RE: [PATCH v7 2/5] vdpa: Add support for querying vendor statistics

From: Eli Cohen
Date: Wed May 18 2022 - 02:12:41 EST

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> From: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>
> Sent: Wednesday, May 18, 2022 4:03 AM
> To: Eli Cohen <elic@xxxxxxxxxx>; mst@xxxxxxxxxx; jasowang@xxxxxxxxxx
> Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v7 2/5] vdpa: Add support for querying vendor statistics
>
>
>
> On 5/17/2022 6:13 AM, Eli Cohen wrote:
> > Allows to read vendor statistics of a vdpa device. The specific
> > statistics data are received from the upstream driver in the form of an
> > (attribute name, attribute value) pairs.
> >
> > An example of statistics for mlx5_vdpa device are:
> >
> > received_desc - number of descriptors received by the virtqueue
> > completed_desc - number of descriptors completed by the virtqueue
> >
> > A descriptor using indirect buffers is still counted as 1. In addition,
> > N chained descriptors are counted correctly N times as one would expect.
> >
> > A new callback was added to vdpa_config_ops which provides the means for
> > the vdpa driver to return statistics results.
> >
> > The interface allows for reading all the supported virtqueues, including
> > the control virtqueue if it exists.
> >
> > Below are some examples taken from mlx5_vdpa which are introduced in the
> > following patch:
> >
> > 1. Read statistics for the virtqueue at index 1
> >
> > $ vdpa dev vstats show vdpa-a qidx 1
> > vdpa-a:
> > queue_type tx queue_index 1 received_desc 3844836 completed_desc 3844836
> >
> > 2. Read statistics for the virtqueue at index 32
> > $ vdpa dev vstats show vdpa-a qidx 32
> > vdpa-a:
> > queue_type control_vq queue_index 32 received_desc 62 completed_desc 62
> >
> > 3. Read statisitics for the virtqueue at index 0 with json output
> > $ vdpa -j dev vstats show vdpa-a qidx 0
> > {"vstats":{"vdpa-a":{
> > "queue_type":"rx","queue_index":0,"name":"received_desc","value":417776,\
> > "name":"completed_desc","value":417548}}}
> >
> > 4. Read statistics for the virtqueue at index 0 with preety json output
> > $ vdpa -jp dev vstats show vdpa-a qidx 0
> > {
> > "vstats": {
> > "vdpa-a": {
> >
> > "queue_type": "rx",
> > "queue_index": 0,
> > "name": "received_desc",
> > "value": 417776,
> > "name": "completed_desc",
> > "value": 417548
> > }
> > }
> > }
> >
> > Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> > ---
> > drivers/vdpa/vdpa.c | 160 ++++++++++++++++++++++++++++++++++++++
> > include/linux/vdpa.h | 3 +
> > include/uapi/linux/vdpa.h | 6 ++
> > 3 files changed, 169 insertions(+)
> >
> > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> > index fac89a0d8178..1b810961ccc3 100644
> > --- a/drivers/vdpa/vdpa.c
> > +++ b/drivers/vdpa/vdpa.c
> > @@ -914,6 +914,106 @@ vdpa_dev_config_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid,
> > return err;
> > }
> >
> > +static int vdpa_fill_stats_rec(struct vdpa_device *vdev, struct sk_buff *msg,
> > + struct genl_info *info, u32 index)
> > +{
> > + struct virtio_net_config config = {};
> > + u64 features;
> > + u16 max_vqp;
> > + u8 status;
> > + int err;
> > +
> This entire function should perhaps need to take cf_mutex (worth
> converting to rwsem as well) to guard against concurrent modification
> via .set_status() or .set_config() from the upper stack. Similar to
> vdpa_dev_config_fill().
>

Right.

