Re: [dpdk-dev] [PATCH] net/virtio: fix link update in speed feature case

[Andrew Rybchenko]

On 10/29/21 12:42 PM, Maxime Coquelin wrote:

On 10/22/21 15:17, Andrew Rybchenko wrote:

From: Ivan Ilchenko <ivan.ilche...@oktetlabs.ru>

Link update callback reports speed/duplex based on data
filled on device initialization. This is wrong in case of
VIRTIO_NET_F_SPEED_DUPLEX is negotiated since link could
be down at this time. Fix this function to actually
update the HW data in this case with respect to the fact
that specifying speed via devarg is a highest priority.

Fixes: 1357b4b36246 ("net/virtio: support Virtio link speed feature")
Cc: sta...@dpdk.org

Signed-off-by: Ivan Ilchenko <ivan.ilche...@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>
---
  drivers/net/virtio/virtio.h        |  5 ++++
  drivers/net/virtio/virtio_ethdev.c | 47 +++++++++++++++++++++---------
  2 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/drivers/net/virtio/virtio.h b/drivers/net/virtio/virtio.h
index e78b2e429e..4fd1427375 100644
--- a/drivers/net/virtio/virtio.h
+++ b/drivers/net/virtio/virtio.h
@@ -178,6 +178,11 @@ struct virtio_hw {
      uint16_t port_id;
      uint8_t mac_addr[RTE_ETHER_ADDR_LEN];
      uint32_t speed;  /* link speed in MB */
+    /*
+     * Speed is specified via 'speed' devarg or
+     * negotiated via VIRTIO_NET_F_SPEED_DUPLEX
+     */
+    bool get_speed_via_feat;

For better packing of this struct, it may be better to place it just
before the speed field as it already has a 2 bytes hole above.

      uint8_t duplex;
      uint8_t intr_lsc;
      uint16_t max_mtu;

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c

index 4001368bc4..3d80f664b3 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1777,6 +1777,32 @@ virtio_configure_intr(struct rte_eth_dev *dev)
      return 0;
  }
+
+static void
+virtio_get_speed_duplex(struct rte_eth_dev *eth_dev,
+            struct rte_eth_link *link)
+{
+    struct virtio_hw *hw = eth_dev->data->dev_private;
+    struct virtio_net_config *config;
+    struct virtio_net_config local_config;
+
+    config = &local_config;
+    virtio_read_dev_config(hw,
+        offsetof(struct virtio_net_config, speed),
+        &config->speed, sizeof(config->speed));
+    virtio_read_dev_config(hw,
+        offsetof(struct virtio_net_config, duplex),
+        &config->duplex, sizeof(config->duplex));
+    hw->speed = config->speed;
+    hw->duplex = config->duplex;
+    if (link != NULL) {
+        link->link_duplex = hw->duplex;
+        link->link_speed  = hw->speed;
+    }
+    PMD_INIT_LOG(DEBUG, "link speed = %d, duplex = %d",
+             hw->speed, hw->duplex);
+}
+
  #define DUPLEX_UNKNOWN   0xff
  /* reset device and renegotiate features if needed */
  static int

@@ -1830,19 +1856,10 @@ virtio_init_device(struct rte_eth_dev *eth_dev, uint64_t req_features)

               hw->mac_addr[0], hw->mac_addr[1], hw->mac_addr[2],
               hw->mac_addr[3], hw->mac_addr[4], hw->mac_addr[5]);
-    if (hw->speed == ETH_SPEED_NUM_UNKNOWN) {
-        if (virtio_with_feature(hw, VIRTIO_NET_F_SPEED_DUPLEX)) {
-            config = &local_config;
-            virtio_read_dev_config(hw,
-                offsetof(struct virtio_net_config, speed),
-                &config->speed, sizeof(config->speed));
-            virtio_read_dev_config(hw,
-                offsetof(struct virtio_net_config, duplex),
-                &config->duplex, sizeof(config->duplex));
-            hw->speed = config->speed;
-            hw->duplex = config->duplex;
-        }
-    }
+    hw->get_speed_via_feat = hw->speed == ETH_SPEED_NUM_UNKNOWN &&
+                 virtio_with_feature(hw, VIRTIO_NET_F_SPEED_DUPLEX);
+    if (hw->get_speed_via_feat)
+        virtio_get_speed_duplex(eth_dev, NULL);
      if (hw->duplex == DUPLEX_UNKNOWN)
          hw->duplex = ETH_LINK_FULL_DUPLEX;
      PMD_INIT_LOG(DEBUG, "link speed = %d, duplex = %d",

@@ -2554,11 +2571,15 @@ virtio_dev_link_update(struct rte_eth_dev *dev, __rte_unused int wait_to_complet

                       dev->data->port_id);
          } else {
              link.link_status = ETH_LINK_UP;
+            if (hw->get_speed_via_feat)
+                virtio_get_speed_duplex(dev, &link);
              PMD_INIT_LOG(DEBUG, "Port %d is up",
                       dev->data->port_id);
          }
      } else {
          link.link_status = ETH_LINK_UP;
+        if (hw->get_speed_via_feat)
+            virtio_get_speed_duplex(dev, &link);
      }
      return rte_eth_linkstatus_set(dev, &link);

If you agree with the change, I can do it while applying.

Yes, please, do.

Other than that:
Reviewed-by: Maxime Coquelin <maxime.coque...@redhat.com>

Thanks,
Maxime

Many thanks,
Andrew.