On Tue, Sep 20, 2022 at 5:58 PM Zhu, Lingshan [off-list ref] wrote:

On 9/20/2022 10:02 AM, Jason Wang wrote:

quoted

On Fri, Sep 9, 2022 at 5:05 PM Zhu Lingshan [off-list ref] wrote:

quoted

This commit adds a new vDPA netlink attribution
VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES. Userspace can query
features of vDPA devices through this new attr.

This commit invokes vdpa_config_ops.get_config() than
vdpa_get_config_unlocked() to read the device config
spcae, so no raeces in vdpa_set_features_unlocked()

Signed-off-by: Zhu Lingshan <redacted>

It's better to share the userspace code as well.

OK, will share it in V2.

quoted

quoted

---
  drivers/vdpa/vdpa.c       | 19 ++++++++++++++-----
  include/uapi/linux/vdpa.h |  4 ++++
  2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index c06c02704461..798a02c7aa94 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c

@@ -491,6 +491,8 @@ static int vdpa_mgmtdev_fill(const struct vdpa_mgmt_dev *mdev, struct sk_buff *m
                 err = -EMSGSIZE;
                 goto msg_err;
         }
+
+       /* report features of a vDPA management device through VDPA_ATTR_DEV_SUPPORTED_FEATURES */

The code explains itself, there's no need for the comment.

these comments are required in other discussions

I think it's more than sufficient to clarify the semantic where it is defined.

quoted

quoted

         if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_SUPPORTED_FEATURES,
                               mdev->supported_features, VDPA_ATTR_PAD)) {
                 err = -EMSGSIZE;

@@ -815,10 +817,10 @@ static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev,
  static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
  {
         struct virtio_net_config config = {};
-       u64 features;
+       u64 features_device, features_driver;
         u16 val_u16;

-       vdpa_get_config_unlocked(vdev, 0, &config, sizeof(config));
+       vdev->config->get_config(vdev, 0, &config, sizeof(config));

         if (nla_put(msg, VDPA_ATTR_DEV_NET_CFG_MACADDR, sizeof(config.mac),
                     config.mac))

@@ -832,12 +834,19 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
         if (nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MTU, val_u16))
                 return -EMSGSIZE;

-       features = vdev->config->get_driver_features(vdev);
-       if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features,
+       features_driver = vdev->config->get_driver_features(vdev);
+       if (nla_put_u64_64bit(msg, VDPA_ATTR_DEV_NEGOTIATED_FEATURES, features_driver,
+                             VDPA_ATTR_PAD))
+               return -EMSGSIZE;
+
+       features_device = vdev->config->get_device_features(vdev);
+
+       /* report features of a vDPA device through VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES */
+       if (nla_put_u64_64bit(msg, VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES, features_device,
                               VDPA_ATTR_PAD))
                 return -EMSGSIZE;

-       return vdpa_dev_net_mq_config_fill(vdev, msg, features, &config);
+       return vdpa_dev_net_mq_config_fill(vdev, msg, features_driver, &config);
  }

  static int

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index 25c55cab3d7c..97531b52dcbe 100644
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h

@@ -46,12 +46,16 @@ enum vdpa_attr {

         VDPA_ATTR_DEV_NEGOTIATED_FEATURES,      /* u64 */
         VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,          /* u32 */
+       /* features of a vDPA management device */
         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 */

+       /* features of a vDPA device, e.g., /dev/vhost-vdpa0 */
+       VDPA_ATTR_VDPA_DEV_SUPPORTED_FEATURES,  /* u64 */

What's the difference between this and VDPA_ATTR_DEV_SUPPORTED_FEATURES?

This is to report a vDPA device features, and
VDPA_ATTR_DEV_SUPPORTED_FEATURES
is used for reporting the management device features, we have a long
discussion
on this before.

Yes, but the comment is not clear in many ways:

" features of a vDPA management device" sounds like features that is
out of the scope of the virtio.

And

"/dev/vhost-vdpa0" is not a vDPA device but a vhost-vDPA device.

Thanks

quoted

Thanks

quoted

+
         /* new attributes must be added above here */
         VDPA_ATTR_MAX,
  };
--
2.31.1