> > + status = vdev->config->get_status(vdev);
> > + if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
> > + NL_SET_ERR_MSG_MOD(info->extack, "feature negotiation not complete");
> > + return -EAGAIN;
> > + }
> > + vdpa_get_config(vdev, 0, &config, sizeof(config));
> This should use vdpa_get_config_unlocked() without lock.
>
> Regards,
> -Siwei
>
> > +
> > + max_vqp = le16_to_cpu(config.max_virtqueue_pairs);
> > + if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, max_vqp))
> > + return -EMSGSIZE;
> > +
> > + features = vdev->config->get_driver_features(vdev);
> > + if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES,
> > + features, VDPA_ATTR_PAD))
> > + return -EMSGSIZE;
> > +
> > + if (nla_put_u32(msg, VDPA_ATTR_DEV_QUEUE_INDEX, index))
> > + return -EMSGSIZE;
> > +
> > + err = vdev->config->get_vendor_vq_stats(vdev, index, msg, info->extack);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int vendor_stats_fill(struct vdpa_device *vdev, struct sk_buff *msg,
> > + struct genl_info *info, u32 index)
> > +{
> > + int err;
> > +
> > + if (!vdev->config->get_vendor_vq_stats)
> > + return -EOPNOTSUPP;
> > +
> > + err = vdpa_fill_stats_rec(vdev, msg, info, index);
> > + if (err)
> > + return err;
> > +
> > + return 0;
> > +}
> > +
> > +static int vdpa_dev_vendor_stats_fill(struct vdpa_device *vdev,
> > + struct sk_buff *msg,
> > + struct genl_info *info, u32 index)
> > +{
> > + u32 device_id;
> > + void *hdr;
> > + int err;
> > + u32 portid = info->snd_portid;
> > + u32 seq = info->snd_seq;
> > + u32 flags = 0;
> > +
> > + hdr = genlmsg_put(msg, portid, seq, &vdpa_nl_family, flags,
> > + VDPA_CMD_DEV_VSTATS_GET);
> > + if (!hdr)
> > + return -EMSGSIZE;
> > +
> > + if (nla_put_string(msg, VDPA_ATTR_DEV_NAME, dev_name(&vdev->dev))) {
> > + err = -EMSGSIZE;
> > + goto undo_msg;
> > + }
> > +
> > + device_id = vdev->config->get_device_id(vdev);
> > + if (nla_put_u32(msg, VDPA_ATTR_DEV_ID, device_id)) {
> > + err = -EMSGSIZE;
> > + goto undo_msg;
> > + }
> > +
> > + switch (device_id) {
> > + case VIRTIO_ID_NET:
> > + if (index > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX) {
> > + NL_SET_ERR_MSG_MOD(info->extack, "queue index excceeds max value");
> > + err = -ERANGE;
> > + break;
> > + }
> > +
> > + err = vendor_stats_fill(vdev, msg, info, index);
> > + break;
> > + default:
> > + err = -EOPNOTSUPP;
> > + break;
> > + }
> > + genlmsg_end(msg, hdr);
> > +
> > + return err;
> > +
> > +undo_msg:
> > + genlmsg_cancel(msg, hdr);
> > + return err;
> > +}
> > +
> > static int vdpa_nl_cmd_dev_config_get_doit(struct sk_buff *skb, struct genl_info *info)
> > {
> > struct vdpa_device *vdev;
> > @@ -995,6 +1095,60 @@ vdpa_nl_cmd_dev_config_get_dumpit(struct sk_buff *msg, struct netlink_callback *
> > return msg->len;
> > }
> >
> > +static int vdpa_nl_cmd_dev_stats_get_doit(struct sk_buff *skb,
> > + struct genl_info *info)
> > +{
> > + struct vdpa_device *vdev;
> > + struct sk_buff *msg;
> > + const char *devname;
> > + struct device *dev;
> > + u32 index;
> > + int err;
> > +
> > + if (!info->attrs[VDPA_ATTR_DEV_NAME])
> > + return -EINVAL;
> > +
> > + if (!info->attrs[VDPA_ATTR_DEV_QUEUE_INDEX])
> > + return -EINVAL;
> > +
> > + devname = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);
> > + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
> > + if (!msg)
> > + return -ENOMEM;
> > +
