device supports Receive Flow

					 * Steering */

#define VIRTIO_NET_F_CTRL_MAC_ADDR 23	/* Set MAC address */



#define VIRTIO_NET_F_NOTF_COAL	53	/* Guest can handle notifications coalescing */

#define VIRTIO_NET_F_HASH_REPORT  57	/* Supports hash report */

#define VIRTIO_NET_F_RSS	  60	/* Supports RSS RX steering */

#define VIRTIO_NET_F_RSC_EXT	  61	/* extended coalescing info */
@@ -355,4 +355,36 @@ struct virtio_net_hash_config { 
#define VIRTIO_NET_CTRL_GUEST_OFFLOADS   5

#define VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET        0



/*

 * Control notifications coalescing.

 *

 * Request the device to change the notifications coalescing parameters.

 *

 * Available with the VIRTIO_NET_F_NOTF_COAL feature bit.

 */

#define VIRTIO_NET_CTRL_NOTF_COAL		6

/*

 * Set the tx-usecs/tx-max-packets patameters.

 * tx-usecs - Maximum number of usecs to delay a TX notification.

 * tx-max-packets - Maximum number of packets to send before a TX notification.

 */

struct virtio_net_ctrl_coal_tx {

	__le32 tx_max_packets;

	__le32 tx_usecs;

};



#define VIRTIO_NET_CTRL_NOTF_COAL_TX_SET		0



/*

 * Set the rx-usecs/rx-max-packets patameters.

 * rx-usecs - Maximum number of usecs to delay a RX notification.

 * rx-max-frames - Maximum number of packets to receive before a RX notification.

 */

struct virtio_net_ctrl_coal_rx {

	__le32 rx_max_packets;

	__le32 rx_usecs;

};



#define VIRTIO_NET_CTRL_NOTF_COAL_RX_SET		1



#endif /* _UAPI_LINUX_VIRTIO_NET_H */