Re: [PATCH 2/2] vdpa: Add support to update speed/duplex in vDPA/mlx5_vnet

On Fri, Aug 30, 2024 at 5:08 AM Dragos Tatulea [off-list ref] wrote:

(resending as I accidentally replied only to Carlos)

On 29.08.24 18:16, Carlos Bilbao wrote:

quoted

From: Carlos Bilbao <redacted>

Include support to update the vDPA configuration fields of speed and
duplex (as needed by VHOST_VDPA_SET_CONFIG). This includes function
mlx5_vdpa_set_config() as well as changes in vdpa.c to fill the initial
values to UNKNOWN. Also add a warning message for when
mlx5_vdpa_get_config() receives offset and length out of bounds.

Signed-off-by: Carlos Bilbao <redacted>
---
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 34 ++++++++++++++++++++++++++++++-
 drivers/vdpa/vdpa.c               | 27 ++++++++++++++++++++++++
 include/uapi/linux/vdpa.h         |  2 ++
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index c47009a8b472..a44bb2072eec 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -3221,12 +3221,44 @@ static void mlx5_vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,

      if (offset + len <= sizeof(struct virtio_net_config))
              memcpy(buf, (u8 *)&ndev->config + offset, len);
+     else
+             mlx5_vdpa_warn(mvdev, "Offset and length out of bounds\n");
 }

 static void mlx5_vdpa_set_config(struct vdpa_device *vdev, unsigned int offset, const void *buf,
                               unsigned int len)
 {
-     /* not supported */
+     struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
+     struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
+
+     if (offset + len > sizeof(struct virtio_net_config)) {
+             mlx5_vdpa_warn(mvdev, "Offset and length out of bounds\n");
+             return;
+     }
+
+     /*
+      * Note that this will update the speed/duplex configuration fields
+      * but the hardware support to actually perform this change does
+      * not exist yet.
+      */
+     switch (offset) {
+     case offsetof(struct virtio_net_config, speed):
+             if (len == sizeof(((struct virtio_net_config *) 0)->speed))
+                     memcpy(&ndev->config.speed, buf, len);
+             else
+                     mlx5_vdpa_warn(mvdev, "Invalid length for speed.\n");
+             break;
+
+     case offsetof(struct virtio_net_config, duplex):
+             if (len == sizeof(((struct virtio_net_config *)0)->duplex))
+                     memcpy(&ndev->config.duplex, buf, len);
+             else
+                     mlx5_vdpa_warn(mvdev, "Invalid length for duplex.\n");
+             break;
+
+     default:
+             mlx5_vdpa_warn(mvdev, "Configuration field not supported.\n");

This will trigger noise in dmesg because there is a MAC configuration here.

quoted

+     }

I would prefer that the .set_config remains a stub TBH. Setting the fields here is
misleading: the user might deduce that the configuration worked when they read the
values and see that they were updated.

Yes, and actually, those fields are read-only according to the spec:

"""
The network device has the following device configuration layout. All
of the device configuration fields are read-only for the driver.
"""

Thanks

Thanks,
dragos

quoted

 }

 static u32 mlx5_vdpa_get_generation(struct vdpa_device *vdev)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 4dbd2e55a288..b920e4405f6d 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c

@@ -15,6 +15,7 @@
 #include <net/genetlink.h>
 #include <linux/mod_devicetable.h>
 #include <linux/virtio_ids.h>
+#include <uapi/linux/ethtool.h>

 static LIST_HEAD(mdev_head);
 /* A global mutex that protects vdpa management device and device level operations. */

@@ -919,6 +920,22 @@ static int vdpa_dev_net_status_config_fill(struct sk_buff *msg, u64 features,
      return nla_put_u16(msg, VDPA_ATTR_DEV_NET_STATUS, val_u16);
 }

+static int vdpa_dev_net_speed_config_fill(struct sk_buff *msg, u64 features,
+                                     struct virtio_net_config *config)
+{
+     __le32 speed = cpu_to_le32(SPEED_UNKNOWN);
+
+     return nla_put(msg, VDPA_ATTR_DEV_NET_CFG_SPEED, sizeof(speed), &speed);
+}
+
+static int vdpa_dev_net_duplex_config_fill(struct sk_buff *msg, u64 features,
+                                     struct virtio_net_config *config)
+{
+     u8 duplex = DUPLEX_UNKNOWN;
+
+     return nla_put(msg, VDPA_ATTR_DEV_NET_CFG_DUPLEX, sizeof(duplex), &duplex);
+}
+
 static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *msg)
 {
      struct virtio_net_config config = {};

@@ -940,6 +957,16 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms

      if (vdpa_dev_net_status_config_fill(msg, features_device, &config))
              return -EMSGSIZE;
+     /*
+      * mlx5_vdpa vDPA devicess currently do not support the
+      * VIRTIO_NET_F_SPEED_DUPLEX feature, which reports speed and
+      * duplex; hence these are set to UNKNOWN for now.
+      */
+     if (vdpa_dev_net_speed_config_fill(msg, features_device, &config))
+             return -EMSGSIZE;
+
+     if (vdpa_dev_net_duplex_config_fill(msg, features_device, &config))
+             return -EMSGSIZE;

      return vdpa_dev_net_mq_config_fill(msg, features_device, &config);
 }

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index 842bf1201ac4..1c64ee0dd7b1 100644
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h

@@ -43,6 +43,8 @@ enum vdpa_attr {
      VDPA_ATTR_DEV_NET_STATUS,               /* u8 */
      VDPA_ATTR_DEV_NET_CFG_MAX_VQP,          /* u16 */
      VDPA_ATTR_DEV_NET_CFG_MTU,              /* u16 */
+     VDPA_ATTR_DEV_NET_CFG_SPEED,            /* u32 */
+     VDPA_ATTR_DEV_NET_CFG_DUPLEX,           /* u8 */

      VDPA_ATTR_DEV_NEGOTIATED_FEATURES,      /* u64 */
      VDPA_ATTR_DEV_MGMTDEV_MAX_VQS,          /* u32 */