> > + index = nla_get_u32(info->attrs[VDPA_ATTR_DEV_QUEUE_INDEX]);
> > + mutex_lock(&vdpa_dev_mutex);
> > + dev = bus_find_device(&vdpa_bus, NULL, devname, vdpa_name_match);
> > + if (!dev) {
> > + NL_SET_ERR_MSG_MOD(info->extack, "device not found");
> > + err = -ENODEV;
> > + goto dev_err;
> > + }
> > + vdev = container_of(dev, struct vdpa_device, dev);
> > + if (!vdev->mdev) {
> > + NL_SET_ERR_MSG_MOD(info->extack, "unmanaged vdpa device");
> > + err = -EINVAL;
> > + goto mdev_err;
> > + }
> > + err = vdpa_dev_vendor_stats_fill(vdev, msg, info, index);
> > + if (err)
> > + goto mdev_err;
> > +
> > + err = genlmsg_reply(msg, info);
> > +
> > + put_device(dev);
> > + mutex_unlock(&vdpa_dev_mutex);
> > +
> > + return err;
> > +
> > +mdev_err:
> > + put_device(dev);
> > +dev_err:
> > + nlmsg_free(msg);
> > + mutex_unlock(&vdpa_dev_mutex);
> > + return err;
> > +}
> > +
> > static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
> > [VDPA_ATTR_MGMTDEV_BUS_NAME] = { .type = NLA_NUL_STRING },
> > [VDPA_ATTR_MGMTDEV_DEV_NAME] = { .type = NLA_STRING },
> > @@ -1035,6 +1189,12 @@ static const struct genl_ops vdpa_nl_ops[] = {
> > .doit = vdpa_nl_cmd_dev_config_get_doit,
> > .dumpit = vdpa_nl_cmd_dev_config_get_dumpit,
> > },
> > + {
> > + .cmd = VDPA_CMD_DEV_VSTATS_GET,
> > + .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
> > + .doit = vdpa_nl_cmd_dev_stats_get_doit,
> > + .flags = GENL_ADMIN_PERM,
> > + },
> > };
> >
> > static struct genl_family vdpa_nl_family __ro_after_init = {
> > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > index 8943a209202e..2ae8443331e1 100644
> > --- a/include/linux/vdpa.h
> > +++ b/include/linux/vdpa.h
> > @@ -276,6 +276,9 @@ struct vdpa_config_ops {
> > const struct vdpa_vq_state *state);
> > int (*get_vq_state)(struct vdpa_device *vdev, u16 idx,
> > struct vdpa_vq_state *state);
> > + int (*get_vendor_vq_stats)(struct vdpa_device *vdev, u16 idx,
> > + struct sk_buff *msg,
> > + struct netlink_ext_ack *extack);
> > struct vdpa_notification_area
> > (*get_vq_notification)(struct vdpa_device *vdev, u16 idx);
> > /* vq irq is not expected to be changed once DRIVER_OK is set */
> > diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
> > index 1061d8d2d09d..25c55cab3d7c 100644
> > --- a/include/uapi/linux/vdpa.h
> > +++ b/include/uapi/linux/vdpa.h
> > @@ -18,6 +18,7 @@ enum vdpa_command {
> > VDPA_CMD_DEV_DEL,
> > VDPA_CMD_DEV_GET, /* can dump */
> > VDPA_CMD_DEV_CONFIG_GET, /* can dump */
> > + VDPA_CMD_DEV_VSTATS_GET,
> > };
> >
> > enum vdpa_attr {
> > @@ -46,6 +47,11 @@ enum vdpa_attr {
> > VDPA_ATTR_DEV_NEGOTIATED_FEATURES, /* u64 */
> > VDPA_ATTR_DEV_MGMTDEV_MAX_VQS, /* u32 */
> > VDPA_ATTR_DEV_SUPPORTED_FEATURES, /* u64 */
> > +
> > + VDPA_ATTR_DEV_QUEUE_INDEX, /* u32 */
> > + VDPA_ATTR_DEV_VENDOR_ATTR_NAME, /* string */
> > + VDPA_ATTR_DEV_VENDOR_ATTR_VALUE, /* u64 */
> > +
> > /* new attributes must be added above here */
> > VDPA_ATTR_MAX,
> > };

Next message: Albert Wang: "[PATCH v5] usb: dwc3: gadget: Move null pinter check to proper place"
Previous message: Leo Yan: "Re: [PATCH v2 9/11] perf c2c: Sort on peer snooping for load operations"
In reply to: Si-Wei Liu: "Re: [PATCH v7 2/5] vdpa: Add support for querying vendor statistics"
Next in thread: Eli Cohen: "[PATCH v7 3/5] net/vdpa: Use readers/writers semaphore instead of mutex"
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